Develop Reference

node js:add mysql query result to json in forloop

I am trying to add query result from in for loop to JSON
function (req,res){
var result = [{id:1
},{id:2},{id:3}];
for(var i=0;i<result.length;i++){
//query run
collection.getImages(result[i].id,function (status,error,image) {
//add query result to json
result[i]['images']=image;
});
}
res.json(result);
}
But the final result doesn't contains the newly added key value(ie images) it because collection.getImages() is asynchronous so how can i
solve this?

You could use Promises to handle your asynchronous calls. Then you can use Promise.all() to await all actions before sending your result back to the client.
var result = [
{id: 1}, {id: 2}, {id: 3}
];
var promises = [];
for (var i = 0; i < result.length; i++) {
//query run
promises.push(new Promise(function (resolve, reject) {
collection.getImages(result[i].id, function (status, error, image) {
if (error) {
reject(error);
} else {
resolve(image);
}
});
}));
}
Promise.all(promises).then(function (images) {
for (var i = 0; i < images.length; i++) {
result[i]['image'] = images[i];
}
res.json(result)
}).catch(function (error) {
// handle error
});

mongoose-random response 500

I've just opened a nodeJS code trying to get random documents from my mongoose collection using mongoose-random, but for any reason when I call to findRandom() method, it responses a 500.
test.js
Here bellow I paste my code:
var mongoose = require('mongoose');
var random = require('mongoose-random');
var Promise = require('bluebird');
mongoose.Promise = Promise;
var TestSchema = new mongoose.Schema({
_id: {
type: Number,
default: 0
}
});
TestSchema.plugin(random, {path: 'r'});
TestSchema.statics = {
start: function (value) {
var array = [], i = 1;
for (i; i < value; i += 1) {
array.push({ _id: i });
}
return this.create(array);
},
getRandom: function () {
return new Promise(function(resolve, reject) {
TestSchema.findRandom().limit(10).exec(function (err, songs) {
if (err) {
reject(err);
} else {
resolve(songs);
}
});
});
}
};
module.exports = mongoose.model('TestSchema', TestSchema);
routes.js
var router = require('express').Router();
var path = require('path');
var Promise = require('bluebird');
var request = require('request');
var test = require('./models/test.js');
router.get('/fill', function (req, res) {
test.start(40)
.then(function () {
res.status(200).send('You can start your hack :)');
})
.catch(function (error) {
res.status(400).send(error);
});
});
router.get('/vote', function (req, res) {
test.getRandom()
.then(function (data) {
res.status(200).send(data);
})
.catch(function (error) {
res.status(400).send(error);
});
});
module.exports = router;
Reading other post here as a solution purposes to use syncRandom() method, but that doesn't work for me. Neither using random()
Any help? Thanks in advice.
UPDATE
Digging more into the issue, I've realiced my model TestSchema, which should contain mongoose-random methods is being overrided, so I only have my statics methods.

Don't set statics to a new object, just add methods to it:
TestSchema.statics.start = function (value) {
var array = [], i = 1;
for (i; i < value; i += 1) {
array.push({ _id: i });
}
return this.create(array);
};
TestSchema.statics.getRandom = function () {
return new Promise(function(resolve, reject) {
TestSchema.findRandom().limit(10).exec(function (err, songs) {
if (err) {
reject(err);
} else {
resolve(songs);
}
});
});
};
However, if your MongoDB server is at least 3.2, you're probably better off using the built-in $sample pipeline operator instead of a plugin to select random documents.
test.aggregate([{$sample: 10}], callback);

