We Keep Coding

getting progress callback with jQuery and node express server

I am trying to grasp using node express server and jQuery.ajax() in tandem. I have created a code repository with the following structure:
/
|-public
| |-index.html
|-server.js
My index page has the following JS snippet in it:
var successHandler = function (data, status, jqXHR) {
console.log('success')
};
var failHandler = function (jqXHR, status, errorThrown) {
console.log('fail')
};
var progressHandler = function () {
console.log('progress')
};
var ajaxConfig = {
url: 'http://localhost:4444/test',
type: 'GET'
};
$.ajax(ajaxConfig).then(successHandler, failHandler, progressHandler);
the server-side code is defined as such:
const express = require('express')
const app = express()
const sleep = require('sleep')
app.get('/test', function (req, res) {
console.log('/test method called!');
sleep.sleep(3);
res.status(202).send({"thing":"stuff"})
})
app.post('/test', function(req,res){
res.status(202).send('ok')
})
app.use(express.static('public'))
app.use(express.static('node_modules/jquery/dist'))
app.listen(4444, function () {
console.log('Running on localhost:4444!')
})
The thing that I want to accomplish is to get some hits on the progress handler, just to get it to write data in the console.
According to this page, I need to use the deffered.notify() method to trigger the handler but I have no idea how to get to the deffered object. I tried saving the return value of $.ajax() but that doesn't seem to have the notify() method since it is a jqXHR object.
It is my understanding that I need to have a progress handler defined on the server-side (the post handler for the /test route) that gets called to get to the current status of the pending task. Don't think making a new ajax request is the way to go, but I might be wrong. I have also found some articles that utilize the setTimeout method, My guess is that it gets used in order to repeatedly call the endpoint that gives status info.

Node.js app receives empty response from GET request to API

I'm new to node.js so I'll try my best to explain the problem here. Let me know if any clerification is needed.
In my node.js application I'm trying to take a code (which was received from the response of the 1st call to an API), and use that a code to make a 2nd request(GET request) to another API service. The callback url of the 1st call is /pass. However I got an empty response from the service for this 2nd call.
My understanding is that after the call back from the 1st call, the function in app.get('/pass', function (req, res).. gets invoked and it sends a GET request. What am I doing wrong here? Many thanks in advance!
Here is the part where I try to make a GET request from node.js server and receive an empty response:
app.get('/pass', function (req, res){
var options = {
url: 'https://the url that I make GET request to',
method: 'GET',
headers: {
'authorization_code': code,
'Customer-Id':'someID',
'Customer-Secret':'somePassword'
}
};
request(options, function(err, res, body) {
console.log(res);
});
});

Im a little confused by what you are asking so ill just try to cover what i think you're looking for.
app.get('/pass', (req, res) => {
res.send("hello!"); // localhost:port/pass will return hello
})
Now, if you are trying to call a get request from the request library when the /pass endpoint is called things are still similar. First, i think you can remove the 'method' : 'GET' keys and values as they are not necessary. Now the code will be mostly the same as before except for the response.
app.get('/pass', (req, res) => {
var options = {
url: 'https://the url that I make GET request to',
headers: {
'authorization_code': code,
'Customer-Id':'someID',
'Customer-Secret':'somePassword'
}
};
request(options, function(err, res, body) {
// may need to JSONparse the body before sending depending on what is to be expected.
res.send(body); // this sends the data back
});
});

Node request() not being sent

I'm using the npm request library and am running into an issue where the request is never sent if I call express's res.send() after calling request. I realize the request callback won't fire if I close the connection, but I'm not even seeing the request being sent in the first place.
This code is being executed on RunKit (formerly TonicDev), an online code editor that allows code execution via endpoints. I'm not seeing this issue on my local machine, so it seems like it may have to do with RunKit. Anyone have any ideas as to what's going on here or how I might work around this?
You can execute the code yourself by going to:
https://runkit.com/gragland/58056bc6e9d9ed00130c84d5 and clicking the endpoint link at the top.
// Helper to return a RunKit compatible express app (runkit.com/tonic/express-endpoint)
var tonicExpress = require("#runkit/tonic/express-endpoint/1.0.0")
// Provide the exports object to the tonicExpress helper
var app = tonicExpress(module.exports)
var request = require('request')
app.get("/", function(req, res){
var request_number = 9
request({
// To see if request is sent go to: https://requestb.in/1coqbqn1?inspect
url: 'http://requestb.in/1coqbqn1',
method: 'POST',
json: {
request_number: request_number,
message: 'hello'
}
})
// The line below has to be commented out for the above request to be sent
// I don't care about the request callback() firing, I just want the request to be sent
res.send('Done')
})

