diff options
Diffstat (limited to 'guides/source/asset_pipeline.textile')
| -rw-r--r-- | guides/source/asset_pipeline.textile | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/guides/source/asset_pipeline.textile b/guides/source/asset_pipeline.textile index 464788f30f..010154f1d1 100644 --- a/guides/source/asset_pipeline.textile +++ b/guides/source/asset_pipeline.textile @@ -204,6 +204,8 @@ Images can also be organized into subdirectories if required, and they can be ac <%= image_tag "icons/rails.png" %> </erb> +WARNING: If you're precompiling your assets (see "In Production":#in-production below), linking to an asset that does not exist will raise an exception in the calling page. This includes linking to a blank string. As such, be careful using <tt>image_tag</tt> and the other helpers with user-supplied data. + h5. CSS and ERB The asset pipeline automatically evaluates ERB. This means that if you add an +erb+ extension to a CSS asset (for example, +application.css.erb+), then helpers like +asset_path+ are available in your CSS rules: @@ -328,9 +330,9 @@ This manifest +app/assets/javascripts/application.js+: would generate this HTML: <html> -<script src="/assets/core.js?body=1" type="text/javascript"></script> -<script src="/assets/projects.js?body=1" type="text/javascript"></script> -<script src="/assets/tickets.js?body=1" type="text/javascript"></script> +<script src="/assets/core.js?body=1"></script> +<script src="/assets/projects.js?body=1"></script> +<script src="/assets/tickets.js?body=1"></script> </html> The +body+ param is required by Sprockets. @@ -346,7 +348,7 @@ config.assets.debug = false When debug mode is off, Sprockets concatenates and runs the necessary preprocessors on all files. With debug mode turned off the manifest above would generate instead: <html> -<script src="/assets/application.js" type="text/javascript"></script> +<script src="/assets/application.js"></script> </html> Assets are compiled and cached on the first request after the server is started. Sprockets sets a +must-revalidate+ Cache-Control HTTP header to reduce request overhead on subsequent requests -- on these the browser gets a 304 (Not Modified) response. @@ -380,8 +382,8 @@ For example this: generates something like this: <html> -<script src="/assets/application-908e25f4bf641868d8683022a5b62f54.js" type="text/javascript"></script> -<link href="/assets/application-4dd5b109ee3439da54f5bdfd78a80473.css" media="screen" rel="stylesheet" type="text/css" /> +<script src="/assets/application-908e25f4bf641868d8683022a5b62f54.js"></script> +<link href="/assets/application-4dd5b109ee3439da54f5bdfd78a80473.css" media="screen" rel="stylesheet" /> </html> The fingerprinting behavior is controlled by the setting of +config.assets.digest+ setting in Rails (which defaults to +true+ for production and +false+ for everything else). @@ -409,9 +411,9 @@ cannot see application objects or methods. *Heroku requires this to be false.* WARNING: If you set +config.assets.initialize_on_precompile+ to false, be sure to test +rake assets:precompile+ locally before deploying. It may expose bugs where your assets reference application objects or methods, since those are still -in scope in development mode regardless of the value of this flag. Changing this flag also effects +in scope in development mode regardless of the value of this flag. Changing this flag also affects engines. Engines can define assets for precompilation as well. Since the complete environment is not loaded, -engines (or other gems) will not be loaded which can cause missing assets. +engines (or other gems) will not be loaded, which can cause missing assets. Capistrano (v2.8.0 and above) includes a recipe to handle this in deployment. Add the following line to +Capfile+: |