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Moderator: Today’s webinar is Integrating a CDN with Acquia Cloud. Our Acquia presenters are Kieran Lal, Wim Leers and Alex Jarvis. We also have Christopher Meyfarth from Akamai we’re very excited to have him on.

Kieran Lal: So a few months ago, actually starting back in June of 2012, I started really exploring how we could go beyond what Acquia Cloud had in terms of performance and the most obvious answer once we had tuned the stack, got the reverse proxy right and tuned the PHP stack and tuned the database and got everything together, we start looking at some of the really great web performance optimization tools that were available and so that got me thinking about using CDN. So I started talking to a lot of people at Acquia and collecting more and more information, looking at all the different CDNs that had been integrated with Acquia Cloud and started asking people about what were the different scenarios and different use cases that came together. So I sort of had this on the shelf for a while and then we’re lucky enough to see that Wim Leers who I thought was going to work somewhere else actually ended up joining the Office of the CTO and so that was really exciting and I think within a few days of him joining, I immediately reached out and told them that I wanted to do a webinar off somewhere in the future on CDN. Wim I’ve known for many years and we hung out together when I was over for a conference in Hungary and so I knew about his interest in CDNs and more recently some of the work that he’d been doing through his master’s and/or an internship that he had done at Facebook. So it was really great to have what I consider to be one of the leading experts of CDN integration with Drupal here at Acquia and so we worked together, put together some outlines. I showed him my notes and we planned to do this, and then as we started getting close to the webinar, I was able to reach out to some new partners at Akamai and so I’m really excited to have Christopher Meyfarth from Akamai join us who’s one of the sales engineers, but a real expert in Akamai, and so we’re able to really focus on what is the premiere CDN in the space.

Then more recently, I was at BADcamp and then bumped into Alex Jarvis who’s one of our senior technical account managers and he was talking to me about some work that he was doing and we were going back and forth and I brought up the idea of Akamai and so he started telling me about all the expertise and some of the notes and training that he’d been doing internally, and so I was really excited to really bring what I think is one of the strongest teams of technical contributors that we have in our webinar series together to show off the advantages of using a CDN with Acquia Cloud and in particular using Akamai. So we’ll see three different perspectives, but they’ll keep it pretty thorough and we’ll have a lot of great content. I’m really looking forward to some excellent Q&A and even I know a lot of the staff at Acquia are really excited to learn about this because it’s a tier of knowledge that they really want and something that almost 50 people on our support team are keen to learn about so that they can use Akamai and use chris’ knowledge of CDN’s to improve the performance of their sites. So without further delay, I’m going to hand it over to Christopher who will go first and then we’ll have Wim talk about CDNs and some specific expertise that he’s got and then Alex will finish off and talk about specific configurations of Drupal with Akamai, and then we’ll try to pause. If we see questions that are relevant or particularly topical while our speakers are talking, we’ll take the time to answering the questions in context, but the most of them, if they’re generic-enough questions, we’ll hold it to until the end where possible and then try to leave enough time to do a Q&A. So Christopher, without further delay, I’m going to hand over the slide to you.

Christopher Meyfarth: Great. Thank you, Kieran. I’ll just make sure we got the presenter view here. So as Kieran mentioned, I’m Chris Meyfarth. I’m a lead senior sales engineer working with our channel program at Akamai. I’m going to talk a little bit today about the inherent problems of the internet. We’ll talk a little bit about the Akamai technology that we’ve created to help combat those inherent problems and we’re going to look at some test results that we did last week on Acquia.com. So without further ado, I’ll just jump right into it and talk a little bit about the inherent problems of delivering traffic over the public internet. I think that it’s important to understand why you need a CDN. Acquia is spending a lot of time honing Drupal, putting a lot of time into the data centers and regardless if it’s Drupal or an application that you have in-house, you don’t want to spend all that time on the application, all that time on the data center and then just cross your fingers as that information goes out across the wilds of the public internet. When you look at the public internet, it’s a network of networks and the protocols that control the public internet, there are three major protocols: you have BGP, TCP and HTTP. The issue here is BGP first and foremost which controls the route, it’s based on the number of steps that you take, not the performance. TCP of course is an antiquated protocol, it has a slow start and then you have HTTP and HTTPS which is just the sheer volume of information that we’re sending across the line. A great example is with commerce websites now in Akamai, the average commerce customers has about a two-meg footprint of their commerce website. I can remember 10 years ago when we were willing to wait 10 or 15 minutes to download a two-meg MP3, and now according to Forrester and Gartner, we have the two-second rule. We’re looking two download a site in two seconds or else we’re going to start seeing exponential abandonment. We’re doing in two seconds today what we were willing to wait 10 or 15 minutes to do 10 years ago. So when you step back and look at the public internet, you really have a compounding inefficiency. You have a ton of data going over a pipe that has a slow start, going over a route that isn’t based on performance. It’s just simply based on the number of steps that it needs to take.

So I’m going to talk about some of the newer Akamai technologies. I’m going to leave a lot of the caching and some of the traditional CDN stuff to Wim and to Alex, but to combat this compounding inefficiency, Akamai has developed some technology called SureRoute. SureRoute leverages our 125,000 servers in 2,000 different locations. They basically all talk to each other. They build a virtual weather map of internet traffic conditions, so anytime an end user connects to an Akamai server, we go to that weather map and in real time we query it and we pull down the three fastest routes given his exact location and where he’s going. We’ll actually take it a step further. We’ll actually send a little piece of information across each one of these routes. We’ll run a race, if you would, and the one that comes in first will start passing traffic across that route. Now, we’ll continue to run those races, so if anytime maybe internet traffic conditions change, people are coming back from lunch, there’s congestion on different lines, we continue to run those races, we detect if that’s no longer the fastest route, we failover to the second fastest route and then go back to that weather map to get three new routes.

Now, it’s an extreme example, but to see SureRoute in action, this is a cable cut that happens. So this, as I said, an extreme example of internet traffic pattern shifting very quickly. What you see in red is the public. It took the public internet about two weeks to recover and it took Akamai about 20 minutes. So SureRoute is just one technology that we have; of course Akamai is known for doing caching. We continue to push a lot of that caching logic out to the edge of the internet so that we can make caching decisions based on languages or cookies and we can make those as far away from the application origin as possible. In addition, the last technology feature we’ll talk about is a feature called prefetch. Prefetch is a really interesting technology because as the end user requests an HTML file and that is coming back and being returned, actually our Akamai edge server will hold on to that HTML file and start to parse it. So we will send out requests, we’ll refresh our cache. If anything is expired, we will refresh those cache objects or request them from the origin before the end user has even received that HTML file, so by the time that end user has parsed that HTML file and starts requesting those objects, they’re located on the edge server 10 milliseconds away from them.

So a quick overview of some of the newer Akamai technologies in action, we did a test last week of Acquia.com. We were looking, so we choose six steps, just generic web pages. We chose the homepage, the Support and Cloud Services, Solutions for Marketers, Network Trial page, Careers page and the PDF. The way we conduct these trials is we’ll actually build a fully functional Akamai configuration and send it out over the public internet, and then we spin up either Gomez or Keynote, one of the major leading performance testing suites and we’ll have them hit both the Akamai configuration as well as Acquia.com as it was being accessed on the public internet. So what we have here is the comparison results. This was over the course of about three days from many cities all over the world and we have the public internet results and then the Akamai results. What’s interesting about this – I mean I’ll let everyone consume the data points on their own, but what really stands out here is step number five. If you look at the average improvement, step five is nowhere close to everyone else, so I wanted to highlight step five and dig in a little bit deeper. Step five is the Careers page and this was a very heavy page that was pulling information from a few different queries and one of the major advantages of Akamai and using Akamai as a CDN is you can build rules into Akamai to handle the caching. So what we did with step five was we said, “Well, let’s rerun these tests, and rather than just cache the images and do the SureRoute acceleration, let’s take a snapshot of that page. Let’s cache the full HTML of that page not for very long, maybe just for a few hours. We want the page to stay dynamic, but in this case we would much rather have maybe a highly performing page that we could clear out from cache on request. Akamai has the ability to interact with an API to purge things out from cache, so let’s cache that full page.” These are the results. You can see that public internet was about five and a half seconds. We turned on Akamai, it’s about four and a half, but then when we started doing that full page caching, it dropped it down to two. Those results will only get better the more people you have requesting that page. It’ll keep it in cache, it’ll keep it in cache longer and more current.

