CODEWITHSUNDEEP
node.jsexpress
Mazzy
Mazzy

Reputation: 14219

Chain requests in expressjs

I need to create the following process. I have two endpoints and I need to pass to the second endpoint the result of the first endpoint in expressejs. I have thought to make something like the guide shows:

var cb0 = function (req, res, next) {
  console.log('CB0');
  next();
}

var cb1 = function (req, res, next) {
  console.log('CB1');
  next();
}

var cb2 = function (req, res) {
  res.send('Hello from C!');
}

app.get('/example/c', [cb0, cb1, cb2]);

How should I pass to the second one function the result produced by the first one?

Upvotes: 0

Views: 2198

Answers (2)

KlwntSingh
KlwntSingh

Reputation: 1092

you need to create new property to req parameter like 

var cb0 = function (req, res, next) {
  // set data to be used in next middleware
  req.forCB0 = "data you want to send";
  console.log('CB0');
  next();
}

var cb1 = function (req, res, next) {
  // accessing data from cb0
  var dataFromCB0 = req.forCB0

  // set data to be used in next middleware
  req.forCB1 = "data you want to send";
  console.log('CB1');
  next();
}

var cb2 = function (req, res) {
  // accessing data from cb1
  var dataFromCB2 = req.forCB1

  // set data to be used in next middleware
  req.forCB2 = "data you want to send";
  res.send('Hello from C!');
}

app.get('/example/c', [cb0, cb1, cb2]);

Upvotes: 5

Laxmikant Dange
Laxmikant Dange

Reputation: 7688

Simple thing,

Just add result of one chain to request object, so you can access that object in another.

Here is your code.

var cb0 = function(req, res, next) {
  req["CB0"] = "Result of CB0";

  console.log('CB0');
  next();
}

var cb1 = function(req, res, next) {
  req["CB1"] = "Result of CB1";
  console.log('CB1: Result of CB0: ' + req["CB0"]);
  next();
}

var cb2 = function(req, res) {
  console.log('CB2: Result of CB0: ' + req["CB0"]);
  console.log('CB2: Result of CB1: ' + req["CB1"]);
  res.send('Hello from C!');
}

app.get('/example/c', [cb0, cb1, cb2]);

Upvotes: 2

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