Simplify course URL discovery util.

common/djangoapps/util/request.py

@@ -37,21 +37,9 @@ def course_id_from_url(url):
     """
     if not url:
         return None
-
-    deprecated = False
-    if '/' in url:
-        deprecated = True
-
     # Ignore query string
     url = url.split('?')[0]
 
-    if deprecated:
-        COURSE_REGEX = re.compile(r'^.*/courses/(?P<course_id>[^/]+/[^/]+/[^/]+)')
-        key_generator = SlashSeparatedCourseKey.from_deprecated_string
-    else:
-        COURSE_REGEX = re.compile(r'^.*?/courses/(?P<course_id>[a-zA-Z0-9_+\/:]+)')
-        key_generator = CourseKey.from_string
-
     match = COURSE_REGEX.match(url)
     if match is None:
         return None
@@ -60,7 +48,7 @@ def course_id_from_url(url):
         return None
 
     try:
-        course_key = key_generator(course_id)
+        return CourseKey.from_string(course_id)
     except InvalidKeyError:
         log.warning(
             'unable to parse course_id "{}"'.format(course_id),
@@ -68,8 +56,6 @@ def course_id_from_url(url):
         )
         return None
 
-    return course_key
-
 
 class RequestMock(RequestFactory):
     """