So before I hand things over to Wim, just to summarize quickly for Akamai, the trial we did for Acquia.com is very easy to do. We do it for many customers, so if you want to get set up with the CDN, we strongly advise you to talk to an Acquia rep. We can do one of those trials, we can set up the steps, build that configuration, send it out over the public internet and in just a couple of weeks we can get some real world results for you. So at that point, if there are any questions, we can open it up quickly or we can pass it over to Wim.

Moderator: There’re no questions at this point, so I’m going to pass it over to Wim.

Christopher Meyfarth: Great. Thanks guys!

Wim Leers: Hi everyone, my name is Wim. As Kieran explained, I’m a senior software engineer with Acquia and I’ll be talking a bit about Drupal plus CDN, but before I really begin, I just want to make sure that everybody actually knows what a CDN is. If you’re not quite sure yet what that is, please raise your hand right now. [Pause] Okay, I do see that at least one or a few people are raising their hand, so a CDN is essentially a short name for content delivery network. In a nutshell, what it does is move content closer to the end user, meaning that to get the data for a website, for example, there will be less physical distance to cover, meaning that the data will be faster at the end user’s computer. So essentially, move the data closer to the end user so that everything on the web becomes faster. I hope that is clear; if not, I recommend the explanation on Wikipedia. So let’s dive into the real stuff.

First of all, you should know about page loading performance. I’ll keep this also very short. I think most of you have already noticed, but in any case, when you load a webpage, then only about 10% of the time is actually spent on loading the HTML, the webpage itself, the textual content of the webpage, and about 90% is actually spent on loading the resources referenced by the HTML. These are the JavaScript files of course, but also images, fonts, videos and so on. So when we’re trying to make websites faster, it’s really important that we keep in mind that the biggest gains are to be gained in the resources department, not on the HTML side, so improving websites in the sense of making the rendering work faster, that’s nice, but it will never have the same kind of impact that you can achieve by making sure that the resources are loaded and served fast to the end user. This is what we’ll keep in mind and this actually brings us to the next aspect of using CDN.

There are actually two types of – you can use CDN in two big different ways. The first one is use a CDN for serving resources, static files, and the second way is using a CDN for everything in HTML. So the serving of resources should always be the first step since this is the thing that affects 90% of the page load time. It’s easy to do especially with origin-pull CDNs – more about that later – but in any case, the most important aspect is that this will give you the most benefit with the least amount of effort. You can also go for serving everything from a CDN, so this is an optional second step. It makes sense that this is a second step because the first aspect you can do without much changes to your application logic and it’s very easy to do, so it makes sense to always do the resources [Audio Gap], but if you go for the full approach, then you will affect 100% of your page load time since everything is being served from a CDN minus of course third party scripts. The downside is that you will have to carefully plan the integration; it takes quite a bit of effort especially if you have a website in which you are serving authenticated users a lot of content, meaning that if you have for example a news website where the typical user is not logged in, then you can serve the exact same content to millions of users, but imagine the case where you have for example a news website where each user can make his individual preferences for topics of interest. Well, then things become a lot more complex because not the same content can be served to every single user, meaning that you have to do far more complex page building to achieve the same performance. To do this kind of authenticated user, and thus, personalized content through CDN, what is typically used is Edge Side Includes and Akamai is I think the company who pioneered this.

More about that in just a second, but the one thing that you should also know is that in either of these cases, in both scenarios there will be less requests to the app server, exactly because static files are no longer served by your app server, your web server. That actually means that there is less load on your web servers. If you have many of those web servers, then it’s possible that you can even retire some of them, meaning that overall your costs for your app server should go down. So CDNs may cough some money, but they may also save some to some degree, at least. So I just mentioned Edge Side Includes which is really important if you want to serve the HTML of your website from a CDN while still having the ability to serve personalized content to every user. In Drupal 5, 6 and 7, it has been pretty difficult or rather complex and not well supported out of the box to do Edge Side Includes, but I’m happy to report that in Drupal 8, it will become much easier because in Drupal 8, there is the Blocks and Layouts Everywhere Initiative, codenamed SCOTCH. The single keyword that is really important here is Blocks Everywhere. Blocks you can regard as the atoms in the Drupal universe, as it were, the atoms of the Drupal webpage. In Drupal 5, 6 and 7, many things are blocks, but not everything is, so if we make everything a block, every single compartmentalized piece of content, if each of those is a block, then we can do much more interesting things.

In Drupal 8, we are adopting the Symfony which is another open source project, so we’re sharing code and sharing the effort there. We’re adopting the HttpKernel components from Symfony. What we’ll be doing is making sure that each part of the page, each block, each atom can be requested individually and when you, for example, would ask a Drupal 8 website to render the front page, what it will do then is use in-process subrequest to build a page. So it will actually fire subrequests within the PHP process to render each of those blocks individually. As you can tell, this very closely resembles ESI and is actually pretty much the exact same thing. Drupal 8 will make it much easier, if not trivial to support Edge Side Includes. So ESI plus CDN will become trivial in Drupal 8, but please remember that not every CDN supports Edge Side Includes.

So now we have an idea of the two big different ways of using a CDN and I’ve clarified that one of them will become significantly easier in Drupal 8, so let’s move on to the key properties of a CDN. The single most important property I believe is the geographical spread, the points of presence. PoP stands for “point of presence.” A point of presence is essentially a location where the CDN has edge servers as Chris pointed out already in his presentation, meaning that as a PoP, a CDN connects with local ISPs, so the more connections with local ISPs around the world or in different regions, the closer you are to the end user with that CDN. So what you need to do is make sure that the latency between your [Audio Gap] and your content is as low as possible, globally speaking, meaning that for as many users as possible, you want to have the lowest latency possible because then web pages will be rendered faster. So if you put those things together, what really matters is that you match your CDN to match your audience, so if you’re a company that’s mostly oriented towards European users, for example, then you would probably choose a CDN that has a strong European presence that has many PoPs in Europe. It could also be that you are going with a global CDN provider, provided that they do have a lot of presence in Europe.

So as you can see, it really depends on your needs, on your target audience which CDN is the best choice from a geographical point of view, from a best lowest latency point of view. The second most important property is the way you get files onto the CDN. Actually, there are two types: origin-pull CDNs and push CDNs. For origin-pull CDNs, there is not really a special transfer protocol involved. Your web server obviously speaks HTTP because otherwise it would not be a web server, so what origin-pull CDNs actually do is when they receive a request for a certain file, they will just go back to the origin server which is your web server and go and get the file over there. The upside is of course that there’s virtually no setup. You just do very, very little and everything will work just fine. The downside is exactly because it will work almost automatically, that there is very little flexibility in terms of what kind of preprocessing or optimization you can do before getting the file onto the CDN. Another downside can be redundant traffic. For most websites, this will not be a problem since requesting caches Again, it’s not really an issue since they’re so small, but imagine a case where you have multi-gigabyte video streams, for example. As Chris already explained, at least Specific edge servers, the PoPs of a CDN, tend to clear out files that have been requested least often in a certain period of time, so it is possible that your video file has only been requested a few times in a given timeframe, meaning that it will be removed from the CDN temporarily until it’s requested again, but that means that your origin server – meaning your web server – will have to serve the file again to your CDN. So multiply that by a number of edge servers and then you might be looking at significant traffic, but it really depends of course on your specific site and your specific goals.

That’s exactly where a push CDN can be advantageous. Exactly because it’s a push CDN, you have to push the files onto the CDN, so you control when a file is transferred from your origin server onto the CDN, so there is no redundant traffic since exactly it’s you who control that. You also have more flexibility in terms of potential preprocessing exactly because it pushes onto the CDN, but the big downside here is that there is a lot of setup involved. You have to write the script or code or some sync layer, whatever it is going to be. You have to somehow get the file onto the CDN and that might be a lot of work. I failed to add this on the slide, but this is exactly what I try to solve with my bachelor’s thesis. It’s called FileConveyor.org and it’s a Python daemon that is intended to simplify the setup of a push CDN. Essentially, its job is to weigh the differences between different ones, so it makes it easy to switch from one to the other or to advanced preprocessing and whatnot, but in any case, this is another component that you have to deal with which you don’t have to do with an origin-pull CDN.

That actually brings us to the last thing which is lock-in. Depending on the kind of CDN that you choose and its features, you may be looking at some or significant lock-in. For example, if you’re using Amazon S3 as a CDN, then you’re actually using a custom transfer protocol which means that if you want to switch to another CDN, you have to rewrite your sync layer, your script, whatever it is, so that is some degree of lock-in. Some CDNs offer unique features – for example, some kind of statistics – and you may not have the same in another CDN and so on, so you have to be careful there. You have to weigh the differences to figure out which things are most important to you.

