http client: option to not raise errors

Pass raise_error=False to the fetch method to disable the raising of
HTTPError on errors.

diff --git a/tornado/httpclient.py b/tornado/httpclient.py
index df4295171eec8de6efdeed2bd29b9abcd8aaa89a..6ea872de2aca7f801f2f2ab2293182afcaf5c27f 100644 (file)
--- a/tornado/httpclient.py
+++ b/tornado/httpclient.py
@@ -95,7 +95,8 @@ class HTTPClient(object):
         If it is a string, we construct an `HTTPRequest` using any additional
         kwargs: ``HTTPRequest(request, **kwargs)``
 
-        If an error occurs during the fetch, we raise an `HTTPError`.
+        If an error occurs during the fetch, we raise an `HTTPError` unless
+        the ``raise_error`` keyword argument is set to False.
         """
         response = self._io_loop.run_sync(functools.partial(
             self._async_client.fetch, request, **kwargs))
@@ -200,7 +201,7 @@ class AsyncHTTPClient(Configurable):
                 raise RuntimeError("inconsistent AsyncHTTPClient cache")
             del self._instance_cache[self.io_loop]
 
-    def fetch(self, request, callback=None, **kwargs):
+    def fetch(self, request, callback=None, raise_error=True, **kwargs):
         """Executes a request, asynchronously returning an `HTTPResponse`.
 
         The request may be either a string URL or an `HTTPRequest` object.
@@ -208,8 +209,10 @@ class AsyncHTTPClient(Configurable):
         kwargs: ``HTTPRequest(request, **kwargs)``
 
         This method returns a `.Future` whose result is an
-        `HTTPResponse`.  The ``Future`` will raise an `HTTPError` if
-        the request returned a non-200 response code.
+        `HTTPResponse`.  By default, the ``Future`` will raise an `HTTPError`
+        if the request returned a non-200 response code. Instead, if
+        ``raise_error`` is set to False, the response will always be
+        returned regardless of the response code.
 
         If a ``callback`` is given, it will be invoked with the `HTTPResponse`.
         In the callback interface, `HTTPError` is not automatically raised.
@@ -243,7 +246,7 @@ class AsyncHTTPClient(Configurable):
             future.add_done_callback(handle_future)
 
         def handle_response(response):
-            if response.error:
+            if raise_error and response.error:
                 future.set_exception(response.error)
             else:
                 future.set_result(response)

diff --git a/tornado/test/httpclient_test.py b/tornado/test/httpclient_test.py
index bfb50d878d05bbbc6926959c2f48955b529b9cf5..b155c6eebf688ad5178337bebc37905816dcde45 100644 (file)
--- a/tornado/test/httpclient_test.py
+++ b/tornado/test/httpclient_test.py
@@ -404,6 +404,11 @@ Transfer-Encoding: chunked
         self.assertEqual(context.exception.code, 404)
         self.assertEqual(context.exception.response.code, 404)
 
+    @gen_test
+    def test_future_http_error_no_raise(self):
+        response = yield self.http_client.fetch(self.get_url('/notfound'), raise_error=False)
+        self.assertEqual(response.code, 404)
+
     @gen_test
     def test_reuse_request_from_response(self):
         # The response.request attribute should be an HTTPRequest, not