serve: Add ability to get all types of keys in /keys

pywidevine/serve.py

@@ -150,6 +150,9 @@ async def keys(request: web.Request) -> web.Response:
 
     # get key type
     key_type = request.match_info["key_type"]
+    if key_type == "ALL":
+        key_type = None
+    else:
         try:
             if key_type.isdigit():
                 key_type = License.KeyContainer.KeyType.Name(int(key_type))
@@ -183,7 +186,7 @@ async def keys(request: web.Request) -> web.Response:
             "permissions": key.permissions,
         }
         for key in cdm._sessions[session_id].keys
-        if key.type == key_type
+        if not key_type or key.type == key_type
     ]
 
     return web.json_response({