I have an AngularJS frontend to my API-based application. There are services which make API calls, such as the following. I want to compare a variable from each of these calls:
Get the user data:
this.getUserData = function () {
var apiCall = $http({
method: 'GET',
url: 'http://example.com/api/userdata',
headers: {
'Authorization': 'Bearer ' + localStorage.getItem('token'),
'Access-Control-Allow-Origin': 'Any'
}
});
return apiCall;
};
Get the page data:
this.getPageData = function(slug){
var apiCall = $http.get('http://example.com/api/public/page?slug=' + slug, {
headers: { 'Authorization': 'Bearer ' + localStorage.getItem('token') }
}
)
return apiCall;
};
In my controller I wish to compare a var from each of these calls, like so :
if (apiService.getUserData.likes.page_id == apiService.getPageData.page_id){ // do stuff }
What is the most efficient way of doing this, given that API calls can take a while.. I don't have to make an API call everytime I want to access a variable from the API do I? Bear in mind that these API calls would normally be made in DIFFERENT controllers, so the results are stored in different scopes.
Basically, I'm confused whether that bit of logic should go in a controller, in the service itself, or somewhere else. Any advice is appreciated. Thanks.
If you are comparing them in a controller you can easily call one followed by the other and compare. Since you say you have an "API-based application" and use an auth token from localStorage you should call the API in each different controller you have in case your auth token expires or something.
I would most likely create a service like (flushing it out to more to show all pieces):
angular.module('app').service('CompareService', CompareService);
CompareService.$inject = ['apiService', '$q'];
function CompareService(apiService, $q) {
return {
arePageIdsEqual: apie
};
function apie() {
var deferred = $q.defer();
apiService.getUserData().$promise.then(function(userData) {
apiService.getPageData().$promise.then(function(pageData) {
deferred.resolve(userData.likes.page_id === pageData.page_id);
}, function(err) {
deferred.reject(err);
});
}, function(err) {
deferred.reject(err);
});
return deferred.promise;
}
}
And in your controller just inject it and call it like:
CompareService.arePageIdsEqual(function(yes) {
if(yes) {
// do something
}
}, function(err) {
// err making the calls
});
You should implement it with a Promise.all.
function doCompare(userData,pageData){
if (userData.likes.page_id == pageData.page_id){
// do stuff
}
}
var promises = [apiService.getUserData,apiService.getPageData]
$q.all(promises).then(doCompare);
Related
I have service to get some data from API and serve them to application.
Simple function like this:
getEnvironmentStatus() {
var _this = this;
var req = {
method: "GET",
url: "/api/system/hosting",
headers: {},
data: {}
}
return _this.$http(req);
}
In some other place I have:
determineHostingEnv() {
var _this = this;
this.$env.getEnvironmentStatus()
.then(function(response){
_this.EnvHositng = response.data.cloud_hosted;
}, function(error) {
});
}
If I need the same information in other place (other controller), I would need to call api again.
How can I make getEnvironmentStatus() function to call API only once and store data in local variable, so it can serve that variable next time it is asked for it, instead of calling API?
Also, what if that value will get requested a few times before the first API will return value? Can I prevent calling that API a few times?
One can cache the promise:
httpPromiseCache = null;
getEnvironmentStatus() {
var _this = this;
var req = {
method: "GET",
url: "/api/system/hosting",
headers: {},
data: {}
}
if (!_this.httpPromiseCache) _this.httpPromiseCache = _this.$http(req);
return _this.httpPromiseCache;
}
The service will only execute the HTTP request once.
I'm working on a small project with MEAN in order to get started with it. I've been following the tutorial on thinkster.io (with some minor modifications made by me) and so far I've obtained good results. I've tested the API routes with Postman and everything is working. Problem is, for some reason (keep in mind that I'm new to NodeJS), it only accepts requests with Content-type: x-www-form-urlencoded.
The solution I've come across several times is to change the headers in the options parameter of the $resource. This is the code I have
register: function(user){
var deferred = $q.defer();
var UserResource = $resource('/api/users/register', {}, {
save: {
method: 'POST',
headers: {
'Content-Type': 'application/x-www-form-urlencoded'
},
transformRequest: function (data, headersGetter) {
console.log(data); // data is undefined ??
var str = [];
for (var d in data)
str.push(encodeURIComponent(d) + "=" + encodeURIComponent(data[d]));
return str.join("&");
}
}
});
UserResource.save(function(user){
this.saveToken(user.token);
deferred.resolve(user);
}, function(user){
deferred.reject(user);
});
return deferred.promise;
}
The register function is declared on an angular service. Problem is that the backend is sending me an error because the req.body object is empty. This is due to the fact that the transformRequest method is not executing correctly. Doing a little debugging I found that the 'data' parameter is undefined.
