Visualforce Remoting with Empty String Ids

Question

Here's a fairly simple example illustrating the problem that uses only standard objects:

.pages/MyPage.page

A page with an input text box and a button.

<apex:page controller="Remote_MyPage" >

<input id="account-id" />

<button id="button">go</button>

<span
 id="script-params"
 data-remote-action="{!$RemoteAction.Remote_MyPage.query}"
/>

<script src="{!$Resource.MyPageScript}" ></script>

</apex:page>

./staticresources/MyPageScript.resource

A js script that takes the value from the input text box and sends it as the AccountId of a contact to a vf remoting method.

var button = document.getElementById('button')
  , accountId = document.getElementById('account-id')
  , remoteAction = document.getElementById('script-params').dataset.remoteAction

var buildContact = function(){
    var c = {}
    c.AccountId = accountId.value
    return c;
}

var buttonClickHandler = function(){
    var c = buildContact()
    console.log( c )
    Visualforce.remoting.Manager.invokeAction(
        remoteAction
    ,   c
    ,   function(){ console.log(arguments) }
    )
}

button.addEventListener('click',buttonClickHandler);

./classes/Remote_MyPage.cls

A class with a remote action method that takes the contact object and returns a list of contacts from the same account.

public class Remote_MyPage
{

    @RemoteAction
    public static list<Contact> query( Contact c ){
        String QueryString = 
            'SELECT Id, LastName FROM Contact '
        +   ( ( c.AccountId != NULL )
              ? ' WHERE AccountId = \'' + c.AccountId + '\' '
              : '' )
        ;

        return (list<Contact>) Database.query( QueryString );
    }

}

---

The problem is with the behavior when the AccountId is the empty string. In that situation, I want to get contacts from any Account, and not just contacts who are not associated with an account.

I've tried adding an empty string check after the null check in line 8 of the controller

        +   ( ( c.AccountId != NULL && c.AccountId != '' )

However, the code above causes an Apex run-time exception:

Visualforce Remoting Exception: Invalid id:

What is typically your approach for handling this situation?

Answer 1

Don't use "empty string" as an Id. Id can ever only be a null value, a 15-character string, or an 18-character string.

In your JavaScript:

c.AccountId = accountId.value || null;

This will convert an empty string to a null value.

In your Apex Code, do not compare an Id to an empty string.