用户在关注与取消关注公众号时，微信会把这个事件推送到开发者填写的URL。
微信服务器在五秒内收不到响应会断掉连接，并且重新发起请求，总共重试三次。
假如服务器无法保证在五秒内处理并回复，可以直接回复空串，微信服务器不会对此作任何处理，并且不会发起重试。
<xml> <ToUserName><![CDATA[toUser]]></ToUserName> <FromUserName><![CDATA[FromUser]]></FromUserName> <CreateTime>123456789</CreateTime> <MsgType><![CDATA[event]]></MsgType> <Event><![CDATA[subscribe]]></Event> </xml>
class WeChatHandler(WeChatBaseHandler): """微信接入接口""" def get(self): """开发者验证接口""" echostr = self.get_argument("echostr") self.write(echostr) def post(self): """收发消息接口""" req_xml = self.request.body req = xmltodict.parse(req_xml)['xml'] msg_type = req.get("MsgType") if "text" == msg_type: resp = { "ToUserName":req.get("FromUserName", ""), "FromUserName":req.get("ToUserName", ""), "CreateTime":int(time.time()), "MsgType":"text", "Content":req.get("Content", "") } elif "voice" == msg_type: resp = { "ToUserName":req.get("FromUserName", ""), "FromUserName":req.get("ToUserName", ""), "CreateTime":int(time.time()), "MsgType":"text", "Content":req.get("Recognition", u"未识别") } elif "event" == msg_type: if "subscribe" == req.get("Event"): resp = { "ToUserName":req.get("FromUserName", ""), "FromUserName":req.get("ToUserName", ""), "CreateTime":int(time.time()), "MsgType":"text", "Content":u"感谢您的关注！" } else: resp = None else: resp = { "ToUserName":req.get("FromUserName", ""), "FromUserName":req.get("ToUserName", ""), "CreateTime":int(time.time()), "MsgType":"text", "Content":"I love you, itcast!" } if resp: resp_xml = xmltodict.unparse({"xml":resp}) else: resp_xml = "" self.write(resp_xml)
