Node passing parameters through Q service promise - node.js

Question

I have a middleware setup in node to perform a task and call next upon success or failure. The task is called after an initial promise block runs. It is called in the .then function:
var Q = require('q');
var dataPromise = getCustomerId();
dataPromise
.then(function(data) {
getGUID(req, res, next);
}, function(error) {
console.log('Failure...', error);
});
};
The server hangs though because the (req,res,next) parameters are all undefined when in the context of the .then function.
Here is getCustomerId function:
var getCustomerId = function() {
var getCustomerIdOptions = {
options...
};
var deferred = Q.defer();
request(getCustomerIdOptions, function(err,resp,body){
if(err){
deferred.reject(err);
console.log(err);
return;
}else{
deferred.resolve(body);
}
});
return deferred.promise;
};
What would be the correct way to pass these parameters to the function called in the .then block?
EDIT:
The (req,res,next) parameters are from the outer function and are accessible when getGUID(req,res,next) is called outside of the .then() block.
var assureGUID = function(req, res, next) {
if(app.locals.guid){
next();
return;
}
var dataPromise = getCustomerId();
dataPromise
.then(function(data) {
getGUID(req, res, next)
}, function(error) {
console.log('Failure...', error);
}).;
};

Answer 1

Not sure what you are trying to do exactly, but you can call your promise function inside a express common middleware function like the next sample.
var express = require('express');
var $q = require('q');
var request = require('request');
var app = express();
// Middleware 1
app.use( function(req, res, next) {
console.log('i\'m the first middleware');
getCustomerId().then( function(body) {
console.log('response body', body);
return next();
},
function(err) {
console.log('Error on middlware 1: ', err);
});
});
// Middleware 2
app.use( function(req, res, next) {
console.log('i\'m the second middleware');
return next();
});
app.get('/', function(req, res) {
res.send('hi world');
});
app.listen(3000);
// Your custom function definition
function getCustomerId() {
var deferred = $q.defer();
request('http://someurltogetjsondata/user/id', function(err, resp, body) {
if(err) return deferred.reject(err);
deferred.resolve(body);
});
return deferred.promise;
}
I hope this helps a little, good luck.