What is RestResponse class in salesforce?

We use the RestResponce class to pass data from an apex RESTful web service method to an HTTP response.

Below are the method available with RestResponse class.

1) responseBody

Returns or sets the body of the response.

The return type is of Type: Blob.

2) headers

Returns the headers to be sent to the response.

The return type is of Type: Map<String, String>.

3) statusCode

Returns or sets the response status code.

The return type is of Type: Integer.

Note: If we set the RestResponse.statusCode property to a value that's not listed in below table then an HTTP status of 500 is returned with the error message “Invalid status code for HTTP response: nnn” where nnn is the invalid status code value.

Status Code  Description

200         OK

201         CREATED

202         ACCEPTED

204         NO_CONTENT

206         PARTIAL_CONTENT

300         MULTIPLE_CHOICES

301         MOVED_PERMANENTLY

302         FOUND

304         NOT_MODIFIED

400         BAD_REQUEST

401         UNAUTHORIZED

403         FORBIDDEN

404         NOT_FOUND

405         METHOD_NOT_ALLOWED

406         NOT_ACCEPTABLE

409         CONFLICT

410         GONE

412         PRECONDITION_FAILED

413         REQUEST_ENTITY_TOO_LARGE

414         REQUEST_URI_TOO_LARGE

415         UNSUPPORTED_MEDIA_TYPE

417         EXPECTATION_FAILED

500         INTERNAL_SERVER_ERROR

503         SERVER_UNAVAILABLE

Now, let us try to understand with an example.

Let us try to call the below webservice from workbench.

Below is an example of webservice which need id or any unique identifier as a parameter in request and it will return record associated with it.

@RestResource(urlMapping='/getAccountOnExternalIdtofetchsinglerecord/*')

   global with sharing class getAccounttoSingleRecord {

        @Httpget

      global static Account fettringchAccount(){

        Account obj=new Account();

        RestRequest req = RestContext.request;

        RestResponse res = Restcontext.response;

        string accId = req.requestURI.substring(req.requestURI.lastIndexOf('/')+1);

        obj=[Select id , name from Account where id=:accId];

        //string ser=JSON.Serialize(obj);

        return obj;

      }

   }

Click "Execute" button and now click "Show Raw Response".

As we can see as the operation of calling this webservice is successfull the HTTP status code returned is 200 by default and now based on requirement of external system if we want to modify the HTTP status code we can do it by using RestResponse class as shown below.

@RestResource(urlMapping='/getAccountOnExternalIdtofetchsinglerecord/*')

   global with sharing class getAccounttoSingleRecord {

        @Httpget

      global static Account fettringchAccount(){

        Account obj=new Account();

        RestRequest req = RestContext.request;

        RestResponse res = Restcontext.response;

        string accId = req.requestURI.substring(req.requestURI.lastIndexOf('/')+1);

        obj=[Select id , name from Account where id=:accId];

       /***Modify the HTTP status code that will be returned to external system***/

        res.statuscode=201;

       /***Modify the HTTP status code that will be returned to external system***/

        return obj;

      }

   }

Now, Let us try to call the below webservice from workbench.

As we have modified the statuscode to 201 using RestResponse class, we are now able to see the HTTP status code that is returned is 201.