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Diffstat (limited to 'guides/source/asset_pipeline.md')
| -rw-r--r-- | guides/source/asset_pipeline.md | 386 |
1 files changed, 295 insertions, 91 deletions
diff --git a/guides/source/asset_pipeline.md b/guides/source/asset_pipeline.md index bce5d6c55f..52ea605a72 100644 --- a/guides/source/asset_pipeline.md +++ b/guides/source/asset_pipeline.md @@ -1,3 +1,5 @@ +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.** + The Asset Pipeline ================== @@ -56,11 +58,11 @@ the comment operator on that line to later enable the asset pipeline: To set asset compression methods, set the appropriate configuration options in `production.rb` - `config.assets.css_compressor` for your CSS and -`config.assets.js_compressor` for your Javascript: +`config.assets.js_compressor` for your JavaScript: ```ruby config.assets.css_compressor = :yui -config.assets.js_compressor = :uglify +config.assets.js_compressor = :uglifier ``` NOTE: The `sass-rails` gem is automatically used for CSS compression if included @@ -124,19 +126,22 @@ with a built-in helper. In the source the generated code looked like this: The query string strategy has several disadvantages: 1. **Not all caches will reliably cache content where the filename only differs by -query parameters**<br> +query parameters** + [Steve Souders recommends](http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/), "...avoiding a querystring for cacheable resources". He found that in this case 5-20% of requests will not be cached. Query strings in particular do not work at all with some CDNs for cache invalidation. -2. **The file name can change between nodes in multi-server environments.**<br> +2. **The file name can change between nodes in multi-server environments.** + The default query string in Rails 2.x is based on the modification time of the files. When assets are deployed to a cluster, there is no guarantee that the timestamps will be the same, resulting in different values being used depending on which server handles the request. -3. **Too much cache invalidation**<br> +3. **Too much cache invalidation** + When static assets are deployed with each new release of code, the mtime (time of last modification) of _all_ these files changes, forcing all remote clients to fetch them again, even when the content of those assets has not changed. @@ -144,7 +149,7 @@ clients to fetch them again, even when the content of those assets has not chang Fingerprinting fixes these problems by avoiding query strings, and by ensuring that filenames are consistent based on their content. -Fingerprinting is enabled by default for production and disabled for all other +Fingerprinting is enabled by default for both the development and production environments. You can enable or disable it in your configuration through the `config.assets.digest` option. @@ -163,9 +168,9 @@ pipeline, the preferred location for these assets is now the `app/assets` directory. Files in this directory are served by the Sprockets middleware. Assets can still be placed in the `public` hierarchy. Any assets under `public` -will be served as static files by the application or web server. You should use -`app/assets` for files that must undergo some pre-processing before they are -served. +will be served as static files by the application or web server when +`config.serve_static_files` is set to true. You should use `app/assets` for +files that must undergo some pre-processing before they are served. In production, Rails precompiles these files to `public/assets` by default. The precompiled copies are then served as static assets by the web server. The files @@ -177,12 +182,12 @@ When you generate a scaffold or a controller, Rails also generates a JavaScript file (or CoffeeScript file if the `coffee-rails` gem is in the `Gemfile`) and a Cascading Style Sheet file (or SCSS file if `sass-rails` is in the `Gemfile`) for that controller. Additionally, when generating a scaffold, Rails generates -the file scaffolds.css (or scaffolds.css.scss if `sass-rails` is in the +the file scaffolds.css (or scaffolds.scss if `sass-rails` is in the `Gemfile`.) For example, if you generate a `ProjectsController`, Rails will also add a new -file at `app/assets/javascripts/projects.js.coffee` and another at -`app/assets/stylesheets/projects.css.scss`. By default these files will be ready +file at `app/assets/javascripts/projects.coffee` and another at +`app/assets/stylesheets/projects.scss`. By default these files will be ready to use by your application immediately using the `require_tree` directive. See [Manifest Files and Directives](#manifest-files-and-directives) for more details on require_tree. @@ -198,18 +203,13 @@ will result in your assets being included more than once. WARNING: When using asset precompilation, you will need to ensure that your controller assets will be precompiled when loading them on a per page basis. By -default .coffee and .scss files will not be precompiled on their own. This will -result in false positives during development as these files will work just fine -since assets are compiled on the fly in development mode. When running in -production, however, you will see 500 errors since live compilation is turned -off by default. See [Precompiling Assets](#precompiling-assets) for more -information on how precompiling works. +default .coffee and .scss files will not be precompiled on their own. See +[Precompiling Assets](#precompiling-assets) for more information on how +precompiling works. NOTE: You must have an ExecJS supported runtime in order to use CoffeeScript. If you are using Mac OS X or Windows, you have a JavaScript runtime installed in -your operating system. Check -[ExecJS](https://github.com/sstephenson/execjs#readme) documentation to know all -supported JavaScript runtimes. +your operating system. Check [ExecJS](https://github.com/sstephenson/execjs#readme) documentation to know all supported JavaScript runtimes. You can also disable generation of controller specific asset files by adding the following to your `config/application.rb` configuration: @@ -232,7 +232,9 @@ images, JavaScript files or stylesheets. scope of the application or those libraries which are shared across applications. * `vendor/assets` is for assets that are owned by outside entities, such as -code for JavaScript plugins and CSS frameworks. +code for JavaScript plugins and CSS frameworks. Keep in mind that third party +code with references to other files also processed by the asset Pipeline (images, +stylesheets, etc.), will need to be rewritten to use helpers like `asset_path`. WARNING: If you are upgrading from Rails 3, please take into account that assets under `lib/assets` or `vendor/assets` are available for inclusion via the @@ -245,7 +247,7 @@ When a file is referenced from a manifest or a helper, Sprockets searches the three default asset locations for it. The default locations are: the `images`, `javascripts` and `stylesheets` -directories under the `apps/assets` folder, but these subdirectories +directories under the `app/assets` folder, but these subdirectories are not special - any path under `assets/*` will be searched. For example, these files: @@ -302,7 +304,7 @@ Sprockets uses files named `index` (with the relevant extensions) for a special purpose. For example, if you have a jQuery library with many modules, which is stored in -`lib/assets/library_name`, the file `lib/assets/library_name/index.js` serves as +`lib/assets/javascripts/library_name`, the file `lib/assets/javascripts/library_name/index.js` serves as the manifest for all files in this library. This file could include a list of all the required files in order, or a simple `require_tree` directive. @@ -422,7 +424,7 @@ $('#logo').attr({ src: "<%= asset_path('logo.png') %>" }); This writes the path to the particular asset being referenced. Similarly, you can use the `asset_path` helper in CoffeeScript files with `erb` -extension (e.g., `application.js.coffee.erb`): +extension (e.g., `application.coffee.erb`): ```js $('#logo').attr src: "<%= asset_path('logo.png') %>" @@ -493,19 +495,13 @@ The directives that work in JavaScript files also work in stylesheets one, requiring all stylesheets from the current directory. In this example, `require_self` is used. This puts the CSS contained within the -file (if any) at the precise location of the `require_self` call. If -`require_self` is called more than once, only the last call is respected. - -NOTE. If you want to use multiple Sass files, you should generally use the [Sass -`@import` -rule](http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html#import) instead -of these Sprockets directives. Using Sprockets directives all Sass files exist -within their own scope, making variables or mixins only