Develop Reference

How to wait until 2 $http requests end in angularjs

I need to process responses of two different $http requests. What is the best way to do so, knowing that I have to wait for answers of both request before to process their results.
I think I must use something like async, promise, await features, but I cannot figure out how to do so.
var app = angular.module('Async', []);
app.controller('async', function($scope, $http, $timeout, $interval) {
$scope.getCamionTypes = function() {
$http.get("../services/getCamionTypes.php")
.then(function mySucces(response) {
$scope.camionTypes = response.data;
}, function myError(response) {
camionTypes = [];
});
} ;
$scope.getParametres = function() {
var b = $http.get("../services/getParametres.php")
.then(function mySucces(response) {
$scope.parametres = response.data;
}, function myError(response) {
$scope.parametres = [];
});
}
//I make here the first call
$scope.getCamionTypes();
//I make here the second call
$scope.getParametres();
//The following instruction must wait for the end of the 2 calls
console.log('Types de camion : ' + $scope.camionTypes + '\n' + 'Parametres : ' + $scope.parametres);
})

check this
let promise1 = $http.get("../services/getParametres.php");
let promise2 = $http.get("../services/getParametres.php");
$q.all([promise1, promise2]).then(result=>{
//console.log('Both promises have resolved', result);
})

Use Promise.all for such use cases. Promise.all takes an array of promises and gets resolved when both the promises are resolved. It will fail if any of the promises fail.
$scope.getCamionTypes = function() {
return $http.get("../services/getCamionTypes.php")
} ;
$scope.getParametres = function() {
return $http.get("../services/getParametres.php")
}
Promise.all([$scope.getCamionTypes(), $scope.getParametres()]).then(resp => {
//resp[0] and resp[1] will contain data from two calls.
//do all your stuff here
}).catch()

Thank you very much Samira and Shubham for your usefull help !
Here the code modified thank to your advises with the less impact on the architecture of my application.
Best regards.
var app = angular.module('Async', []);
app.controller('async', function($scope, $http, $timeout, $interval, $q) {
$scope.getCamionTypes = function() {
let promise = $http.get("https://www.alphox.fr/ModulPierres_dev/services/getCamionTypes.php")
promise.then(function mySucces(response) {
$scope.camionTypes = response.data;
}, function myError(response) {
camionTypes = [];
});
return promise;
} ;
$scope.getParametres = function() {
let promise = $http.get("https://www.alphox.fr/ModulPierres_dev/services/getParametres.php")
promise.then(function mySucces(response) {
$scope.parametres = response.data;
}, function myError(response) {
$scope.parametres = [];
});
return promise;
}
//I make here the first call
let promise1 = $scope.getCamionTypes();
//I make here the second call
let promise2 = $scope.getParametres();
$q.all([promise1, promise2]).then (result=>{
//The following instructions wait for the end of the 2 calls
console.log('Types de camion : ');
console.log($scope.camionTypes);
console.log('Parametres : ');
console.log($scope.parametres);
$scope.both = {camionTypes: $scope.camionTypes, parametres: $scope.parametres}
});
});

Calling instagram API without using callback

I am consuming the Instagram API through Angular. i am consuming it without authentication.
My code looks like below. Can anyone advise if this is the best way to call this API, by using a callback. Is there a better approach by using promises? If so how would this look? and also, how can I add an error handler to this code?
factory.js
app.factory('socialMedia', ['$http', function($http){
return {
fetchInstagram: function(callback){
var url = "https://api.instagram.com/v1/users/*******/media/recent?client_id=*****&callback=JSON_CALLBACK";
$http.jsonp(url).success(function(response){
callback(response.data);
});
}
}
}]);
controller.js
app.controller("instagramCtrl", ["socialMedia", function (socialMedia) {
instagramCtrl = this;
this.instagramPosts = [];
this.loading = true;
socialMedia.fetchInstagram(function (data){
instagramCtrl.loading = false;
for(var i = 0; i < 5; i++){
instagramCtrl.instagramPosts.push(data[i]);
}
});
}]);

