Saving PFObject to Relation in Cloud Code (Parse.com)

Question

I've been trying to figure this out for quite a while, but I'm pretty stumped. I'm building an app with a Parse.com backend and I'm trying to implement this feature where when User A tries to send a game request to User B, both User A and User B acquire the game in a PFRelation. I've already done the part where I save the game to User A's (current user's) relation once he initiates the request:

NSString *challengePuzzleSize = [NSString stringWithFormat: @"%ld", (long)self.sizeSegmentedControl.selectedSegmentIndex + 5];
self.aNewMatch = [PFObject objectWithClassName:@"Messages"];
[self.aNewMatch setObject:file forKey:@"file"];
[self.aNewMatch setObject:fileType forKey:@"fileType"];
[self.aNewMatch setObject:self.opponent.objectId forKey:@"opponentIDs"];
[self.aNewMatch setObject:self.opponent.username forKey:@"opponentName"];
[self.aNewMatch setObject:[[PFUser currentUser] objectId] forKey:@"senderID"];
[self.aNewMatch setObject:[[PFUser currentUser] username] forKey:@"senderName"];
[self.aNewMatch setObject:self.opponent forKey:@"receiver"];
[self.aNewMatch setObject:challengePuzzleSize forKey:@"puzzleSize"];
[self.aNewMatch setObject:[PFUser currentUser] forKey:@"sender"];

[self.aNewMatch saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
    if (error) {
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"An error occurred." message:@"Please try sending your message again." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil];
        [alertView show];
    }

    else {
        PFRelation *currentGamesSender = [self.currentUser relationForKey:@"currentGames"];
        NSLog(@"opponent: %@", self.opponent);

        [currentGamesSender addObject:self.aNewMatch];

        [self.currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
            if (error) {
                NSLog(@"Error %@ %@", error, [error userInfo]);
            }

            else {
                NSLog(@"WORKS");
            }
        }];

I'm aware that I can't do the same thing with User B because he's not the current user and Parse restricts saving non-current users for security reasons. So, I'm trying to do this through Cloud Code which is what another person recommended when I was browsing for a solution. I have this as the call in Objective C:

[PFCloud callFunction:@"addCurrentGame" withParameters:@{@"userId": self.opponent.objectId, @"currentGameId": self.aNewMatch.objectId}];

But I'm unfamiliar with Javascript and I've been trying to figure out how to save a PFObject to User B's relation, and it isn't working for me. Here's that code:

Parse.Cloud.define("addCurrentGame", function(request, response) {
Parse.Cloud.useMasterKey();

var receiver = null;
var currentGame = null;

queryReceiverUser = new Parse.Query("User");
queryCurrentGame = new Parse.Query(“Messages”);
var receiverUserId = request.params.userId;
var currentGameId = request.params.currentGameId;

queryCurrentGame.get( currentGameId, {
    success: function(_currentGame) {
        currentGame = _currentGame;

    error: function(error) {
        console.log("Error retrieving user in query!");
    }
});

queryReceiverUser.get( receiverUserId, {
    success: function(_receiver) {
        receiver = _receiver;

        var currentGames = receiver.relation(“currentGames”);
        currentGames.add(currentGame);

        receiver.save(null, {
        success: function() { console.log("Saved receiver”); },
                                          error: function(err) { console.log("Error saving receiver, " + err.code); }
                                          });

        response.success("success");

    },

    error: function(error) {
        console.log("Error retrieving user in query!");
    }
});
});

I'm not at all sure how to create the PFObject game in Javascript and save it to the User B relation (my code isn't correct). If someone could please help me out with this, that would be awesome.

eth3lbert eth3lbert · Accepted Answer · 2014-12-22T01:13:14

Parse.Cloud.define('addCurrentGame', function(request, response) {
    Parse.Cloud.useMasterKey();
    var queryReceiverUser = new Parse.Query(Parse.User);
    var queryCurrentGame = new Parse.Query('Messages');
    var receiverUserId = request.params.userId;
    var currentGameId = request.params.currentGameId;
    return Parse.Promise.when([queryReceiverUser.get(receiverUserId), queryCurrentGame.get(currentGameId)])
        .then(function(user, game) {
            gameRelation = user.relation('currentGames');
            gameRelation.add(game);
            return user.save(null, {userMasterKey: true})
        }).then(function() {
            response.success('success');
        }, function() {
            response.error('error');
        });
});

Saving PFObject to Relation in Cloud Code (Parse.com)

1 Answers