WcfWebApi REST JSON Services

Overview

Here is an example of using WcfWebApi to produce a RESTful JSON data service.  We have three areas to consider:

• Our data (model) is a simple Contact class
• Our service is exposed via IContractService interface and implemented as ContractService
• Our data store (repository) is exposed via IContactRepository interface and implemented as ContractRepository

RESTful Interface

Data Operation	HTTP Verb	Has Side Effects?	Idempotent?	Example Uri
Read All	GET	No	Yes	http://localhost:8000/contacts
Read Single	GET	No	Yes	http://localhost:8000/contacts/1
Insert	POST	Yes	No	http://localhost:8000/contacts
Update	PUT	Yes	Yes	http://localhost:8000/contacts
Delete	DELETE	Yes	Yes	http://localhost:8000/contacts/3

HTTP Status (Return) Codes

Http Code	Description	Examples
200	OK	Successful (read, update or delete)
201	CREATED	Successful (insert)
400	BAD REQUEST	Passing id as “X” when an integer is expected
404	NOT FOUND	Item not found (based on id)
500	SERVER ERROR	Exception thrown within service on server with the message contained within response body.

Service Interface

Service Implementation

Service Unit Tests

Hosting The Service in an ASP.NET Web Application

Alternatively…. Console Hosting

The source code also contains an example of hosting within a client application:

Client Access to the REST service interface from a Console App

Output

Monitoring

HTTP

You can use Fiddler to monitor all HTTP requests and responses.  The screenshot below shows Fiddler on the left hand side picking up all requests and responses from the WCF Web API Test Client (explained within Debugging below) on the right hand side.

Debugging

Configure the Firewall (if required)

Make sure you punch a hole in your firewall before testing (or change the port from 8010 to 80 in the source code). 

On Windows 7 > Control Panel > Windows Firewall > Allow a Program or Feature through the Firewall

Fiddler

We are now ready to open Fiddler and use the Request Builder tab to enter your URI, set the HTTP verb (defaults to GET) and execute your request.  On the left hand side you’ll see the HTTP response and headers, in this case the result was 200 (OK):

Then switch to the Inspectors tab to view the response body containing our data.

For PUT and POST requests you must add the following to the request headers:

Content-Type: application/json; charset=utf-8

WCF Web API Test Client

We switched this new Microsoft Tool on in the Global.asax page with “EnableTestClient = true” which automatically routes:

• http://{baseUri}/{serviceName}/Test request onto the test client

In our case this would be http://localhost:8010/Contacts/Test:

 

Full source code:  http://stevenhollidge.com/blog-source-code/RestDemo.zip