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# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
"""
An application that proxies WSGI requests to a remote server.
TODO:
* Send ``Via`` header? It's not clear to me this is a Via in the
style of a typical proxy.
* Other headers or metadata? I put in X-Forwarded-For, but that's it.
* Signed data of non-HTTP keys? This would be for things like
REMOTE_USER.
* Something to indicate what the original URL was? The original host,
scheme, and base path.
* Rewriting ``Location`` headers? mod_proxy does this.
* Rewriting body? (Probably not on this one -- that can be done with
a different middleware that wraps this middleware)
* Example::
use = egg:Paste#proxy
address = http://server3:8680/exist/rest/db/orgs/sch/config/
allowed_request_methods = GET
"""
import httplib
import urlparse
from paste import httpexceptions
# Remove these headers from response (specify lower case header
# names):
filtered_headers = (
'transfer-encoding',
)
class Proxy(object):
def __init__(self, address, allowed_request_methods=()):
self.address = address
self.parsed = urlparse.urlsplit(address)
self.scheme = self.parsed[0].lower()
self.host = self.parsed[1]
self.path = self.parsed[2]
self.allowed_request_methods = [
x.lower() for x in allowed_request_methods if x]
def __call__(self, environ, start_response):
if (self.allowed_request_methods and
environ['REQUEST_METHOD'].lower() not in self.allowed_request_methods):
return httpexceptions.HTTPBadRequest("Disallowed")(environ, start_response)
if self.scheme == 'http':
ConnClass = httplib.HTTPConnection
elif self.scheme == 'https':
ConnClass = httplib.HTTPSConnection
else:
raise ValueError(
"Unknown scheme for %r: %r" % (self.address, self.scheme))
conn = ConnClass(self.host)
headers = {}
for key, value in environ.items():
if key.startswith('HTTP_'):
key = key[5:].lower().replace('_', '-')
if key == 'host':
continue
headers[key] = value
headers['host'] = self.host
if 'REMOTE_ADDR' in environ:
headers['x-forwarded-for'] = environ['REMOTE_ADDR']
if environ.get('CONTENT_TYPE'):
headers['content-type'] = environ['CONTENT_TYPE']
if environ.get('CONTENT_LENGTH'):
length = int(environ['CONTENT_LENGTH'])
body = environ['wsgi.input'].read(length)
else:
body = ''
if self.path:
request_path = environ['PATH_INFO']
if request_path[0] == '/':
request_path = request_path[1:]
path = urlparse.urljoin(self.path, request_path)
else:
path = environ['PATH_INFO']
conn.request(environ['REQUEST_METHOD'],
path,
body, headers)
res = conn.getresponse()
headers_out = []
for header, value in res.getheaders():
if header.lower() not in filtered_headers:
headers_out.append((header, value))
status = '%s %s' % (res.status, res.reason)
start_response(status, headers_out)
# @@: Default?
length = res.getheader('content-length')
if length is not None:
body = res.read(int(length))
else:
body = res.read()
conn.close()
return [body]
def make_proxy(global_conf, address, allowed_request_methods=""):
"""
Make a WSGI application that proxies to another address --
'address' should be the full URL ending with a trailing /
'allowed_request_methods' is a space seperated list of request methods
"""
from paste.deploy.converters import aslist
allowed_request_methods = aslist(allowed_request_methods)
return Proxy(address, allowed_request_methods=allowed_request_methods)
class TransparentProxy(object):
"""
A proxy that sends the request just as it was given, including
respecting HTTP_HOST, wsgi.url_scheme, etc.
This is a way of translating WSGI requests directly to real HTTP
requests. All information goes in the environment; modify it to
modify the way the request is made.
"""
def __init__(self):
pass
def __call__(self, environ, start_response):
scheme = environ['wsgi.url_scheme']
if scheme == 'http':
ConnClass = httplib.HTTPConnection
elif scheme == 'https':
ConnClass = httplib.HTTPSConnection
else:
raise ValueError(
"Unknown scheme %r" % scheme)
if 'HTTP_HOST' not in environ:
raise ValueError(
"WSGI environ must contain an HTTP_HOST key")
host = environ['HTTP_HOST']
conn = ConnClass(host)
headers = {}
for key, value in environ.items():
if key.startswith('HTTP_'):
key = key[5:].lower().replace('_', '-')
headers[key] = value
headers['host'] = host
if 'REMOTE_ADDR' in environ:
headers['x-forwarded-for'] = environ['REMOTE_ADDR']
if environ.get('CONTENT_TYPE'):
headers['content-type'] = environ['CONTENT_TYPE']
if environ.get('CONTENT_LENGTH'):
length = int(environ['CONTENT_LENGTH'])
body = environ['wsgi.input'].read(length)
else:
body = environ['wsgi.input'].read(length)
length = len(body)
path = (environ.get('SCRIPT_NAME', '')
+ environ.get('PATH_INFO', ''))
if 'QUERY_STRING' in environ:
path += '?' + environ['QUERY_STRING']
conn.request(environ['REQUEST_METHOD'],
path, body, headers)
res = conn.getresponse()
headers_out = []
for header, value in res.getheaders():
if header.lower() not in filtered_headers:
headers_out.append((header, value))
status = '%s %s' % (res.status, res.reason)
start_response(status, headers_out)
# @@: Default?
length = res.getheader('content-length')
if length is not None:
body = res.read(int(length))
else:
body = res.read()
conn.close()
return [body]
|
