Package: django-mediasync
One of the more significant development roadblocks we have relates to local vs.
deployed media. Ideally all media (graphics, css, scripts) development would
occur locally and not use production media. Then, when ready to deploy, the
media should be pushed to production. That way there can be significant changes
to media without disturbing the production web site.The goal of mediasync is to develop locally and then flip a switch in production
that makes all the media URLs point to remote media URLs instead of the local
media directory.All code is under a BSD-style license, see LICENSE for details.Source:http://github.com/sunlightlabs/django-mediasync/Requirementsdjango >= 1.0boto >= 1.8dslimmer == 0.1.30 (optional)python-cloudfiles == 1.7.5 (optional, for Rackspace Cloud Files backend)Upgrading from mediasync 1.xUpdate your mediasync settings as described in the next section.Run./manage.py syncmedia –forceto force updates of all files:gzip instead of deflate compressionsync both compressed and original versions of filesadd “django.core.context_processors.request” to TEMPLATE_CONTEXT_PROCESSORSAn important note about Django 1.3When DEBUG = True and the project is run withmanage.py runserver, Django 1.3
automatically adds django.views.static.serve to urlpatterns. While this feature
makes local development easier for most people, it screws everything up if
you’ve added mediasync.urls to urlpatterns. As of now, the only way I can find
to disable the automatic addition of django.views.static.serve is to use a full
URL for STATIC_URL instead of just a path:STATIC_URL = "http://localhost:8000/static/"Configurationsettings.pyAdd toINSTALLED_APPS:'mediasync'Add toTEMPLATE_CONTEXT_PROCESSORS:'django.core.context_processors.request'Make sure yourSTATIC_ROOTsetting is the correct path to your media:STATIC_ROOT = '/path/to/media'When media is being served locally (instead of from S3 or Cloud Files),
mediasync serves media through a Django view. Set yourSTATIC_URLto what
you’d like that local media URL to be. This can be whatever you’d like, as long
as you’re using the {% media_url %} tag (more details on this later):STATIC_URL = 'http://localhost:8000/devmedia/'STATIC_URLis the URL that will be used in debug mode. Otherwise,
theSTATIC_URLwill be loaded from the backend settings. Please seeAn important note about Django 1.3.The following settings dict must also be added:MEDIASYNC = {
    'BACKEND': 'path.to.backend',
}If you want to use a different media URL than that specified
insettings.STATIC_URL, you can addSTATIC_URLto theMEDIASYNCsettings dict:MEDIASYNC = {
    ...
    'STATIC_URL': '/url/to/media/', # becomes http://yourhost.com/url/to/media/
    ...
}Same goes forSTATIC_ROOT:MEDIASYNC = {
    ...
    'STATIC_ROOT': '/path/to/media/',
    ...
}mediasync supports pluggable backends. Please see below for information on
the provided backends as well as directions on implementing your own.Media expirationIf the client supports media expiration, all files are set to expire 365 days
after the file was synced. You may override this value by addingEXPIRATION_DAYSto the MEDIASYNC settings dict.# Expire in 10 years.
MEDIASYNC['EXPIRATION_DAYS'] = 365 * 10Serving media remote (S3/Cloud Files) or locallyThe media URL is selected based on theSERVE_REMOTEattribute in theMEDIASYNCdict in settings.py. WhenTrue, media will be served locally
instead of from S3.# This would force mediasync to serve all media through the value
# specified in settings.STATIC_URL.
MEDIASYNC['SERVE_REMOTE'] = False

# This would serve all media through S3/Cloud Files.
MEDIASYNC['SERVE_REMOTE'] = True

# This would serve media locally while in DEBUG mode, and remotely when
# in production (DEBUG == False).
MEDIASYNC['SERVE_REMOTE'] = not DEBUGWhen serving files locally, you can emulate the CSS/JS combo/minifying
behavior we get from using media processors by specifying the following.MEDIASYNC['SERVE_REMOTE'] = False
MEDIASYNC['EMULATE_COMBO'] = TrueNote that this will only work if yourSTATIC_URLis pointing at your
Django dev server. Also keep in mind that some processors may take a while,
and is best used to check things over before rolling out to production.DOCTYPElink and script tags are written using XHTML syntax. The rendering can be
overridden by using theDOCTYPEsetting. Allowed values are‘html4’,‘html5’, or‘xhtml’. The default in mediasync 2.0 is html5, just as
the DOCTYPE on your site should be.MEDIASYNC['DOCTYPE'] = 'html5'For each doctype, the following tags are rendered:html4<link rel="stylesheet" href="..." type="text/css" media="...">
<script type="text/javascript" charset="utf-8" src="..."></script>html5<link rel="stylesheet" href="..." media="...">
<script src="..."></script>xhtml<link rel="stylesheet" href="..." type="text/css" media="..." />
<script type="text/javascript" charset="utf-8" src="..."></script>SSLmediasync will attempt to intelligently determine if your media should be
served using HTTPS. In order to use automatic SSL detection,django.core.context_processors.requestmust be added toTEMPLATE_CONTEXT_PROCESSORSin settings.py:TEMPLATE_CONTEXT_PROCESSORS = (
    ...
