Develop Reference

Passing $scope variable from Controller to Service

Currently writing a prototype app in Ionic, pretty new to ionic and angular. I've written a small JSON API with about 25 objects in it, I've been able to display the list of them on a page we'll call "Library", I'm trying now to use those list items as links to an individual page for each item we will call a "Lesson". The variable $scope.lessonId is being set properly in the controller but being set as undefined in the service. Is it possible to achieve what I'm trying to, or am I just flat out doing this wrong?
.controller('LibraryLessonCtrl', function($scope, $stateParams, LessonService) {
$scope.lessonId = $stateParams.libraryId;
console.log($scope.lessonId);
LessonService.getLessonId()
.then(function(response){
$scope.lesson = response;
console.log($scope.lesson);
});
})
.service ('LessonService', function($http){
return { getLessonId: function() {
return $http.get('api/postsAPI.json')
.then(function (response, lessonId) {
console.log(lessonId);
for(i=0;i<response.data.length;i++){
if(response.data[i].post_id == lessonId){
return response.data[i];
}
}
});
}
};
})

You have to pass your $scope.lessonId variable to your service call if you like to use the value inside your service.
.controller('LibraryLessonCtrl', function($scope, $stateParams, LessonService) {
$scope.lessonId = $stateParams.libraryId;
console.log($scope.lessonId);
LessonService.getLessonId($scope.lessonId)
.then(function(response){
$scope.lesson = response;
console.log($scope.lesson);
});
}).service ('LessonService', function($http){
return { getLessonId: function(lessonId) {
return $http.get('api/postsAPI.json')
.then(function (response) {
console.log(lessonId);
for(i=0;i<response.data.length;i++){
if(response.data[i].post_id == lessonId){
return response.data[i];
}
}
});
}
};
})

You could do it by passing Id to service and storing it there. Please try not to pass $scope variable to service as it is not a good practice. You can do following:
.service ('LessonService', function($http){
var lessionId;
return {
/*other methods*/
setLessionId: function(id) {
lessionId = id;
},
getLessionId: function(){
return lessionId;
}
};
})

AngularJS Initialize provider data

I have code:
angular.module('admin', [])
.provider('users', function () {
this.users = 'default';
this.$get = function () {
var that = this;
return {
getUsers: function () {
return that.users;
}
}
};
})
.run(function (users, $http) {
users.users = $http('url'); // and others
})
.controller('test', function ($scope, users) {
$scope.users = users.getUsers();
});
I would like to intitalize data in .run() method (I can't use .config() method because it doesn't let to pass any services like $http). I found .run() method, but this code doesn't work... Data aren't saved in provider. Official documentation says:
"Execute this function after injector creation. Useful for application initialization."
I think it's best way to initialize data.

You may want to use an Angular Factory/Service for this kind of need. That is what I do. And pass that into the application. That service will be your singleton or source of truth about the dat.
angular.module('myData.services', [])
.factory('myData', ['$rootScope', '$http' , function($rootScope,$http) {
var factory = {
myData : {}
};
$http('/api/call', function(apiData) {
factory.myData = apiData;
});
return factory;
}]);
You could then use this in your controllers:
angular.module('myApp.controllers', [])
.controller('myCtrl', ['myData', '$scope', function(myData, $scope){
$scope.users = myData;
}]);
Check out the documentation on services: https://docs.angularjs.org/guide/services

Second attempt
angular.module('admin', [])
.factory('users', function ($http) {
var users = {};
var data = [];
$http.get('database.php')
.then(function (response) {
data = response.data;
});
users.getData = function () {
return data;
};
return users;
})
.controller('test', function ($scope, users) {
console.log(users.getData());
});
I would like to have data private. Empty Array returned, reponse comes with all data.

