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<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="content-type" content="text/html;charset=UTF-8" />
<meta http-equiv="X-UA-Compatible" content="chrome=1">
<title>Jammit: Industrial Strength Asset Packaging for Rails</title>
<style>
body {
font-size: 16px;
line-height: 24px;
background: #fafcff;
color: #192535;
font-family: Arial;
font-family: "Palatino Linotype", "Book Antiqua", Palatino, FreeSerif, serif;
}
div.container {
width: 720px;
margin: 50px 0 50px 50px;
}
p, li {
margin: 16px 0 16px 0;
width: 550px;
}
a, a:visited {
padding: 0 2px;
text-decoration: none;
background: #cadaea;
color: #192535;
}
a:active, a:hover {
color: #000;
background: #bacada;
}
h1, h2, h3, h4, h5, h6 {
margin-top: 40px;
}
b.header {
font-size: 18px;
}
span.alias {
font-size: 14px;
font-style: italic;
margin-left: 20px;
}
table {
margin: 16px 0; padding: 0;
}
tr, td {
margin: 0; padding: 0;
}
td {
padding: 9px 15px 9px 0;
}
td.definition {
line-height: 18px;
font-size: 14px;
}
code, pre, tt {
font-family: Monaco, Consolas, "Lucida Console", monospace;
font-size: 12px;
line-height: 18px;
color: #294555;
}
code {
margin-left: 20px;
}
pre {
font-size: 12px;
padding: 2px 0 2px 12px;
border-left: 6px solid #99aabb;
margin: 0px 0 30px;
}
#diagram {
margin: 20px 0 0 0;
}
</style>
</head>
<body>
<div class="container">
<p>
<img src="http://jashkenas.s3.amazonaws.com/images/jammit/jammit.png" alt="Jammit" />
</p>
<p>
<a href="http://github.com/documentcloud/jammit/">Jammit</a> is an
industrial strength asset packaging library for <b>Rails</b>, providing
both the CSS and JavaScript concatenation and compression
that you'd expect, as well as <b>YUI Compressor</b> and <b>Closure Compiler</b>
compatibility, ahead-of-time gzipping, built-in JavaScript template
support, and optional <b>Data-URI / MHTML image and font embedding</b>.
</p>
<p>
<b>Current Version:</b> <a href="http://rubygems.org/gems/jammit/">0.5.0</a>
</p>
<p>
<i>Jammit is an open-source component of <a href="http://documentcloud.org/">DocumentCloud</a>.</i>
</p>
<h2>Table of Contents</h2>
<p style="line-height: 30px;">
<a href="#installation">Installation</a> |
<a href="#configuration">Configuration</a> |
<a href="#usage">Usage</a> |
<a href="#compressors">YUI & Closure</a> |
<a href="#precaching">Precaching Assets</a> <br />
<a href="#expires">Expires Headers</a> |
<a href="#embedding">Embedding Assets</a> |
<a href="#jst">JavaScript Templates</a> |
<a href="#changes">Changes</a>
</p>
<h2>Links</h2>
<p style="line-height: 30px;">
<a href="http://github.com/documentcloud/jammit">Source Code</a> |
<a href="http://documentcloud.github.com/jammit/doc/">Internal Docs</a> |
<a href="http://jashkenas.s3.amazonaws.com/misc/jammit_example/normal.html">Image Embedding Example</a>
</p>
<h2 id="installation">Installation</h2>
<ol>
<li>
Grab the gem:<br />
<tt>gem install jammit</tt>
</li>
<li>
Add the gem to Rails' <b>environment.rb</b> inside of the initializer:<br />
<tt>config.gem "jammit"</tt>
</li>
<li>
If you're using <b>Rails 2</b>, edit <b>config/routes.rb</b> to give Jammit a route
( <b>/assets</b> by default) for dynamic asset packaging and caching.
In <b>Rails 3</b>, this route is loaded automatically.
<br /><br />
<pre>
ActionController::Routing::Routes.draw do |map|
...