All of this is about the differences between the different CDNs. So how do you select a CDN? Which CDNs should you choose? The first and foremost reason to go with a CDN is of course performance. That’s the whole reason we’re having this webinar. The most important thing is low latency. This is again about matching your target audience well to your CDN and making sure that the PoPs the CDN has correspond well with the geographical location of your visitors. However, this is not always the single most important thing. If you’re serving a lot of small files, for a typical website, it definitely is, but in the case of serving video streams for example or large software downloads or whatnot, what might matter more is high throughput - some call this bandwidth – meaning that it doesn’t really matter if you have to wait 0.1 or 0.2 seconds for your video to start streaming, but what you really want is that your video stream does not get interrupted. That’s the difference that you have to weigh there.

The other aspect based upon which you might want to choose a CDN is the type, origin-pull versus push, because of the inherent differences in how you get files onto the CDN and how you integrate with them. Also, advanced CDN-specific features such as, for example, automatic lossless image optimization, real time statistics, authentication in the sense that, for example, you have an ecommerce website and you sell digital goods, meaning that you don’t want everybody to be able to access the files, so then you want some kind of signed URL or [Audio Gap]. So it really depends on your use case. You have to make sure that the CDN offers the features that you really, really need.

Finally, of course there are also the support aspects, different CDNs with different kinds of support and the costs. Now, how can you maximally exploit a CDN for resources, meaning for static files? These are simple tricks that can have a significant performance impact, so it’s really recommended that you always use them. The first one is actually the one with probably the least amount of performance impact, but it’s also the single most simple one. It’s DNS prefetching; it’s just adding a small tag to your HTML head on every webpage where you use a CDN or even where you don’t use a CDN, and what you do there is reference the DNS, the domain name, for your CDN so that the web browser will already be able to look up the IP address for your CDN, meaning that when – so this is at the top of the page and only after that the loaded script images and so on are referenced. So by the time that the browser gets to parsing the actual resources, the DNS lookup will already have happened and you don’t incur the DNS lookup wait time.

The second thing is auto-balancing over multiple CDN domain names, also known as domain charting. This is very useful in cases where you have a lot of resources in a single webpage. For example, say that you have an ecommerce web shop and you have 100 product images on a single webpage. The typical web browser will do between 6 and 10 simultaneous HTTP requests to a single domain name, meaning that only, say, about 10 downloads are happening at the same time. So only when one of those 10 is ready can the next one occur, and so on. So as you can see, there is a lot of waiting going on for no good reason and the way you can solve that is by having multiple CDN domain names, multiple host names and balancing them automatically. For example, say that you would have four CDN domain names. You could automatically balance those 100 images over the four different domain names so that each has approximately the same amount - in this case, 25 – and then what you get is not 10 images being downloaded at the same time, but 40 images being downloaded at the same time. So given this theoretical case, this would accelerate the download of these 100 images by fourfold, so that’s a very significant increase, but again, it’s really only useful when you have a lot of images, or in any case, a lot of resource from a single page.

The last one is actually the one with the most impact in my experience also for very small websites and it’s called Far Future expiration. It’s actually really simple, really logical. Essentially, browser caches are always faster than a CDN unless you have an extremely, extremely slow hard disk drive. If you needed to get a file from a CDN, then you’re always going to incur some level of latency. You have to download the file, you have to save the file on the disk and so on. Browser caches avoid that. If the file is in the browser cache, you don’t need to go to the CDN. How do you make sure that files remain in the browser cache for as long as possible? Well, you need to mark them to expire many years from now and that’s why it’s called Far Future expiration. The one downside to this is that if you are changing, for example, your web shop logo and then what happens if the file is cached in the browser cache is that it will not be downloaded again exactly because it is still in the browser cache. So now for some reason, some subset of users is still seeing the old logo. The way you can solve that is by using unique file URLs. You need to make sure that each file, whenever its contents change, it’s served from a different unique file URL and that will cause of course the browser cache to retrieve the new file. One funny side aspect or interesting side aspect to this is that actually if you implement this, it will actually cause your CDN costs to go down because there will be fewer requests to the CDN since the browser cache retains the file longer. So yes, these are free tricks that are really useful.

Now I’ve explained the different types of usage and overall CDN information, so now let’s move on to the Drupal CDN module. I maintain this module and if you have any questions, I look forward to seeing you in the question queue. As you can see, this is the default admin screen for the CDN module and there is a message at the top that says “If you install the advanced help module, the CDN module will provide more and better help.” So if you install it for the first time and you’re still finding your way around it, please install it and it will give you examples and technical background information, but in any case, there is very little to configure as you will soon see. This is the general tab and here you can either disable or enable the integration with CDN or you can enable the testing mode. In testing mode, you can play around with it without harming your actual users. You can give specific users access to the files on the CDN by giving them specific permission that allows them to do so, so this is great for giving it a try.

The second tab is called “Details” and this is where the bulk of the work happens, the bulk of the configuration. Essentially, there are two modes: origin-pull CDNs and file conveyor for integrating with the project that I mentioned earlier for doing more advanced CDN integration. So we are going to go with origin-pull; this is actually exactly how it’s configured on my personal website. All you have to do really is copy-paste the CDN domain name that you get from your CDN provider, paste it in the CDN mapping field that you can see at the bottom of the current slide and that’s it. Just hit save and you will have CDN integration. I really tried to make it as simple as possible; however, you can also enable Far Future expiration. CDN module automatically does all the aforementioned maximally-exploiting CDN tricks. Far Future expiration obviously involves the unique file URL aspect and the CDN module shifts with several methods for generating unique file identifiers. You can even add your own.

The Drupal CDN module is great, I hope and believe, for simple use cases or for many use cases, even for more advanced ones that also does domain charting, but there are also times when you should not use it. That’s when every millisecond matters. It’s really designed for ease of use and frontend performance, i.e., the serving from a CDN in the most easy manner possible. It’s not designed to have the absolute lowest overhead possible. In that case, you should just write a hook implementation of “hook_file_url_alter” which I added to Drupal 7 and that will allow you to easily do what you need to do without the overhead of an entire Drupal module. It’s also feasible or reasonable to use your own code when you have a very complex CDN mapping, but even the CDN module has support for that in the sense that it has a callback in which you can implement custom logic to determine which CDN should be used for which file.

So now I’ve explained the different ways you can use the CDN, how we can maximally exploit it, how we can use it with Drupal, but what you really want to do is actually prove that the CDN integration that you’ve done is actually having a positive performance impact on your website. That’s what these last two slides will be about. Ideally you are already doing continuous integration for your website or your application which is essentially making sure that no new bugs enter the website and that everything continues to work correctly while you should also, in theory or in the best case possible, have a continuous performance monitoring that makes sure that whenever you add new features or make improvements and so on, you’re not actually making or adding performance regressions. You want to make sure that your website stays as fast or gets faster, or at least if it got slower, that you actually know it got slower.

So there are two ways to do that: synthetic user monitoring which is a test script essentially, but it only works in a few browsers and it’s a very controlled environment in terms of networking and OS and so on, so it’s not really realistic. It doesn’t give a realistic picture of what your end users are seeing or experiencing, but it is really great as a reference point for tracking the performance of your sites as it evolves. Exactly because it is in a controlled environment, the only variable is really the changing code, so for internal use, this is excellent, but for making sure that your website as it is experienced by your actual visitors and you want to improve that, then what you need is real use monitoring. This is actually measuring your actual visitors, hence in all browsers, hence in real world environments and does give very realistic results. It actually shows you how fast your website is for real users. This also gives you the ability to see in which specific location or if browser site performance is good or bad so that you have more useful information on reproducing the problem and improving it for those specific cases.

So if we go look at synthetic user monitoring, I’m going to show you how you can do synthetic user monitoring for free as well as real user monitoring for free. So the first step here is configure a dev or staging app or web server. Maybe you want to do this on production traffic; that’s also possible, but I’m assuming that you want to do this internally so that you can track the performance internally before it is pushed live. What you need to do is ensure that your pages’ resources are served from the CDN domain, then you can perform a test with the free and open source WebPageTest.org with a node, i.e., a desk server, a browser that is far away from your origin app server. Why exactly one that is far away? Well, we want to make sure that the CDN is having a positive performance impact and if it’s far away from your app server, then by definition the latency is higher, and in theory, if the CDN is working well, it should have a lower latency. Hence, this should show a significant difference with the case where you’re not using a CDN.

