[SalesForce] pass string value from apex controller to js controller in lightning

I'm new to lightning. Need your help.

I have to check for a field value in Case fields and add an error Div / Message on the component. This component will be used for Lightning actions as a custom button. I have tried this to pass the value of the String to js Controller but it throws null error.

Component :

<aura:component controller="FreightJSONAWBController" implements="flexipage:availableForAllPageTypes,force:hasRecordId,force:lightningQuickAction">
<aura:attribute name="messageError" type="Boolean" />
<aura:attribute name="message" type="String" />
<aura:attribute name="recordId" type="String" />

<aura:handler name="init" value="{!this}" action="{!c.doInit}" />
<aura:handler event="force:refreshView" action="{!c.doInit}" />

<aura:if isTrue="{!v.messageError}">
    <!-- Load error -->
    <div class="userCreateError">
        <ui:message title="Error" severity="error" closable="true">
            <ui:outputText value="{!v.message}"/>
        </ui:message>
    </div>
</aura:if>

Apex Controller: 

    global class Freight_AWBDetailsRequestController {

    public class ErrorHandler{

        @AuraEnabled
        public Boolean isSuccess { get; set; }

        @AuraEnabled
        public String message { get; set; }

        public ErrorHandler(Boolean isSuccess,String msg){
            this.isSuccess = isSuccess;
            this.message = msg;
        }
    }

    @AuraEnabled
    public static ErrorHandler getRecordUpdate(Id CaseId){

        String msg;
        ErrorHandler errH;

        Case caseRecord = [SELECT Id, Freight_AWB_Number__c, Freight_AWB_Status__c FROM Case WHERE Id =: CaseId];

        // Checking availability of AWB Number, accordingly requesting 
        if(caseRecord.Freight_AWB_Number__c != ''){
            requestJson = getRequestString(username, password, caseRecord.Freight_AWB_Number__c);
        }
        else{
            // show error AWB Number not provided. Lightning work to be done
            msg = 'AWB Freight Number cannot be null';
            errH = new ErrorHandler(false,msg);
            return errH;
        }

        try{
            caseRecord = returnParsedCase(res.getBody(), caseRecord);
            caseRecord.Freight_AWB_Status__c = 'Infomation Recieved';
            update caseRecord;
            errH = new ErrorHandler(true,'');
            return errH;
        }
        catch (JSONException jsonExcep){
            system.debug(' @@ No Response @@ ' + jsonExcep);
            caseRecord.Freight_AWB_Status__c = 'Infomation Not Available';
            msg = 'Case did not update. Error has occured.';
            update caseRecord;
            errH = new ErrorHandler(false,msg);
            return errH;
        }


    }
}

Client side controller : 

    ({
    doInit : function(component, event, helper) {

        var action = component.get("c.getRecordUpdate"); // dummy call for dummy method

        action.setParams({
            "CaseId" : component.get("v.recordId")
        });
        console.log("caseId :" + component.get("v.recordId"));

        action.setCallback(this, function(response) {
            var output = response.getReturnValue();
            console.log('output :'+output);

            var state = response.getState();
            if(component.isValid() && state == "SUCCESS" && output.isSuccess){
                $A.get("e.force:closeQuickAction").fire();
                var toastEvent = $A.get("e.force:showToast");
                toastEvent.setParams({
                    "title": "Success!",
                    "message": "AWB Details updated to Case Successfully!"
                });
                toastEvent.fire();
                $A.get('e.force:refreshView').fire();
            } else if (state == "ERROR" || !output.isSuccess) {
                var errors = response.getError();
                if (errors[0] && errors[0].message) {
                    // Did not catch on the Server Side
                    component.set("v.message", errors[0].message);
                    component.set("v.messageError", true);
                } else if ( !output.isSuccess ) {
                    // Did catch on the Server Side
                    component.set("v.message", output.message);
                    component.set("v.messageError", true);
                }
            }

        });
        $A.enqueueAction(action);
    }
})

In Console log, am getting output value as null. What am i missing here ?

Best Answer

By a "null error", I'm assuming you mean a null pointer exception. If that's the case, you'll want to use a try-catch block where you catch the null-pointer exception. I'd also recommend you change your If condition to isEmpty. Your code in the server side controller would look something like this:

try{

if(!isEmpty(caseRecord.Freight_AWB_Number__c){
            requestJson = getRequestString(username, password, caseRecord.Freight_AWB_Number__c);
        }
}catch(nullpointerexception e){

            // show error AWB Number not provided. Lightning work to be done
            msg = 'AWB Freight Number cannot be null';
            errH = new ErrorHandler(false,msg);
            return errH;
}
Related Topic