Jammit::Routes.draw(map)
...
end</pre>
</li>
</ol>
<p>
<i>Note: If you don't already have the
<a href="http://github.com/sstephenson/ruby-yui-compressor">ruby-yui-compressor</a> or
<a href="http://github.com/documentcloud/closure-compiler">closure-compiler</a>
gems installed, downloading make take a minute — the jar files together
weigh in at 5 megabytes.</i>
</p>
<h2 id="configuration">Configuration</h2>
<p>
Jammit uses the <b>config/assets.yml</b> YAML configuration file to define
packages and to set extra options. A package is an ordered set of directory glob
rules that will be expanded into a unique list of files. An example of
a complete <b>assets.yml</b> follows:
</p>
<pre>
embed_assets: on
javascripts:
workspace:
- public/javascripts/vendor/jquery.js
- public/javascripts/lib/*.js
- public/javascripts/views/**/*.js
- app/views/workspace/*.jst
stylesheets:
common:
- public/stylesheets/reset.css
- public/stylesheets/widgets/*.css
workspace:
- public/stylesheets/pages/workspace.css
empty:
- public/stylesheets/pages/empty.css</pre>
<p>
There are a number of extra configuration options that you may add to the
<b>assets.yml</b> configuration file to customize the way Jammit behaves.
Here's an <a href="http://gist.github.com/237848">example configuration file</a>
using all of the possible options. The meaning of the options and their
default values are listed below. Don't be bewildered by the length of the
list — none of the options are required, they just give you fine-grained
control over how your packages are generated.
</p>
<table>
<tr>
<td><b>package_assets</b></td>
<td><tt>on | off | always</tt></td>
<td class="definition">
Defaults to <b>on</b>, packaging and caching assets in every environment but development.
Never packages when <b>off</b>, always packages when <b>always</b>.
</td>
</tr>
<tr>
<td><b>embed_assets</b></td>
<td><tt>on | off | datauri</tt></td>
<td class="definition">
Defaults to <b>off</b>. When <b>on</b>, packages and caches Data-URI
and MTHML variants of your stylesheets, with whitelisted images
embedded inline. Using <b>datauri</b> serves embedded images only
to browsers that support Data-URIs, and serves unmodified stylesheets
to Internet Explorer 7 or lower.
</td>
</tr>
<tr>
<td><b>compress_assets</b></td>
<td><tt>on | off</tt></td>
<td class="definition">
Defaults to <b>on</b>. When <b>off</b>, JavaScript and CSS packages
will be left uncompressed (by YUI or Closure). Disabling compression is only recommended
if you're packaging assets in development.
</td>
</tr>
<tr>
<td><b>gzip_assets</b></td>
<td><tt>on | off</tt></td>
<td class="definition">
Defaults to <b>on</b>. When <b>off</b>, only the plain version of the
asset will be written out, not the <tt>.gz</tt> alternative. Disable this
if you don't plan on configuring your webserver to serve the static
gzip alternatives.
</td>
</tr>
<tr>
<td><b>javascript_compressor</b></td>
<td><tt>yui | closure</tt></td>
<td class="definition">
Defaults to <b>yui</b>. As of <b>0.2.0</b>, the Jammit gem can use either the
<a href="http://developer.yahoo.com/yui/compressor/">YUI Compressor</a>
or the
<a href="http://code.google.com/closure/compiler/">Google Closure Compiler</a>
to compress your JavaScript.
</td>
</tr>
<tr>
<td><b>template_function</b></td>
<td><tt>on | off | ...</tt></td>
<td class="definition">
The JavaScript function that compiles your JavaScript templates (<b>JST</b>).
Defaults to <b>on</b>, which uses a bundled variant of
<a href="http://ejohn.org/blog/javascript-micro-templating/">Micro-Templating</a>.
Set it to <b>_.template</b> if you use
<a href="http://documentcloud.github.com/underscore/">Underscore.js</a>,
or <b>new Template</b> for
<a href="http://www.prototypejs.org/">Prototype</a>. Turn it <b>off</b>
to pass through the template strings unaltered.