available within the -document they were defined in. You can do file globbing as well using -`@import "*"`, and `@import "**/*"` to add the whole tree equivalent to how -`require_tree` works. Check the [sass-rails -documentation](https://github.com/rails/sass-rails#features) for more info and -important caveats. +file (if any) at the precise location of the `require_self` call. + +NOTE. If you want to use multiple Sass files, you should generally use the [Sass `@import` rule](http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html#import) +instead of these Sprockets directives. When using Sprockets directives, Sass files exist within +their own scope, making variables or mixins only available within the document they were defined in. + +You can do file globbing as well using `@import "*"`, and `@import "**/*"` to add the whole tree which is equivalent to how `require_tree` works. Check the [sass-rails documentation](https://github.com/rails/sass-rails#features) for more info and important caveats. You can have as many manifest files as you need. For example, the `admin.css` and `admin.js` manifest could contain the JS and CSS files that are used for the @@ -529,8 +525,8 @@ The file extensions used on an asset determine what preprocessing is applied. When a controller or a scaffold is generated with the default Rails gemset, a CoffeeScript file and a SCSS file are generated in place of a regular JavaScript and CSS file. The example used before was a controller called "projects", which -generated an `app/assets/javascripts/projects.js.coffee` and an -`app/assets/stylesheets/projects.css.scss` file. +generated an `app/assets/javascripts/projects.coffee` and an +`app/assets/stylesheets/projects.scss` file. In development mode, or if the asset pipeline is disabled, when these files are requested they are processed by the processors provided by the `coffee-script` @@ -542,13 +538,13 @@ web server. Additional layers of preprocessing can be requested by adding other extensions, where each extension is processed in a right-to-left manner. These should be used in the order the processing should be applied. For example, a stylesheet -called `app/assets/stylesheets/projects.css.scss.erb` is first processed as ERB, +called `app/assets/stylesheets/projects.scss.erb` is first processed as ERB, then SCSS, and finally served as CSS. The same applies to a JavaScript file - -`app/assets/javascripts/projects.js.coffee.erb` is processed as ERB, then +`app/assets/javascripts/projects.coffee.erb` is processed as ERB, then CoffeeScript, and served as JavaScript. Keep in mind the order of these preprocessors is important. For example, if -you called your JavaScript file `app/assets/javascripts/projects.js.erb.coffee` +you called your JavaScript file `app/assets/javascripts/projects.erb.coffee` then it would be processed with the CoffeeScript interpreter first, which wouldn't understand ERB and therefore you would run into problems. @@ -586,23 +582,21 @@ runtime. To disable this behavior you can set: config.assets.raise_runtime_errors = false ``` -When `raise_runtime_errors` is set to `false` sprockets will not check that dependencies of assets are declared properly. Here is a scenario where you must tell the asset pipeline about a dependency: - -If you have `application.css.erb` that references `logo.png` like this: +When this option is true, the asset pipeline will check if all the assets loaded +in your application are included in the `config.assets.precompile` list. +If `config.assets.digest` is also true, the asset pipeline will require that +all requests for assets include digests. -```css -#logo { background: url(<%= asset_data_uri 'logo.png' %>) } -``` +### Turning Digests Off -Then you must declare that `logo.png` is a dependency of `application.css.erb`, so when the image gets re-compiled, the css file does as well. You can do this using the `//= depend_on_asset` declaration: +You can turn off digests by updating `config/environments/development.rb` to +include: -```css -//= depend_on_asset "logo.png" -#logo { background: url(<%= asset_data_uri 'logo.png' %>) } +```ruby +config.assets.digest = false ``` -Without this declaration you may experience strange behavior when pushing to production that is difficult to debug. When you have `raise_runtime_errors` set to `true`, dependencies will be checked at runtime so you can ensure that all dependencies are met. - +When this option is true, digests will be generated for asset URLs. ### Turning Debugging Off @@ -696,7 +690,7 @@ information on compiling locally. The rake task is: ```bash -$ RAILS_ENV=production bundle exec rake assets:precompile +$ RAILS_ENV=production bin/rake assets:precompile ``` Capistrano (v2.15.1 and above) includes a recipe to handle this in deployment. @@ -719,7 +713,7 @@ The default matcher for compiling files includes `application.js`, automatically) from `app/assets` folders including your gems: ```ruby -[ Proc.new { |path, fn| fn =~ /app\/assets/ && !