How to get a URL parameter in Express

Question

I am facing an issue on getting the value of tagid from my URL  localhost 8888 p tagid 1234   Help me out to correct my controller code  I am not able to get the tagid value   My code is as follows   app js   var express   require  express      http   require  http      path   require  path    var app   express    var controller   require    controller       app  app         all environments app configure function       app set  port   process env PORT    8888     app use express json       app use express urlencoded       app use express methodOverride       app use app router     app use express static path join   dirname   public        app set  view engine    jade      app set  views     dirname     views      app use app router     app get      function req  res        res render  index              http createServer app  listen app get  port    function       console log  Express server listening on port     app get  port           Controller index js   function controller params      var app   params app      var query string   request query query string     app get   p tagId     function request  response           userId is a parameter in the url request     response writeHead 200      return 200 HTTP OK status     response end  You are looking for tagId    request route query tagId            module exports   controller    routes index js   require    controllers          GET home page       exports index   function req  res      res render  index         title   Express

User · Answer

This will work if your route looks like this: localhost:8888/p?tagid=1234

var tagId = req.query.tagid;
console.log(tagId); // outputs: 1234
console.log(req.query.tagid); // outputs: 1234

Otherwise use the following code if your route looks like this: localhost:8888/p/1234

var tagId = req.params.tagid;
console.log(tagId); // outputs: 1234
console.log(req.params.tagid); // outputs: 1234

User · Answer

If you want to grab the query parameter value in the URL  follow below code pieces    url localhost 8888 p tagid 1234 req query tagid OR req param tagid   If you want to grab the URL parameter using Express param function  Express param function to grab a specific parameter  This is considered middleware and will run before the route is called   This can be used for validations  or grabbing important information about item   An example for this would be      parameter middleware that will run before the next routes app param  tagid   function req  res  next  tagid        check if the tagid exists    do some validations    add something to the tagid var modified   tagid   123       save name to the request req tagid  modified   next            http   localhost 8080 api tags 98 app get   api tags  tagid   function req  res       the tagid was found and is available in req tagid res send  New tag id     req tagid

User · Answer

Express 4 x  To get a URL parameter s value  use req params  app get   p  tagId   function req  res      res send  tagId is set to     req params tagId           GET  p 5    tagId is set to 5   If you want to get a query parameter  tagId 5  then use req query  app get   p   function req  res      res send  tagId is set to     req query tagId           GET  p tagId 5    tagId is set to 5     Express 3 x  URL parameter  app get   p  tagId   function req  res      res send  tagId is set to     req param  tagId             GET  p 5    tagId is set to 5   Query parameter  app get   p   function req  res      res send  tagId is set to     req query  tagId             GET  p tagId 5    tagId is set to 5

User · Answer

You can do something like req param  tagId

[javascript] How to get a URL parameter in Express?

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