Saving PFFile Eventually

Question

A PFObject can be saveEventually to be sync on Parse when network is reachable, while keeping it locally meanwhile.

If your file contains a PFFile, the file must be savedInBackground before your PFObject can be save.

How to saveEventually a PFFile, for it to be send now, or later when network is reachable ?

Answer 1

As you might know, that feature isn't available within ParseSDK, so after seeing a few posts vaguely explaining how to bypass this, I wrote a sample working XCode project

That's only a working PoC with limitations such as only working for a single Parse class to associate saved PFFile on.

It requires Reachability pod 'Reachability', '~> 3.2'

How to use it ? Well, I guess the sample projects describes it well, but here is a piece of code to understand how it works :

(Remember to run pod install to resolve dependencies before running example)

/*
 This example uses an UIImage, but this works with any file writable as NSData
 We begin by writing this image in our tmp directory with an uuid as name.
 */
UIImage *nyancat = [UIImage imageNamed:@"nyancat.jpg"];
NSData *imageData = UIImageJPEGRepresentation(nyancat, 0.5);

NSString *filename = [[NSUUID UUID] UUIDString];
NSURL *fileUrl = [PFFileEventuallySaver fileURLInTmpWithName:filename];

[imageData writeToURL:fileUrl atomically:YES];


/*
 We create a PFObject (you can pass an array to below function if you need your file to be saved on several objects). If upload works on first time, do what you want with your file, like linking it on your PFobject.

 If saving fails, it'll be retried as soon as network is available, on this session or nexts launches of app.
 In that case, the pointer at key kPFFILE_MANAGER_OBJECT_FILE_KEY of your PFFObject will be set with the PFFile, then saved eventually within PFFileEventuallySaver
 */
PFObject *object = [PFObject objectWithClassName:kPFFILE_CONTAINER_OBJECT_CLASSNAME];

[[PFFileEventuallySaver getInstance] trySaveobjectAtURL:fileUrl associatedObjects:@[object] withBlock:^(PFFile *file, NSError *error) {
    if(!error)
    {
        NSLog(@"[First try, network is fine] File saved, saving PFObject");

        object[kPFFILE_MANAGER_OBJECT_FILE_KEY] = file;
        [object saveEventually];

        NSLog(@"Try again disabling your network connection");
    }
    else
    {
        NSLog(@"No network, connect back your wifi, or relaunch app. Your file will be sent");
    }
} progressBlock:^(int percentDone) {
    NSLog(@"[First try, network is fine] Sending file %d/100%%", percentDone);
}];

This could be greatly improved, but I thought you guys might found that useful, as I would've wanted to find a similar working example.