Provider configuration can be doable inside config block only, you can't do that inside run block
Though I don't find a reason to load users object while configuring app. I'd say that you should use either service/factory for this.
Code
angular.module('admin', [])
.service('users', function($http, $q) {
var users = [];
//make an get call to fetch users
function getUsers() {
return $http.get('database.php')
.then(function(response) {
data = response.data;
});
}
//will make a call if users aren't there
this.getData = function() {
// Handled below two conditions
// 1. If users aren't fetched the do an Ajax
// 2. If last ajax doesn't return a data then DO it again..
if (users.length > 0)
return $q.resolve(data); //do return data using dummy promise
return getUsers();
};
return users;
})
.controller('test', function($scope, users) {
users.getData().then(function(data){
console.log(data);
});
});

use angular factory to hold a value for rest of application to access to minimize server calls

I have the following factory:
angularModule
.factory('ArticleCategoryService', function ($http, $q) {
// Service logic
// ...
var categories = [];
var _getCategories = $http.get('/api/articles/category').success(function (_categories) {
categories = _categories;
});
// .error( function (data, status, headers, config) {
// });
// Public API here
return {
getCategories: function () {
var deferred = $q.defer();
deferred.resolve(_getCategories);
return deferred.promise;
}
};
});
and this is the section that calls this service in the controller:
// Calls the getCategories function from the ArticleCategory Service,
// Will return a promise
ArticleCategoryService.getCategories()
.then(function (categoriesResult) {
$scope.categories = categoriesResult.data;
}, function (err) {
console.log(err);
});
This works but there will be a GET call to the server every time user comes back to this view/state and the categories object that belongs to the factory is never used.
I'm trying to make it so that it will return the categories variable in the factory singleton, and have it initialize on site load (or from first GET call).
But if I just return categories when user calls getCategories, it will return nothing since we need time for the $http call.

Check if categories is defined, and resolve the promise with the variable rather than the GET request if it is:
return {
getCategories: function () {
var deferred = $q.defer();
if (categories.length > 0) {
deferred.resolve(categories);
} else {
deferred.resolve(_getCategories);
}
return deferred.promise;
}
};

I'm doing exactly same thing on my app. I have a main module and a main controller within it that wraps any other controllers, so its scope is persistent over views.
In this main controller you could assign the factory's getCategory() data to a scope variable and then you could use that in your entire app, because the scope will be inherited to child scopes.
angularMainModule
.factory('ArticleCategoryService', function ($http) {
var ArticleCategoryServiceMethods = {};
//fn: getCategories
ArticleCategoryServiceMethods.getCategories = function(fromWhere){
return $http.get(fromWhere)
.then(function(res){
return res.data;
}, function(err){
return err.status;
});
}
return ArticleCategoryServiceMethods;
}
angularMainModule
.controller('MAINCTRL', function($scope, ArticleCategoryService) {
//get all categories
$scope.categories = ArticleCategoryService.getCategories('/api/articles/category');
//... the rest of the main ctrl code ... //
}
... when you define the main module, make sure you inject the rest of your modules in it
var angularMainModule = angular.module('angularMainModule', [
'ngRoute',
'ngTouch',
'ngAnimate',
//< ng - etc >,
'Module1',
'Module2',
//< module - n >
]);
...and the markup (i'm bootstrapping my angular app manually, but you could add the ng-app="angularMainModule" attribute on the html tag if you're doing it that way):
<html ng-controller="MAINCTRL">
<!-- head data -->
<body>
<div id="page" ng-view></div>
If you want to make sure data is loaded before your app opens the main page, you could add that service call in the routeProvider block of your app (on the default route), so when the MAINCTRL will be loaded the data will be already there, ready to be assigned.

angularModule
.factory('ArticleCategoryService', function ($http) {
// Service logic
// ...
var categories = [];
$http.get('/api/articles/category').success(function (_categories) {
categories = _categories;
});
// Public API here
return {
categories: categories
};
});
angularModule
.controller('ControllerMain', function($scope, ArticleCategoryService) {
$scope.categories = ArticleCategoryService.categories;
});