This is the code in the backend
router.post('/register', function(req, res, next){
if(!req.body.username || !req.body.password){
console.log(req.body.username);
return res.status(400).json({message: 'Por favor llene todos los campos'});
}
var user = new User();
user.username = req.body.username;
user.fullname = req.body.fullname;
user.setPassword(req.body.password);
user.save(function (err){
if(err){ return next(err); }
return res.json({token: user.generateJWT()})
});
});
Any ideas would be appreciated. Thanks in advance
You should pass user data in 1st parameter of save method(that will pass through the request body), there after you can place successCallback & errorCallback
UserResource.save(user, function(user){
this.saveToken(user.token);
deferred.resolve(user);
}, function(user){
deferred.reject(user);
});
Checkout this article
I am uploading attachments using rest api in SharePoint 2013,for this I need to call upload attachment method on synchronous.
Because If I call upload attachment method asynchronous I am getting 409 conflict error.
How to chain promise objects in for loop.i.e I want to call second attachment method in first attachment success and so on..
Please help me in best approach of chaining of promises in for loop.
Common method for saving attachments:
var saveFileAngularJS = function (file, url) {
var deferred = $q.defer();
getFileBuffer(file).then(function (fileArrBuffer) {
$http({
method: 'POST',
url: baseUrl + url,
headers: {
'Accept': 'application/json;odata=verbose',
'Content-Type': undefined,
'X-RequestDigest': jQuery("#__REQUESTDIGEST").val()
},
data: new Uint8Array(fileArrBuffer),
transformRequest: []
}).then(function successCallback(data) {
deferred.resolve(data);
alert('Successfully saved.', data);
}, function errorCallback(error) {
deferred.reject(error);
alert('Failed to save!!!.', error);
});
});
return deferred.promise;
};
Method calling :
for (var i = 0; i < $scope.files.length; i++) {
var file = $scope.files[i]._file;
var response = lssDealService.insertAttachment(transactionId, file);
}
var insertAttachment = function (dealId, file) {
var attachmentUrl = listEndPoint + "/GetByTitle('TransactionList')/GetItemById(" + dealId + ")/AttachmentFiles/add(FileName='" + file.name + "')";
return baseService.saveFile(file, attachmentUrl);
};
Insert attachment will call SaveFile method.
I want to run this for loop sequentially, once the loop has been completed I need to process all promises and display success message to user.
Please help me to writing the chaining promises in effective way.
Lets say you have the attachements as an array,
function uploadMyAttachements() {
return myAttachements.reduce(function(promise, attachment) {
return promise.then(function () {
return upload(attachment);
})
.then(function(result) {
console.log('RESULT FOR LAST UPLOAD', result);
});
}, Promise.resolve());
}
function upload(attachment) {
//upload the attachment to sharepoint
//and return a promise here
}
uploadMyAttachements().catch(function(err) {
//if anything in the promise chain fails
//it stops then and there and CATCHED here
});
Now whats happening here, using the Array.reduce, we create a chain of promises like shown below
upload(0).then(handleResult_0).upload(1).then(handleResult_1)....
and it execute one by one as you expected
Throwing my 2 pennies:
$scope.attachments = []; //modified via binding.
function uploadAttachments(){
//Reduce the files array into a promise array with the uploadOne method
//then return the promise when every promise has been resolved or one has rejected.
return $q.all($scope.attachments.reduce(uploadOne, []));
}
function uploadOne(file){
//Upload one, return promise. Use $http or $resource.
}
//Note - a more advanced way of doing this would be to send the files as batch (one
//$http post) as FormData. There are some good wrappers for angular.
$scope.upload = function(){
uploadAttachments().then(function(results){
//Array of results
}).catch(function(e){
//Error handler
});
}
I have an service in my Angular app that is responsible for authorizing the user and returning the auth token back.
However, due to the async nature of $http, I cannot properly isolate the logic of my service. Instead I must return a promise and push the logic of interpreting the response to the caller of the service (single responsibility red flag).
Given this, it's made me reconsider whether I am thinking about this correctly. I come from a Java world where the majority of interactions are synchronous, so something isn't sitting well with me as I try to architect a clean design with single responsibility.
What am I missing here?
UPDATE
I realize the below will not work as intended, but that's my thought of how I'd like it to work at least:
app.service('AuthenticationService', ['$http', '$httpParamSerializerJQLike', function($http, $httpParamSerializerJQLike)
{
this.authServerBaseURL = "...";
this.clientId = "...";
this.authenticate = function(username, password)
{
var config =
{
headers:
{
"Content-Type" : 'application/x-www-form-urlencoded',
"Authorization" : "Basic " + btoa(this.clientId + ":")
}
}
var body = $httpParamSerializerJQLike(
{
grant_type : "password",
username : username,
password : password
});
return $http.post(this.authServerBaseURL + '/oauth/token', body, config).
success(function(data, status, headers, config)
{
return data.access_token;
}).
error(function(data, status, headers, config)
{
return false;
});
}
}]);
Update after you added code: Your thought process can work, see below. However, $http docs say not to use .success and .error. If you instead use .then, as in my examples below, it will work.
