Creating a WCF Service with JSON Data and Using it on iOS

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Introduction

Web services are very important for mobile development. In this tip, we will learn to create a WCF service which returns JSON data. We will also learn to generate request to this service on iOS side in this article.

Background

I assume you already have a WCF service that you created. If you didn't create it, please create a new "WCF Service Application".

Using the Code

First of all, let's make the necessary import operations.

//Interface 
Imports System.ServiceModel

//Implement
Imports System.Web.Script.Serialization
Imports System.ServiceModel.Activation
Imports System.ServiceModel
Imports System.ServiceModel.Web  

After this, you should define some function and class in the interface side.

For example:

<OperationContract()>
    <WebGet(UriTemplate:="GetUser", RequestFormat:=WebMessageFormat.Json, _
    ResponseFormat:=WebMessageFormat.Json, BodyStyle:=WebMessageBodyStyle.Wrapped)> _
    Function GetUser() As List(Of Users)

<DataContract()>
    Class Users
        <DataMember>
        Public Property ID As Integer
        <DataMember>
        Public Property NAME As String
        <DataMember>
        Public Property SURNAME As String
    End Class

As you see, we should set the RequestFormat to JSON. We should also set the ResponseFormat to JSON.

Then, we need to implement this function.

Public Function GetUser() As List(Of IService1.Users) Implements IService1.GetUser
    Dim users As New List(Of IService1.Users)
    Dim user As New IService1.Users
    user.ID = 1
    user.NAME = "Melih"
    user.SURNAME = "Mucuk"
    users.Add(user) 
    Return users 
End Function 

We created a list and returned it.

Also the Web.config file must be arranged.

<?xml version="1.0"?>
<configuration>
  <system.web>
    <compilation debug="true" strict="false" explicit="true" targetFramework="4.0" />
  </system.web>
  <system.serviceModel>
    <services>
      <service name="WcfService1.Service1" behaviorConfiguration="BehConfig">
        <endpoint address="" binding="webHttpBinding" 
                contract="WcfService1.IService1" behaviorConfiguration="web">
        </endpoint>
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="BehConfig">
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
      <endpointBehaviors>
        <behavior name="web">
          <webHttp/>
        </behavior>
      </endpointBehaviors>
    </behaviors>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
  </system.serviceModel>
  <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
    <directoryBrowse enabled="true"/>
  </system.webServer>
</configuration> 

That's it. WCF Service is ready. Let's see how to generate a request to this service on iOS side.

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    NSString *request = [NSString stringWithFormat:
    		@"http://localhost:portnumber/Service1.svc/GetUser"]; 
    NSURL *URL = [NSURL URLWithString:
    	[request stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]; 
    NSError *error = nil; 
    NSData *data = [NSData dataWithContentsOfURL:URL options:NSDataReadingUncached error:&error]; 
    if(!error)
    { 
        NSDictionary *json = [NSJSONSerialization
                              JSONObjectWithData:data
                              options:NSJSONReadingMutableContainers
                              error:&error]; 
        NSMutableArray *array= [json objectForKey:@"GetUserResult"]; 
        for(int i=0; i< array.count; i++)
        { 
            NSDictionary *userInfo= [array objectAtIndex:i]; 
            NSInteger *id = [userInfo objectForKey:@"ID"]; 
            NSString *name = [userInfo objectForKey:@"NAME"]; 
            NSString *surname = [userInfo objectForKey:@"SURNAME"]; 
            NSLog(@"ID: %d NAME: %@ SURNAME: %@", id,name,surname);
        } 
    } 
} 

Everything is ready. Run it and enjoy it.

Points of Interest

Attention:

For UriTemplate:

RequestFormat:=WebMessageFormat.Json, ResponseFormat:=WebMessageFormat.Json // For Json 

For Web.config:

service name="WcfService1.Service1" // Application_Name.Implement_Class

contract="WcfService1.IService1" //Application_Name.Interface_Class

binding="webHttpBinding" // for  web request