Angular share asynchronous data across controllers and bind to views

I have a service which I would like to use across multiple controllers. The services is defined like this:
app.factory('Data', ['$http',
function($http) {
var Data = this;
var theProduct = {};
return {
product: function() {
return theProduct;
},
getProduct: function(ext_id) {
return $http.post('get_product', {
product_id: ext_id
}).success(function(data) {
theProduct = data;
});
}
}
}
]);
I have a form, that uses the ProductFormController to retrieve product data when it's submitted. That controller looks like this:
app.controller('ProductFormController', ['$scope', '$http', 'Data',
function($scope, $http, Data) {
/*
* Get a product and all of it's data from the server
*/
$scope.getProduct = function() {
Data.getProduct($scope.extProductId).success(function(data) {
console.log(data);
});
}
}
]);
Then, I have an AppController, which should display certain sections when a product object exists in the Data service.
<div class="row" id="productInfo" ng-show="product().id" ng-controller="AppController">/div>
Within AppController, I have this line:
$scope.product = Data.product;
I would like the productInfo div to show whenever a product object exists in the Data service, but it seems that the variable never gets updated. I've seen this question, but do not believe the accepted answer actually answers the question:
Angular: share asynchronous service data between controllers

update scopes in multiple controllers after $http

I'm struggling to figure out how to do this. Hope anyone can help :)
I have multiple controllers in my Angular app. Like titleCtrl and SettingsCtrl
I have a service which holds a variable like this:
var myVar = {title: 'test', settings: {color: 'black', font: 'verdana'}};
I'm making a $http.get request to update the "myVar" variable from the server.
The question is, how do I update the $scope.title in titleCtrl and $scope.settings in SettingsCtrl AFTER the http request has finished? I know how to do it in a single controller, but how do I update the $scopes in multiple controllers?

Use a watch on that variable in the service. When its updated, then update your values in controller scope. Here's an example:
Inside your controller, you can watch a var myVar on YourService and when it changes, update a variable called myVarInController with the value it changed to.
$scope.$watch(
// This function returns the value being watched.
function() {
return YourService.myVar;
},
// This is the change listener, called when the value returned above changes
function(newValue, oldValue) {
if ( newValue !== oldValue ) {
$scope.myVarInController = newValue;
}
}
);

Just in you service create a object when you get data from you server copy it to that object, so all your controllers can reference to that object.
Please see here http://plnkr.co/edit/j25GJLTHlzTEVS8HNqcA?p=preview
JS:
var app = angular.module('plunker', []);
app.service('dataSer', function($http) {
var obj = {};
getData = function() {
$http.get("test.json").then(function(response) {
angular.copy(response.data, obj);
});
}
return {
obj: obj,
getData: getData
};
});
app.controller('MainCtrl', function($scope, dataSer) {
$scope.data = dataSer;
$scope.get = function() {
$scope.data.getData()
}
});
app.controller('SecondCtrl', function($scope, dataSer) {
$scope.data = dataSer;
});
HTML:
<div ng-controller="MainCtrl">
<button ng-click="get()">get data</button>
<p>Fist Controller:
<br/>{{ data.obj.title}}</p>
</div>
<div ng-controller="SecondCtrl">
<p>Second Controller:
<br/>{{data.obj.settings}}</p>
</div>

Use both factory and service to pass value to two controllers. This is the only way to pass value
angular.module('mulipleCtrlApp', [])
.service('shareService', function () {
return {
title: 'test',
settings: {
color: 'black',
font: 'verdana'
}
};
})
.controller('titleCtrl', function ($scope, shareService) {
$scope.myVar = shareService;
$scope.testchange = function () {
$scope.myVar.title = 'Completed test';
};
})
.controller('settingCtrl', function ($scope, shareService) {
$scope.myVar = shareService;
});
Egghead Link
Jsfiddler Link example

Make your service return promise object.
Then in controller you can define a success call back to fetch title in one and settings in
another controller once the promise is resolved.
Code to use promises
In your service class:
var factory = {};
var factory.fetchData = function () {
return $http({method: 'GET', url: '/someUrl'});
}
return factory;
In controller 1:
$scope.getData = function(){
factory.fetchData().success(response){
$scope.title = response.title;
}
}
Similarly you can update controller 2, to set settings data.

I've found a better and easier maintainable solution in my opinion. Simply do the following to achieve to-way data-binding between one (or more) controller(s) with a service:
Lets assume you fetch (i.e. $http) and store data in your service (serviceName) in the variable serviceData.
In your controller reference the service like this to achieve to-way data-binding:
$scope.data = serviceName
In your view/html bind to the data properties like this:
<input ng-model="data.serviceData.title">
Thats it! :) When your serviceData variable updates the view/scope does as well. This will work with multiple controllers.