Parse Cloud Code response is null after calling a function with callback

Question

I have a cloud code from which I call an external function. The cloud code response is null but the console displays the response

my cloud code ;

Parse.Cloud.define("testccadd", async request => {
    try {
        var ccaddrequest = {  
            conversationId: '123456789',
            email: 'email@email.com', 
        };
        externalFunction (ccaddrequest, function (err, result) {
            console.log(result);
            return result;
        }) ;
    } catch (e) {
        console.log("Error");  
    }
});

console.log (result); shows the values from the external function, but the return result; returns null

how can I get the external function response as response of my cloud code function ?

Answer 1

The problem is that your externalFunction uses a callback to return its result. That is an asynchronous event, meaning that it happens after your cloud functions has been processed.

The cloud function will execute var ccaddrequest... and then call externalFunction but it won't "wait" for externalFunction to call the callback function if it contains asynchronous commands.

So you need to wrap the externalFunction in a Promise (see how to promisify callbacks) and then await the result of it.

Plus you need to return the result of the Promise, so in your code you need to add

Parse.Cloud.define("testccadd", async request => {
    try {
        var ccaddrequest = {  
            conversationId: '123456789',
            email: 'email@email.com', 
        };
        var result = await externalFunctionPromise(...);
        return result;
    } catch (e) {
        console.log("Error");  
    }
});