Angular Factory returns null - javascript

I'm trying to build a database in my angular factory:
angular.module("App")
.factory("DatabaseFactory", function () {
var database = null;
var factory = {};
factory.getDatabase = function () {
if (database == null) {
window.sqlitePlugin.openDatabase({
name: "myDB.db",
androidDatabaseImplementation: 2,
androidLockWorkaround: 1
}, function (db) {
database = db;
database.transaction(function (transaction) {
transaction.executeSql(create_user, [], function (transaction, result) {
console.log("table user created: " + JSON.stringify(result));
}, function (error) {
console.log("table user error: " + error.message);
});
}, function (error) {
console.log("transaction error: " + error.message);
}, function () {
console.log("transaction ok");
return database;
});
});
} else {
return database;
}
}
return factory;
});
The creation of the database works, the transaction is also ok. I now provide a service with a function to init the database:
angular.module("App")
.service("DatabaseService", function (DatabaseFactory) {
var database;
function initDatabase() {
console.log("init before database: " + JSON.stringify(database));
database = DatabaseFactory.getDatabase();
console.log("intit after database: " + JSON.stringify(database));
}
return {
initDatabase: function () {
initDatabase();
}
};
});
It gets called on device ready:
angular.module("App", ["ionic", "ngCordova", "App.Home"])
.config(function ($stateProvider, $urlRouterProvider) {
$stateProvider.state("app", {
url: "/app",
abstract: true,
templateUrl: "templates/main.html"
});
$urlRouterProvider.otherwise("/app/home");
})
.run(function ($rootScope, $ionicPlatform, DatabaseService) {
$ionicPlatform.ready(function () {
console.log("ionic Ready");
if (window.cordova && window.cordova.plugins.Keyboard) {
cordova.plugins.Keyboard.hideKeyboardAccessoryBar(true);
}
if (window.StatusBar) {
StatusBar.styleDefault();
}
DatabaseService.initDatabase();
});
});
The log output:
init before database: + undefined
init after database: + undefined
So the return of the database in my factory returns undefined, but I don't know why. It should return the database since it is correctly initialized.

You can't return the database from the function, because the function that receives it is an asynchronous callback.
You can only use the return statement if the entire function is synchronous (e.g. doesn't do any async work, such as reading from files, connecting to databases, network requests, sockets etc).
In your case, window.sqlitePlugin.openDatabase does some asynchronous work and asks for a callback as the second argument. This callback will be called after the database connection has opened, which will be after your getDatabase function has returned a value.
window.sqlitePlugin.openDatabase({
name: "myDB.db",
androidDatabaseImplementation: 2,
androidLockWorkaround: 1
}, function (db) {
database = db
// this happens at some point in the future
});
// this happens straight away
// at this point database is still undefined
return database;
A good way to test this for future reference is to use console.log to see at what time and in what order your code is run.
window.sqlitePlugin.openDatabase({
// ...
}, function (db) {
database = db
console.log('A');
});
console.log('B');
return database;
You would see that rather than being executed in the order the statements are written, B is logged first, then A second.
If you make your getDatabase method take a callback argument, you can pass the db object into it as soon as it is ready.
factory.getDatabase = function (callback) {
window.sqlitePlugin.openDatabase({
// ...
}, function (db) {
// do some stuff with db, when you are ready
// pass it to the callback, with null as the
// first argument (because there isn't an error
callback(null, db);
});
Then you would rewrite your code to make use of the callback.
DatabaseFactory.getDatabase(function(err, db) {
console.log("intit after database: " + JSON.stringify(database));
});
You might be wondering why the callback has an err argument too.
In node.js, it is considered standard practice to handle errors in asynchronous functions by returning them as the first argument to the current function's callback. If there is an error, the first parameter is passed an Error object with all the details. Otherwise, the first parameter is null.
(From NodeJitsu)

I think you should replace
var database = null;
var factory = {};
by
var factory = {};
and do
return factory.database
in your factory.getDatabase