Don't use callbacks, it's the past. $http service returns promise object, which is much more convenient option (error handling, promise chaining):
app.factory('socialMedia', ['$http', function($http){
return {
fetchInstagram: function() {
var url = "https://api.instagram.com/v1/users/*******/media/recent?client_id=*****&callback=JSON_CALLBACK";
return $http.jsonp(url).then(function(response) {
return response.data;
});
}
}
}]);
Make sure you return Promise from fetchInstagram method.
Then in controller you would use it like this:
socialMedia.fetchInstagram().then(function(data) {
$scope.data = data;
});

cannot update variable using AngularJS

I am new to AngularJS and I am trying to send http request using .foreach loop. Here's my code
app.controller('myCtrl', function($scope, $http) {
var rd;
$http.get(furl,config).then(function mySucces(response) {
rd = response.data;
var webcontent = "";
angular.forEach(rd, function(rd1){
$http.get(furl1 + rd1.slug,config).then(function(res){
webcontent += res.data.title;
console.log(webcontent);//console 1
});
});
console.log(webcontent);//console 2
$scope.myWelcome = webcontent;
}, function myError(response) {$scope.myWelcome = response.statusText;});});
I was expected the console 2 will display the combined "res.data.title", however, it only shows the initial value.(which is empty in this case). The console log 1 is showing correctly - list the increasing "webcontent" variable.
Not sure how to keep the "webcontent" (console 2) updated value. Any response will be appreciated! Thanks!

This isn't an angular problem, this is an asynchronous javascript problem. Your code finished before your promise completes. You could use the query library to wait for all the promises to resolve, like so:
app.controller('myCtrl', function($scope, $http, $q) {
var rd;
$http.get(furl, config).then(function mySucces(response) {
rd = response.data;
var webcontent = "";
var promises = [];
angular.forEach(rd, function(rd1) {
promises.push($http.get(furl1 + rd1.slug, config);
});
$q.all(promises).then(function (results) {
angular.forEach(results, function (result) {
webcontent += result.data.title;
}
$scope.myWelcome = webcontent;
});
}, function myError(response) {
$scope.myWelcome = response.statusText;
});
});

You could just remove the webcontent variable entirely and update the $scope.myWelcome variable directly in it's place, it should work then. So:
app.controller('myCtrl', function($scope, $http) {
var rd;
$http.get(furl,config).then(function mySucces(response) {
rd = response.data;
$scope.myWelcome = "";
angular.forEach(rd, function(rd1){
$http.get(furl1 + rd1.slug,config).then(function(res){
$scope.myWelcome += res.data.title;
console.log(webcontent);//console 1
});
});
}, function myError(response) {$scope.myWelcome = response.statusText;});});

Ajax Calls are always async tasks, they are something similar window.setTimeout. It is impossible to write your code task by task. have a look:
console.log(1);
window.setTimeout(console.log.bind(console, 2));
console.log(3);
This happens because async tasks are executed in subsequent event loops (in the future).
Finally, your snippet could be something like that:
$http
.get(furl, config)
.then(function(response) { return response.data; })
.then(function(resources) {
return $q.all(resources.map(function(resource) {
return $http.get(furl1 + resource.slug, config);
}));
})
.then(function(results) {
return results.map(function(result) {
return result.data.title;
}).join('');
})
.catch(function(response) {
return response.statusText;
})
.then(function(greetings) {
$scope.myWelcome = greetings;
})
;

Execute function after another AngularJS

I need to execute a function which fetches data after a kind of login function who provides the sessionId. This sessionId is necessary for the second function.
app.controller('TestController',
function ($scope, dbObjectsDAO, loginService){
var sessionID = loginService.getSessionID(); //Login function
var self = this;
this.items = [];
this.constructor = function() {
dbObjectsDAO.getAll(sessionID).then(function(arrObjItems){
$scope.items = arrObjItems;
});
};
this.constructor(); //get the data
return this;
});
I tried several variations like:
loginService.getSessionID().then(function(sessionID){
this.constructor(); //also with just constructor();
});
But I always receive errors (in the case above: Illegal constructor).
So how can I manage to execute one function after another ? Maybe a callback structure would help here but I have no clue how to realize it.
EDIT
Here is the code for the login:
app.service('loginService', function($http, $q) {
this.getSessionID = function()
{
return $http({
method: "GET",
url: "http://localhost:8080/someRequestDoneHere"
}).then(function(response)
{
return response.data.sessionId; // for example rYBmh53xbVIo0yE1qdtAwg
});
};
return this;
});

Does your getSessionID() function return a promise? If so you want code like this:
app.controller('TestController',
function ($scope, dbObjectsDAO, loginService){
var sessionID;
var vm = this;
vm.items = [];
loginService.getSessionID()
.then(function(sid) {
sessionID = sid;
return dbObjectsDAO.getAll(sessionID);
})
.then(function(arrObjItems){
vm.items = arrObjItems;
});
});
So your login service returns a promise which resolves to the session id. You can save that in a variable for use elsewhere, and also use it to trigger fetching the items.
I also changed your self to vm as that naming is an Angular convention, and stored the items in vm.items rather than directly in the scope.
Edit:
Your login code already returns a promise, not a session id. return inside a then is simply going to return a new promise that resolves to the value you are returning.
There are several ways to chain multiple $http requests. If they are independent of each other just fire off a bunch of requests and use $q.all to handle when they have all completed.
var promise1 = $http(something)
.then(function(response) { vm.data1 = response.data; return vm.data1; });
var promise2 = $http(something)
.then(function(response) { vm.data2 = response.data; return vm.data2; });
$q.all([promise1, promise2], function(values) {
// here can safely use vm.data1 or values[0] as equivalent
// and vm.data2 or values[1].
});
If one request depends on the result of another you could even do this:
var promise1 = $http(something)
.then(function(response) {
vm.data1 = response.data;
return { method:'GET', url: response.data.link}
});
var promise2 = promise1.then($http)
.then(function(response) { vm.data2 = response.data; return vm.data2; });
Your template needs to declare the controller using the 'controller as something' syntax:
<div ng-controller="TestController as test" ng-bind="test.items"></div>