</td>
</tr>
<tr>
<td><b>template_namespace</b></td>
<td><tt>...</tt></td>
<td class="definition">
By default, all of your compiled templates will be added to a top-level
<b>window.JST</b> object. If you'd like to add them instead to your
own JavaScript namespace, change it to the
object of your choice.
</td>
</tr>
<tr>
<td><b>template_extension</b></td>
<td><tt>...</tt></td>
<td class="definition">
By default, Jammit treats files with a <tt>jst</tt> extension as
JavaScript templates. If you'd prefer to use a different extension, like
<tt>html.mustache</tt>, set the <b>template_extension</b> option.
</td>
</tr>
<tr>
<td><b>package_path</b></td>
<td><tt>...</tt></td>
<td class="definition">
The URL at which packaged assets are cached and made available.
Defaults to <b>assets</b>, but if you already have an existing
AssetsController with a different purpose, you could change it to, say,
<b>packages</b>. <i>(Single directory names only, please.)</i>
</td>
</tr>
<tr>
<td><b>compressor_options</b></td>
<td><tt>...</tt></td>
<td class="definition">
Pass an options hash directly to the underlying JavaScript compressor
to configure it. See the
<a href="http://github.com/sstephenson/ruby-yui-compressor">ruby-yui-compressor</a> or
<a href="http://github.com/documentcloud/closure-compiler">closure-compiler</a>
gem documentation for the full list of available options.
</td>
</tr>
<tr>
<td><b>css_compressor_options</b></td>
<td><tt>...</tt></td>
<td class="definition">
Pass an options hash directly to the YUI CSS Compressor.
<a href="http://yui.rubyforge.org/classes/YUI/CssCompressor.html">Available options</a>
are <b>charset</b>, and <b>line_break</b>, which can be used to write
out each CSS rule on a separate line.
</td>
</tr>
</table>
<p>
The contents of <tt>assets.yml</tt> are passed through <b>ERB</b> before
being loaded, in case you find the need to configure Jammit
for different environments.
</p>
<h2 id="usage">Usage</h2>
<p>
To access your packages in views, use the corresponding helper. The
helper methods can include multiple packages at once:
</p>
<pre>
<%= include_stylesheets :common, :workspace, :media => 'all' %>
<%= include_javascripts :workspace %></pre>
<p>
In development, no packaging is performed, so you'll see a list of individual
references to all of the JavaScript and CSS files. The <b>assets.yml</b>
configuration file is reloaded on every development request, so you can
change the contents of your packages without needing to restart Rails.
In all other environments, or if <b>package_assets</b> is set to "<b>always</b>",
you'll get tags for the merged packages.
</p>
<p>
It's recommended to keep the default behavior of unpackaged assets in
development, because it's so much easier to debug JavaScript that way.
But if you'd like to use fully packaged assets in development, while only rebuilding the packages whose
sources have changed between requests, use "<b>always</b>" and add the following
<b>before_filter</b> to your <b>ApplicationController</b> to keep your
packages fresh:
</p>
<pre>before_filter { Jammit.packager.precache_all } if Rails.env.development?</pre>
<h2 id="compressors">YUI & Closure</h2>
<p>
Jammit can be configured to use either the
<a href="http://developer.yahoo.com/yui/compressor/">YUI Compressor</a> or the
<a href="http://code.google.com/closure/compiler/">Google Closure Compiler</a>
to compress and optimize your JavaScript. (CSS is always run through the
YUI Compressor.) Specify the <b>javascript_compressor</b> to choose either <b>yui</b>
or <b>closure</b> backends. If left blank, Jammit defaults to <b>yui</b>.