Using promises in my mean stack app

I've created a controller that does a bing search based on the user's input into the url. Based on my results from doing a console.log the controller is working correctly and I have set that variable to return. In the route file the information is not displaying to the page. I thought it might be an asynchronous issue so I am trying to use promises to make sure the controller has returned before it tries to do the res.json but I'm not very familiar with promises so my syntax might be off or I might be going about this the wrong way. Will someone take a look at this syntax and see if there is an issue.Currently only an empty object is displaying on the page.
app.route('/imagesearch/:keyword')
.get(function (req, res) {
var resObj = [];
resObj = new Promise (function(resolve, reject){
resolve(bingSearchHandler.findImages(req.params));
});
resObj.then(res.json(resObj));
});
//BINGSEARCHHANDLER
'use strict';
var bingAPPID = 'fwHyQAoJMJYmK8L4a3dIV2GAEUfXAlFRjCnBx0YbfPE=';
var Search = require('bing.search');
var util = require('util');
var search = new Search(bingAPPID);
function bingSearchHandler () {
this.findImages = function(userInput){
var keyword = userInput.keyword;
search.images(keyword,
{top: 10},
function(err, results) {
if(err)
{
console.log(err);
}
else
{
var resArr = [];
(util.inspect(results,
{colors: true, depth: null}));
for(var i=0;i<results.length;i++)
{
var tempObj = {};
tempObj.url = results[i].url;
tempObj.snippet = results[i].title;
tempObj.thumbnail = results[i].thumbnail.url;
tempObj.context = results[i].sourceUrl;
resArr.push(tempObj);
}
console.log(resArr);
return resArr;
}
}
);
}
}
module.exports = bingSearchHandler;

Could you please try this code? Here you have the bing.search documentation, https://www.npmjs.com/package/bing.search Always try to use callbacks instead of promises in NodeJs, remember that the first parameter of a callback is always the error (if there is any), then the response
app.route('/imagesearch/:keyword')
.get(function (req, res) {
bingSearchHandler.findImages(req.params, function (err, response) {
if (err) return res.status(400)
res.json(response)
})
});
//BINGSEARCHHANDLER
'use strict';
var bingAPPID = 'fwHyQAoJMJYmK8L4a3dIV2GAEUfXAlFRjCnBx0YbfPE=';
var Search = require('bing.search');
var util = require('util');
var search = new Search(bingAPPID);
function bingSearchHandler () {
this.findImages = function(userInput, callback){
var keyword = userInput.keyword;
search.images(keyword,
{top: 10},
function(err, results) {
if(err) callback(err)
else
{
var resArr = [];
(util.inspect(results,
{colors: true, depth: null}));
for(var i=0;i<results.length;i++)
{
var tempObj = {};
tempObj.url = results[i].url;
tempObj.snippet = results[i].title;
tempObj.thumbnail = results[i].thumbnail.url;
tempObj.context = results[i].sourceUrl;
resArr.push(tempObj);
}
console.log(resArr);
return callback(null, resArr);
}
}
);
}
}
module.exports = bingSearchHandler;

Something like this should work.
Using callbacks
app.route('/imagesearch/:keyword')
.get(function (req, res) {
// Make the async request, pass the callback function
bingSearchHandler.findImages(req.params, (error, response) => {
if (error === null) {
res.json(response);
}
});
});
Additionally, you'll need to rework your findImages function.
this.findImages = (userInput, callback) => {
var keyword = userInput.keyword;
search.images(keyword, {top: 10}, function (err, results) {
if (err) {
callback(err);
}
else {
var resArr = [];
util.inspect(results, {colors: true, depth: null});
for(var i = 0; i < results.length; i++) {
var tempObj = {};
tempObj.url = results[i].url;
tempObj.snippet = results[i].title;
tempObj.thumbnail = results[i].thumbnail.url;
tempObj.context = results[i].sourceUrl;
resArr.push(tempObj);
}
callback(null, resArr);
}
});
}
Using promises
app.route('/imagesearch/:keyword')
.get(function (req, res) {
// Make the async request, pass the callback function
bingSearchHandler.findImages(req.params).then(response =>
res.json(response);
});
});
// Images function
this.findImages = (userInput) => {
return new Promise((resolve, reject) => {
var keyword = userInput.keyword;
search.images(keyword, {top: 10}, function (err, results) {
if (err && typeof reject === 'function') {
reject(err);
}
else {
var resArr = [];
util.inspect(results, {colors: true, depth: null});
for(var i = 0; i < results.length; i++) {
var tempObj = {};
tempObj.url = results[i].url;
tempObj.snippet = results[i].title;
tempObj.thumbnail = results[i].thumbnail.url;
tempObj.context = results[i].sourceUrl;
resArr.push(tempObj);
}
if (typeof resolve === 'function') {
resolve(resArr);
}
}
});
});
}

Cant send headers after already sent?

