Restful API for Android Using ASP.net and SQL Server Part 1 Tutorial

Restful API for Android using ASP.NET and SQL Server Part 1 By Ahamed Ishak - Mar 12, 2014

Message from Author Following tutorial is currently not up to date and there are lots of bug in it. Please don’t use this tutorial to any of your production work. Please click below link to the new tutorial in restful api Restful API for Android and IOS using ASP.NET Web API 2

Thank you

Most of the android applications use an API (Application Programming Interface) for send and receive data from servers to client (App).  API is very useful when application need to show dynamic data to end user. For an instance think how Gmail app receives emails?  It uses an API to communicate with Google mail server. When there is a new email, server notifies the application through API. Flipboard application also uses the same mechanism to update flipboard. When flipboard server database is updated it notifies the app then application download the data through API. This is the basic usage of

APIs in android. In this tutorial I’ll show you how to create a restful API for android  (JSON based API) application using ASP.net and Microsoft SQL Server Database.  You can use MySQL or other databases instead of SQL server. I’ll use SQL server because it is easy to use with ASP.net (Both are Microsoft Products).  I’ll try to make this tutorial simple and clear to understand. If you find any issue please feel free to ask. You can use the comment section to communicate with me.

Demo Video [quote_box_center] This tutorial is quite long; to make it simple I divided it to two parts. In this tutorial (Part 1) I’ll cover the Creation of the API using ASP.net and SQL Server.  In Restful API for Android  Part 2 I’ll cover how to implement this API in Android Application. [/quote_box_center]

Overview Of the tutorial This tutorial will show you the basic implementation of the restful API. I’ll show you how to connect android application with SQL server through a restful API. In android application users able create a user account and login to the account through the restful API. Application will retrieve department details from SQL Server database and display in a listview.

Step 1: Download Resources Download and extract the resource files need to implement the restful API from below download button.

Json Services : 

Download DLL Files

[quote_box_center]

I’ll use C# as the primary programming language in Visual Studio 2012.  I will use .NET Framework 4.5 to demonstrate this tutorial. This is also work with .NET Framework 3.5 and .NET Framework 4. [/quote_box_center]

Step 2: Creating a Project and Initialization Open Visual Studio and create an “ASP.NET Empty Web Application” project.  Project name is “JSONWebAPI”. Follow below steps to create the project. 1. Go to “File=>New” Click “Project” or Press “Ctrl+Shift+N” 2. From the New Project window select  Web category from left panel 3. Then Select “ASP.NET Empty Web Application” from center panel 4. Give Name as “JSONWebAPI” 5. Select project “Location” from Browse (Or keep the default) 6. Make sure “Create directory for solution” is checked 7. Click “OK” button

Create New Project

Now you need to add those “dll” files in “JsonServices (0.3.4)” folder in downloaded resource to the .NET Web Application. Follow below steps to add dll file to the project.

1. Right click on “JSONWebAPI” project in “Solution Explorer” 2. From the menu click on “Add Reference” item  to open the “Reference Manager” 3. Click “Browse” from the left panel 4. Then click “Browse” button at bottom of “Reference Manager” 5. Then go to the location where you extract the downloaded  Resource Files 6. Then select all three “.dll” files and click “Add” button 7. Then click “OK” button (Make sure to checked all three file)

Add DLL Files as Reference

Now you need to add a “Generic Handler” to your “Solution Explore”. Follow below steps. 1. Go to “PROJECT” menu in Visual Studio 2012 then click “Add New Item” (Ctrl+Shift+A) 2. From “Add New Item” window select “Web” category from left panel 3. From center panel select “Generic Handler” 4. Keep the default Name “Handler1.ashx” 5. Then click “Add” button Now create three classes namely “ServiceAPI.cs”, “IServiceAPI.cs” and “DBConnect.cs”. Follow below steps to create a new class

1. Go to “PROJECT” menu then click “Add New Item” 2. From left panel select “Code” category 3. Select “Class” item from center panel 4. Give the class name as “ServiceAPI.cs” 5. Click “Add” button Repeat the same instruction to create “IServiceAPI.cs” and “DBConnect.cs” class.

Step 3: SQL Server Database Creation and Manipulation Now we jump from visual studio to SQL server. I’ll not go in-depth about SQL Server. I’ll only show you basic stuff you need to know in order to complete this tutorial. If you are beginner then follow all the instruction carefully. Firstly open the SQL Server Management Studio and connect to the server. Please keep the server name in your mind. Later you need that Server Name to connect to SQL Server from API. In my case it is “AHAMEDISHAK”

Connect To SQL Server

Press Connect button to connect your Server. Now I’ll do the tutorial part by

part.

