node.js - 向 req 添加方法？

Question

像express-validation和passport这样的库会向req-variable添加方法，例如req.assert和req.user。我知道我可以从路线内部执行此操作:

app.get('/', (req,res,next) => {
   req.foo = bar;
   next();
}

但是我如何从库或外部模块中做到这一点？

Answer 1

简而言之:您公开了一个处理程序函数，您的消费者将需要该函数app.use() .

这是一般方法。考虑以下模块:

module.exports = function myExtension() {
  return function myExtensionHandler(req, res, next) {
    // This is called for every request - you can extend req or res here
    req.myFun = myFun

    // Make sure to call next() in order to continue the
    // chain of handlers
    return next()
  }
}

function myFun() {
  // My magic function
}

现在，从消费者的角度来看:

const express = require('express')
const myExtension = require('my-extension')
const app = express()

// Here you tell Express to use your extension for incoming requests
app.use(myExtension())
// ...