Related

Testing asynchronous Ajax call

I am trying to have the function GetUsername to call the actual implementation and return the username if it is found back into the variable result. I am using Jasmine's done function but the test is not correct. It keeps on passing even if the expected and actual value are not the same. Any help or suggestion would be great! Thanks in advance.
Here are my objects:
var Git = {
VerifyGitUser: function (username, callback) {
$.ajax({
url: 'https://api.github.com/users/' + username
})
.done(function (data) {
callback.call(this, data);
})
.fail(function (data) {
callback.call(this, data);
})
}
}
var User = {
GetUsername: function (username) {
Git.VerifyGitUser(username, function (data) {
if (data.login) {
return data.login;
} else {
return null;
}
});
}
}
Here is my test:
describe('User', function () {
it('should return username', function (done) {
spyOn(Git, 'VerifyGitUser');
spyOn(User, 'GetUsername').and.callThrough();
var result = User.GetUsername('test');
done();
expect(Git.VerifyGitUser).toHaveBeenCalledWith('test');
expect(User.GetUsername).toHaveBeenCalled();
expect(result).toEqual('test');
})
});
There is currently no way to retrieve the data from User.GetUsername whenever it completes, so it will just return undefined. Plus your call to done() is completing the test before you assert anything with expect.
You can have User.GetUsername take a callback, just like you are doing for Git.VerifyGitUser:
var User = {
GetUsername: function (username, callback) {
Git.VerifyGitUser(username, function (data) {
if (data.login) {
callback(data.login);
} else {
callback(null);
}
});
}
}
Now you know when User.GetUserName has completed. So in your test, you can pass User.GetUserName a callback which can call done():
describe('User', function () {
it('should return username', function (done) {
spyOn(Git, 'VerifyGitUser');
spyOn(User, 'GetUsername').and.callThrough();
User.GetUsername('test', function(result) {
expect(Git.VerifyGitUser).toHaveBeenCalledWith('test');
expect(User.GetUsername).toHaveBeenCalled();
expect(result).toEqual('test');
done();
});
})
});
Other thoughts:
Do you need to call the actual API during this test? You can look into returning mock API data from VerifyGitUser using Jasmine spies.
In VerifyGitUser I don't see why you need to force context using callback.call(this, data). It seems like callback(data) is enough.
You may want to look into returning promises from async functions, instead of having them take in callbacks.

Node Js express async response with request and Redis call

So i'm having an issue with handling async actions in NodeJS while trying to send response to a request, with some async calls in the middle. (And to make this party even more complicated, i'm also want to use async.parallel )
Basically i'm trying to get value from Redis, and if he doesn't exist, get it from a provider (with request and response based using axios).
This is the code snippet :
this.getFixturesByTimeFrame = function (timeFrame, res) {
function getGamesData(timeFrame,finalCallback) {
var calls = [];
var readyList = [];
//Creating calls for parallel
timeFrame.forEach(function(startDay){
calls.push(function(callback) {
//Problematic async call
redisClient.get(startDay, function (error, exist) {
console.log('Got into the redis get!');
if (error){
console.log('Redis error : '+error);
}
if (exist) {
console.log('Date is in the cache! return it');
return exist;
} else {
//We need to fetch the data from the provider
console.log('Date is not in the cache, get it from the provider');
getFixturesDataFromProvider(startDay)
.then(organizeByLeagues)
.then(function (gamesForADay) {
redisClient.setex(startDay, 600, gamesForADay);
responsesList.add(gamesForADay);
callback(null, gamesForADay);
}).catch(function (response) {
if (response.status == 404) {
callback('Cant get games from provider');
}
});
}
});
}
)});
async.parallel(calls, function(err, responsesList) {
/* this code will run after all calls finished the job or
when any of the calls passes an error */
if (err){
res.send(501);
} else {
console.log('Here is the final call, return the list here');
//Some data manipulation here - just some list ordering and for each loops
console.log('finished listing, send the list');
finalCallback(responsesList);
}
});
}
getGamesData(timeFrame, function (readyList) {
res.send(readyList);
});
};
function getFixturesDataFromProvider(date) {
var requestUrl = 'someURL/ + date;
return axios.get(requestUrl, config);
}
function organizeByLeagues(matchDay) {
if (matchDay.count == 0) {
console.log('No games in this day from the provider');
return [];
} else {
var organizedSet = [];
//Some list manipulations using for each
return organizedSet;
}
}
But the response is been sent before parallel has been starting doing his things...
i'm missing something with the callbacks and the async calls for sure but i'm not sure where...
Thanks

how to write unit test to "request" node module with sinon.stub?

