Drupal is not your Website
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Drupal is not intended to directly generate entire web pages. It is better suited as a back-end content management system, with other technologies handling page assembly and delivery. For high-traffic sites, offloading elements like user comments, real-time updates and cached content to external services improves scalability. Edge side includes and client-side technologies can incorporate dynamic fragments into cached pages without involving Drupal. This allows Drupal to focus on content while distributing page load across the technical stack.
Drupal is not your Website
- 2. Drupal is Not Your Web Site ! Develop for high-scale, fragmented sites DrupalCon Austin - June 3, 2014 ! Tobby Hagler @thagler d.o: tobby
- 3. Presumptions and Expectations • Beginner level discussion, but still familiar and comfortable with site building with Drupal • Passing familiarity with topics presented here, but not significant experience with them • Will be an overview of concepts; an introduction designed to lead you to thinking about your site build approach • Suggested modules
- 4. Overview • What a Web site really is • How does Drupal fit into the stack that is your Web site? • Other elements of a Web site to consider • Removing things from Drupal to help overall performance • Real-time content updates on your Web site
- 5. The Web site
- 6. A location connected to the Internet that maintains one or more pages on the World Wide Web. Merriam-Webster “ ”
- 8. Common Page Assembly Methods • Static (flat) HTML files • Server-side Includes (SSI) • CGI • Scripting and template languages • Content Management Systems (CMS) • Edge-side Includes (ESI)
- 9. Server-Side Includes (SSI) • HTTP/Web server parses files (.shtml) for commands • <!--#include file="/path/to/file.txt" --> • <!--#include virtual="menu.cgi" —> • <!--#if expr="${SomeBoolean}" --> … <!--#endif -->
- 10. ;
- 12. Drupal Theming & Page Assembly • User makes request for a Web page “/node/123” • Drupal bootstrap process begins, callback function executed, hooks invoked, etc. • Content is dynamically rendered to HTML via theme functions * • HTML document is delivered to the user * Ignore cache and other steps for now
- 13. How the page is ultimately generated, it matters not to the Web browser requesting the page. In the end, it will receive HTML that it will parse, and make requests for additional elements (images, CSS files, JavaScript files, etc.) and deliver the final presentation to the end user.
- 14. How the page is ultimately generated, it matters not to the Web browser requesting the page. In the end, it will receive HTML that it will parse, and make requests for additional elements (images, CSS files, JavaScript files, etc.) and deliver the final presentation to the end user. ! What the browser displays may be different than the HTML it receives. i.e., JavaScript may hide content or make additional requests for more things to display.
- 15. Why is Drupal not my Web site?
- 16. A Typical Drupal Implementation • Nodes contain articles, stories, blog posts, etc. • Blocks provide ancillary content that can be repeated • Views lists pages of related or similar content • Panels allows the arrangement of content pieces • Theme provides design and user experience
- 17. So Drupal is my Web site? With this simple implementation, what Drupal generates and the HTML documents the user receives are essentially the same. ! ! 2 + 2 = 4 and 2 + x* = 4 are also essentially the same. * Where x = 2
- 19. Document delivery costs • Static HTML costs (practically) nothing, file I/O; difficult to maintain (even with a CMS) • SSI is largely file I/O and somewhat CPU intensive • PHP code execution is memory intensive and CPU bound • MySQL uses CPU, memory, and I/O heavily • Resources limit the number of simultaneous users (traffic)
- 20. PHP execution is costly Having the Web server invoke PHP, and having PHP retrieve content and render a full HTML document on every page request is resource intensive. ! Drupal employs a number of caching systems and optimization to reduce server stress.
- 22. Scaling Drupal To be able to handle traffic, introduce multiple Web servers that all serve Drupal’s content. ! Employ various caching schemes in front and behind Drupal.
- 24. Drupal is the back-end When behind Varnish or a CDN, the (unauthenticated) Web user does not interact with Drupal directly*. The request is handled by delivering content from cache, returning the same HTML document sent to any other user requesting the same path. Drupal does not and cannot return something different since the request is not sent to Drupal. * Assuming cache is already primed
- 25. Fragmentation
- 26. Drupal and Fragmentation Drupal is already doing enough. It doesn’t need to do additional processing to fetch content and ingest it. Offload some of the work to other services. It’s OK to decentralize. ! Use 3rd-party services because that’s where the content originates. ! Sometimes Drupal isn’t the best thing to handle all of your content
- 27. Assembling Fragments • Client-side Javascript • AJAX • WebSockets • Varnish/CDN Edge-Side Includes • Include content into a Varnish-cached page
- 29. Typical 3rd-Party Content • User comments (Facebook, Disqus, LiveFyre) • Twitter • Real-time scores or standings • Web pages hosted on legacy systems • Breaking news alerts • Analytics
- 31. Externally Hosted Comments Most commenting systems provide code (HTML, JavaScript, etc.) that can be placed on the page. ! Simply adding code and simple references to the parent page are all that is needed. Drupal is otherwise unaware of that content.
- 32. Implementing Real-Time Updates • WebSocket specification • WebSocket JavaScript Interface • Socket.IO — Node.js project • JavaScript framework and WebSocket API with long polling • Jetty — Java servlets and HTTP server
- 33. Live Scoring & Real-Time Updates
- 34. Socket.io <script src="/socket.io/socket.io.js"></script> <script> var socket = io.connect('http://localhost'); socket.on('scores', function (data) { console.log(data); socket.emit('score event', { my: 'data' }); }); </script>
- 35. Live Scoring & Real-Time Updates • The node template places a placeholder with a token for the score block • Browser makes asynchronous HTTP request to the scoring server, establishing a web socket between server and client • Score changes are pushed to browser without polling or updating the page • Drupal is unaware of the content of that placeholder
- 36. Edge-Side Includes Varnish and many CDNs established the ESI specification. ! Allows for fragments of content to reside elsewhere and be assembled on the Edge. ! Allows for mixing of unauthenticated (cached) content with authenticated elements (i.e., “Welcome user”).
- 37. ESI Fragments • Register a menu callback in Drupal to generate content with an abbreviated callback • /esi/user/welcome/f1667cc8f3f9f55a • <esi:include src=“/path/to/callback”/> • <esi:include src="http://example.com/some/path"/>
- 39. Authenticated/Unauthenticated • Authenticated traffic bypasses much of the caching layer • Use ESI to provide customized service on an otherwise unauthenticated, cached page • An unauthenticated page is heavily cached; ESI provides the customization users are used to seeing
- 40. Drupal Modules and Resources • drupal.org/project/cdn • drupal.org/project/esi • socket.io • www.varnish-cache.org/docs/3.0/tutorial/esi.html • www.akamai.com/html/support/esi.html
- 41. Questions?
- 42. Software Architect Email: [email protected] Tobby Hagler Twitter: @thagler Drupal.org: tobby