Node.js: POST request sent twice by system

I send JSON POST data via a form in a MEAN environment to my server. On the server side, I process the data inside of a waterfall function, using the async library, including various operations such as:
[...]
- create a database entry for a new author
- create a database entry for a new book
- associate the new book to an author (reference to book ID)
[...]
This is the method called by my route, which handles the associated POST-request:
exports.createAuthor = function(req, res) {
console.log(req.url+' !!!POST REQUEST INCOMING!!! '+req.body);
async.waterfall([
function(callback){
//create Author db entry
},
function(parameter, callback){
//add author to additional directory (db action)
},
function(parameter, callback){
//create book db entry
},
function(parameter, callback){
//associate book to author (db action)
}
], function (err, result) {
console.log('DONE!!!');
res.send('200');
});
}
This is the client-side AngularJS controller code:
searchApp = angular.module("searchApp",[]);
searchApp.controller('authorCreator', function ($scope,$http) {
$scope.tags = [];
$scope.sendAuthor = function(){
alert('I was called!');
$http({
method: 'POST',
url: '/newauthor/',
data: { 'authorname' : $scope.authorName,
'authordescription' : $scope.authorDescr,
'bookname' : $scope.bookName,
'tags' : $scope.tags }
})
.success(function(data){
//no actions yet
})
.error(function(){
//no actions yet
});
};
});
This is the AngularJS form:
<div ng-controller="authorCreator">
<form>
<p>Author name: <input ng-model="authorName"></p>
<p>Author description: <input ng-model="authorDescr"></p>
<p>Book name: <input ng-model="bookName"></p>
<p>Tags:<input ng-model="tags"></p>
<p><button ng-click="sendAuthor()">Send</button></p>
</form>
</div>
I noticed that, if the waterfall-process is "stuck" somewhere, meaning the client does not get an answer to it's request whatsoever, the POST request seems to be sent a second time automatically (as soon as the browser is giving a timeout according to firebug). According to firebug, a second POST request does not seem to be sent by the browser, so the call must be initiated from somewhere else.
I found out by checking the database (multiple documents with identical values, except the ObjectID of course) and monitoring the node.js console window where I output incoming POST data. Again: as soon as the entire waterfall-process completes, hence the client browser does not abort the post request after a while, and res.send('200') executes, the error does not occur (= no multiple db entries).
Can anyone please tell me, who does initiate this second POST request and how may I deactivate it?
Cheers
Igor

Try adding this:
exports.createAuthor = function(req, res) {
if(req.method == 'POST' && req.url = 'REQUESTEDURL'){
console.log('POST REQUEST INCOMING!!! '+req.body);
async.waterfall([
//TODO...
]);
}
Maybe the problem is that the favicon or some other resource is doing a request to

After spending some time on that issue I found out, that this error seems to be based on missing answers to the client (be it via res.json, res.sendfile, ...). Therefore the client seems to re-send the request after some time, thus executing server-side code a second time. Responding to the client in reasonable time solves this issue. Sorry for the confusion.

i "fixed" this by adding
.get('/favicon.ico:1', (req, res) =>{
//do nothing because i dont care
})

Getting Data from Node.js file and displaying it in HTML/JS page

I am new to Node.js and this is my first project with it.
I have made a node.js file named test.js. It has an array say a.
Now I want to make a HTML file that calls this test.js on button click event. Then get the data from that file and publish it on a table in the HTML file.
I have already written the node.js file and I can see the results on console.log(a). But I cant understand how to send this array to HTML when it will ask for it.
Meanwhile, I googled and made up some code. The request reaches the server but I always get error response from server. Why so?
Client Side -
function fetch() {
$.ajax({
type: 'POST',
url: "http://127.0.0.1:8888",
data: 'China',
datatype: 'json',
success: function (data) {
alert("hi");
var ret = jQuery.parseJSON(data);
$('#q').html(ret.msg);
},
error: function (xhr, status, error) {
alert("hii");
}
});
Server side :
http.createServer(function(request, response) {
console.log("Request received");
response.writeHeader(200, {"Content-Type": "application/json"});
request.on('data', function (chunk) {
console.log(chunk.toString('utf8'));
consol.log(result);
response.write(JSON.stringify({data : result}));
});
response.end();
}).listen(8888);
I can see China on the console.But I dont get back the result array back to the client. Here result is an array and I get its value on the console. Just that I dont get it back to the client. Any help ?

You should start by setting up a server to serve requests. I use expressjs for this - http://expressjs.com/
This will allow you to run nodejs as a web application.
Setup a route in express JS to serve your data - http://expressjs.com/api.html#express
var express = require('express');
var app = express();
app.get('/data', function(req, res){
res.send('hello world'); //replace with your data here
});
app.listen(3000);
Open up a browser, and type in http://MY_SERVER_ADDR:3000/data and you should see your output there.
Next, you'll need to attach an event handler to your HTML file that will trigger a $.get() request when it is triggered. Add the previous url to your data in your $.get call and do something with it.
$('.my_selector').click(function(){
$.get('http://MY_SERVER_ADDR:3000/data', {}, function(data){
console.log(data)
});
});
That should get you going.

After wrestling with the same question, i found that this is exactly where a template engine comes into the node-picture.
EJS solved it for me, but there are many more available.
This article compares 10 template engines.