So point three is using it with a CDN and in point four, what we’re going to do is use WebPagTest’s scripting engine to point to your origin server instead of a CDN, so the CDN domain name will make it point to your origin server by remapping it to a different fixed IP address, run the test again and then all you have to do is compare the results. Of course this is a single measurement; you can repeat it, of course, but you have to make sure that what you’re looking at is actually representative of the real world, so I recommend to repeat it a few times to at least make sure that the largest variance is mitigated.

Finally, real user monitoring, what you need to do then ensure your production site’s pages’ resources are served from the CDN domain. Why production? Well, exactly because otherwise you’re not really testing with production with real users, unless of course you have some kind of mechanism where you’re serving the newest version of your website to a subset of your users, then you can use that instead, but in either of those cases, what you need to do is make sure that you’re using a CDN only for a subset of your users - for example, 50% of the users that you’re testing this against because we want to compare non-CDN traffic versus CDN traffic. What you need to do then is install some kind of real user monitoring performance measurement tool - New Relic RUM and Torbit Insight have both got free packages, so you can try either of those – and then again compare the results.

So that’s all I wanted to share with you. I hope it was clear. If there’re any questions, then I’m sure I’ll hear about it later. I’ll now pass it on to Alex who will talk about Drupal plus Acquia.

Alex Jarvis: Hi everyone. Thanks, Wim. My name’s Alex Jarvis. I’m a senior technical account manager at Acquia and it’s been my good fortune over the last two years to help some of Acquia’s biggest customers adopt Akamai and integrate Akamai tools to improve their site. I’m going to go over fairly quickly in high level the steps you’ll want to take on a Drupal site to take advantage of the Akamai network.

So the first rule of a CDN and an Akamai integration is really that every site is unique. I mean as Wim was pointing out, there’re a lot of factors and you need to customize the experience to be what your site needs. Really, I’m going to go over some best practices, but work with Akamai or your CDN provider to really understand the feature sets that they’re offering and to figure out how those work for your site because that’s going to be the most important thing. That said, for Akamai in particular, there are certainly some best practices and some initial steps that you need to take to really be able to leverage Akamai integration. At the most basic level, those changes that you need to make are in settings.php, so Drupal, as I hope you know, already has some CDN reverse proxy flags in settings.php and you’ll want to uncomment those or they’re commented by default. In particular, you’ll want to change the “reverse_proxy”, “reverse_proxy_header” and “omit_vary_cookie” config lines and uncomment those. What that’s going to do is tell Drupal that it is now behind a reverse proxy in the CDN and so that it will track its traffic differently particularly like the reverse proxy header tells it to look at a different HTTP header for the real IP address of the users that are accessing it.

Akamai for example sends requests as a HTTP true client IP header and that’s the user. The reason you want to do that is, for example, in Drupal 7, there’s an automatic throttling in place for things like failed login attempts. If you’re behind the CDN, all of your users’ IPs that are coming from the same edge servers will look the same, so if you have a university and a city that are all hitting the same edge networks and one person in the city makes a failure to log in, suddenly the users in the university nearby are getting blocked even though they have a different IP because it all looks the same. So that’s the note there. Similarly for Akamai and I believe others as well, the CDNs do not handle the very headers that Drupal sends out by default. Those are seen as cache busters and they will break cacheability of your site, so saying omit the vary cookie header will solve that because the vary cookie header encoding will not be included on request.

Finally, another issue that comes up fairly frequently for basic configuration is the base URL for your content where Drupal will try to use the URL that the request is coming into it for all of the static assets. So this is your aggregated CSS and JS and often your embedded content like images as well and it will preserve that URL, but when you’re behind Akamai, when it makes requests back to origin, it makes it against an Akamai name, so the Akamai name may be “origin-akamaidomain.com” and you don’t want users making requests past Akamai. You want them to be going through Akamai for everything and to ensure that that happens, you need to check what the request that’s coming into you is – so that’s the line about forwarded hosts there – and grab the name of the server that is being requested and if that matches that origin domain, that means this request is coming to your origin from Akamai and you want to then rewrite your base URL to be the public Akamai domain so that all those static assets are served from that domain and are coming to Akamai and not to your origin directly.

Alright, so we got a quick question here. I think we’ll keep that for a later time. So two other best practices for Drupal and Akamai is Akamai provides a staging network that they set up and by default they will point that at your production site along with their production network and when you’re doing testing, you’re testing against production. A much more helpful configuration is to have Akamai point their staging network at your staging tier so that you can test things, change configurations and work with Akamai to make changes without impacting production at all or having any risk of impacting our users. The second piece of that is that you should really have separate domains for the public, so a CDN-facing domain which is where users are coming in and an edit domain which is for your administrative users where people log in that are really creating the content and administering the site and this is a best practice with the CDN in general in my experience because you don’t want your administrators coming to the same site that the public is using for a variety of reasons. Chief among those are the CDN is specifically designed to cache as much as it can. I mean if you’re optimizing for the site, you want it to be as performing as it can be and give the best experience to the users, and that’s not really the same objective that you have for your administrators who, by definition, need to see an un-cached version of the page or have access to really see the latest and greatest that’s happening in the site before anyone else. For that reason, they shouldn’t be going through the front door, as it were, because the objectives of those two experiences are quite different. In Akamai especially, you will have unpredictable experiences where administrators will not see the content that they expect or they’ll be seeing some cache things, or even worse, Akamai or whatever network you’re using can cache administrative content on the public-facing site. So the user comes to a page that the administrator was just on and sees your admin bar or other undesirable content.

Similarly, by splitting out an edit domain from the rest of the site, you can take advantage of a whole bunch of additional security measures to make sure that the only thing talking to you from the public domain is your CDN environment and the only thing talking to your edit domain are your privileged users. I’ll talk about that a little bit more in a minute. Finally, as I already mentioned, you really want to make sure that you’re able to maximize cacheability and that you don’t need to put in any special rules or needlessly complicate your caching strategy by trying to use the same domain for both purposes. As I mentioned a moment ago, since you’re securing access, the way that I typically recommend that we approach that is if at all possible, if your company is running an internal DNS server, to have the edit domains entirely on your internal DNS so that no one outside of your network has access to it and the few people that hopefully do need access are able to set up their own host file entries for accessing that domain. Similarly, you can implement an IP whitelist that says “I don’t allow any access to my edit domain except from this IP range inside my network, my administrator’s home IP address” – hopefully they’re using a VPN and that may not even be necessary – “and my CDN or Akamai edge servers.”

So those are the best practices and there’s a whole lot more that you can do as I talked here briefly about some of the other things that you can take advantage of once you have those split domains. One that I really enjoy and adds a lot of security to the site is a blank user roles table. So Drupal by default stores all of the user’s role mapping. So user ID 19 has these roles in the users role table and if you create a copy of that and if you’re using MySQL, you use the BLACKHOLE storage engine where it’s basically writing everything to blackhole and nothing is actually written there. With a separate edit domain, you can add a database prefix to your user’s roles table to be “blank_” and then it will use this newly BLACKHOLE’d table when it does its lookups. As a result, everyone on the site will have no roles assigned, so even someone who’s an administrator on the site, if they accidentally logged in on the public-facing domain, will not have any roles assigned to them and there is no risk that they can access administrative content and have that cached for the public. It’s fairly easy to set up and it gives you a really nice benefit and then you only have to grant access to content that you have for authenticated users. That becomes the only thing where if maybe you have some content like comments that are only available to authenticated users, they’ll still be authenticated, but they will not have any other privilege roles assigned to them.

Similarly, you can mask that you’re even a Drupal site or that your site allows login or has any administrative functions. By modifying your .htaccess file for the site, you can check again incoming domain requests and if it matches the public-facing site, you can 403 or even 404 Not Found administrative paths, the user path, the directories that are in the site by default that are not needed typically for serving site content, and if you really want to mask potentially that it’s Drupal, for example, you can disallow all access to node and only allow your aliases to be accessed, so this gives you a lot of control over customizing the user experiencing and securing the site in a way that isn’t generally convenient otherwise.

