mp.start()

The starting middleware, to parse a Wechat message request, and set req.body as a JS object.

mp.end()

The ending middleware, to response a xml based on res.body. For how to set res.body for multi media messages, see source code lib/xml.js.

If your set res.body to a string, will reply a text message. When res.body is an object, a res.body.msgType is expected, otherwise it will be treated as text message, and res.body.content will be replied as it was a string.

典型的响应:

{
  msgType: 'news',
  content: [{
    title: 'news 1',
    url: 'http://...',
    picUrl: 'http://...'
  }, {
    title: 'news 2',
    url: 'http://...',
    picUrl: 'http://...'
  }]
}