[SalesForce] Apex REST class – why can’t I have multiple Apex methods for the same HTTP method

This is a newb question.

The following is my Apex REST Class.

@RestResource(urlMapping='/Expense/*')
global class MyExpenseWebService
{

@HttpGet
    global static Expense__c getExpense()
    {
        RestRequest req = RestContext.request;
        String eId = req.requestURI.substring(req.requestURI.lastIndexOf('/')+1);

        Expense__c e = [SELECT Id,Name,Amount__c,Comments__c,Expense_Date__c FROM Expense__c WHERE Id = :eId];
        return e;
    }

@HttpPost
global static String createExpense(String Type,Integer Amount,String Comments)
{
    Expense__c e =  new Expense__c(Type__c = Type, Amount__c = Amount, Comments__c = Comments);
    insert e;
    return e.Id;

}    



}

I tried to add another HttpGet method but I got a compiler error.

From the compiler error I discerned that only one occurrence of a specific type of HTTP method is allowed per class.

Can someone tell me why ?

Best Answer

The HTTP verb is GET and the URL of the request is matched against the urlMapping associated with the class. There is no more information available to Salesforce to know which class/method to invoke - hence the limitation on a single GET, POST, PATCH, PUT, DELETE method in the class.

Use either multiple REST classes with different URL patterns or use information within the parm string of the GET to dispatch logic in the GET method.

Think hard about ensuring your URL is really RESTFul; that way of thinking helps structure your class(es).

Related Solutions

[SalesForce] Can we create multiple @Http Methods (REST) annotations of the same type in a single class

Expanding on Mohith's answer, you may only define a single @HttpGet annotated method on your class, but, according to the docs,

Methods annotated with @HttpGet or @HttpDelete should have no parameters. This is because GET and DELETE requests have no request body, so there's nothing to deserialize.

So you should have a single REST method that examines query parameters and responds accordingly:

@RestResource(urlMapping='/RestResearch/v1/Test')
global with sharing class RestResearch {
    @HttpGet
    global static Account doGet() {
        RestRequest req = RestContext.request;
        RestResponse res = RestContext.response;

        // Was the method called like http://na1.salesforce.com/services/apexrest/RestResearch/v1/Test?s2=something
        String s2 = req.params.get('s2');
        if (s2 != null) {
            // Process s2 version
        } else {
            // Do something else
        }

        return result;
    }
}

Similarly, for a @HttpPost method, you would deserialize the body and examine it:

@HttpPost
global static String doPost(){
    RestRequest req = RestContext.request;
    RestResponse res = Restcontext.response;

    Blob body = req.requestBody;

    Map<String, Object> m = (Map<String, Object>)JSON.deserializeUntyped(body.toString());

    if (m.get('s2')) {
        // Process s2 version
    } else {
        // Do something else
    }

    return result;
}

[SalesForce] Http Callout to Rest API from apex

 Http http1=new Http();
 HttpRequest req1=new HttpRequest();
 req1.setendpoint('URL');
 req1.Setheader('String','String');
 req1.setmethod('POST'); //you can also SET method `GET` with Get there is no need of req1.setbody()
 req1.setbody(string);
 HttpResponse res1;
 res1 = http1.send(req1);
 String str=res1.getbody();

Best Answer

Related Solutions

[SalesForce] Can we create multiple @Http Methods (REST) annotations of the same type in a single class

[SalesForce] Http Callout to Rest API from apex

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