So some other things, again, this is fairly high level and it’s site-specific, but some other cool options that you can do with something like Akamai in front of your site or a similarly good CDN is you can work with them and set up exclusion paths for certain things where AJAX callback paths may not be safe to cache in your CDN, so things to look out for are things like a login, lockout paths, AJAX callback, obviously any content creation that any of those paths need to be excluded. Another issue that comes up frequently is if you’re really caching content on your site for a long time and since you have a long TTL – time to live - on the site because maybe certain pieces of content don’t change frequently that Drupal’s aggregated CSS and JS files by default go away after a period of time and that can be problematic if the CDN maybe has the content of the page in place, but doesn’t have all the static assets in cache anymore and then comes back to your origin and requests these aggregated files that haven’t existed for a week or however long. There’re a couple of options for that. In Drupal 7, there’s a new variable, “drupal_stale_file_threshold” that you can increase to be as long as your maximum TTL time on your CDN and it will ensure that those files are preserved for at least that length of time. On Drupal 6, that variable’s not yet present; however, there is the advanced aggregation module called “advagg” available that can similarly be set to preserve these files for an extended period.

Some other things that often come into play are issues around cookie domains making sure that sessions are handled as you’d expect. You may need to change the cookie domains in your settings and if you’re leveraging Akamai in particular, Akamai has a lot of other really nice options for using their services including net storage where you can switch Akamai from being a pull-based system where it’s coming to origin for its request to you have a pushed-based system – and Wim was giving the benefits of those earlier – where you can push the assets that you want to be served on the edge.

Moderator: Alex?

Alex Jarvis: Yes?

Moderator: I’m sorry to interrupt, but I just wanted to say thank you to anyone that has to sign off now. If anyone wants to stay on and finish the presentation and ask questions, we’ll continue.

Alex Jarvis: I’m sorry; we’ve run a little bit over. I’m almost done here, so I’ll wrap it up really quickly. So NetStorage has nice advantages for going from a pull to a push-based system. Similarly for securing the site, Akamai SiteShield allows you to restrict access back to your origin webs and if you really hone the advantages of CDNs in Akamai, you can do some crazy things like allow users to sign in, get details about what role they have on a site and then send them over to your Akamai domain and give them customized content as an anonymous user, but that’s still customized to what rules they have. It’s cool things like that that can be done that Akamai and Acquia have done together that we’d be happy to help you with, and Acquia’s cloud is set up to do this. Aside from the initial configuration that I already mentioned, we work out of the box with Akamai on these things and the sky is the limit of some of the ways that you can optimize and enhance the experience on your website.

So that’s all I had. Thank you so much and I believe I may give it back to Kieran here and we’ll have some Q&A.

Kieran Lal: Great. Thanks, Alex. That was really great content from everybody. One of the things we seem to have found through the presentation was that people were either asking questions directly of the speakers or maybe there’s something going on with WebEx. As the organizers, we only saw some of the questions, so I’d like to ask the panelists, Chris and Wim and Alex, if you’ve seen any additional questions that have shown up in your windows, if you could assign them to me, then we’re going to go ahead and we’re going to take a couple of questions that were directed at Wim earlier and Wim had had a chance to read them, but they were around talking a little bit more about targeting assets that are pushed to a CDN versus one that are not. So Wim, do you want to take that away?

Wim Leers: Sure. So essentially the question was “Can you talk a bit more about targeting what assets are pushed to CDN versus which ones are not?” Looking at the exact timestamp, I think this question relates to the Drupal CDN module. In general, you can implement any kind of logic you want to determine which files are served by the CDN or not. In the case of a push CDN, you control which files are pushed. In the case of an origin-pull CDN, you control the URL, and if you control the URL, then you determine when it’s served from the CDN or not because for example, if your CDN would be mysite.CDN.com, if you use that domain name, then the origin-pull CDN will come back to your origin and get the file so it’s served from the CDN. If you decide to serve it from mysite.com, then it won’t be. So that’s the general answer, and in specific cases, a Drupal CDN module, what you do there is essentially say, “Hey, these specific file types should be served from the CDN.” So you list the domain name then you list file extensions – for example, CSS, JS, JPEG, PNG, GIF, whatnot. Those files are then searched from the CDN, so it’s based on file extension in the case of the CDN module because that’s the easiest and most understandable and most performance solution there.

The other question was “Can dynamic responses static assets be targeted for CDN?” The answer is yes, but it really depends on what you understand on dynamic responses. So essentially anything is possible, but for example, in the case of – I don’t know – a thumbnail that shows the latest promoted product and that changes every day, that is something that can definitely be a use case. The tricky thing is always to ensure that it’s not cached for too long or to make sure that it’s cleared when it needs to be cleared. In the case of Akamai for example, they support explicit purging, so there you can execute or perform a purge command on that specific file so that then the CDN will come and get the new version. That’s one way of doing it, but the most HTTP standard-like way is by using the proper cache control. Essentially what you do there is say this file can be cached for X hours or X days or X seconds and if your CDN listens or takes that specific method into account, then you can rely on it, but you should make sure that your CDN actually listens to those correctly because that’s not the case for every single CDN, or maybe they ignore any caching duration that is below, for example, five minutes or below one minute because otherwise the caching doesn’t make sense from a CDN point of view.

So the answer depends there, but if you’re talking about dynamic responses in the sense of page caching, serving the entire website from the CDN, then I think that maybe Alex or Chris from Akamai can answer the question better because I have little experience in that area.

Alex Jarvis: Sure, I’ll pick up on that. I’m going to jump back real quickly to the first question about pushing content to the CDN and just say from an Akamai perspective, for example, if you’re using NetStorage, that your Akamai configuration will control what kind of assets you want to do and what the lookup order is. You should look for these sorts of assets in that storage first and then you will explicitly control yourself which files you push up to that environment. Speaking more to the second question about dynamic content, in most cases, as Wim indicated, you have some options there being creative with your cache control, but if it’s something where you really need something to be completely dynamic and it cannot be cached every single time, then what you’re usually looking at doing is some form of ESI where you’re going to expose that dynamic piece in some individually-chunkable way that can be requested by ESI so that when the page renders, three-fourths of the page comes from the cache hopefully or as much of it as possible comes from the cache and the dynamic pieces making a callback to some service or some portion of the site that can deliver that dynamic content very efficiently and very quickly because you’re bypassing the CDN for that. In my experience, it’s not particularly feasible to have the CDN directly cache or directly hold dynamic content because the CDN is going back to the origin for anything that it doesn’t have on itself. It’s not processing things. In order to be fast, it needs to be able to just serve something itself and not be concerned about computing it, so if you need to do that, you really need to be looking at how to provide a way for origin to provide that quickly.

Kieran Lal: Okay, great. Thanks, Alex. We’ve got one more question and let me just pull it up here so that I can read it. So it was from Kai and he said “We’ve seen examples with which media files are hosted independently from the site itself. When or why would this be used instead of a traditional CDN?”

Alex Jarvis: I guess I’m not quite following the question. It sounds to me like that basically is a CDN or at least that approach to charting the assets so that they can be requested separately from the site content. I’d be curious if perhaps I’m misunderstanding the question slightly.

Kieran Lal: Kai, feel free to jump in and clarify your question, but I guess my thought would be when do I put my videos on YouTube and have them embedded and delivered as part of my site from YouTube? Then when do I host them, but have the videos delivered directly from the CDN or something along those lines?

Alex Jarvis: So in a case like that, I mean basically anything that you can offload from your origin is a win. The advantage to running your own CDN versus something like YouTube is that you have a lot more control over where that content is coming from and how it’s being handled. If you’re relying on a third party, then you’re also relying on your content delivery system, so you don’t know how YouTube distributes access to their videos. I mean in this case, in YouTube specifically, we’re talking about Google and we can assume probably that it’s going to be pretty good, but you don’t know precisely what’s happening, whereas with the CDN, you, by definition, have a lot more control even if it’s an abstract flavor. I mean you don’t know where every single edge server in Akamai is for instance, but you do know that you can look at the statistics, you can get the information about what’s being served, you can get a sense of where in the world those things are coming from and how they’re being used, so it really comes down to having a better sense of where your content is and how it’s being accessed by whom and how it’s being served. That’s where having a CDN that you’ve set up and you understand empowers you in ways that using a third party service that may not provide or that won’t provide the same level of information that’s helpful.

Kieran Lal: Great. Thanks, Alex. Kai, if you needed to – okay, so one of the things he was saying, the example he was thinking about was, say, an audio hosted independently, but I think he understands based on your response, so great.

