在GAE Blobstore Java中创建文件

Question

In my application I have a string which is a file content. I need to create new file with this content in blobstore. I tryed to use File API like this:

    FileService fileService = FileServiceFactory.getFileService();
    AppEngineFile file = fileService.createNewBlobFile("text/plain");
    FileWriteChannel writeChannel = fileService.openWriteChannel(file, true);

    writeChannel.write(ByteBuffer.wrap(content.getBytes()));
    writeChannel.closeFinally();
    BlobKey blobKey = fileService.getBlobKey(file);
    res.sendRedirect("/serve?blob-key=" + blobKey);

But since the File API is deprecated I only get this error:

HTTP ERROR 500

Problem accessing /create_timetable. Reason:

The Files API is disabled. Further information: https://cloud.google.com/appengine/docs/deprecations/files_api
Caused by:

com.google.apphosting.api.ApiProxy$FeatureNotEnabledException: The Files API is disabled. Further information: https://cloud.google.com/appengine/docs/deprecations/files_api
at com.google.appengine.tools.development.ApiProxyLocalImpl$AsyncApiCall.callInternal(ApiProxyLocalImpl.java:515)
at com.google.appengine.tools.development.ApiProxyLocalImpl$AsyncApiCall.call(ApiProxyLocalImpl.java:484)
at com.google.appengine.tools.development.ApiProxyLocalImpl$AsyncApiCall.call(ApiProxyLocalImpl.java:461)
at java.util.concurrent.Executors$PrivilegedCallable$1.run(Executors.java:533)
at java.security.AccessController.doPrivileged(Native Method)
at java.util.concurrent.Executors$PrivilegedCallable.call(Executors.java:530)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

How can I manually create file in blobstore since user only gives me data content as string, not a file itself, so I can't use <form action="blobstoreService.createUploadUrl("/upload") %>" and <input type="file">

Update

As @ozarov suggested I did it using Google Cloude Storage API and wrote the function below. It also returns BlobKey of this file so you can access it using Blobstore API.

private BlobKey saveFile(String gcsBucket, String fileName,
        String content) throws IOException {
    GcsFilename gcsFileName = new GcsFilename(gcsBucket, fileName);
    GcsOutputChannel outputChannel =
            gcsService.createOrReplace(gcsFileName, GcsFileOptions.getDefaultInstance());
    outputChannel.write(ByteBuffer.wrap(content.getBytes()));
    outputChannel.close();

    return blobstoreService.createGsBlobKey(
            "/gs/" + gcsFileName.getBucketName() + "/" + gcsFileName.getObjectName());
}

Answer 1

You should write to Google Cloud Storage instead. Files API is deprecated and you are correct that the Blobstore API does not provide a programmatic way to write directly to it.

Later you can read directly from Google Cloud Storage using its own API or you can also use the Blobstore API to do so by creating a BlobKey for it.