</p>
<p>
You can configure the JavaScript compilation by adding <b>compressor_options</b>
to your <b>assets.yml</b>. The <b>compressor_options</b>
will be passed directly to the Gem backend of your chosen compressor. See the
<a href="http://github.com/sstephenson/ruby-yui-compressor">ruby-yui-compressor</a> or
<a href="http://github.com/documentcloud/closure-compiler">closure-compiler</a>
gem documentation for all the available options. For example, to configure
the Closure Compiler to use its
<a href="http://code.google.com/closure/compiler/docs/compilation_levels.html">advanced optimizations</a>,
you would add the <b>compilation_level</b>:
</p>
<pre>
javascript_compressor: closure
compressor_options:
compilation_level: "ADVANCED_OPTIMIZATIONS"
</pre>
<p>
Jammit always uses the YUI CSS Compressor to compress CSS files. You can
<a href="http://yui.rubyforge.org/classes/YUI/CssCompressor.html">configure it</a>
by specifying the <b>css_compressor_options</b>, in <b>assets.yml</b>.
</p>
<p>
<i>
<b>Warning:</b> Google's Closure Compiler has been known to choke on certain
already pre-compressed JavaScripts, such as the production version of jQuery.
Using the uncompressed development version is recommended.
</i>
</p>
<h2 id="precaching">Precaching Assets</h2>
<p>
Installing the Jammit gem provides the optional but handy <tt>jammit</tt> command-line utility,
which can be hooked into your deployment process. The <tt>jammit</tt>
command reads in your configuration file, generates all of the defined
packages, and gzips them at the highest compression setting. In order to
serve these static gzipped versions, configure your <b>Nginx</b>
<a href="http://wiki.nginx.org/NginxHttpGzipStaticModule">http_gzip_static_module</a>,
or your <b>Apache</b>
<a href="http://httpd.apache.org/docs/2.0/content-negotiation.html">Content Negotiation MultiViews</a>.
It's also a good idea to have gzip compression turned on for the remainder
of your static assets, including any asset packages that aren't gzipped-in-advance.
Adding <b>Nginx</b>'s
<a href="http://wiki.nginx.org/NginxHttpGzipModule">http_gzip_module</a>
or <b>Apache</b>'s
<a href="http://httpd.apache.org/docs/2.0/mod/mod_deflate.html">mod_deflate</a>
will do the trick.
</p>
<p>
The <tt>jammit</tt> command can be passed options to configure the
path to <b>assets.yml</b>, and the output directory in which all packages
are compiled. Run <tt>jammit --help</tt> to see all of the options. For
speedy builds, <tt>jammit</tt> will check the modification times of your packages
and source files: only the packages that have changed are rebuilt. If you'd
like to force all packages to build, use <tt>jammit --force</tt>.
</p>
<p>
In production, you'll want to run Jammit during deployment, somewhere
in between updating the source and symlinking to the new release. Whether you're
using <a href="http://www.capify.org/index.php/Capistrano">Capistrano</a>,
<a href="http://rubyhitsquad.com/Vlad_the_Deployer.html">Vlad</a>,
or just good 'ol <a href="http://rake.rubyforge.org/">Rake</a>,
it shouldn't be too hard to add a step that calls the <tt>jammit</tt> command.
For an example Jammit setup under Capistrano and Apache, see
<a href="http://afreshcup.com/home/2010/1/18/notes-on-using-jammit-with-rails.html">Mike Gunderloy's blog post</a>.
</p>
<h2 id="expires">Expires Headers</h2>
<p>
To get the fastest page load times for your regular visitors, it's recommended
to set the HTTP Expires header to a date far in the future. You don't need
to worry about clearing the cached assets when you deploy a new release,
because Rails will write out the asset's modification time as part of the URL,
causing browsers to fetch a fresh copy of the asset.
</p>
<p>
If you're using an <b>Nginx</b> webserver, add the following snippet to the
<br /><tt>server { ... }</tt> block for your application:
</p>
<pre>
location ~ ^/assets/ {
passenger_enabled on;
expires max;
}</pre>
<p>
If you're using <b>Apache</b>, make sure that
<a href="http://httpd.apache.org/docs/1.3/mod/mod_expires.html">mod_expires</a>
is enabled, and then add the following snippet to the
appropriate <b>VirtualHost</b> section of your configuration,
filling in the path to your deployed application:
</p>
<pre>
ExpiresActive On
<Directory "/path/to/public/assets">
ExpiresDefault "access plus 1 year"
</Directory></pre>
<p>
If for any reason (multiple physical servers, rsync-only deploys) you don't
wish to rely on modification times for cache expiry, Jammit uses the
standard Rails helpers to generate URLs, and will respect
the <tt>RAILS_ASSET_ID</tt> environment variable.