1. Create a New Database To create a new database called “AndroidAppDB” follow the below steps 1. Select “New Database” from right clicking “Database” folder in “Object Explore” 2. In “New Database” window  give the Database Name as “AndroidAppDB” 3. Then click “OK” button to create the database.

2. Create Database Tables Before create tables create a “New Query” file and select the correct database. In this case “AndroidAppDB”. If you’re a beginner keep this in mind because before doing any updates to a database we need to select database first.  It is very important step you need to follow every time you update the database through a Query file.

Select Correct Database

Now “Execute” below sql queries to create table. I’ll create two tables. SQL Queries to Create Tables and Insert Data 1 2 3 4 5 6

-------------Table 1: UserDetails (To store user information CREATE TABLE UserDetails (       id INT IDENTITY,       firstName VARCHAR(50),       lastName VARCHAR(50),

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      userName VARCHAR(50),       p password VARCHAR(50), );

-------------Table 2: Dept (To store Department information) CREATE TABLE Dept(       n no INT,       n name VARCHAR(50),       P PRIMARY KEY (n no) );

----------------------Insert data to Dept Table------------INSERT INSERT INSERT INSERT INSERT INSERT INSERT INSERT INSERT INSERT

INTO INTO INTO INTO INTO INTO INTO INTO INTO INTO

Dept Dept Dept Dept Dept Dept Dept Dept Dept Dept

VALUES VALUES VALUES VALUES VALUES VALUES VALUES VALUES VALUES VALUES

(1,'Accounting'); (2,'Marketing'); (3,'Information Technology'); (4,'Networking'); (5,'Management'); (6,'Medical'); (7,'Electronics'); (8,'Finance'); (9,'Engineering'); (10,'Defense');

Step 4: Connect and Con�gure the SQL Server Database to JSONWebAPI Now come back to Visual Studio. Next part of the tutorials is to connect the newly created database to our API project. By doing this we can programmatically retrieve and update information in database. To configure the connection open the “Web.config” file in Solution Explorer. Update your file by adding below configuration lines. Please add below lines between and Web.config updates 1 2

ConString" connectionString="Data Source=AHAMEDISHAK; Initial

Above configuration code is used to connect SQL Server database in my PC.  So this will not work for your API until you change the “Data Source” value to your “Server Name”. Simply delete the “AHAMEDISHAK” value and use your SQL “Server Name” there. “Catalog” value should be the database name. If you need to connect different database give the correct Database Name there.

“ConString” is the name of the “Connection String”.  If you need to connect more than one database at same time you need to create a new “Connection String” with different name and configurations. Next Open the “DBConnect.cs” class. This class is used to connect with the database. Update your class according to below code.  Don’t forget to add correct header files. Otherwise it will show you errors. DBConnect.cs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

using System.Configuration; using System.Data.SqlClient; namespace JSONWebAPI {     /// /// This class is used to connect to sql server database     /// public class DBConnect     {

        p private static SqlConnection NewCon;         p private static string conStr = ConfigurationManager.         p public static SqlConnection getConnection()         { NewCon = new SqlConnection(conStr);             r return NewCon;         }           p public DBConnect()           {           }     } }

Now connecting and configuration part is over.

Step 5: Let’s Code Next we need to configure the API interface which is used to handle the communication between android application and API. To configure the API interface open the “Handler1.ashx” file. Delete the example codes given in the file. Update the “Handler1.ashx” according to below code.  Use correct header files in your code.

Handler1.ashx 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

using JsonServices; using JsonServices.Web;

namespace JSONWebAPI {     p public class Handler1 : JsonHandler     {        p public Handler1() {             t this.service.Name = "JSONWebAPI";             t this.service.Description = "JSON API for android             InterfaceConfiguration IConfig = new InterfaceCo             t this.service.Interfaces.Add(IConfig);         }     } }

Now you need to do some small changes to “IServiceAPI.cs” and “ServiceAPI.cs” class. “IServiceAPI.cs” should be an interface instead of a class. To change the “IServiceAPI.cs” to an interface open the file and change the class keyword to interface. Next “ServiceAPI.cs” class should extend the “IServiceAPI.cs” interface.  See below codes to if you didn’t understand. IServiceAPI.cs 1 2 3 4 5 6 7

namespace JSONWebAPI {     p public interface IServiceAPI     {     } }

ServiceAPI.cs 1 2 3 4 5 6 7

namespace JSONWebAPI {     p public class ServiceAPI : IServiceAPI     { }

}

[quote_box_center] Interface is similar to class file. Main different is we only declare methods in

interface. We will not implement any method in interface. Interface is extends by a class. Class which extends the interface should implement all the methods in interface. [/quote_box_center] Now open the” IServiceAPI.cs” interface file. Add following method declarations according to below code. IServiceAPI.cs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

using System.Data;

namespace JSONWebAPI {     /// /// This interface declare the methods need to be implement.     ///     p public interface IServiceAPI {         v void CreateNewAccount(s string firstName, string         DataTable GetUserDetails(s string userName);         b bool UserAuthentication(s string userName, string         DataTable GetDepartmentDetails();     } }

