[tor-commits] [meek/master] WSGI reflector.

[dcf at torproject.org]

commit e28a053e89b9fbdf83283203c26053a39fa72038
Author: David Fifield <david at bamsoftware.com>
Date:   Sun Sep 21 23:38:13 2014 -0700

    WSGI reflector.
---
 README          |    3 ++
 wsgi/README     |   10 +++++
 wsgi/reflect.py |  121 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 134 insertions(+)

diff --git a/README b/README
index b216059..4348942 100644
--- a/README
+++ b/README
@@ -63,6 +63,9 @@ A php reflector similar to the appengine one above. Ideally, it can be run on
 any platform that supports php. A public instance is at:
 https://meek-reflect.herokuapp.com/
 
+wsgi:
+A WSGI Python reflector.
+
 To the extent possible under law, the authors have dedicated all
 copyright and related and neighboring rights to this software to the
 public domain worldwide. This software is distributed without any
diff --git a/wsgi/README b/wsgi/README
new file mode 100644
index 0000000..a0e55b2
--- /dev/null
+++ b/wsgi/README
@@ -0,0 +1,10 @@
+This is a reflector program using Python and WSGI. The application
+string to put in your WSGI configuration is "reflect.main".
+
+To test locally, run:
+	python reflect.py
+
+It will listen on port 8000. Configure tor as:
+	UseBridges 1
+	Bridge meek 0.0.2.0:1
+	ClientTransportPlugin meek exec ./meek-client --url=http://127.0.0.1:8000/
diff --git a/wsgi/reflect.py b/wsgi/reflect.py
new file mode 100644
index 0000000..be62b1a
--- /dev/null
+++ b/wsgi/reflect.py
@@ -0,0 +1,121 @@
+# WSGI: https://www.python.org/dev/peps/pep-3333/
+
+import httplib
+import urlparse
+
+FORWARD_URL = "http://meek.bamsoftware.com:7002/"
+TIMEOUT = 20
+BUFSIZ = 2048
+
+REFLECTED_HEADER_FIELDS = [
+    "X-Session-Id",
+]
+
+# Limits a file-like object to reading only n bytes. Used to keep limit
+# wsgi.input to the Content-Length, otherwise it blocks.
+class LimitedReader(object):
+    def __init__(self, f, n):
+        self.f = f
+        self.n = n
+
+    def __getattr__(self, name):
+        return getattr(self.f, name)
+
+    def read(self, size=None):
+        if self.n <= 0:
+            return ""
+        if size is not None and size > self.n:
+            size = self.n
+        data = self.f.read(size)
+        self.n -= len(data)
+        return data
+
+# Join two URL paths.
+def path_join(a, b):
+    if a.endswith("/"):
+        a = a[:-1]
+    if not b.startswith("/"):
+        b = "/" + b
+    return a + b
+
+def get_header(environ, name):
+    if name.lower() == "content-type":
+        envar = "CONTENT_TYPE"
+    elif name.lower() == "content-length":
+        envar = "CONTENT_LENGTH"
+    else:
+        envar = "HTTP_" + name.replace("-", "_").upper()
+    return environ.get(envar)
+
+def copy_request(environ, url):
+    method = environ["REQUEST_METHOD"]
+
+    # Append PATH_INFO to the path of url.
+    u = urlparse.urlsplit(url)
+    path = path_join(u.path, environ["PATH_INFO"])
+    url = urlparse.urlunsplit((u.scheme, u.netloc, path, u.query, u.fragment))
+
+    headers = []
+
+    content_length = environ.get("CONTENT_LENGTH")
+    if content_length:
+        body = LimitedReader(environ["wsgi.input"], int(content_length))
+        headers.append(("Content-Length", content_length))
+    else:
+        body = ""
+
+    for name in REFLECTED_HEADER_FIELDS:
+        value = get_header(environ, name)
+        if value is not None:
+            headers.append((name, value))
+    headers = dict(headers)
+
+    return method, url, body, headers
+
+def make_conn(url):
+    u = urlparse.urlsplit(url)
+    create_connection = httplib.HTTPConnection
+    if u.scheme == "https":
+        create_connection = httplib.HTTPSConnection
+    return create_connection(u.hostname, u.port, strict=True, timeout=TIMEOUT)
+
+def make_request(conn, method, url, body, headers):
+    u = urlparse.urlsplit(url)
+    path = urlparse.urlunsplit(("", "", u.path, u.query, ""))
+    conn.request(method, path, body, headers)
+    return conn.getresponse()
+
+def main(environ, start_response):
+    try:
+        method, url, body, headers = copy_request(environ, FORWARD_URL)
+    except Exception, e:
+        start_response("400 Bad Request", [("Content-Type", "text/plain; charset=utf-8")])
+        yield "Bad Request"
+        return
+    try:
+        conn = make_conn(url)
+        resp = make_request(conn, method, url, body, headers)
+    except Exception, e:
+        start_response("500 Internal Server Error", [("Content-Type", "text/plain; charset=utf-8")])
+        yield "Internal Server Error"
+        return
+
+    headers = []
+    for name in REFLECTED_HEADER_FIELDS:
+        value = resp.getheader(name)
+        if value is not None:
+            headers.append((name, value))
+
+    start_response("%d %s" % (resp.status, resp.reason), headers)
+    while True:
+        data = resp.read(BUFSIZ)
+        if not data:
+            break
+        yield data
+
+    conn.close()
+
+if __name__ == "__main__":
+    import wsgiref.simple_server
+    server = wsgiref.simple_server.make_server("127.0.0.1", 8000, main)
+    server.serve_forever()