wsgi.input: Make send_hundred_continue_headers a public API

Per HTTP RFC 7231 (http://tools.ietf.org/html/rfc7231#section-6.2)
a client is required to be able to process one or more 100 continue
responses.

-- RFC 7231 --------------------

6.2.  Informational 1xx

[snip]

   A client MUST be able to parse one or more 1xx responses received
   prior to a final response, even if the client does not expect one.
   A user agent MAY ignore unexpected 1xx responses.
...
--------------------------------

This patch adds a send_hundred_continue_headers() public API method
to wsgi.input, thus allowing WSGI apps to send more than one 100-
continue response.  This does not change existing semantics for the
first 100-continue response sent on read() or readline().

eventlet/wsgi.py

@@ -88,8 +88,9 @@ class Input(object):
         # (optional) headers to send with a "100 Continue" response. Set by
         # calling set_hundred_continue_respose_headers() on env['wsgi.input']
         self.hundred_continue_headers = None
+        self.is_hundred_continue_response_sent = False
 
-    def _send_hundred_continue_response(self):
+    def send_hundred_continue_response(self):
         towrite = []
 
         # 100 Continue status line
@@ -105,13 +106,16 @@ class Input(object):
         towrite.append(b'\r\n')
 
         self.wfile.writelines(towrite)
-        self.wfile = None
+
-        self.wfile_line = None
+        # Reinitialize chunk_length (expect more data)
+        self.chunk_length = -1
 
     def _do_read(self, reader, length=None):
-        if self.wfile is not None:
+        if self.wfile is not None and \
+                not self.is_hundred_continue_response_sent:
             # 100 Continue response
-            self._send_hundred_continue_response()
+            self.send_hundred_continue_response()
+            self.is_hundred_continue_response_sent = True
         if length is None and self.content_length is not None:
             length = self.content_length - self.position
         if length and length > self.content_length - self.position:
@@ -126,9 +130,11 @@ class Input(object):
         return read
 
     def _chunked_read(self, rfile, length=None, use_readline=False):
-        if self.wfile is not None:
+        if self.wfile is not None and \
+                not self.is_hundred_continue_response_sent:
             # 100 Continue response
-            self._send_hundred_continue_response()
+            self.send_hundred_continue_response()
+            self.is_hundred_continue_response_sent = True
         try:
             if length == 0:
                 return ""

tests/wsgi_test.py

@@ -830,6 +830,160 @@ class TestHttpd(_TestBase):
         fd.close()
         sock.close()
 
