#!/usr/bin/python3
# Copyright (c) 2015, Ralf Jung <post@ralfj.de>
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 
# 1. Redistributions of source code must retain the above copyright notice, this
#    list of conditions and the following disclaimer. 
# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#==============================================================================

# This is the CGI script receiving GitHub webhooks.
# You may have to change the location of the "main" webhook script:
webhook_core = "/home/git/git-mirror/webhook-core.py"
#
import urllib.request, urllib.parse, json, os, sys

def is_github(remote_addr):
    '''Returns whether the address is a github hook address. This function requires Python 3.3.'''
    from ipaddress import ip_address, ip_network
    remote_addr = ip_address(ip_network)
    github = urllib.request.urlopen('https://api.github.com/meta').read()
    github = json.loads(github.decode('utf-8'))
    for net in github['hooks']:
        if remote_addr in ip_network(net):
            return True
    return False

# get repository from query string
query = os.getenv("QUERY_STRING")
query = urllib.parse.parse_qs(query)
repository = query.get('repository', [])
repository = repository[0] if len(repository) else ''

# execute the actual script
os.execlp("sudo", "sudo", "-n", "-u", "git", webhook_core, repository)