如何使用 CloudKit API 将 PHLivePhoto 保存到 iCloud

Posted 2023-03-08

【中文标题】如何使用 CloudKit API 将 PHLivePhoto 保存到 iCloud

【英文标题】：How can I save an PHLivePhoto to iCloud using CloudKit API

【发布时间】：2016-06-29 17:11:18

【问题描述】：

现在我正在使用以下代码。但是发生了一些奇怪的事情。

PHLivePhoto *livePhoto = .....;

NSString *fileName = [[NSProcessInfo processInfo] globallyUniqueString];
NSURL *url = [NSURL fileURLWithPath: NSTemporaryDirectory()];
url = [url URLByAppendingPathComponent: fileName];
NSData *data = [NSKeyedArchiver archivedDataWithRootObject: livePhoto];
[data writeToURL: url atomically: YES];

CKAsset *asset = [[CKAsset alloc] initWithFileURL: url];

然后使用CKModifyRecordsOperation将该资产保存到iCloud，然后取回。

NSData *data = [NSData dataWithContentsOfURL: fetchedAsset.fileURL];
PHLivePhoto *thePhoto = [NSKeyedUnarchiver unarchiveObjectWithData: data];
PHLivePhotoView *photoView = ......;
photoView.livePhoto = thePhoto;

大部分都可以，除了当photoView停止播放时，photoView的图像就消失了。如果我再次长按它，它会正常播放。

为什么会这样？

【问题讨论】：

也许可以尝试保存个人PHAssetResources？

如何将 PHAssetResources 保存到 iCloud？有什么建议吗？谢谢。

我发现 NSKeyedArchiver 和 NSKeyedUnarchiver 应该为这个错误负责。我正在尝试在没有它们的情况下将 PHLivePhoto 写入 url。

【参考方案1】：

NSKeyedArchiver 似乎没有按预期保存实时照片。作为解决方案之一，您应该拆除PHLivePhoto，分别检索视频和静止图像，然后将它们上传到iCloud：

#import <Photos/Photos.h>
#import <CloudKit/CloudKit.h>
#import <MobileCoreServices/MobileCoreServices.h>

+ (void) disassembleLivePhoto:(nonnull PHLivePhoto*)livePhoto completion:(void (^__nonnull)(UIImage * _Nullable stillImage, AVURLAsset * _Nullable video, NSURL* _Nullable imageURL, NSURL* _Nullable videoURL))block

    NSArray<PHAssetResource*>* resources = [PHAssetResource assetResourcesForLivePhoto:livePhoto];

    __block PHAssetResource *resImage = nil, *resVideo = nil;
    NSString *fileName = [[NSUUID UUID] UUIDString];
    NSURL *urlMov = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:[fileName stringByAppendingPathExtension:@"mov"]]];
    NSURL *urlImg = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:[fileName stringByAppendingPathExtension:@"jpg"]]];

    [resources enumerateObjectsUsingBlock:^(PHAssetResource * _Nonnull res, NSUInteger idx, BOOL * _Nonnull stop) 
        if (res.type == PHAssetResourceTypePairedVideo)
            resVideo = res;
         else if (res.type == PHAssetResourceTypePhoto)
            resImage = res;
        
    ];

    [[PHAssetResourceManager defaultManager] writeDataForAssetResource:resVideo toFile:urlMov options:nil completionHandler:^(NSError * _Nullable error)     
        [[PHAssetResourceManager defaultManager] writeDataForAssetResource:resImage toFile:urlImg options:nil completionHandler:^(NSError * _Nullable error) 
            block([UIImage imageWithData:[NSData dataWithContentsOfURL:urlImg]], [AVURLAsset assetWithURL:urlMov], urlImg, urlMov);
        ];
    ];


- (void) sendLivePhotoComponentsWithImageURL:(nonnull NSURL*)urlImage videoURL:(nonnull NSURL*)urlVideo completionBlock:(void(^ __nonnull)(CKRecord* __nullable recordLivePhoto))block
    
    CKAsset *assetVideo = [[CKAsset alloc] initWithFileURL:urlVideo];
    CKAsset *assetImage = [[CKAsset alloc] initWithFileURL:urlImage];

    CKContainer *ckcContainer = [CKContainer defaultContainer];
    CKDatabase *ckdbPublic = [ckcContainer publicCloudDatabase];    // in this example I use public DB

