CREATE RESTful WCF Service API Using POST: Step By Step Guide

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Introduction

In my previous article, I tried to explain about WCF Restful service using HTTP Get method. This works well as long as you are sending small data as information to the service. But if want to deliver huge data, HTTP GET Method is not a good choice. In this article, we will create one WCF RESTFul POST API. I will also try to explain why and where to use POST method.

Why to use POST, not GET?

When I write any WCF service, I always use POST. The reason is the advantage of POST over GET. Using HTTP POST method, you can almost achieve everything which you can achieve from GET. Despite this, you will get some additional feature if using POST. We might say that "GET" is basically for just getting (retrieving) data whereas "POST" may involve anything, like storing or updating data, or ordering a product, or sending E-mail, etc.

POST

1. Easy Character Encoding using application/x-www-form-urlencoded
2. No Proxy by default so always actual data from web server
3. Data length can be restricted by webserver, not by browser

GET

1. Character encoding will reduce the amount of data that can be used because of URL encoding entities (i.e. three Japanese characters are converted to this: %26%2312454%3B%26%2312455%3B%26%2312502%3B)
2. Running an HTTP request with GET can be cached on your web browser or a configured proxy server
3. Maximum URL length is 2,083 characters in Internet Explorer (see MaxClientRequestBuffer: Use POST instead of GET to send large amounts of data in request)

and lot more...

Extremely long URLs are usually a mistake. URLs over 2,000 characters will not work in the most popular web browser. Sending long information via URL is not a good way of implementation and also it has many restrictions, i.e., max length of URL, information format, bla bla bla. For example, Internet Explorer has a limitation implemented at 2083 characters. URI is meant to be readable not to send information.

So if you are writing any REST service and your information is long enough, better to choose POST instead of GET method.

In this article, I am going to create WCF Restful service using POST method and access it using HTTP Request. So we will have client and server both in this example code. I am creating one service which accepts HTTP Post XML request and response request data in XML format.

Step by Step Guide

STEP 1

Launch Visual Studio 2010. Click FILE->NEW->PROJECT. Create new "WCF Service Application".

STEP 2

Once you create the project, you can see in solution that by default WCF service and interface file are already created. Delete by default created file as we will create our own interface and WCF service file.

STEP 3

Now right click on solution and create one new WCF service file. I have given name to the service file as “RestServiceImpl.svc”.

STEP 4

We will create two DataContract classes for request and response purposes.

RequestData will receive the request from the client and ResponseData response. One very important thing is that POST XML format to the service should be the same as RequestData. So the post XML request format can be like below:

We must have to use namespace for the data contract in POST RESTFul service, which has multiple uses, i.e., reflects the current version of your code. The same namespace should use in XML to Post data. Here, I have given http://www.eysnap.com/mPlayer as namespace which can be changed.

STEP 5

Now we will write the OperationContract in IRestServiceImpl which is an interface. Below is the code for that.

As we can see in the above code, here Request and Response format is XML. We can change it to JSON also by changing the WebMessageFormat from WebMessageFormat.Xml to WebMessageFormat.Json.

STEP 6

Implementation of Auth OperationContract in RestServiceImpl.svc.cs here.

STEP 7

Now let’s move to the configuration part which is the last one. There will be two basic parts of the configurations file which we must have to understand.

Services

Behaviors

And that’s it. Our Restful WCF POST RESTful service is ready to test.

SERVICE IS READY

I have created one Test WebClient in C# which makes HTTP request with some XML data. My application is hosted on localhost and URL is http://localhost:35798/RestServiceImpl.svc/auth. I launched and invoked service using WebClient. Below is my XML response which is the correct one.

This service can be used by any language application (.NET, PHP, JAVA, etc.) and that is the major reason to use REST service in the application.

Hope the article is useful for the community. Comments, suggestions and criticisms are all welcome.
Thanks.

History

• 25^th May, 2011: Initial post