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@oerd
Forked from gear11/main.py
Created December 19, 2015 20:42
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Simple Python proxy server based on Flask and Requests. See: http:/python-proxy-server/gear11.com/2013/12/python-proxy-server/
"""
A simple proxy server. Usage:
http://hostname:port/p/(URL to be proxied, minus protocol)
For example:
http://localhost:8080/p/www.google.com
"""
from flask import Flask, render_template, request, abort, Response, redirect
import requests
import logging
app = Flask(__name__.split('.')[0])
logging.basicConfig(level=logging.INFO)
APPROVED_HOSTS = set(["google.com", "www.google.com", "yahoo.com"])
CHUNK_SIZE = 1024
LOG = logging.getLogger("main.py")
@app.route('/<path:url>')
def root(url):
LOG.info("Root route, path: %s", url)
# If referred from a proxy request, then redirect to a URL with the proxy prefix.
# This allows server-relative and protocol-relative URLs to work.
proxy_ref = proxy_ref_info(request)
if proxy_ref:
redirect_url = "/p/%s/%s%s" % (proxy_ref[0], url, ("?" + request.query_string if request.query_string else ""))
LOG.info("Redirecting referred URL to: %s", redirect_url)
return redirect(redirect_url)
# Otherwise, default behavior
return render_template('hello.html', name=url,request=request)
@app.route('/p/<path:url>')
def proxy(url):
"""Fetches the specified URL and streams it out to the client.
If the request was referred by the proxy itself (e.g. this is an image fetch for
a previously proxied HTML page), then the original Referer is passed."""
r = get_source_rsp(url)
LOG.info("Got %s response from %s",r.status_code, url)
headers = dict(r.headers)
def generate():
for chunk in r.iter_content(CHUNK_SIZE):
yield chunk
return Response(generate(), headers = headers)
def get_source_rsp(url):
url = 'http://%s' % url
LOG.info("Fetching %s", url)
# Ensure the URL is approved, else abort
if not is_approved(url):
LOG.warn("URL is not approved: %s", url)
abort(403)
# Pass original Referer for subsequent resource requests
proxy_ref = proxy_ref_info(request)
headers = { "Referer" : "http://%s/%s" % (proxy_ref[0], proxy_ref[1])} if proxy_ref else {}
# Fetch the URL, and stream it back
LOG.info("Fetching with headers: %s, %s", url, headers)
return requests.get(url, stream=True , params = request.args, headers=headers)
def is_approved(url):
"""Indicates whether the given URL is allowed to be fetched. This
prevents the server from becoming an open proxy"""
host = split_url(url)[1]
return host in APPROVED_HOSTS
def split_url(url):
"""Splits the given URL into a tuple of (protocol, host, uri)"""
proto, rest = url.split(':', 1)
rest = rest[2:].split('/', 1)
host, uri = (rest[0], rest[1]) if len(rest) == 2 else (rest[0], "")
return (proto, host, uri)
def proxy_ref_info(request):
"""Parses out Referer info indicating the request is from a previously proxied page.
For example, if:
Referer: http://localhost:8080/p/google.com/search?q=foo
then the result is:
("google.com", "search?q=foo")
"""
ref = request.headers.get('referer')
if ref:
_, _, uri = split_url(ref)
if uri.find("/") < 0:
return None
first, rest = uri.split("/", 1)
if first in "pd":
parts = rest.split("/", 1)
r = (parts[0], parts[1]) if len(parts) == 2 else (parts[0], "")
LOG.info("Referred by proxy host, uri: %s, %s", r[0], r[1])
return r
return None
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