    'django.core.context_processors.request',
    ...
)TheUSE_SSLmediasync setting can be used to override the SSL
URL detection.# Force HTTPS.
MEDIASYNC['USE_SSL'] = Trueor# Force HTTP.
MEDIASYNC['USE_SSL'] = FalseSome backends will be unable to use SSL. In these casesUSE_SSLand SSL
detection will be ignored.urls.pyTo serve local media through mediasync, add a reference to mediasync.urls in
your main urls.py file.urlpatterns = ('',
    ...
    url(r'^', include('mediasync.urls)),
    ...
)Backendsmediasync now supports pluggable backends. A backend is a Python module that
contains a Client class that implements a mediasync-provided BaseClient class.S3MEDIASYNC['BACKEND'] = 'mediasync.backends.s3'SettingsThe following settings are required in the mediasync settings dict:MEDIASYNC = {
    'AWS_KEY': "s3_key",
    'AWS_SECRET': "s3_secret",
    'AWS_BUCKET': "bucket_name",
}Optionally you may specify a path prefix:MEDIASYNC['AWS_PREFIX'] = "key_prefix"Assuming a correct DNS CNAME entry, settingAWS_BUCKETtoassets.sunlightlabs.comandAWS_PREFIXtomyproject/mediawould
sync the media directory tohttp://assets.sunlightlabs.com/myproject/media/.Amazon allows users to create DNS CNAME entries to map custom domain names
to an AWS bucket. MEDIASYNC can be configured to use the bucket as the media
URL by settingAWS_BUCKET_CNAMEtoTrue.MEDIASYNC['AWS_BUCKET_CNAME'] = TrueIf you would prefer to not use gzip compression with the S3 client, it can be
disabled:MEDIASYNC['AWS_GZIP'] = FalseTipsSince files are given a far future expires header, one needs a way to do
“cache busting” when you want the browser to fetch new files before the expire
date arrives.  One of the best and easiest ways to accomplish this is to alter
the path to the media files with some sort of version string using the key
prefix setting:MEDIASYNC['AWS_PREFIX'] = "myproject/media/v20001201"Given that and the above DNS CNAME example, the media directory URL would end
up beinghttp://assets.sunlightlabs.com/myproject/media/v20001201/.  Whenever
you need to update the media files, simply update the key prefix with a new
versioned string.ACACHE_BUSTERsettings can be added to the mainMEDIASYNCsettings
dict to add a query string parameter to all media URLs. The cache buster can
either be a value or a callable which is passed the media URL as a parameter.MEDIASYNC['CACHE_BUSTER'] = 1234567890The above setting will generate a media path similar to:http://yourhost.com/url/to/media/image.png?1234567890An important thing to note is that if you’re running your Django site in a
multi-threaded or multi-node setup, you’ll want to be careful about using a
time-based cache buster value. Each worker/thread will probably have a slightly
different value for datetime.now(), which means your users will find themselves
having cache misses randomly from page to page.Rackspace Cloud FilesMEDIASYNC['BACKEND'] = 'mediasync.backends.cloudfiles'SettingsThe following settings are required in the mediasync settings dict:MEDIASYNC = {
    'CLOUDFILES_CONTAINER': 'container_name',
    'CLOUDFILES_USERNAME': 'cf_username',
    'CLOUDFILES_API_KEY': 'cf_apikey',
}TipsThe Cloud Files backend lacks support for the following features:setting HTTP Expires headersetting HTTP Cache-Control headercontent compression (gzip)SSL supportconditional sync based on file checksumCustom backendsYou can create a custom backend by creating a Python module containing a Client
class. This class must inherit from mediasync.backends.BaseClient. Additionally,
you must implement two methods:def remote_media_url(self, with_ssl):
    ...remote_media_urlreturns the full base URL for remote media. This can be
either a static URL or one generated from mediasync settings:def put(self, filedata, content_type, remote_path, force=False):
    ...put is responsible for pushing a file to the backend storage.filedata - the contents of the filecontent_type - the mime type of the fileremote_path - the remote path (relative from remote_media_url) to which
the file should be writtenforce - if True, write file to remote storage even if it already existsIf the client supports gzipped content, you will need to override supports_gzip
to return True:def supports_gzip(self):
        return TrueFile ProcessorsFile processors allow you to modify the content of a file as it is being
synced or served statically.Mediasync ships with three processor modules:slimis a minifier written in Python and requires theslimmerPython package. The Python package can be found here:http://pypi.python.org/pypi/slimmer/yuicompressoris a minifier written in Java and can be downloaded
from YUI’s download page:http://developer.yahoo.com/yui/compressor/.
