Update dummyserver to work with newer Tornado (#1747)

The tornado.web.asynchronous decorator was deprecated in Tornado 5, and
removed in Tornado 6. This commit rewrites the dummyserver to work on
newer Tornado.

1 files changed, 25 insertions, 31 deletions

diff --git a/dummyserver/proxy.py b/dummyserver/proxy.py
index 7429d441..c4f0b824 100755
--- a/dummyserver/proxy.py
+++ b/dummyserver/proxy.py
@@ -28,6 +28,7 @@
 import sys
 import socket
 
+import tornado.gen
 import tornado.httpserver
 import tornado.ioloop
 import tornado.iostream
@@ -40,7 +41,7 @@ __all__ = ["ProxyHandler", "run_proxy"]
 class ProxyHandler(tornado.web.RequestHandler):
     SUPPORTED_METHODS = ["GET", "POST", "CONNECT"]
 
-    @tornado.web.asynchronous
+    @tornado.gen.coroutine
     def get(self):
         def handle_response(response):
             if response.error and not isinstance(
@@ -76,52 +77,45 @@ class ProxyHandler(tornado.web.RequestHandler):
 
         client = tornado.httpclient.AsyncHTTPClient()
         try:
-            client.fetch(req, handle_response)
+            response = yield client.fetch(req)
+            yield handle_response(response)
         except tornado.httpclient.HTTPError as e:
             if hasattr(e, "response") and e.response:
-                self.handle_response(e.response)
+                yield handle_response(e.response)
             else:
                 self.set_status(500)
                 self.write("Internal server error:\n" + str(e))
                 self.finish()
 
-    @tornado.web.asynchronous
+    @tornado.gen.coroutine
     def post(self):
-        return self.get()
+        yield self.get()
 
-    @tornado.web.asynchronous
+    @tornado.gen.coroutine
     def connect(self):
         host, port = self.request.uri.split(":")
         client = self.request.connection.stream
 
-        def read_from_client(data):
-            upstream.write(data)
-
-        def read_from_upstream(data):
-            client.write(data)
-
-        def client_close(data=None):
-            if upstream.closed():
-                return
-            if data:
-                upstream.write(data)
-            upstream.close()
-
-        def upstream_close(data=None):
-            if client.closed():
-                return
-            if data:
-                client.write(data)
-            client.close()
-
-        def start_tunnel():
-            client.read_until_close(client_close, read_from_client)
-            upstream.read_until_close(upstream_close, read_from_upstream)
-            client.write(b"HTTP/1.0 200 Connection established\r\n\r\n")
+        @tornado.gen.coroutine
+        def start_forward(reader, writer):
+            while True:
+                try:
+                    data = yield reader.read_bytes(4096, partial=True)
+                except tornado.iostream.StreamClosedError:
+                    break
+                if not data:
+                    break
+                writer.write(data)
+            writer.close()
 
         s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)
         upstream = tornado.iostream.IOStream(s)
-        upstream.connect((host, int(port)), start_tunnel)
+        yield upstream.connect((host, int(port)))
+
+        client.write(b"HTTP/1.0 200 Connection established\r\n\r\n")
+        fu1 = start_forward(client, upstream)
+        fu2 = start_forward(upstream, client)
+        yield [fu1, fu2]
 
 
 def run_proxy(port, start_ioloop=True):