    [ckcContainer fetchUserRecordIDWithCompletionHandler:^(CKRecordID * _Nullable ownerRecordID, NSError * _Nullable error) 
        CKRecordID *recordID = [[CKRecordID alloc] initWithRecordName:@"your_record_name_e.g._UUID" zoneID:ownerRecordID.zoneID]; 
        CKRecord *record = [[CKRecord alloc] initWithRecordType:@"your_record_type" recordID:recordID];
        record[@"your_video_asset_CK_key"] = assetVideo;
        record[@"your_image_asset_CK_key"] = assetImage;

        CKModifyRecordsOperation * op = [[CKModifyRecordsOperation alloc] initWithRecordsToSave:@[record] recordIDsToDelete:nil];
        op.modifyRecordsCompletionBlock = ^void(NSArray<CKRecord *> * _Nullable savedRecords, NSArray<CKRecordID *> * _Nullable deletedRecordIDs, NSError * _Nullable operationError)
            block(savedRecords.firstObject);    // Done.
        ; 

        op.qualityOfService = NSQualityOfServiceUserInitiated;

        [ckdbPublic addOperation:op];
    ];

第二部分（从 iCloud 检索）有一个小“技巧”​​——您应该确保图像和视频都具有包含在元数据中的相同资产 ID，否则 ios 将不知道这两个部分（视频和图像）属于到一个复合资产 - 实时照片 - 并且将无法将它们组装成单个 正确 PHLivePhoto 对象（但是，在这种情况下，您很可能将得到 PHLivePhoto ，但它会被构造为静态照片，没有动画）。

这里最简单的方法是从视频资产中提取资产 ID，然后通过为其分配相同的 ID 来修改图像部分：

- (void) assembleLivePhotoWithCKRecord:(nonnull CKRecord*)record completion:(void (^__nullable)(PHLivePhoto* _Nullable livePhoto))block

    // Operational data
    CKAsset *assetVideo = record[@"your_video_asset_CK_key"];
    CKAsset *assetImage = record[@"your_image_asset_CK_key"];

    // Get video and prepare local URLs
    NSString *fileName = [[NSUUID UUID] UUIDString];
    NSString *pathVideo = [NSTemporaryDirectory() stringByAppendingPathComponent:[fileName stringByAppendingPathExtension:@"mov"]];
    NSString *pathImage = [NSTemporaryDirectory() stringByAppendingPathComponent:[fileName stringByAppendingPathExtension:@"jpg"]];
    NSURL *urlVideo = [NSURL fileURLWithPath:pathVideo];
    NSURL *urlImage = [NSURL fileURLWithPath:pathImage];

    NSData *dataVideo = [NSData dataWithContentsOfURL:assetVideo.fileURL];
    [[NSFileManager defaultManager] createFileAtPath:pathVideo contents:dataVideo attributes:nil];

    // Getting video asset ID from metadata
    NSString *metaID = nil;
    NSArray<AVMetadataItem*>* metadata = [[AVURLAsset assetWithURL:urlVideo] metadata];
    for (AVMetadataItem *md in metadata)
        if ([md.identifier containsString:@"com.apple.quicktime.content.identifier"])
            metaID = (NSString*)(md.value);
            break;
        
    

    // Get image
    NSData *dataImage = [NSData dataWithContentsOfURL:assetImage.fileURL];
    UIImage *image = [UIImage imageWithData:dataImage];
    CGImageRef ref = [image CGImage];

    // Update image's metadata to make it conform video metadata
    NSDictionary *imgMetadata = @@"MakerApple": @@"17": metaID;
    NSMutableData *imageData = [NSMutableData new];
    CGImageDestinationRef dest = CGImageDestinationCreateWithData((CFMutableDataRef)imageData, kUTTypeJPEG, 1, nil);
    CGImageDestinationAddImage(dest, ref, (CFDictionaryRef)imgMetadata);
    CGImageDestinationFinalize(dest);

    [imageData writeToFile:pathImage atomically:YES];


    [PHLivePhoto requestLivePhotoWithResourceFileURLs:@[urlImage, urlVideo] placeholderImage:nil targetSize:CGSizeZero contentMode:PHImageContentModeAspectFit resultHandler:^(PHLivePhoto * _Nullable livePhoto, NSDictionary * _Nonnull info) 
        block(livePhoto);       // NOTE: this block may be called several times
    ];

根据 Apple 的文档，可能会多次调用带有实时照片的生成块（有关详细信息，请参阅 PHLivePhoto.h）：

结果处理程序将被多次调用以交付内容越来越多的新 PHLivePhoto 实例。

另外，请记住，您应该添加所有必要的检查（实际上有很多）和错误处理程序等。