I'm trying to get some information from the mongodb server to the frontend with ajax get request. Everything works fine except that if i try to call 5 times the javascript function, i dont get any response from my local server.
I tried to put some console.log() in order to debug in the nodejs function, it appears that the 6th time i call the function, the nodejs function doesn't even run.
javascript ajax front end code :
function addLike(music){
var request = new XMLHttpRequest();
request.open('POST', '/AddLike', true);
request.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
var myobj = {"music": music};
request.send(JSON.stringify(myobj));
setTimeout(function(){
$.ajax({
url: "/getAll",
type: 'GET',
dataType: 'json', // added data type
success: function(res) {
// => the 6th time i launch addLike(music), the function doesn't go there
update(res);
}
});
}, 200);
}
nodejs function :
app.get("/getAll", function(req, res){
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, { useNewUrlParser: true }, function(err, db) {
if (err) throw err;
var dbo = db.db("SoundShare");
var tab = dbo.collection('Musique');
tab.find({}).toArray(function(err2, result) {
if (err2) throw err2;
res.send(JSON.stringify(result));
db.close();
});
});
});
As you can see on the image below, in the console of firefox the last get ajax request doesn't receive any response.
.
.
It seems like it is a server side problem but i don't understand how to fix it.
Thank you in advance for your answer.
Your problem is that you are creating a new connection inside your /getAll function and the default poolsize is 5 as you can see in the docs.
You should be creating the connection when your node.js app starts up and use that connection throughout the application instead of creating a new connection on each request.
Related
I am trying to make a private page dedicated to an Ajax request. Here is the simple request.
window.onload = loaded;
function loaded(){
var xhr = new XMLHttpRequest();
xhr.open('GET', '/data_annotations', true);
xhr.onload = function(){
if(this.status == 200){
var data = xhr.responseText;
console.log(JSON.parse(data));
} else {
console.log("Rip");
}
}
xhr.send();
//httpreq.abort();
}
Here is the node.js that it's running off of:
...
app.get('/', function(req, res, next){
console.log("Connected Successfully.");
res.render('home');
});
app.get('/data_annotations', function(req, res, next){
if(req.xhr || req.headers.accept.indexOf('json') > -1) {
const mc = mongo.MongoClient;
const url = 'mongodb://localhost:27017/';
const dbName = 'practiceMDB';
console.log("Got Data Annotations.");
mc.connect(url, { useNewUrlParser: true }, (err, client) =>{
if(err){
console.log(err);
} else {
const db = client.db(dbName);
data = db.collection('DataAnnotations');
data.find({}).toArray(function(err, data){
res.send(data)
});
client.close();
}
});
} else {
res.redirect('/');
}
});
app.listen(port, function(){
console.log('Server Started on Port '+port);
});
I only want /data_annotaion to run if it's from the Ajax request. If a user types in /data_annotations in the url, it should redirect them to the home page. When I ran this I got these results:
Server Started on Port 3000
Connected Successfully.
Connected Successfully.
This is indicating (to me) that the ajax request isn't registering as an ajax request, and is registering as a normal request. Further, I am getting this error:
Uncaught SyntaxError: Unexpected token < in JSON at position 0
I believe it is due to the redirection. The Ajax request gets redirected, it takes the response of the home page and is unable to parse it (I believe this to be happening because it cannot parse HTML text or string text - don't quote me on that). How do I get Node JS to register my Ajax request?
PS: I looked at this answer to determine if a request is Ajax or not, but it always determines my requests as not Ajax: https://stackoverflow.com/a/28540611/6804700
First thing - In your client-side code you need to set the accept header, because that is what you are looking for in your server side code.
xhr.setRequestHeader("accept", "application/json");
Second you can use the following code to return the data as json in your server side code
res.json(data);
Another comment. It is bad practice to change the result type or redirect in an API. Your url is either returning JSON or redirecting to and HTML page which means the result is not consistent.
Good morning everyone, I have a question regarding the behavior of my firebase database.
I am populating an end point on my database user with multiple POST requests to my express server app.js from my client like so:
element.on("click", function(){
send request 1 - endpoint1
send request 2 - endpoint2
send request 3 - endpoint3
}
Then in my app.js I have handlers at the routes that use the Request package to make three seperate GET request to the Halo Waypoint API like so:
app.post(endpoint1, function(req,res){
request(HaloAPI + endpoint1, function(error, res, body){
[store data from the response body into an
object to be sent to firebase endpoint 'user']
// User's stats
database + "/user".set(dataObject)
}
}
app.post(endpoint2, function(req,res){
request(HaloAPI + endpoint2, function(error, res, body){
[store data from the response body into an
object to be sent to firebase endpoint 'user'.