+    def test_024b_expect_100_continue_with_headers_multiple_chunked(self):
+        def wsgi_app(environ, start_response):
+            environ['wsgi.input'].set_hundred_continue_response_headers(
+                [('Hundred-Continue-Header-1', 'H1'),
+                 ('Hundred-Continue-Header-2', 'H2')])
+            text = environ['wsgi.input'].read()
+
+            environ['wsgi.input'].set_hundred_continue_response_headers(
+                [('Hundred-Continue-Header-3', 'H3')])
+            environ['wsgi.input'].send_hundred_continue_response()
+
+            text += environ['wsgi.input'].read()
+
+            start_response('200 OK', [('Content-Length', str(len(text)))])
+            return [text]
+        self.site.application = wsgi_app
+        sock = eventlet.connect(('localhost', self.port))
+        fd = sock.makefile('rwb')
+        fd.write(b'PUT /a HTTP/1.1\r\n'
+                 b'Host: localhost\r\nConnection: close\r\n'
+                 b'Transfer-Encoding: chunked\r\n'
+                 b'Expect: 100-continue\r\n\r\n')
+        fd.flush()
+
+        # Expect 1st 100-continue response
+        header_lines = []
+        while True:
+            line = fd.readline()
+            if line == b'\r\n':
+                break
+            else:
+                header_lines.append(line.strip())
+        assert header_lines[0].startswith(b'HTTP/1.1 100 Continue')
+        headers = dict((k, v) for k, v in (h.split(b': ', 1)
+                                           for h in header_lines[1:]))
+        assert b'Hundred-Continue-Header-1' in headers
+        assert b'Hundred-Continue-Header-2' in headers
+        self.assertEqual(b'H1', headers[b'Hundred-Continue-Header-1'])
+        self.assertEqual(b'H2', headers[b'Hundred-Continue-Header-2'])
+
+        # Send message 1
+        fd.write(b'5\r\nfirst\r\n8\r\n message\r\n0\r\n\r\n')
+        fd.flush()
+
+        # Expect a 2nd 100-continue response
+        header_lines = []
+        while True:
+            line = fd.readline()
+            if line == b'\r\n':
+                break
+            else:
+                header_lines.append(line.strip())
+        assert header_lines[0].startswith(b'HTTP/1.1 100 Continue')
+        headers = dict((k, v) for k, v in (h.split(b': ', 1)
+                                           for h in header_lines[1:]))
+        assert b'Hundred-Continue-Header-3' in headers
+        self.assertEqual(b'H3', headers[b'Hundred-Continue-Header-3'])
+
+        # Send message 2
+        fd.write(b'8\r\n, second\r\n8\r\n message\r\n0\r\n\r\n')
+        fd.flush()
+
+        # Expect final 200-OK
+        header_lines = []
+        while True:
+            line = fd.readline()
+            if line == b'\r\n':
+                break
+            else:
+                header_lines.append(line.strip())
+        assert header_lines[0].startswith(b'HTTP/1.1 200 OK')
+
+        self.assertEqual(fd.read(29), b'first message, second message')
+        fd.close()
+        sock.close()
+
+    def test_024c_expect_100_continue_with_headers_multiple_nonchunked(self):
+        def wsgi_app(environ, start_response):
+
+            environ['wsgi.input'].set_hundred_continue_response_headers(
+                [('Hundred-Continue-Header-1', 'H1'),
+                 ('Hundred-Continue-Header-2', 'H2')])
+            text = environ['wsgi.input'].read(13)
+
+            environ['wsgi.input'].set_hundred_continue_response_headers(
+                [('Hundred-Continue-Header-3', 'H3')])
+            environ['wsgi.input'].send_hundred_continue_response()
+
+            text += environ['wsgi.input'].read(16)
+
+            start_response('200 OK', [('Content-Length', str(len(text)))])
+            return [text]
+
+        self.site.application = wsgi_app
+        sock = eventlet.connect(('localhost', self.port))
+        fd = sock.makefile('rwb')
+        fd.write(b'PUT /a HTTP/1.1\r\n'
+                 b'Host: localhost\r\nConnection: close\r\n'
+                 b'Content-Length: 29\r\n'
+                 b'Expect: 100-continue\r\n\r\n')
+        fd.flush()
+
+        # Expect 1st 100-continue response
+        header_lines = []
+        while True:
+            line = fd.readline()
+            if line == b'\r\n':
+                break
+            else:
+                header_lines.append(line.strip())
+        assert header_lines[0].startswith(b'HTTP/1.1 100 Continue')
+        headers = dict((k, v) for k, v in (h.split(b': ', 1)
+                                           for h in header_lines[1:]))
+        assert b'Hundred-Continue-Header-1' in headers
+        assert b'Hundred-Continue-Header-2' in headers
+        self.assertEqual(b'H1', headers[b'Hundred-Continue-Header-1'])
+        self.assertEqual(b'H2', headers[b'Hundred-Continue-Header-2'])
+
+        # Send message 1
+        fd.write(b'first message')
+        fd.flush()
+
+        # Expect a 2nd 100-continue response
+        header_lines = []
+        while True:
+            line = fd.readline()
+            if line == b'\r\n':
+                break
+            else:
+                header_lines.append(line.strip())
+        assert header_lines[0].startswith(b'HTTP/1.1 100 Continue')
+        headers = dict((k, v) for k, v in (h.split(b': ', 1)
+                                           for h in header_lines[1:]))
+        assert b'Hundred-Continue-Header-3' in headers
+        self.assertEqual(b'H3', headers[b'Hundred-Continue-Header-3'])
+
+        # Send message 2
+        fd.write(b', second message\r\n')
+        fd.flush()
+
+        # Expect final 200-OK
+        header_lines = []
+        while True:
+            line = fd.readline()
+            if line == b'\r\n':
+                break
+            else:
+                header_lines.append(line.strip())
+        assert header_lines[0].startswith(b'HTTP/1.1 200 OK')
+
+        self.assertEqual(fd.read(29), b'first message, second message')
+        fd.close()
+        sock.close()
+
     def test_025_accept_errors(self):
         debug.hub_exceptions(True)
         listener = greensocket.socket()