Merge flask framework and other stuff from master

1 files changed, 219 insertions, 0 deletions

diff --git a/python/werkzeug/middleware/http_proxy.py b/python/werkzeug/middleware/http_proxy.py
new file mode 100644
index 0000000..bfdc071
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+++ b/python/werkzeug/middleware/http_proxy.py
@@ -0,0 +1,219 @@
+"""
+Basic HTTP Proxy
+================
+
+.. autoclass:: ProxyMiddleware
+
+:copyright: 2007 Pallets
+:license: BSD-3-Clause
+"""
+import socket
+
+from ..datastructures import EnvironHeaders
+from ..http import is_hop_by_hop_header
+from ..urls import url_parse
+from ..urls import url_quote
+from ..wsgi import get_input_stream
+
+try:
+    from http import client
+except ImportError:
+    import httplib as client
+
+
+class ProxyMiddleware(object):
+    """Proxy requests under a path to an external server, routing other
+    requests to the app.
+
+    This middleware can only proxy HTTP requests, as that is the only
+    protocol handled by the WSGI server. Other protocols, such as
+    websocket requests, cannot be proxied at this layer. This should
+    only be used for development, in production a real proxying server
+    should be used.
+
+    The middleware takes a dict that maps a path prefix to a dict
+    describing the host to be proxied to::
+
+        app = ProxyMiddleware(app, {
+            "/static/": {
+                "target": "http://127.0.0.1:5001/",
+            }
+        })
+
+    Each host has the following options:
+
+    ``target``:
+        The target URL to dispatch to. This is required.
+    ``remove_prefix``:
+        Whether to remove the prefix from the URL before dispatching it
+        to the target. The default is ``False``.
+    ``host``:
+        ``"<auto>"`` (default):
+            The host header is automatically rewritten to the URL of the
+            target.
+        ``None``:
+            The host header is unmodified from the client request.
+        Any other value:
+            The host header is overwritten with the value.
+    ``headers``:
+        A dictionary of headers to be sent with the request to the
+        target. The default is ``{}``.
+    ``ssl_context``:
+        A :class:`ssl.SSLContext` defining how to verify requests if the
+        target is HTTPS. The default is ``None``.
+
+    In the example above, everything under ``"/static/"`` is proxied to
+    the server on port 5001. The host header is rewritten to the target,
+    and the ``"/static/"`` prefix is removed from the URLs.
+
+    :param app: The WSGI application to wrap.
+    :param targets: Proxy target configurations. See description above.
+    :param chunk_size: Size of chunks to read from input stream and
+        write to target.
+    :param timeout: Seconds before an operation to a target fails.
+
+    .. versionadded:: 0.14
+    """
+
+    def __init__(self, app, targets, chunk_size=2 << 13, timeout=10):
+        def _set_defaults(opts):
+            opts.setdefault("remove_prefix", False)
+            opts.setdefault("host", "<auto>")
+            opts.setdefault("headers", {})
+            opts.setdefault("ssl_context", None)
+            return opts
+
+        self.app = app
+        self.targets = dict(
+            ("/%s/" % k.strip("/"), _set_defaults(v)) for k, v in targets.items()
+        )
+        self.chunk_size = chunk_size
+        self.timeout = timeout
+
+    def proxy_to(self, opts, path, prefix):
+        target = url_parse(opts["target"])
+
+        def application(environ, start_response):
+            headers = list(EnvironHeaders(environ).items())
+            headers[:] = [
+                (k, v)
+                for k, v in headers
+                if not is_hop_by_hop_header(k)
+                and k.lower() not in ("content-length", "host")
+            ]
+            headers.append(("Connection", "close"))
+
+            if opts["host"] == "<auto>":
+                headers.append(("Host", target.ascii_host))
+            elif opts["host"] is None:
+                headers.append(("Host", environ["HTTP_HOST"]))
+            else:
+                headers.append(("Host", opts["host"]))
+
+            headers.extend(opts["headers"].items())
+            remote_path = path
+
+            if opts["remove_prefix"]:
+                remote_path = "%s/%s" % (
+                    target.path.rstrip("/"),
+                    remote_path[len(prefix) :].lstrip("/"),
+                )
+
+            content_length = environ.get("CONTENT_LENGTH")
+            chunked = False
+
+            if content_length not in ("", None):
+                headers.append(("Content-Length", content_length))
+            elif content_length is not None:
+                headers.append(("Transfer-Encoding", "chunked"))
+                chunked = True
+
+            try:
+                if target.scheme == "http":
+                    con = client.HTTPConnection(
+                        target.ascii_host, target.port or 80, timeout=self.timeout
+                    )
+                elif target.scheme == "https":
+                    con = client.HTTPSConnection(
+                        target.ascii_host,
+                        target.port or 443,
+                        timeout=self.timeout,
+                        context=opts["ssl_context"],
+                    )
+                else:
+                    raise RuntimeError(
+                        "Target scheme must be 'http' or 'https', got '{}'.".format(
+                            target.scheme
+                        )
+                    )
+
+                con.connect()
+                remote_url = url_quote(remote_path)
+                querystring = environ["QUERY_STRING"]
+
+                if querystring:
+                    remote_url = remote_url + "?" + querystring
+
+                con.putrequest(environ["REQUEST_METHOD"], remote_url, skip_host=True)
+
+                for k, v in headers:
+                    if k.lower() == "connection":
+                        v = "close"
+
+                    con.putheader(k, v)
+
+                con.endheaders()
+                stream = get_input_stream(environ)
+
+                while 1:
+                    data = stream.read(self.chunk_size)
+
+                    if not data:
+                        break
+
+                    if chunked:
+                        con.send(b"%x\r\n%s\r\n" % (len(data), data))
+                    else:
+                        con.send(data)
+
+                resp = con.getresponse()
+            except socket.error:
+                from ..exceptions import BadGateway
+
+                return BadGateway()(environ, start_response)
+
+            start_response(
+                "%d %s" % (resp.status, resp.reason),
+                [
+                    (k.title(), v)
+                    for k, v in resp.getheaders()
+                    if not is_hop_by_hop_header(k)
+                ],
+            )
+
+            def read():
+                while 1:
+                    try:
+                        data = resp.read(self.chunk_size)
+                    except socket.error:
+                        break
+
+                    if not data:
+                        break
+
+                    yield data
+
+            return read()
+
+        return application
+
+    def __call__(self, environ, start_response):
+        path = environ["PATH_INFO"]
+        app = self.app
+
+        for prefix, opts in self.targets.items():
+            if path.startswith(prefix):
+                app = self.proxy_to(opts, path, prefix)
+                break
+
+        return app(environ, start_response)