What does that even mean in terms of the following code, the res.send works fine however in my console i get the following message:
http.js:689
throw new Error('Can\'t set headers after they are sent.');
app.get('/summoner/:summonerName', function(req, res) {
lolapi.Summoner.getByName(req.params.summonerName, function(err, obj) {
var options = {
beginIndex: 0,
endIndex: 1
};
lolapi.MatchList.getBySummonerId(obj['savisaar2'].id, options, function(err, matches) {
var gameMatches = matches.matches;
for(var i = 0; i < gameMatches.length; i++) {
lolapi.Match.get(gameMatches[i].matchId, function(err, games) {
res.send({profile : obj, matchHistory : games});
});
}
});
});
});

As I explained in my comments, you are calling res.send() inside a for loop which means you are calling it more than once. You can only call it once per request. That is why you are seeing the error message in the console.
It is not clear exactly what your code really wants to do, but if the desire is to collect all the results into an array and send them all as the response, then you can do that like this:
app.get('/summoner/:summonerName', function (req, res) {
lolapi.Summoner.getByName(req.params.summonerName, function (err, obj) {
if (err) {
return res.status(500).end();
}
var options = {beginIndex: 0, endIndex: 1};
lolapi.MatchList.getBySummonerId(obj['savisaar2'].id, options, function (err, matches) {
var gameMatches = matches.matches;
var results = [];
for (var i = 0; i < gameMatches.length; i++) {
lolapi.Match.get(gameMatches[i].matchId, function (err, games) {
if (err) {
return res.status(500).end();
}
results.push({profile: obj, matchHistory: games});
// if all results are done, then send response
if (results.length === gameMatches.length) {
res.json(results);
}
});
}
});
});
});
Note: I've also added rudimentary error handling.
If you want the results in the particular order that you requested then, then you can add a little more code to do that like this:
app.get('/summoner/:summonerName', function (req, res) {
lolapi.Summoner.getByName(req.params.summonerName, function (err, obj) {
if (err) {
return res.status(500).end();
}
var options = {beginIndex: 0, endIndex: 1};
lolapi.MatchList.getBySummonerId(obj['savisaar2'].id, options, function (err, matches) {
var gameMatches = matches.matches;
var results = new Array(gameMatches.length);
var cntr = 0;
for (var i = 0; i < gameMatches.length; i++) {
(function(index) {
lolapi.Match.get(gameMatches[i].matchId, function (err, games) {
if (err) {
return res.status(500).end();
}
++cntr;
results[index] = {profile: obj, matchHistory: games};
// if all results are done, then send response
if (cntr === gameMatches.length) {
res.json(results);
}
});
})(i);
}
});
});
});
Since Promises are now standard in 2016, here's an idea what this could look like using the Bluebird promise library:
const Promise = require('bluebird');
Promise.promisifyAll(lolapi.Summoner);
Promise.promisifyAll(lolapi.MatchList);
Promise.promisifyAll(lolapi.Match);
app.get('/summoner/:summonerName', function (req, res) {
var main;
lolapi.Summoner.getByNameAsync(req.params.summonerName).then(function(obj) {
main = obj;
var options = {beginIndex: 0, endIndex: 1};
return lolapi.MatchList.getBySummonerIdAsync(obj['savisaar2'].id, options);
}).then(function(matches) {
var gameMatches = matches.matches;
return Promise.map(gameMatches, function(item){
return lolapi.Match.getAsync(item.matchId).then(function(games) {
return {profile: main, matchHistory: games};
});
});
}).then(function(results) {
res.json(results);
}).catch(function(err) {
res.status(500).end();
});
}