</p>
<h2 id="embedding">Embedding Images ...</h2>
<p>
After you've finished concatenating and compressing your JavaScript and
CSS files into streamlined downloads, the slowest part of your page load
is probably the images. It's common to use image sprites to avoid the
avalanche of HTTP requests that are needed to load a bunch of small images.
Unfortunately, image sprites can be complicated to position (especially
with horizontal and vertical tiling), and a real pain to create and
maintain. With a little elbow grease from Jammit, your spriting woes can be a
thing of the past.
</p>
<p>
With <b>embed_assets</b> turned on, Jammit will inline image files directly
into your compiled CSS, using
<a href="http://en.wikipedia.org/wiki/Data_URI_scheme">Data-URIs</a> in
supported browsers, and
<a href="http://en.wikipedia.org/wiki/Mhtml">MHTML</a> in Internet Explorer 7 and below.
Instead of ten CSS files referencing 30 images, you can have a single,
packaged, minified, gzipped CSS file, with the images coming in all at
once instead of piecemeal, making just a single HTTP request.
</p>
<p>
Take a look at this example (especially on a slow connection or wifi):<br />
<a href="http://jashkenas.s3.amazonaws.com/misc/jammit_example/normal.html">Normal Image Loading</a> vs.
<a href="http://jashkenas.s3.amazonaws.com/misc/jammit_example/jammit.html">Jammit Image Embedding</a><br />
</p>
<p>
Embedded images can be a little tricky, which is why using them is strictly
on an opt-in basis. After enabling <b>embed_assets</b> in the configuration file,
you'll need to whitelist the images that you'd like to make embeddable.
When processing CSS, Jammit will only embed images that have
<b>.../embed/...</b> somewhere in their path — the other images will be
left untouched. You can make a single <b>public/images/embed</b> folder for
your embedded images, or organize them into directories however you
prefer. It's not recommended to embed all of your site's images, just
the ones that conform to the following three rules:
</p>
<ol>
<li>
<b>Images that are small.</b> Large images will simply delay the rendering
of your CSS. Jammit won't embed images larger than <b>32 kilobytes</b>, because
Internet Explorer 8 won't render them.
</li>
<li>
<b>Images that are immediately visible.</b> It's better to leave the
images that are hidden at page load time to download in the background.
</li>
<li>
<b>Images that are referenced by a single CSS rule.</b> Referencing the
same embedded image in multiple rules will cause that image's contents to be
embedded more than once, defeating the purpose. Replace the duplicated
rules with an image-specific HTML class, and you're good to go.
</li>
</ol>
<p>
A final <b>cautionary note</b>. Internet Explorer's implementation of MHTML
requires the use of absolute paths in image references. This means that
the timestamp that Rails appends to the stylesheet URL (to allow
far-future expires headers) needs to also be in the contents of the
stylesheet. If a process on your webserver changes the modification time
of the cached MHTML stylesheet, it will break the image references. To fix
it, use the <tt>jammit</tt> command (with <tt>--base-url</tt>) to rebuild your assets, or simply delete
the cached file, and let Jammit automatically rebuild the file on the next
request.
</p>
<p>
If the MHTML stylesheets sound too fragile, or if you encounter any problems
with them in Internet Explorer (such as mixed-mode warnings when serving
MHTML through SSL), we recommend setting <b>embed_assets</b> to "<b>datauri</b>".
Using "<b>datauri</b>" will cause Internet Explorer 7 and below to receive
plain versions of the packaged stylesheets, while all other browsers get the
Data-URI flavor.