Okay, we’re a good chunk over, but as promised, we had some really outstanding content and some real depth and expertise from all of our speakers, from Chris and from Wim and from Alex, so thanks everybody for attending. Hannah, was there anything else you wanted to say to wrap up?

Moderator: No. Thanks everyone for attending. We’ll send you slides and the recording within the next 48 hours.

Alex Jarvis: Alright. Thank you all very much and happy holidays to everyone.

Click to see video transcript

Hannah: Today’s webinar is Accessible Theming in Drupal with Dan Mouyard who’s a Senior Interface Engineer at Forum 1 Communications and I’m Hannah Corey and I’m a marketing specialist here at Acquia

Dan: Hello, I’m hoping everybody can see the slides Accessible Theming in Drupal. As Hannah said my name is Dan Mouyard, Senior Interface Engineer at Forum 1 Communications. I’ve been working in Drupal for about four years now and I’ve been involved in Drupal 8 development core development and I’ve been involved with the HTML5 Initiative, I’ve also been involved with the mobile initiative and I’ve also been a member of the accessibility team for the past couple of years where we get together about once a month and chat and try to talk over some of the accessibility issues going on in Drupal core and contrib. Interface engineer so that’s basically a fancy way of saying themer and so I have a lot of experience with HTML, CSS, Java Script as well as PHP.

As a personal note I’m also legally blind and I wear hearing aids so a lot of the accessibility issues that I work with every day affect me on a personal level and I hope I’ll be able to share some of that insight. The focus for today’s talk is primarily on theming especially in Drupal 7 although some of the topics that I’ll cover I’ll also bring on some of the techniques that we’ve been working on for Drupal 8.

Hopefully you’ll have a good grasp of HTML, CSS and maybe a little bit of Java Script as well as just basic theming topics such as template files and stuff like that and also finally the focus is on accessibility and with a title like accessible theming most of you you tend to probably you’re already familiar with accessibility so I won’t go too much into detail as far as what it is or why it’s important or what that we need to work on but you wanted to point out that my view on accessibility is a little bit different and here’s a great quote from Tim Berners-Lee about the world wide web and he said, “The power of the web or the universality accessed by everyone regardless of disability is an essential aspect.” How that everyone because to me that is the focus of what we do when we build websites is that we want to build them in such a way that everyone can access them regardless of whatever limitations they may have and those could be disability limitations, they could also be device limitations, internet connection, there’s also what’s called situational impairment. Such as being in a bar where it’s very noisy and you’re trying to watch TV. That situation can hamper things so stuff like post captioning could really help and the same thing occurs on the web. There’s things we can do that are vitally important to those with disability but they also help everyone.

Before I get into some of the nitty gritty details of the techniques for advanced theming I just want to highlight really quickly my overall philosophy and that’s through this idea called progressive enhancement and the whole idea of progressive enhancement is just layer on functionality from the simplest most basic to more advanced.

First you start off with HTML. That most – devices and browsers can understand and then you layer on CSS and then you layer on behavior with Java Script and also even within those different areas you can add on layer to more complexity. With HTML you can layer on some of the newer HTML5 elements and with CSS you can layer on top some of the more advanced CSS3 reflective and the rounded corners just stuff like that and again with Java Script.

The reason for this approach is this ground up approach is that regardless of however you’re accessing that page you still get a usable interface and a usable way to consume that content. The main thing that I’ll be covering today is first I’ll be going over some of the accessibility stuff in Drupal Core that you should really be familiar with during theming and then I’ll cover some HTML basic of creating accessible HTML and how you can implementing that in your theme. I’ll also be going over quite a bit of different CSS techniques to make things more accessible and then finally I’ll be going over Aria it’s just a new way you can add basically meta data and semantic to HTML that can help assistive technology understand.

First Drupal Core, what have we done with Drupal Core particularly Drupal 7 that makes things easier accessible to wire that you really should be familiar with when you’re theming? The first one is we’ve added three helper classes. Those are element dash hidden, element dash invisible and element dash focusable.

The first one Element dash hidden here’s to CSS. Basically you’re just applied to CSS property display none. Now what this does is it tells browsers and any other devices that, “Hey, this part of HTML just ignore it.” And so all browsers and devices and such technologies such as screen waiters they won’t present that information. There are times however you want stuff to be hidden visually, but yet that information will still be available to devices such as screen waiters and that’s where we use element dash invisible. You can add this class to anything in Drupal and it’ll essentially hide it from view yet still be there so that screen waiters don’t read aloud whatever the content is inside of it and the finally some of the work done element invisible is the element dash focusable class.

Here’s the CSS. Basically what it does is any hidden element using invisible if you also add element dash focusable class to it whenever keyboard users or other devices tab through the mark up when they hit one of the units focuses it’ll bring it back into view and go back to your tech test and how will you just skip links.

Skip links are the first links on every page which allow users to skip directly to other sections of the same page most often to the main content. Now in Drupal itself it uses only one skip link and it links to the main content but you can have others such as a link to the main navigation or a link to the search box. This is the first link that occur on the page so you really want to limit how many they are. You should never have more than three.

Here’s an example of the bar tech theme and you can see at the very top where it says skip to main content and that’s the skip link. Normally you don’t see that because it has the element dash invisible class but when the keyboard uses a tab to it because it’s using the element dash focusable it pops into view and that allows people to jump down to the main content.

That’s also used in the seven theme here’s an example, which is the default admin theme for Drupal 7. Again if you would tab the first thing that would pop up would be the skip to main content. How this is done is in the HTML template which is provided by the core system module. To add just a little bit of HTML at the very top right after the body tag and the important thing to really focus on here is the target of that link where it says main dash content and the reason that it’s important because that needs to be a valid link and sometimes whenever new themes are created they ignore the skip link or in the page template they don’t provide the target for that link.

Then the page template you should have one of two things. you should either have an anchor tag with the ID of main content or you should have a div or some other HTML with the ID main dash content that enables a skip link to functional correctly and then finally in Drupal Core we do a lot of work on forms and one thing that’s really important about forms and accessibility is that all form elements need to have either a label or a title attribute and Drupal’s form API uses the title property to set these.

Now Drupal’s form API is very powerful. It uses the raise help developers build these forms and so here’s a little a snip at a PHP. Now you’re creating a new form element and just for the sake of this demo we’re creating a text field such as names stuff like that and then the title property that palm title you see where we’re setting a description and for those of you who are not familiar the T function that just allows it to be translated.

What this will do is this will create a text field form element and the label for that element will be description and the markup will be put in such a way that the label is correctly linked to that element but there are times when theming when you might not want to show that label or you might want an attribute of third you might want to move it around. In Drupal 7 the form API was the title display property and there are four possible options.

By default it had before with a label show up before the element. The next after where the label comes after the element in the mark up order and then invisible what this will do just will add the element dash invisible class to the label. It’s still there and screen readers can still hear the association of what that label is to that element and then finally attribute and let you set that then instead of outputting a label for a form element it will set that title as the pedal attribute for that element.

Here’s an example that same one we had before where we added the title display property and we set it to invisible so again this markup will output a text field and description will be the label for that element and it will have the class element dash invisible so it won’t be visible however it will still be read by screen readers.

Next HTML theming, you need to really focus on for accessibility and the first one is just a general best practice is you want to have semantics? Here’s an example code of – no article. Perhaps it’s a node or something like that. You can see where users some of the HTML5 elements and stuff. We have an article, we have the heading, the footer element which is new in HTML5 which doesn’t necessarily have to be at the bottom it’s just a semantic saying, “Hey, this is information about this part of the mark up.”

There’s also the figure element for adding images and the caption and the paragraph where you can emphasize things and even an abbreviation. All this stuff you can make it use different code that’s unsemantic and it will look at the same as well as in theming and just use bids and class and stuff and making it the same exact look however you lose some of that semantic meeting and some of that meeting it doesn’t really make a difference accessibility wise but in the future especially with some of the HTML5 elements newer sister technology can take advantage of this information and so you can change this markup usually in template files in Drupal.

It’s pretty easy you can just open up a template and you can just rename this to article something like that. Where it gets really tricky however is whenever you have custom content types and you have say a bunch of fields on those content types and by default the mark up Drupal outputs for those fields is pretty cluttered because it has to be usable of course through a wide variety of used cases.

You can use individual field templates to overwrite those mark ups to however you want however it’s very difficult to create those field templates that will work across all projects. What I recommend is using the fences module and what defensive module does and its jupitaorg/project/fences and this allows you so that when you create those content types and you create those fields you can define the mark up.

