How to pass an object from a Lightning Component helper to an Apex Controller method

Question

I have an Parameters Apex class for common properties, the real class currently has over 17 properties:

public class Parameters {

    @AuraEnabled
    public String eventId;
    @AuraEnabled
    public String locationId;
    @AuraEnabled
    public String personId;
    @AuraEnabled
    public Long starts;
    @AuraEnabled
    public Long ends;
}

I don't want to keep typing these common properties as parameters into methods, so I want to pass the Parameters object around.

Therefore, I could like to use it as a parameter for an Apex controller method:

@AuraEnabled
public static boolean exampleControllerMethod(Parameters params) 
{
    if (params != null)
    {
        System.debug(params);
        return true;
    }

    return false;
}

The controller is called from a Lightning Component helper method:

exampleHelperMethod: function(component)
{                
    var action = component.get("c.exampleControllerMethod"); 

    var params = this.getParameters(component);

    action.setParams({'params': params});

    action.setCallback(this, function(response) {
        var state = response.getState();
        if(component.isValid() && state === "SUCCESS"){
            var result = response.getReturnValue();
            console.log(result);
        }
    });

    $A.getCallback(function() {
        $A.enqueueAction(action); 
    })();
},

I populate the JavaScript params variable in this helper method:

getParameters : function(c) 
{ 
    return {
        'eventId': c.get("v.eventId"),
        'locationId': c.get("v.locationId"),
        'personId': c.get("v.personId"),
        'starts': c.get("v.starts"),
        'ends': c.get("v.ends")
    };
},

I get this in the Apex Debug logs:

16:55:35.0 (131244)|EXECUTION_STARTED
16:55:35.0 (137794)|CODE_UNIT_STARTED|[EXTERNAL]|Aura
16:55:35.0 (3453904)|CODE_UNIT_STARTED|[EXTERNAL]|01p0O00000BUy1u|ExampleController.exampleMethod
16:55:35.0 (3640477)|HEAP_ALLOCATE|[72]|Bytes:3
16:55:35.0 (3721140)|HEAP_ALLOCATE|[77]|Bytes:152
16:55:35.0 (3744001)|HEAP_ALLOCATE|[342]|Bytes:408
16:55:35.0 (3762162)|HEAP_ALLOCATE|[355]|Bytes:408
16:55:35.0 (3779417)|HEAP_ALLOCATE|[467]|Bytes:48
16:55:35.0 (3817152)|HEAP_ALLOCATE|[139]|Bytes:6
16:55:35.0 (3891112)|HEAP_ALLOCATE|[EXTERNAL]|Bytes:28
16:55:35.0 (3909871)|METHOD_ENTRY|[1]|01p0O00000BUy1u|ExampleController.ExampleController()
16:55:35.0 (3922160)|STATEMENT_EXECUTE|[1]
16:55:35.0 (3931441)|STATEMENT_EXECUTE|[1]
16:55:35.0 (3937276)|METHOD_EXIT|[1]|ExampleController
16:55:35.0 (4055332)|FATAL_ERROR|Internal Salesforce.com Error
16:55:35.0 (4079642)|CODE_UNIT_FINISHED|ExampleController.exampleMethod
16:55:35.0 (8933960)|CODE_UNIT_FINISHED|Aura
16:55:35.0 (12133134)|EXECUTION_FINISHED

Of which the most interesting, yet still unhelpful message is:

16:55:35.0 (4055332)|FATAL_ERROR|Internal Salesforce.com Error

Answer 1

In case anyone is still looking for an answer to this, I found adding {get; set;} to the @AuraEnabled object fields enabled the object to be passed in as a parameter from Aura/LWC. String serialization and deserialization is NOT needed.

So the example given in the question should be:

public class Parameters {
    @AuraEnabled
    public String eventId {get; set;}
    @AuraEnabled
    public String locationId {get; set;}
    @AuraEnabled
    public String personId {get; set;}
    @AuraEnabled
    public Long starts {get; set;}
    @AuraEnabled
    public Long ends {get; set;}
}

Answer 2

Currently I have a workaround...

Which involves using:

JSON.stringify(params);

In the JavaScript helper method:

exampleHelperMethod: function(component)
{                
    var action = component.get("c.exampleControllerMethod"); 

    var params = this.getParameters(component);

    action.setParams({'jsonString': JSON.stringify(params) });

    action.setCallback(this, function(response) {
        var state = response.getState();
        if(component.isValid() && state === "SUCCESS"){
            var result = response.getReturnValue();
            console.log(result);
        }
    });

    $A.getCallback(function() {
        $A.enqueueAction(action); 
    })();
},

And to deserialize:

Parameters p = (Parameters)JSON.deserialize(jsonString, Parameters.class);

In the Apex controller method:

@AuraEnabled
public static boolean exampleControllerMethod(String jsonString) 
{
    Parameters p = (Parameters)JSON.deserialize(jsonString, Parameters.class);

    if (p != null)
    {
        System.debug(p);
        return true;
    }

    return false;
}

Answer 3

Just to update this topic in case anyone is having a similar issue:

1. Serialization and deserialization are not needed as mentioned by @monkeyhandz
2. To ensure successful deserialization, it is essential to add the @AuraEnabled annotation to the attributes of the class. This will make the attributes accessible to the Lightning components.
3. For your controller method to correctly receive and process a JSON payload, the payload must contain a key that matches the parameter name of the method.

So following the given example we could be doing:

public class Parameters {
    @AuraEnabled
    public String eventId {get; set;}
    @AuraEnabled
    public String locationId {get; set;}
    @AuraEnabled
    public String personId {get; set;}
    @AuraEnabled
    public Long starts {get; set;}
    @AuraEnabled
    public Long ends {get; set;}
}

Controller

@AuraEnabled
//Don't forget to match the key name in your payload with the parameter name in this method. E.g: [action.setParams({'parameters': JSON.stringify(params) })]
public static boolean exampleControllerMethod(Parameters parameters) { 
   system.debug('Event ID is:' + parameters.eventId);
}

Javascript Method

exampleHelperMethod: function(component)
{                
    var action = component.get("c.exampleControllerMethod"); 
    var params = this.getParameters(component);
    //The key 'parameters' must match the parameter name in your Controller
    action.setParams({
        'parameters': {
            'eventId': c.get("v.eventId"),
            'locationId': c.get("v.locationId"),
            'personId': c.get("v.personId"),
            'starts': c.get("v.starts"),
            'ends': c.get("v.ends")
         }
    }); 
    action.setCallback(this, function(response) {
        var state = response.getState();
        if(component.isValid() && state === "SUCCESS"){
            var result = response.getReturnValue();
            console.log(result);
        }
    });

    $A.getCallback(function() {
        $A.enqueueAction(action); 
    })();
},