Feature #400 - Resize images to fit on page - Additions

*   `migrations.py`
    *   Removed empty line
    *   Added empty line
*   `models.py`
    *   Added `MediaEntry.get_display_media()` helper function
*   `process_media.__init__.py`
    *	Updated `process_media_initial()`
    	*   Renamed `main` => `original`.
	*   Added condition to `medium`, it's only created if the original
	    dimensions exceed the MEDIUM_SIZE dimensions.
*   `media.html`
    *	The image tag is now populated by `MediaEntry.get_display_media()`
*   `util.py`
    *	Added `DISPLAY_IMAGE_FETCHING_ORDER`, used by `MediaEntry.get_display_media()`

mediagoblin/db/migrations.py

@@ -49,7 +49,7 @@ class MediaEntryMigration(DocumentMigration):
                     '$set': {
                         'description_html': cleaned_markdown_conversion(
                             doc['description'])}}
-        
+
 class UserMigration(DocumentMigration):
     def allmigration01_add_bio_and_url_profile(self):
         """

mediagoblin/db/models.py

@@ -24,6 +24,7 @@ from mediagoblin import mg_globals
 from mediagoblin.db import migrations
 from mediagoblin.db.util import DESCENDING, ObjectId
 from mediagoblin.util import Pagination
+from mediagoblin.util import DISPLAY_IMAGE_FETCHING_ORDER
 
 ###################
 # Custom validators
@@ -109,6 +110,24 @@ class MediaEntry(Document):
 
     migration_handler = migrations.MediaEntryMigration
 
+    def get_display_media(self, media_map, fetch_order=DISPLAY_IMAGE_FETCHING_ORDER):
+        """
+        Find the best media for display.
+
+        Args:
+        - media_map: a dict like
+          {u'image_size': [u'dir1', u'dir2', u'image.jpg']}
+        - fetch_order: the order we should try fetching images in
+
+        Returns:
+        (media_size, media_path)
+        """
+        media_sizes = media_map.keys()
+        print media_sizes
+        for media_size in DISPLAY_IMAGE_FETCHING_ORDER:
+            if media_size in media_sizes:
+                return media_map[media_size]
+
     def main_mediafile(self):
         pass