HTML5, JavaScript, NodeJS

Serve static HTML files locally

Sometimes we need to serve static HTML files in localhost. And we really don’t want to add any server for a simple HTML file.

Serve static HTML files locally

Generally, we can right click on the HTML file and can say “open in browser” and it will open the file in your local browser(Chrome, Firefox, Edge, Safari) but it’s actually not exactly what we always want. rather we want something like a simple web server to serve the files from a directory.

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C#, Cross Domain, HTML5, JavaScript, NodeJS

Visual Studio Code – A Cross Platform Code Editor built with Chromium

Microsoft has launched VSCode few weeks back for Cross Platform (Linux/Mac,Windows) and 55% download was Non-Windows. Shocking , right ?

HackerNews had a post on this and had really lot of comments/traffic on it.

Lets see the first look of Code.

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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, 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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