This processor also requires an additional setting, as defined below.yuicompressoris new and should be considered experimental until
the mediasync 2.1 release.closurecompileris a javascript compiler provided by Google.Custom processors can be specified using thePROCESSORSentry in the
mediasync settings dict.PROCESSORSshould be a list of processor entries.
Each processor entry can be a callable or a string path to a callable. If the
path is to a class definition, the class will be instantiated into an object.
The processor callable should return a string of the processed file data, None
if it chooses to not process the file, or raisemediasync.SyncExceptionif
something goes terribly wrong. The callable should take the following arguments:def proc(filedata, content_type, remote_path, is_active):
        ...filedatathe content of the file as a stringcontent_typethe mimetype of the file being processedremote_paththe path to which the file is being synced (contains the file name)is_activeTrue if the processor should… processIf thePROCESSORSsetting is used, you will need to include the defaults
if you plan on using them:'PROCESSORS': (
    'mediasync.processors.slim.css_minifier',
    'mediasync.processors.slim.js_minifier',
        ...
),mediasync will attempt to useslimmerby default if you have the package
installed and do not use the PROCESSORS setting.Google Closure CompilerGoogle’s JavaScript Closure Compiler provides an API that allows files to be
compressed without installing anything locally. To use the service:'PROCESSORS': ('mediasync.processors.closurecompiler.compile',)YUI CompressorTo configure YUI Compressor you need to define aPROCESSORSandYUI_COMPRESSOR_PATHas follows, assuming you placed the “.jar” file in
your~/binpath:'PROCESSORS': ('mediasync.processors.yuicompressor.css_minifier',
               'mediasync.processors.yuicompressor.js_minifier'),
'YUI_COMPRESSOR_PATH': '~/bin/yuicompressor.jar',FeaturesIgnored DirectoriesAny directory inSTATIC_ROOTthat is hidden or starts with an underscore
will be ignored during syncing.Template TagsWhen referring to media in HTML templates you can use custom template tags.
These tags can by accessed by loading the media template tag collection.{% load media %}Any tag that has a path argument can use either a string or a variable:{% media_url "images/avatar.png" }
{% media_url user.profile.avatar_path %}If you’d like to make the mediasync tags global, you can add the following to
your master urls.py file:from django.template import add_to_builtins
add_to_builtins('mediasync.templatetags.media')Some backends (S3) support https URLs when the requesting page is secure.
In order for the https to be detected, the request must be placed in the
template context with the key ‘request’. This can be done automatically by
adding ‘django.core.context_processors.request’ toTEMPLATE_CONTEXT_PROCESSORSin settings.pymedia_urlRenders the STATIC_URL from settings.py with trailing slashes removed.<img src="{% media_url %}/images/stuff.png">STATIC_URL takes an optional argument that is the media path. Using the argument
allows mediasync to add the CACHE_BUSTER to the URL if one is specified.<img src="{% media_url '/images/stuff.png' %}">IfCACHE_BUSTERis set to 12345, the above example will render as:<img src="http://assets.example.com/path/to/media/images/stuff.png?12345">NOTE: Don’t use this tag to serve CSS or JS files. Use the js and css tags
that were specifically designed for the purpose.jsRenders a script tag with the correct include.{% js "myfile.js" %}cssRenders a <link> tag to include the stylesheet. It takes an optional second
parameter for the media attribute; the default media is “screen, projector”.{% css "myfile.css" %}
{% css "myfile.css" "screen" %}css_printShortcut to render as a print stylesheet.{% css_print "myfile.css" %}which is equivalent to{% css "myfile.css" "print" %}Writing Style SheetsUsers are encouraged to write stylesheets using relative URLS. The media
directory is synced with S3 as is, so relative local paths will still work
when pushed remotely.background: url(../images/arrow_left.png);Joined filesWhen serving media in production, it is beneficial to combine JavaScript and
CSS into single files. This reduces the number of connections the browser needs
to make to the web server. Fewer connections can dramatically decrease page
load times and reduce the server-side load.Joined files are specified in theMEDIASYNCdict usingJOINED. This is
a dict that maps individual media to an alias for the joined files.'JOINED': {
    'styles/joined.css': ['styles/reset.css','styles/text.css'],