Here is a content type where you can manage fields and what fences will do is if you go under operations and you click edit next to one of those fields now that’s where you can set, “Is this required? What’s the maximum length? What’s the default value.” What the fences module does is it allows you to define the rapid mark up for that particular field.

Usually whenever you’re creating these content types, that’s when you have the best idea of the semantic meeting of those individual fields. The next thing to really focus on for HTML is that the document order is the tab order. If you go to any page HTML page and you use a source you see all the mark up and machines and assistive technology and screen readers they will read through that in the order of that code and that’s very important because for keyboard users they might have visibility issues and can’t use a touch device or a mouse. They have to use a tab on the keyboard or some other binary movement device. They can tab through to different areas on the page and it goes in the same order as this code.

Here’s the example, if you look at the page template. Now this is the default how it orders things. It also has the header, the navigation, the bread crumb the main area and then the footer and then within those the header. The logo the site name and slogan then if you have any blocks assigned to header regions they come after that. You can see the order of how things are and the code. Whenever somebody is tabbing through the stuff on a keyboard you have to be mindful of what order these are because whenever they’re tabbing through the page this is the order that they will hit things.

Now you also notice that the header and the navigation they come at the top. You have to go through quite a bit before you actually reach the main content and that’s the big benefit of the skip link because the skip link is in the HTML template which is a wrapper for the page template so it would come first and so if you hit that you can quickly skip and jump down to the content. You don’t always have to continue tabbing through all of the logos and the navigation and that stuff.

Another thing with HTML is in addition to the source order there’s also the mark up that you can use. Now in Drupal 8 with the HTML5 Initiative we went through all the templates and we tried to use the best HTML6 elements that we could. In this example, the page template we can use the new HTML5 elements. Now we can use the header element, there’s the nav element for the navigation stuff. There’s also the section element so you can create different sections and also the footer element.

The next thing for HTML you really want to be mindful of whenever you’re theming accessibility wise pretty much the one thing you have to focus on for images is you need to have text alternatives for that content. Just like with videos you need to have some tech so that people who can’t see the videos, can’t hear or have perhaps they have flash block and they can’t see the video at all there’s some other information there that they can get some the same thing with images and the primary way to give that alternative tech for images is with the alt attribute.

Now the key thing to keep in mind with the alt attribute is one every image element needs to have an alt attribute. For decorative images perhaps it’s a flower that’s part of the design but it’s not really part of the content you can just leave the alt attribute empty. If it’s a content image then you have want to have that alt tech be short concise description about the image and if that image happens to be inside of a link that image is pointing somewhere then that alt tech should describe the destination of that link and the reason you even want an empty alt attribute on the decorative image is because a lot of screen readers if they see the empty alt they’ll ignore the image which is want you want. Otherwise sitting on a screen reader they’ll say, “Blank image blank image or this is an image or unknown image.” It’ll repeat that so like really interrupt the flow of content.

Also with the HTML as we get more and more into not just desktop but also the tablets and mobile devices you also want to keep in mind the view port. The view port is essentially what the screen is for that particular device. How does it render it? What I’ve seen all too often are these two view port Meta tag.

The first one sets an initial scale a minimum scale to maximum scale and they set it all to one and that prevents zooming which you really don’t want to do because on mobile devices and the tablets sometimes the text is too small for people with vision problems so they want to zoom in and they use the touch zoom in and they can’t and so this prevents them from being able to read that text.

The second one prevents scrolling. Sometimes they might have zoomed in but they can’t scroll to part of the page that is now something out of the view port. The recommended that I recommend is just have width equal device width. This works very well on all devise and just says, “Hey, whatever the device width of the device you have set that as the width of this page.” It allows zooming, scrolling and all that kind of stuff.

Okay so the next big section is CSS and so all the styles and there’s a bunch of different stuff you can do with CSS to make sure your site is accessible. The first one is you should be familiar with the image replacement technique. Just like we had images in HTML and we have the alt texts sometimes you might want to add those images that are decorative as CSS backgrounds but you still want screen readers and search engines to still be able to get that text and that information

Here’s an example where you have – here’s a header where the texts visits the capital. You still get that semantic information but you maybe want to show an image set. so you can use CSS to define an image background for that header and then it’s important you set the height and the width to be the dimensions of the image and there’s a couple of different image replacement techniques that you can use and the one that I have shown here is one of the newer ones so that it will hide the text and still only show the image background.

The next important area for CSS is styling links and three main key ideas you want to keep in mind whenever you’re styling links. One is you want to make them obvious. If you have links on the page you want people to know right away, “Hey, that’s a link I can interact with.” Next is you want to design all sticks of lengths. When it first comes up you also want to have something different for hover or focus whenever somebody tabs through and is focused on it. It’s like whenever somebody actually clicked on that link and also visited so people know where they’ve been and that’s why you want to make them easy to click.

This is just general usability best practice and it’s also very helpful for people with mobility problems. They have a hard time being very accurate with their mouse movements. It’s also very helpful for tablets and touch devices where they have to use fingers and people have really big fingers compared to the length that they’re teaching.

Some cool trick that I’ve done with CSS and links is one if you don’t’ have enough time to design the focus state which is ideal just at a really good default is that whenever you set CSS properties on hover do the same thing for focus and this way if you add the background, different color or stuff like that whenever a mouse hovers over a link the same styles get applied whenever somebody is tabbing through on a keyboard. They can easily see where they are and what’s highlighted.

Another problem I often see is the link outline. Now quite often in reset style sheets you’ll see this just generally applied to all anchors it just says outline zero and that’s because on certain links and stuff on browsers if you click on them and stuff you get this weird outline and it sometimes doesn’t look good however that outline is very important for keyboard users who are tabbing through and so a better default is to use this then you reset and set. Where you set the outline to zero for the hover in the active state but for the focus state you make sure it’s still there that way keyboard users still get the benefit of that outline.

Finally you want to have a big target area for people to work on and this is what I like to use as the default anchor tags is set the margin to negative two pixels and the padding to two pixels and this works on all the inline links and basically just to add two pixels of clickable area around each link and also if you’re tabbing through the outline won’t be right next to the text anymore it’ll be two pixels and it’ll make that text a lot more readable.

The one caviar if you’re having this in your reset is that you want to make sure whenever you’re styling other links such as menu links just stuff like that you want to make sure that you’re overwriting the margins and the paddings so it doesn’t screw things up.

The big part of making themes accessible with CSS is to really pay attention to typography. Now and it’s been said web design is like 90% typography because that is basically what people go to websites for is to get content and to read that information and you want to make that as easy as possible for people to do.

Here’s a great quote from Emil Ruder, he was the head of the Swiss Design School then he’s in – he’s a big influence in a lot of typography work and he said, “A printed work which cannot be read become the product without purpose.” That is the essential purpose of text is to be read and so some general things you want to keep in mind with typography is first of all you want to choose the right fonts and you want to make sure that they’re legible and you want to do as much as you can to make sure that they’re readable easy for people to see what they are.

Some of the display fonts sometimes the lens look they may look cool but they’re a lot harder to read and so you have to balance the design versus how readable it is. Another thing is you want to pay attention to the measure.

Now the measure the typographic term essentially saying how wide a line of text is. If you have a block a paragraph the measure is how wide it is and you don’t want that measure to be too wide because then as I read down the line and get to the end and it comes back to the beginning if that distance is too great and you miss your landing spot. It’s hard to see where the next line is but at the same time you don’t want that measure to be too narrow because then your eyes become like a pinball machine jumping back and forth very quickly from one link to the next.

Another thing is to use the appropriate leading. Leading is another typographic term and it basically means how much space is there between lines and text and in CSS this is the line height property and again just use the go to actual. You don’t want too much space between lines and you don’t want too little space so they crowd together.

Another good general rule of typography is you want to create a nice hierarchy. You want to create a nice hierarchy in the sense of perhaps heading structure. You want to have the heading structure be such a way so that you know this chunk of text belongs in this area. You also want to create hierarchy with lengths and stuff to make things easier to scan and you also want to use font sizes to make this hierarchy more noticeable more make this stand out and then some more detail just stuff to pay attention to.

The first big one is font size and so for nay of the body copy – like so you go through a page and it’s an article page you want that text to be the default font size. If you’re on CSS you want it to be 100% which basically is 16 pixels in all bounces. You want make that – they set it at that size for a reason because it’s very readable and back when the spec was first defined the 16 pixels on a monitor with the same size with PowerPoint that you would see in a book and one of the good things about using the default font size to body copy is that I had mentioned before about the hierarchy you have a much broader spectrum of font size that you can use for some of the smaller detailed stuff. The byline, the more information, full length that kind of stuff.