</p>
<h3>... and Embedding Fonts</h3>
<p>
Embedded fonts work in largely the same way as images, <b>TTF</b> and <b>OTF</b> files
that are whitelisted within an "embed" folder will be inlined as Data-URIs.
There is no MHTML variant for fonts, because Internet Explorer only supports
unembeddable <b>EOT</b> files. Embedding is especially important
for fonts in general, because it helps avoid
<a href="http://paulirish.com/2009/fighting-the-font-face-fout/">the flash of unstyled text</a>
that the browser would otherwise display while waiting for the font to
download. If you're looking to get started with web fonts,
<a href="http://www.fontsquirrel.com/fontface/generator">FontSquirrel has a great tool</a>
that can generate the proper fonts and styles you'll need. Here's an example
of a CSS rule that would activate the proper Jammit embedding:
</p>
<pre>
@font-face {
font-family: 'DroidSans';
src: url(/fonts/DroidSans.eot);
src: local('Droid Sans'), local('DroidSans'), url(/fonts/embed/DroidSans.ttf) format('truetype');
}</pre>
<h2 id="jst">JavaScript Templates</h2>
<p>
If you're using enough JavaScript to want it compressed and concatenated,
you're probably using it to generate at least a little of your
HTML. Traditionally, this has been accomplished by joining together strings
and inserting them into the DOM. A far more agreeable way to generate HTML
on the client is to use JavaScript templates (referred to here as <b>JST</b>).
</p>
<p>
Jammit helps keep your JavaScript views organized alongside your Rails
views, bundling them together into packages, and providing them pre-compiled
for your client-side code to evaluate. If left unspecified, Jammit uses a variant of
<a href="http://ejohn.org/blog/javascript-micro-templating/">John Resig's Micro Templating</a>
to compile the templates, but you can choose your preferred JavaScript templating engine
of your choosing by setting the <b>template_function</b> in <b>assets.yml</b>.
Jammit will run all of your templates through the function, and assign
each one by filename to a top-level <b>JST</b> object. For example, the following
template, <b>app/views/drivers/license.jst</b>:
</p>
<pre>
<div class="drivers-license">
<h2>Name: <%= name %></h2>
<em>Hometown: <%= birthplace %></em>
<div class="biography">
<%= bio %>
</div>
</div></pre>
<p>
Including this template within a JavaScript asset package makes it
available within the browser as the <b>JST.license</b> function.
</p>
<pre>
JST.license({name : "Moe", birthplace : "Brooklyn", bio : "Moe was always..."});</pre>
<p>
Since <b>0.5.0</b>, templates should be included in the appropriate
<tt>javascripts</tt> package. Here's an example of an <tt>assets.yml</tt>
that uses templates, and shows the location at which they'll be available
on the client. When including templates from different directories, the
common prefix is ignored, and the rest of the path becomes the name of the
template:
</p>
<pre>
javascripts:
workspace:
- app/views/accounts/badge.jst
- app/views/common/dialog.jst
- app/views/common/menu.jst</pre>
<p>
Then, from your JavaScript:
</p>
<pre>
JST['accounts/badge']
JST['common/dialog']
JST['common/menu']</pre>
<p>
To use <a href="http://documentcloud.github.com/underscore/">Underscore.js</a>
templates, set <b>template_function</b> to "<b>_.template</b>".<br />
To use <a href="http://www.prototypejs.org/">Prototype</a> templates, set
it to "<b>new Template</b>".<br />To use
<a href="http://github.com/janl/mustache.js">Mustache.js</a> templates,
you'll need
<a href="http://gist.github.com/234982">a little extra setup</a>.
</p>
<p>
The default extension for template files is <tt>jst</tt>,
but you can set <b>template_extension</b> in your <tt>assets.yml</tt> if you're
using an engine with a preferred extension, such as <tt>html.mustache</tt>
</p>
<h2 id="changes">Change Log</h2>
<p>
<b class="header">0.5.0</b><br />
The Jammit gem is now compatible with Rails 3. JST template packages are
no longer specified separately. This is a backwards-incompatible change,
and you'll have to update your <tt>assets.yml</tt> file to simply include
the JST in your existing JavaScript packages, as shown above. Alongside
this change, template names are now better namespaced — see the
section on <b>JavaScript Templates</b> for the details.
