ios - 允许PFUser仅一个PFObject

我试图这样做，以便一旦PFUser或client创建了PFObject后，它们将无法再次创建/创建一个。

在这里，我展示了PFObject的创建方式：

-(IBAction)New:(id)sender
{
    PFObject *New = [PFObject objectWithClassName:@"client"];
    PFUser *user = [PFUser currentUser];
    [New setObject:user forKey:@"user"];
    [New setObject:[[self Name] text] forKey:@"name"];
    [New setObject:[[self Team] text] forKey:@"team"];
    [New setObject:[[self Points] text] forKey:@"points"];
    [New setObject:[[self Height] text] forKey:@"height"];
    [New setObject:[[self Weight] text] forKey:@"weight"];
    [New setObject:[[self Position] text] forKey:@"position"];
    [New setObject:[[self Game] text] forKey:@"game"];
    [New setObject:[[self Hometown] text] forKey:@"hometown"];
    [New setObject:[[self Birthday] text] forKey:@"birthday"];
  //  [New setObject:[[self Bio] text] forKey:@"bio"];

    NSData *imageData = UIImageJPEGRepresentation(PlayerImage.image, 0.8);
    NSString *filename = [NSString stringWithFormat:@"%@.png", Name.text];
    PFFile *imageFile = [PFFile fileWithName:filename data:imageData];
    [New setObject:imageFile forKey:@"imageFile"];

    [New saveInBackground];
    NSLog(@"Object Added");
}

通过此代码，将PFObject添加到PFUser，现在我需要一种方法来使User不能创建另一个PFObject

最佳答案

您应该使用Cloud Function来实现。


Cloud Functions
Calling Cloud Functions in iOS


在您的Cloud Function中，您可以检查用户是否已经设置了client，并执行更新而不是添加操作，或者仅返回错误。

示例云代码（在iOS中无需更改）仅阻止保存“客户端”（如果当前用户已存在该客户端）：

// returns an error if a client is already set on the user
Parse.Cloud.beforeSave("client", function (request, response) {
    var user = request.user;
    user.fetch().then(function (user) {
        if (user.get("client")) {
            response.error("user already has a client record");
            return;
        } else {
            response.success();
            return;
        }
    }, function (error) {
        response.error(error);
    });
});

// links the client to the user if the save was allowed
Parse.Cloud.afterSave("client", function (request, response) {
    var user = request.user;
    user.set("client", request.object);
    user.save().then(function () {
        response.success();
    },
    function (error) {
        response.error(error);
    });
});

关于ios - 允许PFUser仅一个PFObject，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/24643553/