Transparent redirect handler instead of returning HTTP 308 to clients

server/handlers/api/v1_compatability.py

@@ -1,29 +1,54 @@
-import json
-
 import tornado
-
-from core.utils import safe_json_dumps
-
-
-class V1GoneHandler(tornado.web.RequestHandler):
-    """Returns 410 Gone with a message for any endpoints in the old API that have breaking changes in the new one or
-    have been retired."""
-
-    def post(self):
-        self.set_status(410)
-        self.write(safe_json_dumps(
-            "This API endpoint has a breaking change or has been removed in the current version of the Spothole API. Please see /apidocs for details of the current API version and the endpoints available."))
-        self.set_header("Cache-Control", "no-store")
-        self.set_header("Content-Type", "application/json")
-
+from tornado.httpclient import AsyncHTTPClient
 
 class V1RedirectHandler(tornado.web.RequestHandler):
-    """Returns 308 Permanent Redirect from any path in the old API to the new one, where there were no breaking changes."""
+    """Transparently proxies requests from the old API to the new one,
+    returning whatever the v2 endpoint returns, for endpoints with no breaking changes."""
 
-    def get(self, path):
-        new_url = "/api/v2/" + path
+    SUPPORTED_METHODS = ("GET", "POST", "PUT", "DELETE", "PATCH", "HEAD", "OPTIONS")
+
+    # Methods where an HTTP body isn't valid
+    _BODYLESS_METHODS = {"GET", "HEAD", "OPTIONS"}
+
+    async def _proxy(self, path):
+        new_url = f"{self.request.protocol}://{self.request.host}/api/v2/{path}"
         if self.request.query:
             new_url += "?" + self.request.query
-        self.set_status(308)
-        self.set_header("Location", new_url)
+
+        client = AsyncHTTPClient()
+        try:
+            response = await client.fetch(
+                new_url,
+                method=self.request.method,
+                headers=self.request.headers,
+                body=None if self.request.method in self._BODYLESS_METHODS else (self.request.body or b""),
+                raise_error=False,
+                follow_redirects=False,
+                request_timeout=10.0,
+            )
+        except Exception as e:
+            raise tornado.web.HTTPError(502, reason=str(e))
+
+        self.set_status(response.code, response.reason)
+        for name, value in response.headers.get_all():
+            # Let Tornado recompute these for the outgoing response
+            if name.lower() not in ("content-length", "transfer-encoding", "connection"):
+                self.add_header(name, value)
+        if response.body:
+            self.write(response.body)
         self.finish()
+
+    async def get(self, path):
+        await self._proxy(path)
+
+    async def post(self, path):
+        await self._proxy(path)
+
+    async def put(self, path):
+        await self._proxy(path)
+
+    async def delete(self, path):
+        await self._proxy(path)
+
+    async def patch(self, path):
+        await self._proxy(path)