I have this function in my code :
let request = require("request");
let getDrillDownData = function (userId, query, callback) {
query.id = userId;
let urlQuery = buildUrlFromQuery(query);
request.get({
url: urlQuery,
json: true
}, function (error, response, data) {
if (!error && response.statusCode === 200) {
return callback(null, calculateExtraData(data));
} else if (error) {
return callback(error, null);
}
});
};
and I wish to write some unit test which verify that when the function is called with correct parameters, it is running OK,
and if there is an error, it did return the error
I wrote this unit test code :
describe.only('Server Service Unit Test', function(){
var sinon = require('sinon'),
rewire = require('rewire');
var reportService;
var reportData = require('./reportData.json');
beforeEach(function(){
reportService = rewire('../../services/reports.server.service');
});
describe('report methods', function(){
var reportData;
var query = { id: "test"};
var userId = 'testuser';
var getDrillDownData;
var request;
beforeEach(function(){
getDrillDownData = reportService.__get__('getDrillDownData');
});
it ('should get drill down data by userId and query', function(done){
var getCallback = sinon.stub();
request = {
get: sinon.stub().withArgs({
url: query,
json: true
}, getCallback.withArgs("error", {statusCode: 200}, reportData))
};
reportService.__set__('request', request);
getDrillDownData(userId, query, function(err, returnData){
(err === null).should.eql(true);
//(getCallback.withArgs(undefined, {statusCode: 200}, reportData).calledOnce).equal(true);
done();
});
});
});
But I keep getting this error:
Error: timeout of 2000ms exceeded. Ensure the done() callback is being called in this test.
Can someone help?
Thanks
I would stub request.get() directly:
describe('report methods', function() {
// Make `request.get()` a Sinon stub.
beforeEach(function() {
sinon.stub(request, 'get');
});
// Restore the original function.
afterEach(function() {
request.get.restore();
});
it ('should get drill down data by userId and query', function(done) {
// See text.
request.get.yields(null, { statusCode : 200 }, { foo : 'bar' });
// Call your function.
getDrillDownData('userId', {}, function(err, data) {
...your test cases here...
done();
});
});
});
Using request.get.yields() (which calls the first function argument that Sinon can find in the argument list; in this case, it's the (error, response, data) callback that gets passed to request.get() in your function) you can tell Sinon which arguments to use to call the callback.
That way, you can check if the callback to request.get() handles all arguments properly.
You can use .withArgs() too (request.get.withArgs(...).yields(...)), although you have to be sure that you're using it correctly; otherwise, if the exact arguments don't match, Sinon will call the original request.get() instead of using the stubbed version.
Instead, I prefer using stub.calledWith() to check for the correct arguments after the call has been made. That integrates much better with Mocha as well, as you can use explicit assertions.

Results of tasks in async.auto

I am kind of confused with the logic of results which go from one task to the other task in async.auto. For example in the following code logic I added some data to models in task1, which is initially an output from initialtask and in finalTask added data to models from task1 is reflected in results.initialTask1 as well. Similarly added data in task2 is reflected in results.initialTask1 in finalTask.
To sum up all of results.initialTask1, results.task1[0], results.task2[0], results.task3[0] are identical in finalTask. Is this the logic of async.auto? Or is it something like reference by pointer in C++ which causes whatever changes for models in task1, it reflects in models in initialTask as well?
async.auto({
initialTask: function(callback) {
//Do some operations
callback(null, name, initialModels);
},
task1: ['initialTask', function(callback, results) {
var models = results.initialTask[1];
//Add some more data to models
callback(null, models);
}],
task2: ['initialTask', function(callback, results) {
var models = results.initialTask[1];
//Add some more data to models
callback(null, models);
}],
task3: ['initialTask', function(callback, results) {
var models = results.initialTask[1];
//Add some more data to models
callback(null, models);
}],
finalTask: ['task1', 'task2', 'task3', function(callback, results) {
//Here the followings are the same: results.initialTask[1], results.task1[0], results.task2[0], results.task3[0]
}]
});
I'm looking for any answer which helps me make sure that is the logic or not? I'm not necessarily looking for any official documents or ...
This is expected behavior. Basically async.auto will execute all the functions in the order it deems necessary. So in your case initialTask will be called first. Then task1, task2, and task3 will be called in parallel. Finally finalTask will be called with the results. The reason all the values are the same is related to JavaScript's call-by-sharing, meaning if you change a function parameter itself, then it won't affect the item that was fed into the parameter. If you change the internals of the parameter, it will carry up to the item.
More info here.
Example:
async.auto({
// this function will just be passed a callback
readData: async.apply(fs.readFile, 'data.txt', 'utf-8'),
showData: ['readData', function(results, cb) {
// results.readData is the file's contents
// ...
}]
}, callback);
async.auto({
get_data: function(callback) {
console.log('in get_data');
// async code to get some data
callback(null, 'data', 'converted to array');
},
make_folder: function(callback) {
console.log('in make_folder');
// async code to create a directory to store a file in
// this is run at the same time as getting the data
callback(null, 'folder');
},
write_file: ['get_data', 'make_folder', function(results, callback) {
console.log('in write_file', JSON.stringify(results));
// once there is some data and the directory exists,
// write the data to a file in the directory
callback(null, 'filename');
}],
email_link: ['write_file', function(results, callback) {
console.log('in email_link', JSON.stringify(results));
// once the file is written let's email a link to it...
// results.write_file contains the filename returned by write_file.
callback(null, {'file':results.write_file,
'email':'user#example.com'});
}]
}, function(err, results) {
console.log('err = ', err);
console.log('results = ', results);
});
async.auto is very useful and powerful function which is provided by Async Lib .it have 3 fields
1-task
2- concurrency
3-callback
In Async.auto, Each function depends on its parent function except the first function, if any function will get any error during execution .then their child function or say .. their below-defined function will not get executed further, an error will occur with callback and the main callback will immediately return with an error
1- Task :- an Object
2- concurrency :- An optional integer for determining the maximum number of tasks that can be run in parallel. By default, as many as possible.
3- callback:- return the response
exapmle-
AnyService.prototype.forgetPassword = function (res, email, isMobile, callback) {
Logger.info("In AnyService service forgetPassword email...", email);
db.User.findOne({
email: email.toLowerCase(),
deleted: false
}, function (err, user) {
if (!user) {
configurationHolder.responseHandler(res, null, configurationHolder.LoginMessage.registerFirst, true, 403)
} else {
async.auto({
token: function (next, results) {
return gereratePasswordToken(next, email, user, isMobile);
},
sendMail: ['token', function (next, result) {
return SendMailService.prototype.forgetPasswordMail(next, result.token, email, user.fullName);
}]
}, function (err, result) {
if (err == null && result != null) {
configurationHolder.ResponseUtil.responseHandler(res, null, configurationHolder.LoginMessage.forgotPassword, false, 200)
} else {
callback(new Error(configurationHolder.errorMessage.oops))
}
})
}
});
}

