AngularJS, ASP.Net MVC, JavaScript, jQuery, jQuery AJAX, MVC WebAPI

Add Request Header for REST API Calling with AngularJS & jQuery

In the Web World , We always call REST APIs from our Web Applications .

When We call REST APIs through jQuery or AngularJS , they added few default Request Headers .

But many a time , we need to pass Custom Request Headers for different purposes.

A Common scenario is for Authentication we need to pass Customer Request header .

But how we can add this ?

Lets see the below samples :::

for jQuery , we can easily add Request Headers when we do AJAX Calling .

$.ajax({
            type: "POST",
            url: '/api/test',
            data: myObj,
            headers: { 'Custom-Header': 'Value'},
            success: function (resp) {
                alert(resp);
            },
            error: function (x, y, z) {
                alert(x);
            }
        });

In AngularJS , If we use $http for REST API calling , we can add Request Header like below , after we create AngularJS Module , we can do :::

myModule.run(['$route', '$http', function ($route, $http) {
            $http.defaults.headers.common.CustomeHeader = 'Value';
        }]);

Thanks

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AngularJS, HTML5, JavaScript

WebSQL : Welcome to client side DB – Part1

I think , We,all the Devs, know about SQL . Like , we have already worked with MySQL , MS SQL Server etc .

But then what is WebSQL ? If I say in a simple statement – WebSQL is SQL which is available in Client Browser .

Inside Browser :S ? Where is it ? I never saw that :@

Then please see the below image 🙂

WebSQL in Chrome Browser

WebSQL in Chrome Browser

Now lets begin…

With HTML5, there was also a desire to develop applications so that they’d run off-line. Where could they store data when there is no Internet?

Currently , we can store Data in browser in the below ways –

1.Local Storage
2.WebSQL
3.IndexedDB

You can get few browsers do not support all these , like previous versions.

LocalStorage can store data in Key-Value pairs but nothing more than that.To know more about LocalStorage , you can check out my another Article on LocalStorage .

WebSQL is based on a free database product called SQLite which is written in C , Go here

In a WebSQL Database , we can create DB and Tables kinda like MySQL or SQL Server and store Data in the same manner what we knew earlier 🙂

Lets do some Coding…

I have used WebSQL in a AngularJS application . I have created an Angular Service which is separated from another Controllers and can be injected in any controller when needed where I have used WebSQL APIs .

Below is the code of my Service…

app.service('WebSqlDbService', function ($resource) {

    this.createDbAndTables = function () {
        var db = openDatabase('myClientDB', '1.0', 'Mobile Client DB', 2 * 1024 * 1024);
        db.transaction(function (tx) {
            tx.executeSql('CREATE TABLE IF NOT EXISTS User (UserInfo)');
        });
    };

    this.storeUserInfo = function (user) {
        var db = openDatabase('myClientDB', '1.0', 'Mobile Client DB', 2 * 1024 * 1024);
        db.transaction(function (tx) {
            tx.executeSql('INSERT INTO User (UserInfo) VALUES ( ?)', [JSON.stringify(user)]);
        });
    };

});

Then I have used WebSqlDbService in my Controller and called the Functions of the Service something like this…

$scope.userInfo = {
            UserId: 'as34fsdf*i#sad454',
            UserName: 'shahjada',
            IsAdmin: true
        };

        webSqlDbService.createDbAndTables();
        webSqlDbService.storeUserInfo($scope.userInfo);

I have saved the JSON Object by Stringifying , and when we will get this from WebSQL , we will convert it to JSON Object…

After saving Object to WebSQL DB , my DB and Table looks like below…

WebSQL in Chrome Browser - DB and Tables

WebSQL in Chrome Browser – DB and Tables

We can also write SQL Queries like SQL Server Management Studio…

Just follow the Image below…

WebSQL in Chrome Browser - SQL Queries

WebSQL in Chrome Browser – SQL Queries

Its nice and cool , right ?

I will write another Article on IndexedDB very soon .
Keep an eye on my Blog Site , Share/Subscribe…

Thanks and regards

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AngularJS, ASP.Net MVC, jQuery AJAX, MVC WebAPI

Delete Functionality : REST API with AngularJS $resource and jQuery-Ajax

For every Web Application , an important feature is Delete Functionality . We can not think a single app without it . But we already know how to develop DELETE Functionality inside a Web App . Then why is this article for?

Well , that’s true . But now , we will see how we can develop DELETE Functionality with $resource of AngularJS and/or also with jQuery . and for both cases , we have a REST URL of the server which is doing the real back-end thing .

Lets jump…

First lets see the Server code of REST API Delete Functionality . Here I have used .Net WebAPI . And the Method looks like below :::

public HttpResponseMessage Delete(int id)
        {
            //Delete Related Logics + Data Access calling etc
            return Request.CreateResponse(HttpStatusCode.OK);
        }

Now lets see the client side function of DELETE which is using AngularJS $resource .

