Add function to generate documentation links

STUD-1090

common/djangoapps/edxmako/middleware.py

@@ -12,6 +12,8 @@
 #   See the License for the specific language governing permissions and
 #   limitations under the License.
 
+import ConfigParser
+from django.conf import settings
 from django.template import RequestContext
 from util.request import safe_get_host
 requestcontext = None
@@ -24,3 +26,21 @@ class MakoMiddleware(object):
         requestcontext = RequestContext(request)
         requestcontext['is_secure'] = request.is_secure()
         requestcontext['site'] = safe_get_host(request)
+        requestcontext['doc_url'] = self.get_doc_url_func(request)
+
+    def get_doc_url_func(self, request):
+        config_file = open(settings.REPO_ROOT / "docs" / "config.ini")
+        config = ConfigParser.ConfigParser()
+        config.readfp(config_file)
+
+        # in the future, we will detect the locale; for now, we will
+        # hardcode en_us, since we only have English documentation
+        locale = "en_us"
+
+        def doc_url(token):
+            try:
+                return config.get(locale, token)
+            except ConfigParser.NoOptionError:
+                return config.get(locale, "default")
+
+        return doc_url

docs/config.ini

+[en_us]
+default=default