%w(.js .css).include?(File.extname(path)) }, +[ Proc.new { |filename, path| path =~ /app\/assets/ && !%w(.js .css).include?(File.extname(filename)) }, /application.(css|js)$/ ] ``` @@ -729,25 +723,25 @@ JS/CSS is excluded, as well as raw JS/CSS files; for example, `.coffee` and `.scss` files are **not** automatically included as they compile to JS/CSS. If you have other manifests or individual stylesheets and JavaScript files to -include, you can add them to the `precompile` array in `config/application.rb`: +include, you can add them to the `precompile` array in `config/initializers/assets.rb`: ```ruby -config.assets.precompile += ['admin.js', 'admin.css', 'swfObject.js'] +Rails.application.config.assets.precompile += ['admin.js', 'admin.css', 'swfObject.js'] ``` Or, you can opt to precompile all assets with something like this: ```ruby -# config/application.rb -config.assets.precompile << Proc.new do |path| +# config/initializers/assets.rb +Rails.application.config.assets.precompile << Proc.new do |path| if path =~ /\.(css|js)\z/ full_path = Rails.application.assets.resolve(path).to_path app_assets_path = Rails.root.join('app', 'assets').to_path if full_path.starts_with? app_assets_path - puts "including asset: " + full_path + logger.info "including asset: " + full_path true else - puts "excluding asset: " + full_path + logger.info "excluding asset: " + full_path false end else @@ -770,7 +764,7 @@ typical manifest file looks like: "digest":"12b3c7dd74d2e9df37e7cbb1efa76a6d"},"application-1c5752789588ac18d7e1a50b1f0fd4c2.css":{"logical_path":"application.css","mtime":"2013-07-26T22:56:17-07:00","size":1591, "digest":"1c5752789588ac18d7e1a50b1f0fd4c2"},"favicon-a9c641bf2b81f0476e876f7c5e375969.ico":{"logical_path":"favicon.ico","mtime":"2013-07-26T23:00:10-07:00","size":1406, "digest":"a9c641bf2b81f0476e876f7c5e375969"},"my_image-231a680f23887d9dd70710ea5efd3c62.png":{"logical_path":"my_image.png","mtime":"2013-07-26T23:00:27-07:00","size":6646, -"digest":"231a680f23887d9dd70710ea5efd3c62"}},"assets"{"application.js": +"digest":"231a680f23887d9dd70710ea5efd3c62"}},"assets":{"application.js": "application-723d1be6cc741a3aabb1cec24276d681.js","application.css": "application-1c5752789588ac18d7e1a50b1f0fd4c2.css", "favicon.ico":"favicona9c641bf2b81f0476e876f7c5e375969.ico","my_image.png": @@ -786,7 +780,7 @@ exception indicating the name of the missing file(s). #### Far-future Expires Header -Precompiled assets exist on the filesystem and are served directly by your web +Precompiled assets exist on the file system and are served directly by your web server. They do not have far-future headers by default, so to get the benefit of fingerprinting you'll have to update your server configuration to add those headers. @@ -798,13 +792,15 @@ For Apache: # `mod_expires` to be enabled. <Location /assets/> # Use of ETag is discouraged when Last-Modified is present - Header unset ETag FileETag None + Header unset ETag + FileETag None # RFC says only cache for 1 year - ExpiresActive On ExpiresDefault "access plus 1 year" + ExpiresActive On + ExpiresDefault "access plus 1 year" </Location> ``` -For nginx: +For NGINX: ```nginx location ~ ^/assets/ { @@ -826,7 +822,7 @@ compression ratio, thus reducing the size of the data transfer to the minimum. On the other hand, web servers can be configured to serve compressed content directly from disk, rather than deflating non-compressed files themselves. -Nginx is able to do this automatically enabling `gzip_static`: +NGINX is able to do this automatically enabling `gzip_static`: ```nginx location ~ ^/(assets)/ { @@ -845,7 +841,7 @@ the module compiled. Otherwise, you may need to perform a manual compilation: ./configure --with-http_gzip_static_module ``` -If you're compiling nginx with Phusion Passenger you'll need to pass that option +If you're compiling NGINX with Phusion Passenger you'll need to pass that option when prompted. A robust configuration for Apache is possible but tricky; please Google around. @@ -864,10 +860,12 @@ duplication of work. Local compilation allows you to commit the compiled files into source control, and deploy as normal. -There are two caveats: +There are three caveats: * You must not run the Capistrano deployment task that precompiles assets. -* You must change the following two application configuration settings. +* You must ensure any necessary compressors or minifiers are +available on your development system. +* You must change the following application configuration setting: In `config/environments/development.rb`, place the following line: @@ -881,9 +879,6 @@ development mode, and pass all requests to Sprockets. The prefix is still set to would serve the precompiled assets from `/assets` in development, and you would not see any local changes until you compile assets again. -You will also need to ensure any necessary compressors or minifiers are -available on your development system. - In practice, this will allow you to precompile locally, have those files in your working tree, and commit those files to source control when needed. Development mode will work as expected. @@ -923,22 +918,213 @@ end ### CDNs -If your assets are being served by a CDN, ensure they don't stick around in your -cache forever. This can cause problems. If you use -`config.action_controller.perform_caching = true`, Rack::Cache will use -`Rails.cache` to store assets. This can cause your cache to fill up quickly. +CDN stands for [Content Delivery +Network](http://en.wikipedia.org/wiki/Content_delivery_network), they are +primarily designed to cache assets all over the world so that when a browser +requests the asset, a cached copy will be geographically close to that browser. +If you are serving assets directly from your Rails server in production, the +best practice is to use a CDN in front of your application. + +A common pattern for using a CDN is to set your production application as the +"origin" server. This means when a browser requests an asset from the CDN and +there is a cache miss, it will grab the file from your server on the fly and +then cache it. For example if you are running a Rails application on +`example.com` and have a CDN configured at `mycdnsubdomain.fictional-cdn.com`, +then when a request is made to `mycdnsubdomain.fictional- +cdn.com/assets/smile.png`, the CDN will query your server once at +`example.com/assets/smile.png` and cache the request. The next request to the +CDN that comes in to the same URL will hit the cached copy. When the CDN can +serve an asset directly the request never touches your Rails server. Since the +assets from a CDN are geographically closer to the browser, the request is +faster, and since your server doesn't need to spend time serving assets, it can +focus on serving application code as fast as possible. + +#### Set up a CDN to Serve Static Assets + +To set up your CDN you have to have your application running in production on +the internet at a publically available URL, for example `example.com`. Next +you'll need to sign up for a CDN service from a cloud hosting provider. When you +do this you need to configure the "origin" of the CDN to point back at your +website `example.com`, check your provider for documentation on configuring the +origin server. + +The CDN you provisioned should give you a custom subdomain for your application +such as `mycdnsubdomain.fictional-cdn.com` (note fictional-cdn.com is not a +valid CDN provider at the time of this writing). Now that you have configured +your CDN server, you need to tell browsers to use your CDN to grab assets +instead of your Rails server directly. You can do this by configuring Rails to +set your CDN as the asset host instead of using a relative path. To set your +asset host in Rails, you need to set `config.action_controller.asset_host` in +`config/production.rb`: -Every cache is different, so evaluate how your CDN handles caching and make sure -that it plays nicely with the pipeline. You may find quirks related to your -specific set up, you may not. The defaults nginx uses, for example, should give -you no problems when used as an HTTP cache. +```ruby +config.action_controller.asset_host = 'mycdnsubdomain.fictional-cdn.com' +``` + +NOTE: You only