I'm hoping the answer to this question is quite simple, but I can't get it working after looking at the Azure Java API documentation.
I am trying to create an empty CloudBlockBlob, which will have blocks uploaded to it at a later point. I have successfully uploaded blocks before, when the blob is created upon the first block being uploaded, but I can't seem to get anything other than ("the specified blob does not exist") when I try to create a new blob without any data and then access it. I require this because in my service, a call is first made to create the new blob in Azure, and then later calls are used to upload blocks (at which point a check is made to see if the blob exists). Is it possible to create an empty blob in Azure, and upload data to it later? What have I missed?
I've not worked with Java SDK so I may be wrong but I tried creating an empty blob using C# code (storage client library 2.0) and if I upload an empty input stream an empty blob with zero byte size is created. I did something like the following:
CloudBlockBlob emptyBlob = blobContainer.GetBlockBlobReference("emptyblob.txt");
using (MemoryStream ms = new MemoryStream())
{
emptyBlob.UploadFromStream(ms);//Empty memory stream. Will create an empty blob.
}
I did look at Azure SDK for Java source code on Github here: https://github.com/WindowsAzure/azure-sdk-for-java/blob/master/microsoft-azure-api/src/main/java/com/microsoft/windowsazure/services/blob/client/CloudBlockBlob.java and found this "upload" function where you can specify an input stream. Try it out and see if it works for you.
Related
So, I'm trying to save the pdf report in database using service methode. I saw that there's a way to specify the output of the generated report by calling : pdfOptions.setOutputStream(output). But how can I call my save methode this way?
I saw this post but i'm stack at the persist point
I apreciate any advice
PDFRenderOption pdfOptions = new PDFRenderOption(options);
pdfOptions.setOutputFormat(FORMAT_PDF);
pdfOptions.setOption(IPDFRenderOption.PAGE_OVERFLOW, IPDFRenderOption.OUTPUT_TO_MULTIPLE_PAGES);
pdfOptions.setOutputStream(response.getOutputStream());//opens report on browser
runAndRenderTask.setRenderOption(pdfOptions);
You are streaming the output directly to the client with
pdfOptions.setOutputStream(response.getOutputStream());//opens report on browser
If you do this, your output gets consumed and you'll not be able to save it to the database.
I would use a "tee" like approach, you know, with one input stream and two output streams.
You could write that yourself, our you just use something like the Apache TeeOutputStream.
This could look like this:
OutputStream blobOutputStream = ...; // for writing to the DB as BLOB.
OutputStream teeStream = TeeOutputStream(response.getOutputStream(), blobOutputStream);
pdfOptions.setOutputStream(teeStream);
I am trying to update the content of a Google Doc file with the content of another Google Doc file. The reason I don't use the copy method of the API is because that creates another file with another ID. My goal is to keep the current ID of the file. This is a code snippet which unfortunately does nothing:
com.google.api.services.drive.Drive.Files.Get getDraft = service.files().get(draftID);
File draft = driveManager.getFileBackoffExponential(getDraft);
com.google.api.services.drive.Drive.Files.Update updatePublished = service.files().update(publishedID, draft);
driveManager.updateFileBackoffExponential(updatePublished);
The two backoffExponential functions just launch the execute method on the object.
Googling around I found out that the update method offers another constructor:
public Update update(java.lang.String fileId, com.google.api.services.drive.model.File content, com.google.api.client.http.AbstractInputStreamContent mediaContent)
Thing is, I have no idea how to retrieve the mediaContent of a Google file such as a Google Doc.
The last resort could be a Google Apps Script but I'd rather avoid that since it's awfully slow and unreliable.
Thank you.
EDIT: I am using Drive API v3.
Try the Google Drive REST update.
Updates a file's metadata and/or content with patch semantics.
This method supports an /upload URI and accepts uploaded media with
the following characteristics:
Maximum file size: 5120GB Accepted Media MIME types: /*
To download a Google File in the format that's usable, you need to specify the mime-type. Since you're using Spreadsheets, you can try application/vnd.openxmlformats-officedocument.spreadsheetml.sheet. Link to Download files for more info.
I'm migrating my GAE app from the deprecated File API to Google Cloud Storage Client Library.