This is a url for an image]
//This is a player's emblem
database + "/user/emblem".set(dataObject)
}
}
app.post(endpoint3, function(req,res){
request(HaloAPI + endpoint3, function(error, res, body){
[store data from the response body into an
object to be sent to firebase endpoint 'user'.
This is a url for an image]
//This is a player's Spartan portrait
database + "/user/spartanImage".set(dataObject)
}
}
I'm expecting the database to be updated all at the same time; however, that is not the case all the time. Usually when I click the button with the event listener attached endpoint 2 and 3 come in at the same time as the data from endpoint 1, but most of the time I only get data from only endpoint 2 or only endpoint 3. Eventually I stop getting the data from endpoint 2 and 3 all together. In fact, with this current setup I can see the endpoints user/emblem and user/spartanImage populate in the database console but then they are taken away as soon as they are added. This has been troubling me from the beginning of this project and I would really appreciate some insight from someone more experience in Firebase than myself. Below I will link my relevant code, thanks in advance for the help.
request.js is where the initial AJAX calls are made client-side:
$searchButton.on("click", function(event){
event.preventDefault();
// the value of the search field creates the request object
// it is just a user's Xbox Live Gamertag and is used for the
// the subsequent requests.
var $search = $("#searchField").val();
$.post(homeRoute + "statSearch", {search: $search}, function(data){
console.log(data)
});
firebase.database().ref().on("value", function(snapshot){
function ez(path){
return snapshot.child(path).val();
}
var dataObject = {
gamertag: ez("gamertag"),
totalKills: ez("totalKills"),
totalDeaths: ez("totalDeaths"),
totalGames: ez("totalGames")
};
console.log(dataObject)
});
$.post(homeRoute + "emblemSearch", {search: $search}, function(data){
console.log(data)
});
$.post(homeRoute + "spartanSearch", {search: $search}, function(data){
console.log(data)
});
From there we go over to app.js my express server to make GET requests to the Halo Waypoint API and send the response formatted with the data I want to firebase:
app.post("/statSearch", function(req, res){
var search = req.body.search;
var statsOptions = new Options("https://www.haloapi.com/stats/h5/servicerecords/warzone?players="+search);
request(statsOptions, function (error, response, body) {
if (error) throw new Error(error);
var body = JSON.parse(response.body)
var playerData = {
gamertag: body.Results[0].Id,
totalKills: body.Results[0].Result.WarzoneStat.TotalKills,
totalDeaths: body.Results[0].Result.WarzoneStat.TotalDeaths,
totalGames: body.Results[0].Result.WarzoneStat.TotalGamesCompleted
};
res.send(playerData)
var userRef = ref.child("user");
// sending off the data object to Firebase at the "user" endpoint
userRef.set(playerData);
});
});
//emblem
app.post("/emblemSearch", function(req, res){
var search = req.body.search;
var imgOptions = new Options('https://www.haloapi.com/profile/h5/profiles/'+search+'/emblem', '512');
request(imgOptions, function (error, response, body) {
if (error) throw new Error(error);
var imgString = response.request.uri.href;
res.send(imgString);
var emblemRef = ref.child("user/emblem");
// sending off the url to Firebase at the endpoint "user/emblem"
emblemRef.set(imgString);
});
});
//spartan image
app.post("/spartanSearch", function(req, res){
var search = req.body.search
var spartanOptions = new Options('https://www.haloapi.com/profile/h5/profiles/'+search+'/spartan', '256');
request(spartanOptions, function (error, response, body) {
if (error) throw new Error(error);
var imgString = response.request.uri.href;
res.send(imgString);
var spartanImage = ref.child("user/spartanImage");
// doing the same as emblem to this endpoint^^^^
spartanImage.set(imgString);
});
});
I'm working on a small web framework to run a HCI study in and came across the following problem:
I have a Node server running with express to serve my local host data from JSON files. Not the best db but since it's a single user system (only one participant will ever be using the system at any time) it really didn't make sense to add any other technology. The following Get request code works just fine:
function getUser(id,last) {
return $.ajax({
type: "GET",
url: "/data/user/"+id,
async: false
}).responseJSON;
}
Which is handled by the following node code:
app.get('/data/:asset/:id', function (req, res) {
var accJSN
res.setHeader('Content-Type', 'application/json');
if(req.params.asset === "user")
{
accJSN = JSON.parse(fs.readFileSync(path.join(__dirname,'/public/data/users.json')));
res.send(JSON.stringify(accJSN.users[req.params.id]));
}
The above code produces a response which I can use/print and contains the responseJSON attribute. The following code does not, I'll note the node code is in the same server.js file and the functions with jquery/ajax calls are in my client page:
Client side code:
function getUserset(ids,last) {
userQuery = "";
for(i=0;i<ids.length;i++)
{
userQuery += ids[i] + ",";
}
userQuery = userQuery.slice(0,-1);
return $.ajax({
type: "GET",
url: "/userset?users=["+userQuery+"]",
async: false
}).responseJSON;
}
Server code:
app.get('/userset', function (req, res) {
var accJSN = JSON.parse(fs.readFileSync(path.join(__dirname,'/public/data/users.json')));
accJSN = accJSN.users;
var users = JSON.parse(req.query.users);
var resJSN = new Array;
for(var i=0;i<users.length;i++)
{
var temp = {};
temp["id"] = users[i];
temp["fName"] = accJSN[users[i]].fName;
temp["lName"] = accJSN[users[i]].lName;
temp["profilePic"] = accJSN[users[i]].profilePic;
resJSN.push(temp);
}
res.setHeader('Content-Type', 'application/json');
res.send(JSON.stringify(resJSN));
})
The data I need is actually available in the response text but I cannot for the life of me figure out why the second example doesn't also include the responseJSON attribute, or, if I'm totally wrong, why the first one does. Any thoughts or solutions appreciated, thanks!