need to provide the "host", this is the subdomain and root +domain, you do not need to specify a protocol or "scheme" such as `http://` or +`https://`. When a web page is requested, the protocol in the link to your asset +that is generated will match how the webpage is accessed by default. + +You can also set this value through an [environment +variable](http://en.wikipedia.org/wiki/Environment_variable) to make running a +staging copy of your site easier: + +``` +config.action_controller.asset_host = ENV['CDN_HOST'] +``` + + + +Note: You would need to set `CDN_HOST` on your server to `mycdnsubdomain +.fictional-cdn.com` for this to work. + +Once you have configured your server and your CDN when you serve a webpage that +has an asset: + +```erb +<%= asset_path('smile.png') %> +``` + +Instead of returning a path such as `/assets/smile.png` (digests are left out +for readability). The URL generated will have the full path to your CDN. + +``` +http://mycdnsubdomain.fictional-cdn.com/assets/smile.png +``` + +If the CDN has a copy of `smile.png` it will serve it to the browser and your +server doesn't even know it was requested. If the CDN does not have a copy it +will try to find it a the "origin" `example.com/assets/smile.png` and then store +it for future use. + +If you want to serve only some assets from your CDN, you can use custom `:host` +option your asset helper, which overwrites value set in +`config.action_controller.asset_host`. + +```erb +<%= asset_path 'image.png', host: 'mycdnsubdomain.fictional-cdn.com' %> +``` + +#### Customize CDN Caching Behavior + +A CDN works by caching content. If the CDN has stale or bad content, then it is +hurting rather than helping your application. The purpose of this section is to +describe general caching behavior of most CDNs, your specific provider may +behave slightly differently. + +##### CDN Request Caching + +While a CDN is described as being good for caching assets, in reality caches the +entire request. This includes the body of the asset as well as any headers. The +most important one being `Cache-Control` which tells the CDN (and web browsers) +how to cache contents. This means that if someone requests an asset that does +not exist `/assets/i-dont-exist.png` and your Rails application returns a 404, +then your CDN will likely cache the 404 page if a valid `Cache-Control` header +is present. + +##### CDN Header Debugging + +One way to check the headers are cached properly in your CDN is by using [curl]( +http://explainshell.com/explain?cmd=curl+-I+http%3A%2F%2Fwww.example.com). You +can request the headers from both your server and your CDN to verify they are +the same: + +``` +$ curl -I http://www.example/assets/application- +d0e099e021c95eb0de3615fd1d8c4d83.css +HTTP/1.1 200 OK +Server: Cowboy +Date: Sun, 24 Aug 2014 20:27:50 GMT +Connection: keep-alive +Last-Modified: Thu, 08 May 2014 01:24:14 GMT +Content-Type: text/css +Cache-Control: public, max-age=2592000 +Content-Length: 126560 +Via: 1.1 vegur +``` + +Versus the CDN copy. + +``` +$ curl -I http://mycdnsubdomain.fictional-cdn.com/application- +d0e099e021c95eb0de3615fd1d8c4d83.css +HTTP/1.1 200 OK Server: Cowboy Last- +Modified: Thu, 08 May 2014 01:24:14 GMT Content-Type: text/css +Cache-Control: +public, max-age=2592000 +Via: 1.1 vegur +Content-Length: 126560 +Accept-Ranges: +bytes +Date: Sun, 24 Aug 2014 20:28:45 GMT +Via: 1.1 varnish +Age: 885814 +Connection: keep-alive +X-Served-By: cache-dfw1828-DFW +X-Cache: HIT +X-Cache-Hits: +68 +X-Timer: S1408912125.211638212,VS0,VE0 +``` + +Check your CDN documentation for any additional information they may provide +such as `X-Cache` or for any additional headers they may add. + +##### CDNs and the Cache-Control Header + +The [cache control +header](http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9) is a W3C +specification that describes how a request can be cached. When no CDN is used, a +browser will use this information to cache contents. This is very helpful for +assets that are not modified so that a browser does not need to re-download a +website's CSS or javascript on every request. Generally we want our Rails server +to tell our CDN (and browser) that the asset is "public", that means any cache +can store the request. Also we commonly want to set `max-age` which is how long +the cache will store the object before invalidating the cache. The `max-age` +value is set to