Delete PFUser with Cloud Code Parse.com iOS - ios

Question

I succeed to add friend with Cloud Code and Parse.com.
Now I would like to delete friend relation with Cloud Code in didSelectRowAtIndexPath
My error is "attempt to insert nil object from objects[0]'"
But I don't know what parameters I need to configure, I found the cloud code for main.js :
Parse.Cloud.define("removeFriend", function(request, response)
{
// here's how to get the client's user making the request
var user = request.user;
// consider checking that user && request.params.friend are valid
// if not, return response.error("missing user or friend id")
getUser(request.params.friend).then(function(friend) {
// your code prematurely called response.success() here, thereby canceling any further steps
friend.relation("friendsRelation").remove(user);
// return the promise returned by save() so we can chain the promises
return friend.save();
}).then(function(result) {
// only now that the save is finished, we can claim victory
response.success(result);
}, function (error) {
response.error(result);
});
});
// EDIT - the OP once referred to a getUser function that we assume to be something like this:
// return a promise to get a user with userId
function getUser(userId) {
var userQuery = new Parse.Query(Parse.User);
return userQuery.get(userId);
}
Here is my code EditFriends.m :
- (void)viewDidLoad
{
[super viewDidLoad];
PFQuery *query = [PFUser query];
[query orderByAscending:#"name"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (error) {
NSLog(#"Error: %# %#", error, [error userInfo]);
}
else {
self.allUsers = objects;
[self.tableView performSelectorOnMainThread:#selector(reloadData) withObject:nil waitUntilDone:NO];
}
}];
self.currentUser = [PFUser currentUser];
[self loadFriends];
}
-(void) loadFriends{
self.friendsRelation = [[PFUser currentUser] objectForKey:#"friends"];
PFQuery *query = [self.friendsRelation query];
[query orderByAscending:#"username"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error)
{
if (error) {
NSLog(#"Error %# %#", error, [error userInfo]);
}
else {
self.friends = objects;
[self.tableView reloadData];
}
}];
}
- (BOOL)isFriend:(PFUser *)user {
for(PFUser *friend in self.friends) {
if ([friend.objectId isEqualToString:user.objectId]) {
return YES;
}
}
return NO;
}
CellForRowAtIndexPath :
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
PFUser *user = [self.allUsers objectAtIndex:indexPath.row];
NSString *name = [[self.allUsers objectAtIndex:indexPath.row] valueForKey:#"username"];
cell.textLabel.text = name;
if ([self isFriend:user]) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
} else {
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
didSelectRowAtIndexPath :
PFUser *selected = [self.allUsers objectAtIndex:indexPath.row];
if ([self isFriend:selected]) {
NSLog(#"déjà amis");
// PFObject *friendRequest = [self.friendRequests objectAtIndex:indexPath.row];
[PFCloud callFunctionInBackground:#"removeFriend" withParameters:#{#"friendRequest" : selected.objectId} block:^(id object, NSError *error) {
if (!error) {
//add the fromuser to the currentUsers friends
//save the current user
[self.currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
if (succeeded) {
} else {
}
}];
}
else {
}
}];
}
else{
PFUser *selectedUser = [self.allUsers objectAtIndex:indexPath.row];
//request them
PFObject *friendRequest = [PFObject objectWithClassName:#"FriendRequest"];
friendRequest[#"from"] = self.currentUser;
friendRequest[#"fromUsername"] = [[PFUser currentUser] objectForKey:#"username"];
//selected user is the user at the cell that was selected
friendRequest[#"to"] = selectedUser;
// set the initial status to pending
friendRequest[#"status"] = #"pending";
[friendRequest saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
if (succeeded) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Yay" message:#"Friend request sent" delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
} else {
// error occurred
}
}];
}

Answer 1

The iOS code looks okay, and only needs to be sure it sends the correct user objectId.
The cloud code is close, but must be improved a little:
Parse.Cloud.define("removeFriend", function(request, response)
{
// here's how to get the client's user making the request
var user = request.user;
// consider checking that user && request.params.friend are valid
// if not, return response.error("missing user or friend id")
getUser(request.params.friendRequest).then(function(friend) {
// your code prematurely called response.success() here, thereby canceling any further steps
console.log("relation is:" + JSON.stringify(friend.relation("friends")));
friend.relation("friends").remove(user);
// return the promise returned by save() so we can chain the promises
return friend.save();
}).then(function(friend) {
// friendship goes both ways, so remove the friend from user's friends
user.relation("friends").remove(friend);
return user.save();
}).then(function(result) {
// only now that the save is finished, we can claim victory
console.log("relation is:" + JSON.stringify(result.relation("friends")));
response.success(result);
}, function (error) {
response.error(error);
});
});
// EDIT - the OP once referred to a getUser function that we assume to be something like this:
// return a promise to get a user with userId
function getUser(userId) {
var userQuery = new Parse.Query(Parse.User);
return userQuery.get(userId);
}
EDIT - to call:
PFUser *selected = [self.allUsers objectAtIndex:indexPath.row];
if ([self isFriend:selected]) {
NSLog(#"déjà amis");
[PFCloud callFunctionInBackground:#"removeFriend" withParameters:#{#"friendRequest" : selected.objectId} block:^(id object, NSError *error) {
// etc.