pass data from a service to controller

i have a factory am passing it to controller LoginCtrl
.factory('Fbdata', function(){
var service = {
data: {
apiData: []
},
login: function () {
facebookConnectPlugin.login(["email"],
function() {
facebookConnectPlugin.api("me/?fields=id,email,name,picture", ["public_info","user_birthday"],
function (results) {
service.data.apiData = results;
console.log(service.data.apiData);
return results;
},
function (error) {
console.error('FB:API', error);
});
},
function(err) {
console.error('FB:Login', err);
});
}
};
return service;
})
LoginCtrl:
.controller('LoginCtrl', function($scope, Fbdata){
$scope.login = function(){
if (!window.cordova) {
var appId = "appId";
facebookConnectPlugin.browserInit(appId);
}
$scope.loginData = Fbdata.login();
console.log(Fbdata.data.apiData);
// got empty array []
$scope.retVal= angular.copy(Fbdata.data.apiData);
};
})
the Fbdata.data.apiData return empty array and i only could see the returned data from the login success function in the console .
my template which is has LoginCtrl as controller:
<div class="event listening button" ng-click="login();">Login with Facebook</div>
<h2>{{loginData.name}}</h2>
<h2>{{retVal.name}}</h2>
There is a variety of ways to achieve this, example:
Now I have never used Cordova Facebook Plugin so I'm not sure if you need to run the api function after the log in, or how those procedures need to be ordered. But I wanted to show you an example of how to retrieve the data from the factory using your code sample. Hope that helps
Edit 2:
I have changed my code to using promises that way we make sure that we don't call one without the other being completed, I am not a fan of chaining the login and api functions within one function since it is possible(?) that you may need to call login() but don't want to call api(), please try my code and paste in your console logs in the bottom of your question.
Factory:
// Let's add promises to our factory using AngularJS $q
.factory('Fbdata', ['$q', function($q){
// You could also just replace `var service =` with `return` but I thought this
// would make it easier to understand whats going on here.
var service = {
// I generally nest result to keep it clean when I log
// So results from functions that retrieve results are stored here
data: {
login: [],
api: []
},
api: function() {
var q = $q.defer();
facebookConnectPlugin.api("me/?fields=id,email,name,picture", ["public_info","user_birthday"],
function (results) {
// assign to the object being returned
service.data.api = results;
// The data has returned successfully so we will resolve our promise
q.resolve(results);
},
function (error) {
// We reject here so we can inform the user within through the error/reject callback
q.reject(error);
console.error('FB:API', error);
});
// Now that we have either resolved or rejected based on what we received
// we will return the promise
return q.promise;
},
login: function () {
var q = $q.defer();
facebookConnectPlugin.login(["email"], function (results) {
// assign to the object being returned
service.data.login = results;
q.resolve(results);
}, function(err) {
q.reject(error);
console.error('FB:Login', err);
});
return q.promise;
}
};
return service;
}])
Controller:
.controller('LoginCtrl', function($scope, Fbdata){
$scope.login = function(){
if (!window.cordova) {
var appId = "appid";
facebookConnectPlugin.browserInit(appId);
}
// By using the promises in our factory be can ensure that API is called after
// login by doing the following
// then(success, reject) function allows us to say once we have a return, do this.
Fbdata.login().then(function () {
$scope.loginData = Fbdata.data.login;
// Check what was returned
console.log('loginData', $scope.loginData);
Fbdata.api().then(function () {
$scope.apiData = Fbdata.data.api;
console.log('apiData', $scope.apiData);
}, function () {
// Tell the user that the api failed, if necessary
});
}, function () {
// Tell the user that the log in failed
});
};
});

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