CODEWITHSUNDEEP
javascriptnode.jsexpress
Learner
Learner

Reputation: 21405

add json data to middleware request

I am new to express and node, I working on a task where I want to add some json data to middleware request, here is the approach I am following:

In my middleware I want to add some details to request like current date and time and then extract the URL path. Here is the code I came up with: 

var express = require('express');

var app = express();
module.exports = app.use('/some-url', function(req, res, next) {
     let logdetails = {
      id: "some-id",
      datetime: Date.now(),
      path: '/path-in-url'
    }
    req.logdetails= logdetails;
    next();
} );

I am using module.exports so it this function is exported. But it is giving errors. Also what is the correct way to access the URL path, for example if URL is /users/john then I want to extract /john and my middleware should be applied only when URL starts with /users.

Upvotes: 1

Views: 1175

Answers (4)

Alexander
Alexander

Reputation: 272

middleware.js

module.exports = {
    handler: (req, res, next) => {
        const userName = req.params.name;

        // add payload to request

        next();
    }
}

app.js

middleware = require("middleware");

app.use('/users/:name', middleware.handler);

Concerning URL path access you could get access using request params, e.g

app.use('/users/:name', (req, res, next) => {
    const userName = req.params.name;

    // add payload to request

    next();
});

 1. Register your specific URL - `/users/:name`, where `:name` is dynamic params e.g *john*
 2. Grab params in the callback

Upvotes: 1

saiteja
saiteja

Reputation: 86

req.originalUrl returns the url path like shown below

// GET /search?q=something
console.dir(req.originalUrl)
// => '/search?q=something'

source: https://expressjs.com/en/api.html

Similarly, get the URL path and split the string accordingly and apply the condition you need.

Here if your originalPath is /users/john then

const result = "/users/john".split("/")

would result in ["", "users", "john"]

Check if the result[1]==="users" and write your condition in the middleware.

You don't have to export the middle ware.

Upvotes: 1

Aritra Chakraborty
Aritra Chakraborty

Reputation: 12542

If you want the middleware then just export the middleware function. Not the Whole app.use part. I think app.use returns an Express object. And :param in your url will make sure that you can access that parameter. You can check out more about path patterns here

middleware.js

module.exports = function(req, res, next) {
     let logdetails = {
      id: "some-id",
      datetime: Date.now(),
      path: '/path-in-url'
    }
    req.logdetails= logdetails;
    next();
}

Your other main.js file:

const express = require('express');
const app = express();
const middleWare = require('./middleware')

app.use('/users/:name', middleWare, (req, res)=>{
  //you can access logDetails
  // and the name
  const name = req.params.name;//This will be john for /users/john
  const logDetails = req.logdetails;
})

Upvotes: 1

Yousaf
Yousaf

Reputation: 29282

Also what is the correct way to access the URL path, for example if URL is /users/john then I want to extract /john

If your request url is /users/john then req.path will give you the path of the request url, i.e. /users/john. To extract john, you can use named route parameters and define your route as /users/:name. After using named route parameter in your route, if your request url is /users/john, req.params.name will give you the route parameter, i.e. john. For more details, take a look at req.params on express docs

and my middleware should be applied only when URL starts with /users

following middleware will only run when request path is /users

app.use('/users', (req, res, next) => {
   ...
}

Upvotes: 2

Related Questions