Intern Server Error on Lightning App preview

Question

I have set up basic functionality in a Lightning Component to query my sandbox for the names of all opportunities on initialization and display them in a set of cards. When I attempt to preview the app, I get an internal server error. I tried the soql in Workbench and it returned a list of results so I'm not sure what the problem is.

Here is my code:

Opportunity List View Component

<aura:component controller="OpportunityListViewController">
      <aura:attribute name="opportunities" type="Opportunity" />
      <aura:handler name="init" action="{!c.doInit}" value="{!this}" />
      <c:cardList opportunities="{!v.opporunities}" />
</aura:component>

Opportunity List View Client Controller

    ({
    // Load opportunities from Salesforce
    doInit: function(component, event, helper) {

        // Create the action
        var action = component.get("c.getOpportunities");

        // Add callback behavior for when response is received
        action.setCallback(this, function(response) {
            var state = response.getState();
            if (component.isValid() && state === "SUCCESS") {
                component.set("v.opportunities", response.getReturnValue());
            }
            else {
                console.log("Failed with state: " + state);
            }
        });

        // Send action off to be executed
        $A.enqueueAction(action);
    }
})

Opportunity List View Server Controller

public with sharing class OpportunityListViewController {
    @AuraEnabled
    public static List<Opportunity> getOpportunities() {
        return [SELECT Name
                FROM Opportunity];
    }
}

Answer 1

I've noticed when an exception is thrown in the related ApexController of the Lightning component we always get "Internal Server Error" error message. So I can suggest to surround your logic in Apex controller with try {} catch() and verify there are no errors in the server-side logic.

Answer 2

Try returning a Wrapper object containing your opportunity list and some error information. An example:

public with sharing class OpportunityListViewController {
  @AuraEnabled
  public static OpportunityResult getOpportunities() {
    OpportunityResult result = new OpportunityResult();

    try {
      result.opportunities = [SELECT Name
            FROM Opportunity];
      result.success = true;
    }
    catch (Exception e){
      result.success = false;
      result.message = e.getMessage();
    }

    return result;

  }

  public class OpportunityResult{
    @AuraEnabled public Opportunity[] opportunities {get;set;}
    @AuraEnabled public Boolean success {get;set;}
    @AuraEnabled public String message {get;set;}

    public OpportunityResult(){
      opportunities = new Opportunity[]{};
    }
  }
}