seconds with a maximum possible value of `31536000` which is one +year. You can do this in your rails application by setting + +``` +config.static_cache_control = "public, max-age=31536000" +``` + +Now when your application serves an asset in production, the CDN will store the +asset for up to a year. Since most CDNs also cache headers of the request, this +`Cache-Control` will be passed along to all future browsers seeking this asset, +the browser then knows that it can store this asset for a very long time before +needing to re-request it. + +##### CDNs and URL based Cache Invalidation + +Most CDNs will cache contents of an asset based on the complete URL. This means +that a request to + +``` +http://mycdnsubdomain.fictional-cdn.com/assets/smile-123.png +``` + +Will be a completely different cache from + +``` +http://mycdnsubdomain.fictional-cdn.com/assets/smile.png +``` + +If you want to set far future `max-age` in your `Cache-Control` (and you do), +then make sure when you change your assets that your cache is invalidated. For +example when changing the smiley face in an image from yellow to blue, you want +all visitors of your site to get the new blue face. When using a CDN with the +Rails asset pipeline `config.assets.digest` is set to true by default so that +each asset will have a different file name when it is changed. This way you +don't have to ever manually invalidate any items in your cache. By using a +different unique asset name instead, your users get the latest asset. Customizing the Pipeline ------------------------ ### CSS Compression -There is currently one option for compressing CSS, YUI. The [YUI CSS +One of the options for compressing CSS is YUI. The [YUI CSS compressor](http://yui.github.io/yuicompressor/css.html) provides minification. @@ -948,6 +1134,11 @@ gem. ```ruby config.assets.css_compressor = :yui ``` +The other option for compressing CSS if you have the sass-rails gem installed is + +```ruby +config.assets.css_compressor = :sass +``` ### JavaScript Compression @@ -1018,14 +1209,15 @@ The X-Sendfile header is a directive to the web server to ignore the response from the application, and instead serve a specified file from disk. This option is off by default, but can be enabled if your server supports it. When enabled, this passes responsibility for serving the file to the web server, which is -faster. +faster. Have a look at [send_file](http://api.rubyonrails.org/classes/ActionController/DataStreaming.html#method-i-send_file) +on how to use this feature. -Apache and nginx support this option, which can be enabled in +Apache and NGINX support this option, which can be enabled in `config/environments/production.rb`: ```ruby -# config.action_dispatch.x_sendfile_header = "X-Sendfile" # for apache -# config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for nginx +# config.action_dispatch.x_sendfile_header = "X-Sendfile" # for Apache +# config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX ``` WARNING: If you are upgrading an existing application and intend to use this @@ -1033,6 +1225,10 @@ option, take care to paste this configuration option only into `production.rb` and any other environments you define with production behavior (not `application.rb`). +TIP: For further details have a look at the docs of your production web server: +- [Apache](https://tn123.org/mod_xsendfile/) +- [NGINX](http://wiki.nginx.org/XSendfile) + Assets Cache Store ------------------ @@ -1051,6 +1247,14 @@ cache store. config.assets.cache_store = :memory_store, { size: 32.megabytes } ``` +To disable the assets cache store: + +```ruby +config.assets.configure do |env| + env.cache = ActiveSupport::Cache.lookup_store(:null_store) +end +``` + Adding Assets to Your Gems -------------------------- @@ -1145,9 +1349,9 @@ config.assets.digest = true ``` Rails 4 no longer sets default config values for Sprockets in `test.rb`, so -`test.rb` now requies Sprockets configuration. The old defaults in the test -environment are: `config.assets.compile = true`, `config.assets.compress = -false`, `config.assets.debug = false` and `config.assets.digest = false`. +`test.rb` now requires Sprockets configuration. The old defaults in the test +environment are: `config.assets.compile = true`, `config.assets.compress = false`, +`config.assets.debug = false` and `config.assets.digest = false`. The following should also be added to `Gemfile`: |