Have you tried to nest the second function, like this ? without the constructor call ?
loginService.getSessionID().then(function(sessionID){
dbObjectsDAO.getAll(sessionID).then(function(arrObjItems){
$scope.items = arrObjItems;
});
});

Mb you have wrong scope in
..then(function(sessionID){...}) ?
you can try some this like this:
var vm=this;
loginService.getSessionID().then(function(sessionID){
vm.constructor();
});

Angularjs Factory deferred's data disapearing

I'm trying to do a caching factory for http requests, so it doesn't make the server do a lot of work for the same request. But It seems my way of using deferred "swallows" the data, and I don't know why.
Console output for below:
data fetched:
Object {state: "OK", data: Object, errorMessage: null, exception: null}
success
undefined
ImportFactory:
factory("importFactory", function ($http, $q, loggingService) {
return{
fetchedData: [],
cacheTransport: function (transportsId, data) {
this.fetchedData.push({"transportsId": transportsId, "data": data});
},
getImport: function (transportsId) {
var factory = this;
var deferred = $q.defer();
var preFetchedTransport = this.findTransport(transportsId);
if (preFetchedTransport === null) {
console.log('fetching from backend');
return $http.post("/import/create/" + transportsId).then(function (data) {
console.log('data fetched:');
console.log(data);
factory.cacheTransport(transportsId, data);
deferred.resolve(data);
});
}
preFetchedTransport = deferred.promise;
return preFetchedTransport;
},
findTransport: function (transportsId) {
for (var i = 0; i < this.fetchedData.length; i++) {
var transportObj = this.fetchedData[i];
if (transportObj.transportsId === transportsId) {
return transportObj.data;
}
}
return null;
}
};
});
Controller
.controller('ImportController', function ($scope, $routeParams, importFactory){
$scope.transportId = $routeParams.id;
importFactory.getImport($scope.transportId).then(function (successData) {
console.log('success');
console.log(successData);
}, function (errorData) {
console.log('error');
console.log(errorData);
});

You basically need this: Demo here.
var cachedPromises = {};
return {
getStuff: function(id) {
if (!cachedPromises[id]) {
cachedPromises[id] = $http.post("/import/create/" + id).then(function(resp) {
return resp.data;
});
}
return cachedPromises[id];
}
};
Now, when you fetch that data, you can manipulate and it will be changed when you access it in the future.
myService.getStuff(whatever).then(function(data) {
data.foo = 'abc';
});
//elsewhere
myService.getStuff(whatever).then(function(data) {
console.log(data.foo); // 'abc'
});
Here's a demo that does this, as well as a view updating trick (bind the object to the view before the data comes in), and an idea of how you could change the data separately from the cache, in case you want to have the original data and the changing data. http://jsbin.com/notawo/2/edit
Remember to avoid that nasty promise anti-pattern. If you already have a promise, use that instead of creating another with $q. $http already returns a promise and that promise is sufficient for whatever you need if you use it properly.

just change the loop condition look like this and then test i think your function and defer is work fine but the loop does not sent the correct data
for(var i = 0; i < this.fetchedData.length; i++) {
if (this.fetchedData[i].transportsId === transportsId) {
return this.fetchedData[i].data;
}
}
return null;
}

The reason you are getting undefined is you are not returning anything from the $http.post().then() !
Also in your getImport() function you are returning an empty promise when the transport is already cached. You need to resolve it to your already cached transport object.
getImport: function (transportsId) {
var factory = this;
var deferred = $q.defer();
var preFetchedTransport = this.findTransport(transportsId);
if (preFetchedTransport === null) {
console.log('fetching from backend');
return $http.post("/import/create/" + transportsId).then(function (data) {
console.log('data fetched:');
console.log(data);
factory.cacheTransport(transportsId, data);
return data; //this was missing
});
}
// resolve it with transport object if cached
deferred.resolve(preFetchedTransport);
return deferred.promise;
},