在Google App Engine中存储旋转/翻转的图像

Question

BlobKey blobKey = new BlobKey(upload.getBlobKey());

ImagesService imagesService = ImagesServiceFactory.getImagesService();
Image image = ImagesServiceFactory.makeImageFromBlob(blobKey);
Transform transform = ImagesServiceFactory.makeRotate(90);
Image newImage = imagesService.applyTransform(transform, image);

newImage.getImageData()

GcsFilename fileName = new GcsFilename("bucket-name", upload.getFileName());
GcsOutputChannel outputChannel = GcsServiceFactory.createGcsService().createOrReplace(fileName, GcsFileOptions.getDefaultInstance());
outputChannel.write(ByteBuffer.wrap(newImage.getImageData()));
outputChannel.close();

BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
Map<String,List<FileInfo>> finfos = blobstoreService.getFileInfos(req);
String gcsFileName = finfos.get("uploadKey").get(0).getGsObjectName();
upload.setGcsFileName(gcsFileName);
upload.persist();

GcsFilename fileName = new GcsFilename( "bucket-name", upload.getGcsFileName());
GcsOutputChannel outputChannel = GcsServiceFactory.createGcsService().createOrReplace(fileName, GcsFileOptions.getDefaultInstance());
outputChannel.write(ByteBuffer.wrap(newImage.getImageData()));
outputChannel.close();

BlobstoreService bs = BlobstoreServiceFactory.getBlobstoreService();
BlobKey bk = bs.createGsBlobKey(fileName.getObjectName());

imagesService.getServingUrl(ServingUrlOptions.Builder.withBlobKey(bk);

imagesService.getServingUrl(ServingUrlOptions.Builder.withGoogleStorageFileName(fileName.getObjectName()));

GcsFilename fileName = new GcsFilename("bucket-name", upload.getGcsFileName());
System.out.println("fileName.getObjectName(): " + fileName.getObjectName());
System.out.println("fileName.getBucketName(): " + fileName.getBucketName());

2014-03-08 09:31:35.076 [s~_____/live-1-0-2.374269833496060124].<stdout>: fileName.getObjectName(): /gs/bucket-name/L2FwcGhvc3RpbmdfcHJvZC9ibG9icy9BRW5CMlI 
2014-03-08 09:31:35.076 [s~_____/live-1-0-2.374269833496060124].<stdout>: fileName.getBucketName(): bucket-name

BlobstoreService bs = BlobstoreServiceFactory.getBlobstoreService();
BlobKey bk = bs.createGsBlobKey(fileName.getObjectName());

System.out.println("GSBlobKey: " + bk.getKeyString());

2014-03-08 09:31:37.993 [s~_____/live-1-0-2.374269833496060124].<stdout>: GSBlobKey: AMIfv94Tj3xO9hPWwMm314Id0obQs1gVWOHYVuGaaAjjMbieBUD6x0nNGbqiY8o5Jk9iLga4pPe9-8L1

String newImageUrl1 = imagesService.getServingUrl(ServingUrlOptions.Builder.withGoogleStorageFileName(fileName.getObjectName())); 
System.out.println("newImageUrl1: " + newImageUrl1);

String newImageUrl2 = imagesService.getServingUrl(ServingUrlOptions.Builder.withBlobKey(bk));
System.out.println("newImageUrl2: " + newImageUrl2);

String newImageUrl3 = imagesService.getServingUrl(bk);
System.out.println("newImageUrl3: " + newImageUrl3);


2014-03-08 09:31:38.116 [s~_____/live-1-0-2.374269833496060124].<stdout>: newImageUrl1: http://lh3.ggpht.com/My7zTT79xOltI3cMzHidx7-Us91Qlp13jdv-vJceQ_OpX3FONSr9YzI2...
2014-03-08 09:31:38.152 [s~_____/live-1-0-2.374269833496060124].<stdout>: newImageUrl2: http://lh3.ggpht.com/My7zTT79xOltI3cMzHidx7-Us91Qlp13jdv-vJceQ_OpX3FONSr9YzI2... 
2014-03-08 09:31:38.218 [s~_____/live-1-0-2.374269833496060124].<stdout>: newImageUrl3: http://lh3.ggpht.com/My7zTT79xOltI3cMzHidx7-Us91Qlp13jdv-vJceQ_OpX3FONSr9YzI2...

这就是它没有覆盖原始内容的原因。我猜是我创建的文件名不正确，还是我创建的GcsOutputChannel正在更改路径？我也很好奇为什么我得到的是原始图像的url而不是新图像的url？

如果我拆分原始的GcsFileName并只取最后一部分,我将得到一个错误：

GcsFilename fileName = new GcsFilename("bucket-name", upload.getGcsFileName().split("/")[3]);

Google存储文件名必须以/gs/为前缀

解决方案

使用以下方法检索blobKey：

BlobKey blobKey = blobstoreService.createGsBlobKey("/gs/" + fileName.getBucketName() + "/" + fileName.getObjectName());

...即使FileName.getObjectName（）在ObjectName前面已经包含“/gs/bucket-name/”。当将其打印为标准输出时，您的文件名应该包含/gs/bucket-name/两次，这很奇怪，但它起作用了。

Answer 1

要重写原始映像，只需指定相同的云存储文件名。

我知道您已经通过应用程序引擎通过BlobStore API将映像上传到云存储。要获得原始映像的实际文件名，必须在上传servlet中添加以下代码：

  Map<String,List<BlobInfo>> uploadInfos = getFileInfos(httpServletRequest);
  String theGCSFilename = uploadInfos.get("yourFileName").getGsObjectName();

注意，如果您不希望覆盖原始文件，但希望向客户提供一个服务URL，您可以：

>

使用ImageService如下所示：

ImagesService imagesService = ImagesServiceFactory.getImagesService();
String url = imagesService.getServingUrl(ServingUrlOptions.Builder.withGoogleStorageFileName(java));

创建一个自定义的GCSServingServlet，它将使用BlobStoreReservice.serve()方法为来自Blobstore或云存储的文件提供服务。在这种情况下，您必须自己检查权限。注意，您可以使用BlobStoreservice.createGsBlobKey()从GCSFileName创建BlobKey。

使用云存储服务URL：

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