I remember it was several years ago where like people would set the body copy in like 13 pixels or 12 pixels because it was very very small it’s hard to read and everything looked the same because you couldn’t really get much smaller than that. so the byline, the more information link they were all the same size and very small and the small tech would create eye strain having to read stuff that’s small especially on monitors because it’s not as crystal clear as it is on a pungent magazine or newspaper and the final one good hint I have for whenever you’re designing with font size is to use actual text rather than just the Latin lorem ipsum because you have actual text there. As you’re designing you’re like, “Oh.” You can tell right away whether something is readable or not.

The other thing you pay attention to typography wide is the text alignment and in general you want to let the link the main chunk of body text. For a line if you have a right to left language and you want to avoid using fully justified texts because they create rivers and rivers are like the larger spaces between words that flow through the document and it can really throw off the rhythm of the text and it’s especially hard for people who are dyslexic and again having text alignment that left align that makes it easier to scan text. It easier to jump from paragraph to paragraph and scan through length and stuff like that.

Finally you want to make sure that there’s enough color contrast between the text and what’s behind it. What’s very good at increasing visibility to make things easier for people to read? Here’s a great website contrast dot com and it’s a great example of how high contrast design can still be beautiful and it also has a lot of good facts of why it’s important and the color contrast you want to make sure the smaller text it needs high contrast because it’s smaller. You need to make it stand out a little more and one caviar however is that you can’t have too much contrast. I don’t see this mentioned often whenever people talk about accessibility contrast but for people who are deflecting if there’s too much contrast it can actually make it harder for them to read and so some good tools I recommend is one is a really good tool that we’ve put out recently the contrast ratio and it uses the W3C W Color 3.0 double A and triple A contrast ratios you can easily input color values and see how readable stuff is.

There’s also online color filters great bit dot com and color filter dot work line dot org and they allow you to just put in the address that whatever website you’re looking at and you can see what that text looks like in black and white and under different types of color blindness and then my favorite is the color blindness simulator is that color ore core dot org and this is the program that you install on your computer and they have versions for Windows, Mac and Linux and what this will do is while you’re working you can have whatever – if you’re in a website or if you’re in Photoshop designing it will easily switch the entire monitor to a certain type of color blindness and you can check out and make sure that the color contrast works for whatever you’re designing.

Finally for CSS techniques the tone to responses design paradigm where you build and theme stuff in such a way that it looks good across all devices. So the big idea behind that is the layout. We use media queries to adjust the layout and media queries are basically just CSS that says, “Hey, if this condition is try apply this CSS.” And then you want to set the break point based on the content rather than the devices.

The break point are the different queries where things change. for example if you had a mobile layout where everything’s a single column at some point you have enough room that you may have two columns and where that changes is the break point and you want to set the break point based on how the content looks make sure it’s still readable rather than changing it at different devices and that’s for two main reasons.

One is device sizes are going to change. In five, ten years there will be a monitor on your refrigerator where you can see the website of the grocery store for example and we don’t know what size that screen is going to be and so if you set these break points based on content.

Another reason why you don’t want to set it on device size is that these media queries can be triggered when people zoom in in their web browser. People who have vision problems can zoom in and they can trigger these media queries on caviar. That doesn’t currently work in web browsers but they’re in the bug for it and they are going to be working on it.

Here’s an example of a media query. Here’s some CSS and so for the body we’re shedding with the margins, the max width and the padding for it and so what’s what every browser and device will use that and below it where it has the media screen and min width so that says, if the device screen if the width is 35M or larger then apply the CSS inside and so that’s where we can have a body and set the max width and change things around.

Finally one area of technically we can work on is WAI and so basically this is the Web Accessibility Initiative which was created by the W3C to tackle accessibility stuff and so this is the accessible rich internet application. There’s are – it’s especially Meta data that you can apply to HTML that helps assistive technology understand the purpose of that HTML. Just another layer of semantic that gives more information.

The use of it. Basically it defines a way to make web content and web application more accessible to people with disabilities. It especially helps with dynamic content and advanced user interface control developed with AJAC, HTML, Java Script and related technology. The different area, roads and landmarks and attributes that you can apply to make things more usable to assistive technology.

The only thing we really need to worry about in theming as far as getting started is the land mark roles. If we look at the page template we’ll see these big areas. We’ll have a dim with an ID header, navigation to make content and the footer. What was done for triple A is that we’ve used a new HTML5 tag the header tag, the nav the footer and in the future those tags will go assistive technology can take advantage and they would know what those tags mean.

Some of these technology however can’t understand those yet. At the stop gap we can use Aria. We can use for example replace it where for the header we give it the role of banner and for the nav we give the role of navigation. For the main content we can give it the role of main and for the footer we can give it the role of info and there’s even a new element called the main element which they’re discussing at the W3C and it looks like it’s going to gain track and it will be used but it’s not quite ready yet. We can use the main element instead of the section with the main content and assistive technology that can understand that can now also have the ability to jump that main content rather than having to use a skip link right now.

Okay, before we stop for questions I just wanted to demo really quickly the responses layout. For the past seven months or so at Forum One we’ve been working on the EPA dot gov that can be moving things over to Drupal and so we’ve been building the Drupal platform for them and I was the fine art architect for that project and theming and so one of their big wishes was for responsive design and also accessibility. They really wanted to focus in on that.

Here’s an example of one of their learning pages and one of the benefits of having these responsive layouts is that in addition to the screen readjusting itself at different device width it’s also help for people who have vision impairment that might need to zoom in and the immediate queries can be handled that way. So for example we can zoom in but first let’s look at the default desktop view and suppose somebody needs to zoom in and wanted to be able to read better.

As they zoom in it triggers the immediate queries and you’ll see things and the layout and stuff will change and you’ll see like for example the search field ban that may not widen the bigger the stuff that’s still readable and usable even for people with vision problems they need to zoom in. they rearrange and fit.

Again maybe people are really need zoom in even more and they keep going they can even get the mobile what people might see on a mobile layout. You could see how things change. Length that gives a little more padding so that people with fingers it’s easier for them to touch stuff and again all this stuff makes things usable not just for people with devices but also people with accessibility problems and they might need to zoom in. Okay, we have some time for questions.

Hannah: Hi everyone, if you have any questions please ask them in the Q&A pad in the web XEY please. Okay we have one question come in. what web accessibility checking tools would you recommend now that Bobby is no longer.

Dan: Yes, as far as automated tools one of my favorite currently is the wave tool bar and the new beta version is like the version five of the wave and it’s actually very good. There are also the new bookmark it basically you add it to your bookmark and it’ll go through and check all the mark up for you.

Hannah: Okay, the next question is do you recommend using Zen theme?

Dan: Yes, basically when it comes to themes you want to use whatever you’re most comfortable and a really good thing is you’re choosing themes and you’re really concerned about accessibility is on each theme they might have the tag D7AX which says they really paid attention to accessibility issues. I know John he has put work accessibility wise into the Zen theme and we also have others such as adaptive themes. I know Omega have done some so yes.

Hannah: One more is there a Jay Query book that focuses on accessibility design?

Dan: As far as accessibility design for Jay Query I haven’t seen on but there’s actually a very good book I think it’s called Progressive Enhancement with Java Script and it’s put out – yes I think like within two years ago and it talks all about progressive enhancement and how you add on Jay Query to create widgets that are accessible.

Hannah: Okay, the next one is can you go over how zooming is accessed in media queries?

Dan: Sure, again with media queries now say here we have the media screen and then inside that parenthesis you can say you can test for different things such as aspect ratio, device width, device height that kind of stuff and in general we tend to use the width as the thing we test for whenever doing these layout stuff. Especially if you use M rather than pixels then whenever you zoom in those media queries get triggered. Stamp on this site zooming in and out it triggers the same media queries just as if you work your resize screen. Any other questions?

Hannah: None are coming through so I want to say thank you so much Dan for the great presentation and thank you everyone for attending. Again the slides and recorded webinar will be posted to the Acuaia dot com website in the next 48 hours. Dan do you want to close with anything?

Dan: Sure, you can reach me at dmouyard@forumone.com if you need to email me any questions and also you can follow me on Twitter at DCmouyard that’s also my Drupal.org user name that’s also my RC Nick and also my Skype handle.

Hannah: Great, thanks. Everyone have a great day.