Next we need to implement declared method in “ServiceAPI.cs”. Open the “ServiceAPI.cs” class. Update the class according to below code. It is important make all methods “public”. ServiceAPI.cs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

using System; using System.Data; using System.Data.SqlClient; namespace JSONWebAPI {     p public class ServiceAPI : IServiceAPI     {         SqlConnection dbConnection;         p public ServiceAPI()         {             dbConnection = DBConnect.getConnection();         }         p public void CreateNewAccount(s string firstName,         { if (dbConnection.State.ToString() == "Closed"

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            {                 dbConnection.Open();             }             s string query = "INSERT INTO UserDetails VALUES

            SqlCommand command = new SqlCommand(query, dbCo             command.ExecuteNonQuery();             dbConnection.Close();         }         p public DataTable GetUserDetails(s string userName)         {             DataTable userDetailsTable = new DataTable();             userDetailsTable.Columns.Add(n new DataColumn(             userDetailsTable.Columns.Add(n new DataColumn(             i if (dbConnection.State.ToString() == "Closed"             {                 dbConnection.Open();             }             s string query = "SELECT firstName,lastName FROM

            SqlCommand command = new SqlCommand(query, dbCo             SqlDataReader reader = command.ExecuteReader();             i if (reader.HasRows)             {                 w while (reader.Read())                 {                     userDetailsTable.Rows.Add(reader[                 }             }             reader.Close();             dbConnection.Close();             r return userDetailsTable;         }         p public bool UserAuthentication(s string userName,         {             b bool auth= false;             i if (dbConnection.State.ToString() == "Closed"             {                 dbConnection.Open();             }

            s string query = "SELECT id FROM UserDetails WHER

            SqlCommand command = new SqlCommand(query, dbCo             SqlDataReader reader = command.ExecuteReader();             i if (reader.HasRows)             {

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                auth = true;             }             reader.Close();             dbConnection.Close();             r return auth;         }         p public DataTable GetDepartmentDetails()         {             DataTable deptTable = new DataTable();             deptTable.Columns.Add("no", typeof(String));             deptTable.Columns.Add("name", typeof(String));             i if (dbConnection.State.ToString() == "Closed"             {                 dbConnection.Open();             }

            s string query = "SELECT no,name FROM Dept;"             SqlCommand command = new SqlCommand(query, dbCo             SqlDataReader reader = command.ExecuteReader();

            i if (reader.HasRows)             {                 w while (reader.Read())                 {                     deptTable.Rows.Add(reader["no"], reader                 }             }             reader.Close();             dbConnection.Close();             r return deptTable;         }     } }

We have completed the restful API in ASP.NET

Step 6: Run Restful API In this step you can run the API in a browser. Use the Play (Run) button in menu bar to run the API or go to “DEBUG” menu and click “Start Debugging” or press F5 from the keyboard. At first you will see a web page like below. This is because you are not pointing to the correct page of the API.

To solve this problem simply add “/Handler1.ashx” to the end of the URL. In my case complete URL is “http://localhost:7541/Handler1.ashx”. “Handler1.ashx” is the handler of the API. If you used any other name for the handler in your API use that name instead of “Handler1”.Then you will see below webpage

API Main Page

As you can see in the output you can use this restful API with different technologies. But I’ll only cover how to use this in android environment. To use this restful API with Android you need to download the client interface file from

Server. To do that enter “?ANDROID” to end of the URL in browser. In my case URL is “http://localhost:7541/Handler1.ashx?ANDROID”. Then it will pop up a “Save As” dialog box to save the file in your PC. Change the file name to “APIClient.zip”.

Save the Client Interface

Step 7: Restful API for Android Part 2  tutorial In Restful API for Android Part 2 tutorial I’ll show you how to use this restful API in a client android application. Subscribe to the website through your email or our social media pages in Google Plus, Facebook, Feed Burner and YouTube to get instant notification about new tutorials and videos.  See the video demonstration of the tutorial how to do this tutorial from start to end. You can download the source code of this tutorial below. If you have any questions related to this tutorial feel free to ask. Comment section is open for you to communicate with me. Share this tutorial with your friends and give a support to my website. Thank you very much for visiting TuteCentral.

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Ahamed Ishak http://www.tutecnetral.com

I'm a self motivated person who love to learn new stuff and share them with others.

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