$scope.delete = function() {
        $resource('api/Ticket/:id').delete({ id: $scope.ticket.Id }, function (data) {
            alert('Succeeded');
        });
    };

We can do the same thing by jQuery also , if we do not use AngularJS . But after learning AngularJS , you will never use jQuery 🙂 For jQuery lovers , we can do this like below with jQuery Ajax:::

$scope.delete = function () {
        $.ajax({
            url: 'api/Ticket/' + $scope.ticket.Id,
            type: 'DELETE',
            success: function (data) {
                alert('Succeeded');
            },
            error: function (x, y, z) {
                alert('Failed');
            }
        });
    };

Well , Thanks . Hope , you liked it .If you do , please share / subscribe …

Cheers 🙂

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AngularJS, HTML5, JavaScript

Using HTML5 LocalStorage with AngularJS

Today , I will talk about LocalStorage Support of HTML5.

We can store named key/value pairs locally, within the client web browser. Like cookies, this data persists even after you navigate away from the web site, close your browser tab, exit your browser, or what have you. Unlike cookies, this data is never transmitted to the remote web server (unless you go out of your way to send it manually). Unlike all previous attempts at providing persistent local storage, it is implemented natively in web browsers, so it is available even when third-party browser plugins are not.

HTML5 STORAGE SUPPORT
IE FIREFOX SAFARI CHROME OPERA IPHONE ANDROID
8.0+ 3.5+ 4.0+ 4.0+ 10.5+ 2.0+ 2.0+

Based on different browsers , we can get 2 MB to 5MB (even more) space in LocalStorage . To get more idea on space check out this link …

BY the below code , we can check our browser supports LocalStorage or Not !

function supports_html5_storage() {
    try {
        return 'localStorage' in window && window['localStorage'] !== null;
    } catch (e) {
        return false;
    }
}

Also we can use Modernizr to check this .

if (Modernizr.localstorage) {
    // window.localStorage is available!
} else {
    // no native support for HTML5 storage :(
}

Lets develop a simple LocalStorage Cache framework with AngularJS .

For this , am gonna create an AngularJS Factory Service to communicate with the HTML5 LocalStorage .

'use strict';

valApp.factory('storageService', function ($rootScope) {

    return {
        
        get: function (key) {
           return localStorage.getItem(key);
        },

        save: function (key, data) {
           localStorage.setItem(key, JSON.stringify(data));
        },

        remove: function (key) {
            localStorage.removeItem(key);
        },
        
        clearAll : function () {
            localStorage.clear();
        }
    };
});

localStorage keyword in the upper is the core API which is responsible for providing LocalStorage facility .

I have not used this storageService directly in the client .I am gonna use another Mid Layer Factory which will communicate with storageService and client code will call this Mid Layer Factory named cacheService . This is like below :::

'use strict';

valApp.factory('cacheService', function ($http, storageService) {
    
    return {
        
        getData: function (key) {
            return storageService.get(key);
        },

        setData: function (key,data) {
            storageService.save(key, data);
        },
        
        removeData: function (key) {
            storageService.remove(key);
        }
    };
});

You can see , I have injected storageService to cacheService .

Now from my AJs Controller , I will call cacheService’s Function to serve my purpose .

Now below is the example , how you can use this Cache Framework …

In My Controller , I’ve simply injected cacheService and can use all the features of it .

var city = [
                  { Id: 1, Name: 'Dhaka' },
                  { Id: 2, Name: 'Ctg' }
    ];
    cacheService.setData('city', city);

I have used the Mid Layer , if we need any new logic later, we can easily add those to the Mid Layer .

Its easy and awesome , right ?

Cheers 🙂

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AngularJS, JavaScript

AngularJS : Using Promise-Part1

In Modern Web (Web 2.0) , We use so many Asynchronous call in our Web Applications . But sometimes , we need that , A Call is depended on another call .That means – After First Method’s Success CallBack another Method should be called . So if both the call occurs asynchronously , It does not fit my requirement .

So We can use AngularJS Promise to do this kind of things .

Lets see an example .

app.controller('PersonCtrl', ['$scope', '$rootScope', '$http', '$q', 'setting', function($scope, $rootScope, $http, $q, setting) {
    
    $scope.personsFromServer = [
        { Id: 1, Name: 'Shahjada' },
        { Id: 2, Name: 'Talukdar' },
        { Id: 3, Name: 'Masoom' }
    ];

    var getPersonPromise = function() {
        var deferred = $q.defer();
        deferred.resolve($scope.personsFromServer);
        return deferred.promise;
    };

    getPersonPromise().then(function(persons) {
        $scope.persons = persons;
        $scope.personId = persons[0].Id;
    }, function (reason) {
        alert('Failed: ' + reason);
    });
    
}]);

I am mocking PersonsFromServer Data in my example (Suppose this is gonna come from Server By an asynchronous call) .Now I am gonna populate a DropDown after successfully returning the data , and am selecting the first Person as selected Item in DropDown .

<div ng-controller="PersonCtrl">
        <select id="Person"
            ng-model="personId"
            ng-options="p.Id as p.Name for p in persons"
            required>
        </select>
    </div>

The Deferred API

A new instance of deferred is constructed by calling $q.defer().

The purpose of the deferred object is to expose the associated Promise instance as well as APIs that can be used for signaling the successful or unsuccessful completion of the task.

The Promise API

A new promise instance is created when a deferred instance is created and can be retrieved by calling deferred.promise.

The purpose of the promise object is to allow for interested parties to get access to the result of the deferred task when it completes.

Hope you got the idea .

Thanks .
In Part2 , I will show Calling API from Server with Resource and of course with Promise .

Cheers

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