Allow arbitrary oEmbed endpoints

Before this change, only three hardcoded oEmbed endpoints were available
for users of the extension; youtube, flickr and vimeo. In the
configuration, it was only possible to pass a subset of those 3 oEmbed
endpoints. It was done by passing the names of the allowed endpoints.

With this change, the API has changed. The allowed_endpoints kwarg now
expects to be passed a list of OEmbedEndpoint objects (as opposed to
names). This means the responsibility of creating OEmbedEndpoint objects
has been shifted to the user of the extension. If the allowed_endpoints
kwarg is omitted, the default oEmbed endpoints used will be the same as
before; youtube, flickr and vimeo.

The motivation is to allow arbitrary oEmbed endpoints, without
necessitating anyone to maintain the list of all possible oEmbed
endpoints out there.

mdx_oembed/endpoints.py

@@ -2,15 +2,20 @@
 import oembed
 
 
-ENDPOINTS = {
-    'youtube': oembed.OEmbedEndpoint('http://www.youtube.com/oembed', [
+DEFAULT_ENDPOINTS = [
+    # Youtube
+    oembed.OEmbedEndpoint('http://www.youtube.com/oembed', [
         'https?://(*.)?youtube.com/*',
         'https?://youtu.be/*',
     ]),
-    'flickr': oembed.OEmbedEndpoint('http://www.flickr.com/services/oembed/', [
+
+    # Flickr
+    oembed.OEmbedEndpoint('http://www.flickr.com/services/oembed/', [
         'https?://*.flickr.com/*',
     ]),
-    'vimeo': oembed.OEmbedEndpoint('http://vimeo.com/api/oembed.json', [
+
+    # Vimeo
+    oembed.OEmbedEndpoint('http://vimeo.com/api/oembed.json', [
         'https?://vimeo.com/*',
     ]),
 }

mdx_oembed/extension.py

@@ -1,21 +1,18 @@
 # -*- coding: utf-8 -*-
 from markdown import Extension
 import oembed
-from mdx_oembed.endpoints import ENDPOINTS
+from mdx_oembed.endpoints import DEFAULT_ENDPOINTS
 from mdx_oembed.inlinepatterns import OEmbedLinkPattern, OEMBED_LINK_RE
 
 
-AVAILABLE_ENDPOINTS = ENDPOINTS.keys()
-
-
 class OEmbedExtension(Extension):
 
     def __init__(self, **kwargs):
         self.config = {
             'allowed_endpoints': [
-                AVAILABLE_ENDPOINTS,
-                "A list of oEmbed endpoints to allow. Possible values are "
-                "{}.".format(', '.join(AVAILABLE_ENDPOINTS)),
+                DEFAULT_ENDPOINTS,
+                "A list of oEmbed endpoints to allow. Defaults to "
+                "endpoints.DEFAULT_ENDPOINTS"
             ],
         }
         super(OEmbedExtension, self).__init__(**kwargs)
@@ -27,10 +24,11 @@ class OEmbedExtension(Extension):
         md.inlinePatterns.add('oembed_link', link_pattern, '<image_link')
 
     def prepare_oembed_consumer(self):
-        allowed_endpoints = self.getConfig('allowed_endpoints',
-                                           AVAILABLE_ENDPOINTS)
+        allowed_endpoints = self.getConfig('allowed_endpoints', DEFAULT_ENDPOINTS)
         consumer = oembed.OEmbedConsumer()
-        [consumer.addEndpoint(v)
-         for k,v in ENDPOINTS.items()
-         if k in allowed_endpoints]
+
+        if allowed_endpoints:
+            for endpoint in allowed_endpoints:
+                consumer.addEndpoint(endpoint)
+
         return consumer