Syncano Codebox - Call API - parse JSON - get Reference - Save new Objects

I am using Syncano as a baas, where I am trying to call an external API to receive a JSON array. This JSON needs to be parsed and afterwards stored in syncano. Before that I need to receive the reference object from the DB to link it to the new team object.
I receive the team (json) array & reference object successfully. But I am unable to get the new data stored, as only 12-14 teams (has to be 18) get saved.
I tried this & that with promises but it didn´t work out. Anyone a good advise how to rewrite the code to store all data? Thank you - here is what I have so far...
//TODO: get from ARGS when executing this codebox
var teamKey = 394;
var requestURL = 'http://api.football-data.org/v1/soccerseasons/' + teamKey + "/teams";
var request = require("request");
var Syncano = require('syncano');
var Promise = require('bluebird');
var account = new Syncano({
accountKey: "abc"
});
var promises = [];
//from: http://docs.syncano.io/v1.0/docs/data-objects-filtering
//"_eq" means equals to
var filter = {
"query": {
"apikey": {
"_eq": apiKey
}
}
};
request({
headers: {
'X-Auth-Token': 'abc'
},
url: requestURL,
'Content-Type': 'application/json;charset=utf-8;',
method: 'GET',
}, function(error, response, body) {
if (error) {
console.log(error);
} else {
var json = JSON.parse(body);
var teamArray = json.teams;
var newObject;
account.instance('instance').class('competition').dataobject().list(filter)
.then(function(compRes) {
var competitionID = compRes.objects[0].id;
for (var i = 0; i < teamArray.length; i++) {
newObject = {
"name": teamArray[i].name,
"nameshort": teamArray[i].code,
"logo": teamArray[i].crestUrl,
"competition": competitionID
};
(account.instance('instance').class('teams').dataobject().add(newObject).then(function(res) {
console.log(res);
}).catch(function(err) {
console.log("Error eq: " + err);
})
);
}
}).catch(function(err) {
console.log(err);
});
}
});

The issue might be you are finishing the request process before all the save calls are made, you could try Promise.all():
account.instance('instance').class('competition').dataobject().list(filter)
.then(function(compRes) {
var competitionID = compRes.objects[0].id, promises=[];
for (var i = 0; i < teamArray.length; i++) {
newObject = {
"name": teamArray[i].name,
"nameshort": teamArray[i].code,
"logo": teamArray[i].crestUrl,
"competition": competitionID
};
promises.push(account.instance('instance').class('teams').dataobject().add(newObject).then(function(res) {
console.log(res);
}).catch(function(err) {
console.log("Error eq: " + err);
})
);
}
return Promise.all(promises);
}).catch(function(err) {
console.log(err);
});
if too many parallel calls at a time is the issue then chain one call after other:
account.instance('instance').class('competition').dataobject().list(filter)
.then(function(compRes) {
var competitionID = compRes.objects[0].id, promise = Promise.resolve();
function chainToPromise(promise, teamObj, waitTime){
waitTime = waitTime || 500;
return promise.then(function(){
return new Promise(function(resolve, reject){
setTimeout(resolve, waitTime);
});
}).then(function(){
return account.instance('instance').class('teams').dataobject().add(teamObj);
}).then(function(res) {
console.log(res);
}).catch(function(err) {
console.log("Error eq: " + err);
});
}
for (var i = 0; i < teamArray.length; i++) {
newObject = {
"name": teamArray[i].name,
"nameshort": teamArray[i].code,
"logo": teamArray[i].crestUrl,
"competition": competitionID
};
promise = chainToPromise(promise, newObject);
}
return promise;
}).catch(function(err) {
console.log(err);
});