I used to persist the blobKey, but since there is partial support for it (as specified here) from now on I'll have to persist the object name.
Unfortunately the object name that comes from the GCS looks more or less like this
/gs/bucketname/819892hjd81dh19gf872g8211
as you can see, it also contains the bucket name
Here's the issue, every time I need to get the file for further processing (or to serve it in a servlet) I need to create an instance of GcsFileName(bucketName, objectName) which gives me something like
/bucketName/gs/bucketName/akahsdjahslagfasgfjkasd
which (of course) doesn't work.
so. my question is:
- how can I generate a GcsFileName form the objectName?
UPDATE
I tried using the objectName as BlobKey. But it just doesn't work :(
InputStream is = new BlobstoreInputStream(blobstoreService.createGsBlobKey("/gs/bucketName/akahsdjahslagfasgfjkasd"));
I got the usual answer
BlobstoreInputStream received an invalid blob key
How do I get the file using the ObjectName???
If you have persisted and retrieved e.g the string String objname worth e.g "/gs/bucketname/819892hjd81dh19gf872g8211", you could split it on "/" (String[] pieces = objname.split("/")) and use the pieces appropriately in the call to GcsFileName.
I wrote a Google App Engine application that makes use of Blobstore to save programmatically-generated data. To do so, I used the Files API, which unfortunately has been deprecated in favor to Google Cloud Storage. So I'm rewriting my helper class to work with GCS.
I'd like to keep the interface as similar as possible as it was before, also because I persist BlobKeys in the Datastore to keep references to the files (and changing the model of a production application is always painful). When i save something to GCS, i retrieve a BlobKey with
BlobKey blobKey = blobstoreService.createGsBlobKey("/gs/" + fileName.getBucketName() + "/" + fileName.getObjectName());
as prescribed here, and I persist it in the Datastore.
So here's the question: the documentation tells me how to serve a GCS file with blobstoreService.serve(blobKey, resp); in a servlet response, BUT how can I retrieve the file content (as InputStream, byte array or whatever) to use it in my code for further processing? In my current implementation I do that with a FileReadChannel reading from an AppEngineFile (both deprecated).
Here is the code to open a Google Storage Object as Input Stream. Unfortunately, you have to use bucket name and object name and not the blob key
GcsFilename gcs_filename = new GcsFilename(bucket_name, object_name);
GcsService service = GcsServiceFactory.createGcsService();
ReadableByteChannel rbc = service.openReadChannel(gcs_filename, 0);
InputStream stream = Channels.newInputStream(rbc);
Given a blobKey, use the BlobstoreInputStream class to read the value from Blobstore, as described in the documentation:
BlobstoreInputStream in = new BlobstoreInputStream(blobKey);
You can get the cloudstorage filename only in the upload handler (fileInfo.gs_object_name) and store it in your database. After that it is lost and it seems not to be preserved in BlobInfo or other metadata structures.
Google says:
Unlike BlobInfo metadata FileInfo metadata is not persisted to
datastore. (There is no blob key either, but you can create one later
if needed by calling create_gs_key.) You must save the gs_object_name
yourself in your upload handler or this data will be lost.
Sorry, this is a python link, but it should be easy to find something similar in java.
https://developers.google.com/appengine/docs/python/blobstore/fileinfoclass
Here is the Blobstore approach (sorry, this is for Python, but I am sure you find it quite similar for Java):
blob_reader = blobstore.BlobReader(blob_key)
if blob_reader:
file_content = blob_reader.read()
I would like to know if is possible get the image via POST method with a HTTP server implemented in Java (With a simple input file form). I already implemented the Java server but I can only get text files via POST method it's because that the my application only copies the file content to another empty file creating the same file with the same characteristics. This does not work with image file or other files, this can only work with text file.
Anyone know how to implement it with images?
Some coordinates would be of great help!
Thanks in advance!
As far as i know you should create something like it:
Server-side: If you use a servlet that receive data in post you have to get the outputStream from the response. Once you have it it is done because you write the data image on the stream.
For example let's suppose your image is a file stored in the server you could do:
response.setContentLength((int) fileSize);
byte b[] = new byte[1024];
while ( fOutStream.read(b) != -1)
response.getOutputStream().write(b);
fOutStream.close() ;
Where the fOutStream is the source stream (your image).