Instead of manually setting the application/json header and sending a response just use
res.json(resJSN);
instead of
res.setHeader('Content-Type', 'application/json');
res.send(JSON.stringify(resJSN));
I'm developing a simple NODE.JS application. First I create an httpServer using http module. Then I route the request to the requestsHandlers.js page. 'Response' parameter cames from the creation of the httpServer. Process1, process2 and process3 should write an answer to the page. This is the objective of this app, that process1, process2 and process3 write its respective text.
requestHandlers.js
var process1 = require("./process1");
var process2 = require("./process2");
var process3 = require("./process3");
function iniciar(response) {
console.log("Manipulador de petición 'iniciar' fue llamado.");
response.writeHead(200, {"Content-Type": "text/html"});
process1.fc1(response);
process2.fc2(response);
process3.fc3(response);
//response.end() //WHERE DO I PLACE IT?
}
As you can see, the response parameter is passed to process1.js, which after parsing some data shoud echo some information.
process1.js
var request = require('request')
function fc1 (response){
var url = 'http://webpagethatreturnsJSONfile.com/'
//Download webpage data and parses it
request(url, function(err, resp, body) {
if (err)
throw err;
var jsonResult = JSON.parse(body);
response.write("Number:" + jsonResult.number + '');
//response.end() //WHERE DO I PLACE IT?
});
}
exports.fc1 = fc1;
The point is that I don't know where to put 'response.end()'. Each process takes some time and I want to 'end' when all processes have echo their text.
How could I do it?
I don't know if the code I've attached is enough for helping me.
I'm actually facing a problem with my javascript code executed with node.js
i need to send http requests in a loop to a distant server (i set www.google.ca in the code).
Here is my code :
var http = require('http');
var options = {
hostname: 'www.google.ca',
port: 80,
path: '/',
method: 'GET'
};
function sendRequest(options){
console.log('hello');
var start = new Date();
var req = http.request(options,function(res) {
console.log('Request took:', new Date() - start, 'ms');
});
req.on('error', function(e) {
console.log('problem with request: ' + e.message);
});
req.end();
};
for(var i=0;i<10;i++){
sendRequest(options);
}
The problem I have is that, no matter how many times i go through my loop, i get a response for only the 5 first of them. For the rest of the requests, the function sendRequest() is called but I don't get any responses, neither error message. And then the program terminates.
However it works fine when I set localhost as a host.
Is anyone would have a solution to this problem ?
Thanks in advance !
perhaps either your machine or the remote machine is getting overwhelmed by the 10 simultaneous requests you make. try sending them one at a time, you will have to wait until the first request completes before continuing. one easy way to do so is with async.timesSeries
var http = require('http');
var async = require('async');
var options = {
hostname: 'www.google.ca',
port: 80,
path: '/',
method: 'GET'
};
function sendRequestWrapper(n, done){
console.log('Calling sendRequest', n);
sendRequest(options, function(err){
done(err);
});
};
function sendRequest(options, callback){
//console.log('hello');
var start = new Date();
var req = http.request(options,function(res) {
// I don't know if this callback is called for error responses
// I have only used the `request` library which slightly simplifies this
// Under some circumstances you can accidentally cause problems by calling
// your callback function more than once (e.g. both here and on('error')
console.log('Request took:', new Date() - start, 'ms');
callback(null);
});
req.on('error', function(e) {
console.log('problem with request: ' + e.message);
callback(err);
});
req.end();
};
async.timesSeries(10, sendRequestWrapper);