Assuming your code is something similar to this:
// AuthService
this.authenticate = function() {
return $http.post('http://example.com', body, config);
}
// Using it:
AuthService.authenticate().then(function(data) {
var token = data.access_token;
});
You can move the knowledge about how the data is extracted to the service like this:
// AuthService
this.authenticate = function() {
return $http.post('http://example.com', body, config).then(function(data) {
return data.access_token;
});
}
// Using it:
AuthService.authenticate().then(function(token) {
var token = token;
});
what happens here is that you make a new promise by calling .then on the $http promise, which is what is returned. The promises are chained, so the $http promise will resolve this new promise, which then resolves itself with the extracted token.
I'm hitting an API which requires all authenticated actions to include an auth token in the request, however, I do not have the auth token until I login.
I've only seen examples of setting default request parameters in Restangular in app.config.
Is it possible to set this until after the user has logged in and User.auth_token is set?
So basically instead of:
app.config(function(RestangularProvider) {
RestangularProvider.setDefaultRequestParams({
auth_token: 'thisistheauthenticationtoken'
});
});
I need:
app.config(function(RestangularProvider) {
RestangularProvider.setDefaultRequestParams({
auth_token: User.auth_token
});
});
Why would you set token as part of the response versus in the header? Like so.
Restangular.setDefaultHeaders({ authentication: 'bearer ' + token.authentication });
I know this is an old thread but this SO question kept appearing when I was Googling (yes, I just used Google as a verb... deal with it :P) for a resolution, so I thought I should provide my solution. Hopefully it will help the OP or anyone else that may come across this page.
angular.module("app").factory("UserService", [
"$rootScope",
"$state",
"$q",
"Restangular",
function ($rootScope, $state, $q, Restangular) {
var UserSvc = {};
var Identity;
/*
This creates a scoped copy of Restangular
Normally this is where you would use setDefaultRequestParams,
but it would only affect this scope and not ALL API requests in your app
*/
var UsersAPI = Restangular.withConfig(function (RestangularConfigurer) {
RestangularConfigurer.setBaseUrl("api/1.0/users");
});
UserSvc.login = function (credentials) {
var $defer = $q.defer();
UsersAPI.all("start-session").post(credentials).then(function(respData){
if (respData.apikey) {
Identity = respData.plain();
/*
User is authenticated and API key is obtained from server response
Note how I do NOT use the setDefaultRequestParams function:
If we do the withConfig/setDefaultRequestParams, it only affects local scope, not global
This method modifies the ROOT Restangular object and
will then propegate through all future use of Restangular in your app
*/
Restangular.configuration.defaultRequestParams.common.apikey = Identity.apikey;
if ($rootScope.toState && $rootScope.toState.name != "login") {
$state.go($rootScope.toState.name, $rootScope.toStateParams || {});
} else {
$state.go("app.dashboard");
}
$defer.resolve(Identity);
}
else {
Identity = undefined;
$defer.reject(Identity);
}
},function (respData) {
$defer.reject(respData);
});
return $defer.promise;
};
return UserSvc;
}
]);
In my case, I use
Restangular.setDefaultRequestParams({token: localstorage.get('token')});
This works with me. Please have a look my snippet here.
https://github.com/fugokidi/ng-snippets/blob/master/rest.js
If you want to do something like this, you need to remove your code from app.cofig and move to when you find user is logged in.
You can set defaultRestParams for restangular at any point of application using Restangular service.
For more info refer https://github.com/mgonto/restangular#setdefaultrequestparams.
A more Angular-ish example from a project that I've been working on:
angular.module('app', [ 'restangular' ])
.factory('API', function(Restangular){
return Restangular.withConfig(function(config){
config
.setBaseUrl('https://api.example.com')
// etc etc etc
; // END config
});
})
.factory('Auth', function(API){
return {
login: function(credentials){
// Assuming I just POST /session/new to get an OAuth token,
// which is totally not a thing that OAuth should do.
API.one('session').post('new', credentials)
.then(function(auth){ // Assuming `auth = { access_token: '...' }`
API.setDefaultHeaders({
Authorization: 'bearer ' + auth.access_token
// Assuming OAuth Bearer Token
});
})
},
logout: function(){ /* . . . */ }
};
})
.controller('MainController', function(API, Auth){
var self = this;
self.user = { };
this.login = function(credentials){
Auth.login(credentials).then(function(){
self.user = API.one('user').$object;
});
});
})
; // END module(app)
The following code will read the token from storage for every request.
app.config(function(RestangularProvider) {
//Injext $cookies manually (there might be better ways to do this)
var $cookies;
angular.injector(['ngCookies']).invoke(['$cookies', function(_$cookies_) {
$cookies = _$cookies_;
}]);
RestangularProvider.setDefaultHeaders({
Authorization: function() {
return $cookies.get('token');
}
});
});
I too struggled with this.
Instead of using
RestangularProvider.setDefaultRequestParams({
auth_token: 'thisistheauthenticationtoken'
});
try using
Restangular.setDefaultRequestParams({auth_token:'thisistheauthenticationtoken'});