Node.js http.get with Node.js step module - node.js

Question

I am new to Node.js world, kind of stuck in situation.
below code is for reference:
var http = require('http');
var step = require('step');
var request = require('request');
exports.readimage2 = function(req, res){
//res.send(200,'OK');
//var image_url = 'http://www.letsgodigital.org/images/artikelen/39/k20d-image.jpg'; //--- 10mb
//var image_url = 'http://upload.wikimedia.org/wikipedia/commons/2/2d/Snake_River_(5mb).jpg';
//var image_url = 'http://www.sandia.gov/images2005/f4_image1.jpg'; //--- 2mb
var image_url = 'http://www.fas.org/nuke/guide/pakistan/pakistan.gif'; // --- some KB
http.get(image_url,
function(responseData) {
var data = new Buffer(parseInt(responseData.headers['content-length'],10));
var pos = 0;
responseData.on('data', function(chunk) {
chunk.copy(data, pos);
pos += chunk.length;
});
responseData.on('end', function () {
res.send(200, data);
});
});
};
Above code fails working for large files if i use it with step module.
Anyone suggest how to do it properly with step.

Answer 1

Here how i did it using step..... although the request module did same for image buffer download thanks to a post on stackoverflow just need to set encoding to null in request to work for buffer response.
var canvas = new Canvas(3000, 3000),
ctx = canvas.getContext('2d'),
Image = Canvas.Image;
var image_url = "http://www.a2hosting.com/images/uploads/landing_images/node.js-hosting.png";
//var image_url = 'http://upload.wikimedia.org/wikipedia/commons/1/16/AsterNovi-belgii-flower-1mb.jpg';
step(
function() {
request.get({
url: image_url,
encoding: null
}, this);
},
function(err, response, body) {
var img = new Image;
img.src = body;
ctx.drawImage(img, 0, 0, img.width, img.height);
//res.send(200, data);
res.send(200, '<img src="' + canvas.toDataURL() + '" />');
}
);
Below is the code working for simple http module of node.
var http = require('http');
var step = require('step');
var request = require('request');
exports.imagedownload = function(req, res){
step(
function(){
console.log('*********** image download start ***********');
fndownload(this);
},
function(err, result){
if(err) {
}
console.log('*********** image download end ***********');
res.send(200, result);
}
);
};
function fndownload(callback) {
var image_url = 'http://upload.wikimedia.org/wikipedia/commons/2/2d/Snake_River_(5mb).jpg'; // --- some KB
http.get(image_url,
function(responseData) {
var data = new Buffer(parseInt(responseData.headers['content-length'],10));
var pos = 0;
responseData.on('data', function(chunk) {
chunk.copy(data, pos);
pos += chunk.length;
});
responseData.on('end', function () {
//res.send(200, data);
callback(null, data);
});
});
};