    'scripts/joined.js': ['scripts/jquery.js','scripts/processing.js'],
},Files listed inJOINEDwill be combined and pushed to S3 with the name of
the alias. The individual CSS files will also be pushed to S3. Aliases must end
in either .css or .js in order for the content-type to be set appropriately.The existing template tags may be used to refer to the joined media. Simply use
the joined alias as the argument:{% css_print "joined.css" %}When served locally, template tags will render an HTML tag for each of the files
that make up the joined file:<link rel="stylesheet" href="/media/styles/reset.css" type="text/css" media="screen, projection" />
<link rel="stylesheet" href="/media/styles/text.css" type="text/css" media="screen, projection" />When served remotely, one HTML tag will be rendered with the name of the joined file:<link rel="stylesheet" href="http://bucket.s3.amazonaws.com/styles/joined.css" type="text/css" media="screen, projection" />Smart GZIP for S3In previous versions of mediasync’s S3 client, certain content was always pushed
in a compressed format. This can cause major issues with clients that do not
support gzip. New in version 2.0, mediasync will push both a gzipped and an
uncompressed version of the file to S3. The template tags look at the request
and direct the user to the appropriate file based on the ACCEPT_ENCODING HTTP
header. Assuming a file styles/layout.css, the following would be synced to S3:styles/layout.css
styles/layout.css.gzSignalsmediasync provides two signals that allow you to hook into the syncing
process.pre_syncis sent after the client is opened, but before the first
file is synced.post_syncis sent after the last file is synced, but before
the client is closed. This allows you to call commands on the client without
having to worry about its state. The signals allow you to do common tasks such
as calling Django 1.3’s collectstatic command, process SASS stylesheets, or
clean up files generated during a pre_sync process.collectstatic receiverA receiver for calling the collectstatic management command is provided:from mediasync.signals import pre_sync, collectstatic_receiver

# run collectstatic before syncing media
pre_sync.connect(collectstatic_receiver)SASS receiverA receiver for compiling SASS into CSS is provided:from mediasync.signals import pre_sync, sass_receiver

# compile SASS files before syncing media
pre_sync.connect(sass_receiver)Any file in static root that has thesassorscssfile extension will be
compiled into CSS. The compiled CSS file will be placed in the same directory
and the original extension will be replaced withcss. If a file exists with
the samecssextension, it will be overwritten.By default mediasync uses thesasscommand with no options. If you would
like to specify your own command, specifySASS_COMMANDin settings:MEDIASYNC = {
    ...
    'SASS_COMMAND': 'sass -scss -l',
    ...
}Running MEDIASYNC./manage.py syncmediaChange Log2.2.0added pre_sync and post_sync signalsprovide basic receiver for calling collectstatic before syncingprovide receiver for compiling SASS before syncingshow media directory listing when serving locally in debug modeadd processor for Google’s Closure Compiler API for JavaScripttemplate tags can now take a variable as the path argument2.1.0default to using STATIC_URL and STATIC_ROOT (Django 1.3), falling back
to MEDIA_URL and MEDIA_ROOT if the STATIC_* settings are not setadd AWS_GZIP setting to optionally disable gzip compression in S3 clientThanks to Rob Hudson and Dolan Antenucci for their contributions to this
release.2.0.0updated Rackspace Cloud Files backenduse gzip instead of deflate for compression (better browser support)smart gzip client support detectionadd pluggable backendsadd pluggable file processorsexperimental YUI Compressorsettings refactorallow override ofsettings.MEDIA_URLImprovements to the logic that decides which files to sync. Safely ignore
a wider variety of hidden files/directories.Make template tags aware of whether the current page is SSL-secured. If it
is, ask the backend for an SSL media URL (if implemented by your backend).made SERVE_REMOTE setting the sole factor in determining if
media should be served locally or remotelyadd many more testsdeprecate CSS_PATH and JS_PATHThanks to Greg Taylor, Peter Sanchez, Jonathan Drosdeck, Rich Leland,
and Rob Hudson for their contributions to this release.1.0.1add application/javascript and application/x-javascript to JavaScript
mimetypesbreak out of CSS and JS mimetypesadd support for HTTPS URLs to S3allow for storage of S3 keys in ~/.boto configuration fileThanks to Rob Hudson and Peter Sanchez for their contributions.1.0.0Initial release.