Merge pull request #17 from w3c/jgraham/connection_close

Always close the connection at the end of a request.

Author: jgraham

docs/pipes.rst

@@ -14,6 +14,12 @@ code 404.
 There are several built-in pipe functions, and it is possible to add
 more using the `@pipe` decorator on a function, if required.
 
+.. note::
+   Because of the way pipes compose, using some pipe functions prevents the
+   content-length of the response from being known in advance. In these cases
+   the server will close the connection to indicate the end of the response,
+   preventing the use of HTTP 1.1 keepalive.
+
 Built-In Pipes
 --------------
 
@@ -109,6 +115,9 @@ Would send the first 20 bytes of example.txt.
 trickle
 ~~~~~~~
 
+.. note::
+   Using this function will force a connection close.
+
 Used to send the body of a response in chunks with delays. Takes a
 single argument that is a microsyntax consisting of colon-separated
 commands. There are three types of commands:

wptserve/response.py

@@ -68,6 +68,7 @@ def __init__(self, handler, request):
         self.add_required_headers = True
         self.send_body_for_head_request = False
         self.explicit_flush = False
+        self.close_connection = False
 
         self.writer = ResponseWriter(handler, self)
 
@@ -401,6 +402,8 @@ def end_headers(self):
             self.write_default_headers()
 
         self.write("\r\n")
+        if not "content-length" in self._headers_seen:
+            self._response.close_connection = True
         if not self._response.explicit_flush:
             self.flush()
         self._headers_complete = True

wptserve/server.py

@@ -218,6 +218,12 @@ def handle_one_request(self):
                                          request.request_path, request.headers.get('Referer'), request.raw_input.length))
             if not response.writer.content_written:
                 response.write()
+                # If we want to remove this in the future, a solution is needed for
+                # scripts that produce a non-string iterable of content, since these
+                # can't set a Content-Length header. A notable example of this kind of
+                # problem is with the trickle pipe i.e. foo.js?pipe=trickle(d1)
+                if response.close_connection:
+                    self.close_connection = 1
 
         except socket.timeout, e:
             self.log_error("Request timed out: %r", e)