Allow to override default request headers

Author: irvind

hyper/http20/connection.py

@@ -170,8 +170,9 @@ def request(self, method, url, body=None, headers={}):
         """
         stream_id = self.putrequest(method, url)
 
+        default_headers = (':method', ':scheme', ':authority', ':path')
         for name, value in headers.items():
-            self.putheader(name, value, stream_id)
+            self.putheader(name, value, stream_id, replace=name in default_headers)
 
         # Convert the body to bytes if needed.
         if isinstance(body, str):
@@ -319,7 +320,7 @@ def putrequest(self, method, selector, **kwargs):
 
         return s.stream_id
 
-    def putheader(self, header, argument, stream_id=None):
+    def putheader(self, header, argument, stream_id=None, replace=False):
         """
         Sends an HTTP header to the server, with name ``header`` and value
         ``argument``.
@@ -341,7 +342,7 @@ def putheader(self, header, argument, stream_id=None):
         :returns: Nothing.
         """
         stream = self._get_stream(stream_id)
-        stream.add_header(header, argument)
+        stream.add_header(header, argument, replace)
 
         return
 

hyper/http20/stream.py

@@ -109,11 +109,22 @@ def __init__(self,
         self._encoder = header_encoder
         self._decoder = header_decoder
 
-    def add_header(self, name, value):
+    def add_header(self, name, value, replace=False):
         """
         Adds a single HTTP header to the headers to be sent on the request.
         """
-        self.headers.append((name.lower(), value))
+        name = name.lower()
+
+        if replace:
+            try:
+                idx = [n for n, _ in self.headers].index(name)
+                self.headers[idx] = (name, value)
+                return
+
+            except ValueError:
+                pass
+        
+        self.headers.append((name, value))
 
     def send_data(self, data, final):
         """

test/test_hyper.py

@@ -109,6 +109,23 @@ def test_putheader_puts_headers(self):
             ('name', 'value'),
         ]
 
+    def test_putheader_replaces_headers(self):
+        c = HTTP20Connection("www.google.com")
+
+        c.putrequest('GET', '/')
+        c.putheader(':authority', 'www.example.org', replace=True)
+        c.putheader('name', 'value')
+        c.putheader('name', 'value2', replace=True)
+        s = c.recent_stream
+
+        assert s.headers == [
+            (':method', 'GET'),
+            (':scheme', 'https'),
+            (':authority', 'www.example.org'),
+            (':path', '/'),
+            ('name', 'value2'),
+        ]
+
     def test_endheaders_sends_data(self):
         frames = []
 
@@ -684,6 +701,23 @@ def test_streams_can_have_headers(self):
         s.add_header("name", "value")
         assert s.headers == [("name", "value")]
 
+    def test_streams_can_replace_headers(self):
+        s = Stream(1, None, None, None, None, None, None)
+        s.add_header("name", "value")
+        s.add_header("name", "other_value", replace=True)
+
+        assert s.headers == [("name", "other_value")]
+
+    def test_streams_can_replace_none_headers(self):
+        s = Stream(1, None, None, None, None, None, None)
+        s.add_header("name", "value")
+        s.add_header("other_name", "other_value", replace=True)
+
+        assert s.headers == [
+            ("name", "value"),
+            ("other_name", "other_value")
+        ]
+        
     def test_stream_opening_sends_headers(self):
         def data_callback(frame):
             assert isinstance(frame, HeadersFrame)