Getting request body from apex Rest Resource class

Question

I have created a rest resource in apex and I am passing in an id through the body through post man via GET request. I then deserialize the body and I am getting an empty string even when I am providing the id. code below.

// rest resource code, More to code but I think this is the important stuff

String res = RestContext.Request.requestBody.toString();
if(res == ''){
   response.statusCode = 400;
   return;
}
HogtieDTO.getDeviceRequestInfoResponse resData = (
          HogtieDTO.getDeviceRequestInfoResponse)JSON.deserialize( 
          RestContext.Request.requestBody.toString(), 
          HogtieDTO.getDeviceRequestInfoResponse.class
      );

//HogtieDTO class

public with sharing class HogtieDTO {
    public class getDeviceRequestInfoResponse {
        public String customerId;
    }
}

// post man

I get the 401 after i make this call.

I can get it to work by passing it via a param but Im trying to get it to work through the body.

Answer 1

More of a comment than answer but it'd be too long.

passing in an id through the body through post man via GET request

If it's a GET request - Postman should ignore the body, GETs use only the url/uri/whatever is the official name. Make sure it's a POST and that your function is also annotated something like @HttpPost @ReadOnly global static String doPost()

I get the 401

401 is Unauthorized. Are you sure you passed Authorization Bearer <session id / access token goes here> header? Was the error response just a header or with body too? Is your user's profile allowed to access that class and the connected app you've used has api access scope?

401 would kick in even before your code has a chance to run, it's not even on the list (https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_rest_methods.htm scroll to bottom). Are you sure it runs? Do you see anything in debug logs?

Also, If someone could answer when you would have an Id in the path vs body that would be awesome

https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_rest_code_sample_basic.htm contains a sample method annotated @httpget and parses account id from the request's /services/apexrest/Account/001... with req.requestURI.substring(req.requestURI.lastIndexOf('/')+1);