# coding:utf-8
from hashlib import sha1
from flask import Flask, request

token = 'xxxxxx'

app = Flask(__name__)

def get_update(token, timestamp, nonce):
  arguments = ''
  for k in sorted([token, timestamp, nonce]):
    arguments = arguments + str(k)
  m = sha1()
  m.update(arguments.encode('utf8'))
  return m.hexdigest()

def check_signature():
  signature = request.args.get('signature', '')
  timestamp = request.args.get('timestamp', '')
  nonce = request.args.get('nonce', '')
  check = get_update(token, timestamp, nonce)
  return True if check == signature else False

def parse_xml(data):
  try:
    import xml.etree.cElementTree as ET
  except ImportError:
    import xml.etree.ElementTree as ET
    root = ET.fromstring(data)
    datas = '<xml>'
    for child in root:
      if child.tag == 'ToUserName':
        toUser = child.text
        datas += '<FromUserName>%s</FromUserName>' % toUser
      elif child.tag == 'FromUserName':
        fromUser = child.text
        datas += '<ToUserName>%s</ToUserName>' % fromUser
      else:
        datas += '<' + child.tag + '>'
        datas += child.text
        datas += '</' + child.tag + '>'
    datas += '</xml>'
    return datas

@app.route('/weixin', methods=['GET', 'POST'])
def weixinInterface():
  if check_signature:
    if request.method == 'GET':
      echostr = request.args.get('echostr', '')
      return echostr
    elif request.method == 'POST':
      data = request.data
      msg = parse_xml(data)
      return msg
  else:
    return 'signature error'

if __name__ == '__main__':
  app.run(host='0.0.0.0')