Bugfix for IE8 and Data-URIs slightly under 32kb in size, as well as
for MHTML in IE7-mode in Vista.
</p>
<p>
<b class="header">0.4.4</b><br />
Jammit will now add the <tt>RAILS_ASSET_ID</tt> timestamp to image URLs
within your CSS packages, if configured, for better cache-busting.
<a href="http://github.com/ghazel/">Greg Hazel</a> contributed a series
of Jammit/Windows bug fixes.
</p>
<p>
<b class="header">0.4.3</b><br />
Bugfix for building on Windows with drive-letter absolute paths.
</p>
<p>
<b class="header">0.4.2</b><br />
Added a logged warning when you have rules in <b>assets.yml</b> that don't
match any files.
</p>
<p>
<b class="header">0.4.1</b><br />
Jammit is now able to embed <tt>@font-face</tt> web fonts in <b>TTF</b> and
<b>OTF</b> formats. The <b>embed_images</b> option has been renamed to
<b>embed_assets</b> for this change. The <b>assets.yml</b> file is now
passed through ERB before being loaded, so you can configure
environment-specific settings, just like you would with <b>database.yml</b>.
</p>
<p>
<b class="header">0.3.3</b><br />
Added <tt>css_compressor_options</tt> to assets.yml, so you can
set <tt>charset</tt> and <tt>line_break</tt> for the YUI CSS Compressor.
</p>
<p>
<b class="header">0.3.2</b><br />
If Java isn't available on your machine, Jammit will now run in a graceful
degraded mode, where assets are packaged but not compressed. You can now
pass <tt>:embed_assets => false</tt> to the <tt>include_stylesheets</tt>
helper to disable image embedding on a per-package basis.
</p>
<p>
<b class="header">0.2.8</b><br />
Jammit now correctly rewrites relative image URLs within CSS, for easier
integration with partial Rails apps deployed on sub-paths.
</p>
<p>
<b class="header">0.2.7</b><br />
The <tt>jammit</tt> command has been enhanced to check the modification times of
your packages — if no source files have changed, the package isn't
rebuilt.
</p>
<p>
<b class="header">0.2.6</b><br />
Jammit now raises an exception if Java isn't installed, or if the Java
version is unsupported by your JavaScript compressor of choice.
</p>
<p>
<b class="header">0.2.5</b><br />
When specifying your asset packages as directory globs, absolute globs are
now absolute, and relative globs are relative to RAILS_ROOT.
</p>
<p>
<b class="header">0.2.4</b><br />
Jammit now throws a <tt>ConfigurationNotFound</tt> error when attempting to load
a nonexistent configuration file. Resolved an issue with asset caching from
daemonized mongrels.
</p>
<p>
<b class="header">0.2.1</b><br />
The <tt>include_stylesheets</tt> helper now takes the same options as the
Rails <tt>stylesheet_link_tag</tt> helper (such as <tt>:media => 'print'</tt>).
</p>
<p>
<b class="header">0.2.0</b><br />
Jammit now supports the <b>Google Closure Compiler</b> as an alternative
to the YUI compressor.
</p>
<p>
<b class="header">0.1.3</b><br />
Fixed a bug that conflicted with other plugins trying to alter
ApplicationController in development.
</p>
<p>
<b class="header">0.1.1</b><br />
Added support for embedding images with stylesheet-relative paths.
Shortened the MHTML identifiers.
</p>
<p>
<b class="header">0.1.0</b><br />
Initial Jammit release.
</p>
<p>
<br />
<a href="http://documentcloud.org/" title="A DocumentCloud Project" style="background:none;">
<img src="http://jashkenas.s3.amazonaws.com/images/a_documentcloud_project.png" alt="A DocumentCloud Project" style="position:relative;left:-10px;" />
</a>
</p>
</div>
</div>
</body>
</html>