From be7aa8f53ae08ba8e4ef40771b6952362968e791 Mon Sep 17 00:00:00 2001
From: Alek Storm <alek.storm@gmail.com>
Date: Sun, 6 Apr 2014 21:33:32 -0700
Subject: [PATCH] Add experimental WSGI server implementation

---
 python/wsgi.py | 119 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 python/wsgi.py

diff --git a/python/wsgi.py b/python/wsgi.py
new file mode 100644
index 00000000..8e19bad6
--- /dev/null
+++ b/python/wsgi.py
@@ -0,0 +1,119 @@
+# nghttp2 - HTTP/2.0 C Library
+
+# Copyright (c) 2013 Tatsuhiro Tsujikawa
+
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+import io
+import sys
+from urllib.parse import urlparse
+
+import nghttp2
+
+def _dance_decode(b):
+    # TODO faster than looping through and mod-128'ing all unicode points?
+    return b.decode('utf-8').encode('latin1').decode('latin1')
+
+class WSGIContainer(nghttp2.BaseRequestHandler):
+
+    _BASE_ENVIRON = {
+        'wsgi.version': (1,0),
+        'wsgi.url_scheme': 'http', # FIXME
+        'wsgi.multithread': True, # TODO I think?
+        'wsgi.multiprocess': False, # TODO no idea
+        'wsgi.run_once': True, # TODO now I'm just guessing
+        'wsgi.errors': sys.stderr, # TODO will work for testing - is this even used by any frameworks?
+    }
+
+    def __init__(self, app, *args, **kwargs):
+        super(WSGIContainer, self).__init__(*args, **kwargs)
+        self.app = app
+        self.chunks = []
+
+    def on_data(self, chunk):
+        self.chunks.append(chunk)
+
+    def on_request_done(self):
+        environ = WSGIContainer._BASE_ENVIRON.copy()
+        parsed = urlparse(self.path)
+
+        environ['wsgi.input'] = io.BytesIO(b''.join(self.chunks))
+
+        for name, value in self.headers:
+            mangled_name = b'HTTP_' + name.replace(b'-', b'_').upper()
+            environ[_dance_decode(mangled_name)] = _dance_decode(value)
+
+        environ.update(dict(
+            REQUEST_METHOD=_dance_decode(self.method),
+            # TODO SCRIPT_NAME? like APPLICATION_ROOT in Flask...
+            PATH_INFO=_dance_decode(parsed.path),
+            QUERY_STRING=_dance_decode(parsed.query),
+            CONTENT_TYPE=environ.get('HTTP_CONTENT_TYPE', ''),
+            CONTENT_LENGTH=environ.get('HTTP_CONTENT_LENGTH', ''),
+            SERVER_NAME=_dance_decode(self.host),
+            SERVER_PORT='', # FIXME probably requires changes in nghttp2
+            SERVER_PROTOCOL='HTTP/2.0',
+        ))
+
+        response_status = [None]
+        response_headers = [None]
+        response_chunks = []
+
+        def start_response(status, headers, exc_info=None):
+            if response_status[0] is not None:
+                raise AssertionError('Response already started')
+            exc_info = None # avoid dangling circular ref - TODO is this necessary? borrowed from snippet in WSGI spec
+
+            response_status[0] = status
+            response_headers[0] = headers
+            # TODO handle exc_info
+
+            return lambda chunk: response_chunks.append(chunk)
+
+        # TODO technically, this breaks the WSGI spec by buffering the status,
+        # headers, and body until all are completely output from the app before
+        # writing the response, but it looks like nghttp2 doesn't support any
+        # other way for now
+
+        # TODO disallow yielding/returning before start_response is called
+        response_chunks.extend(self.app(environ, start_response))
+        response_body = b''.join(response_chunks)
+
+        # TODO automatically set content-length if not provided
+        self.send_response(
+            status=response_status[0],
+            headers=response_headers[0],
+            body=response_body,
+        )
+
+def wsgi_app(app):
+    return lambda *args, **kwargs: WSGIContainer(app, *args, **kwargs)
+
+
+if __name__ == '__main__':
+    import ssl
+    from werkzeug.testapp import test_app
+
+    ssl_ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+    ssl_ctx.options = ssl.OP_ALL | ssl.OP_NO_SSLv2
+    ssl_ctx.load_cert_chain('server.crt', 'server.key')
+
+    server = nghttp2.HTTP2Server(('127.0.0.1', 8443), wsgi_app(test_app),
+                                 ssl=ssl_ctx)
+    server.serve_forever()