Create util functions from templatetags code (#96)

Rather than doing the work in the template tags, we do the work in utils
functions so that the same functionality is available directly to Python
application code.

This can be useful for `media` properties on Django widgets (#95).

The README has been updated to provide simple examples of usage.

Author: michaeljones

README.md

@@ -295,6 +295,20 @@ In the below example, `logo.png` can be any static asset shipped with any npm or
 
 <br>
 
+### From Python code
+
+If you want to access the webpack asset path information from your application code then you can use
+the function in the `webpack_loader.utils` module.
+
+```python
+>>> utils.get_files('main')
+[{'url': '/static/bundles/main.js', u'path': u'/home/mike/root/projects/django-webpack-loader/tests/assets/bundles/main.js', u'name': u'main.js'},
+ {'url': '/static/bundles/styles.css', u'path': u'/home/mike/root/projects/django-webpack-loader/tests/assets/bundles/styles.css', u'name': u'styles.css'}]
+>>> utils.get_as_tags('main')
+['<script type="text/javascript" src="/static/bundles/main.js" ></script>',
+ '<link type="text/css" href="/static/bundles/styles.css" rel="stylesheet" />']
+
+
 ## How to use in Production
 
 **It is up to you**. There are a few ways to handle this. I like to have slightly separate configs for production and local. I tell git to ignore my local stats + bundle file but track the ones for production. Before pushing out newer version to production, I generate a new bundle using production config and commit the new stats file and bundle. I store the stats file and bundles in a directory that is added to the `STATICFILES_DIR`. This gives me integration with collectstatic for free. The generated bundles are automatically collected to the target directory and synched to S3.

webpack_loader/templatetags/webpack_loader.py

@@ -2,52 +2,20 @@
 from django.conf import settings
 from django.utils.safestring import mark_safe
 
-from ..utils import get_loader
+from .. import utils
 
 register = template.Library()
 
 
-def filter_by_extension(bundle, extension):
-    '''Return only files with the given extension'''
-    for chunk in bundle:
-        if chunk['name'].endswith('.{0}'.format(extension)):
-            yield chunk
-
-
-def render_as_tags(bundle, attrs):
-    tags = []
-    for chunk in bundle:
-        if chunk['name'].endswith(('.js', '.js.gz')):
-            tags.append((
-                '<script type="text/javascript" src="{0}" {1}></script>'
-            ).format(chunk['url'], attrs))
-        elif chunk['name'].endswith(('.css', '.css.gz')):
-            tags.append((
-                '<link type="text/css" href="{0}" rel="stylesheet" {1}/>'
-            ).format(chunk['url'], attrs))
-    return mark_safe('\n'.join(tags))
-
-
-def _get_bundle(bundle_name, extension, config):
-    bundle = get_loader(config).get_bundle(bundle_name)
-    if extension:
-        bundle = filter_by_extension(bundle, extension)
-    return bundle
-
-
 @register.simple_tag
 def render_bundle(bundle_name, extension=None, config='DEFAULT', attrs=''):
-    return render_as_tags(_get_bundle(bundle_name, extension, config), attrs)
+    tags = utils.get_as_tags(bundle_name, extension=extension, config=config, attrs=attrs)
+    return mark_safe('\n'.join(tags))
 
 
 @register.simple_tag
 def webpack_static(asset_name, config='DEFAULT'):
-    return "{0}{1}".format(
-        get_loader(config).get_assets().get(
-            'publicPath', getattr(settings, 'STATIC_URL')
-        ),
-        asset_name
-    )
+    return utils.get_static(asset_name, config=config)
 
 
 assignment_tag = register.simple_tag if VERSION >= (1, 9) else register.assignment_tag
@@ -65,4 +33,4 @@ def get_files(bundle_name, extension=None, config='DEFAULT'):
     :param config: (optional) the name of the configuration
     :return: a list of matching chunks
     """
-    return list(_get_bundle(bundle_name, extension, config))
+    return utils.get_files(bundle_name, extension=extension, config=config)

webpack_loader/utils.py

@@ -1,3 +1,5 @@
+from django.conf import settings
+
 from .loader import WebpackLoader
 
 
@@ -8,3 +10,63 @@ def get_loader(config_name):
     if config_name not in _loaders:
         _loaders[config_name] = WebpackLoader(config_name)
     return _loaders[config_name]
+
+
+def _filter_by_extension(bundle, extension):
+    '''Return only files with the given extension'''
+    for chunk in bundle:
+        if chunk['name'].endswith('.{0}'.format(extension)):
+            yield chunk
+
+
+def _get_bundle(bundle_name, extension, config):
+    bundle = get_loader(config).get_bundle(bundle_name)
+    if extension:
+        bundle = _filter_by_extension(bundle, extension)
+    return bundle
+
+
+def get_files(bundle_name, extension=None, config='DEFAULT'):
+    '''Returns list of chunks from named bundle'''
+    return list(_get_bundle(bundle_name, extension, config))
+
+
+def get_as_tags(bundle_name, extension=None, config='DEFAULT', attrs=''):
+    '''
+    Get a list of formatted <script> & <link> tags for the assets in the
+    named bundle.
+
+    :param bundle_name: The name of the bundle
+    :param extension: (optional) filter by extension, eg. 'js' or 'css'
+    :param config: (optional) the name of the configuration
+    :return: a list of formatted tags as strings
+    '''
+
+    bundle = _get_bundle(bundle_name, extension, config)
+    tags = []
+    for chunk in bundle:
+        if chunk['name'].endswith(('.js', '.js.gz')):
+            tags.append((
+                '<script type="text/javascript" src="{0}" {1}></script>'
+            ).format(chunk['url'], attrs))
+        elif chunk['name'].endswith(('.css', '.css.gz')):
+            tags.append((
+                '<link type="text/css" href="{0}" rel="stylesheet" {1}/>'
+            ).format(chunk['url'], attrs))
+    return tags
+
+
+def get_static(asset_name, config='DEFAULT'):
+    '''
+    Equivalent to Django's 'static' look up but for webpack assets.
+
+    :param asset_name: the name of the asset
+    :param config: (optional) the name of the configuration
+    :return: path to webpack asset as a string
+    '''
+    return "{0}{1}".format(
+        get_loader(config).get_assets().get(
+            'publicPath', getattr(settings, 'STATIC_URL')
+        ),
+        asset_name
+    )