Package com.google.appengine.api.blobstore

Interface BlobstoreService

public interface BlobstoreService

BlobstoreService allows you to manage the creation and serving of large, immutable blobs to users.

Field Summary

Fields

Modifier and Type	Field	Description
static int	MAX_BLOB_FETCH_SIZE

Method Summary

Modifier and Type	Method	Description
BlobKey	createGsBlobKey(String filename)	Create a BlobKey for a Google Storage File.
String	createUploadUrl(String successPath)	Create an absolute URL that can be used by a user to asynchronously upload a large blob.
String	createUploadUrl(String successPath, UploadOptions uploadOptions)	Create an absolute URL that can be used by a user to asynchronously upload a large blob.
void	delete(BlobKey... blobKeys)	Permanently deletes the specified blobs.
byte[]	fetchData(BlobKey blobKey, long startIndex, long endIndex)	Get fragment from specified blob.
Map<String,List<BlobInfo>>	getBlobInfos(javax.servlet.http.HttpServletRequest request)	Returns the BlobInfo for any files that were uploaded, keyed by the upload form "name" field.
@Nullable ByteRange	getByteRange(javax.servlet.http.HttpServletRequest request)	Get byte range from the request.
Map<String,List<FileInfo>>	getFileInfos(javax.servlet.http.HttpServletRequest request)	Returns the FileInfo for any files that were uploaded, keyed by the upload form "name" field.
Map<String,BlobKey>	getUploadedBlobs(javax.servlet.http.HttpServletRequest request)	Deprecated. Use getUploads(javax.servlet.http.HttpServletRequest) instead.
Map<String,List<BlobKey>>	getUploads(javax.servlet.http.HttpServletRequest request)	Returns the BlobKey for any files that were uploaded, keyed by the upload form "name" field.
void	serve(BlobKey blobKey, @Nullable ByteRange byteRange, javax.servlet.http.HttpServletResponse response)	Arrange for the specified blob to be served as the response content for the current request.
void	serve(BlobKey blobKey, String rangeHeader, javax.servlet.http.HttpServletResponse response)	Arrange for the specified blob to be served as the response content for the current request.
void	serve(BlobKey blobKey, javax.servlet.http.HttpServletResponse response)	Arrange for the specified blob to be served as the response content for the current request.

Field Detail

MAX_BLOB_FETCH_SIZE

static final int MAX_BLOB_FETCH_SIZE

See Also:

Constant Field Values

Method Detail

createUploadUrl

String createUploadUrl(String successPath)

Create an absolute URL that can be used by a user to asynchronously upload a large blob. Upon completion of the upload, a callback is made to the specified URL.

Parameters:

successPath - A relative URL which will be invoked after the user successfully uploads a blob. Must start with a "/", and must be URL-encoded.

Throws:

IllegalArgumentException - If successPath was not valid.

BlobstoreFailureException - If an error occurred while communicating with the blobstore.

createUploadUrl

String createUploadUrl(String successPath,
                       UploadOptions uploadOptions)

Create an absolute URL that can be used by a user to asynchronously upload a large blob. Upon completion of the upload, a callback is made to the specified URL.

Parameters:

successPath - A relative URL which will be invoked after the user successfully uploads a blob. Must start with a "/".

uploadOptions - Specific options applicable only for this upload URL.

Throws:

IllegalArgumentException - If successPath was not valid.

BlobstoreFailureException - If an error occurred while communicating with the blobstore.

serve

void serve(BlobKey blobKey,
           javax.servlet.http.HttpServletResponse response)
    throws IOException

Arrange for the specified blob to be served as the response content for the current request. response should be uncommitted before invoking this method, and should be assumed to be committed after invoking it. Any content written before calling this method will be ignored. You may, however, append custom headers before or after calling this method.

Range header will be automatically translated from the Content-Range header in the response.

Parameters:

blobKey - Blob-key to serve in response.

response - HTTP response object.

Throws:

IOException - If an I/O error occurred.

IllegalStateException - If response was already committed.

serve

void serve(BlobKey blobKey,
           @Nullable ByteRange byteRange,
           javax.servlet.http.HttpServletResponse response)
    throws IOException

Arrange for the specified blob to be served as the response content for the current request. response should be uncommitted before invoking this method, and should be assumed to be committed after invoking it. Any content written before calling this method will be ignored. You may, however, append custom headers before or after calling this method.

This method will set the App Engine blob range header to serve a byte range of that blob.

Parameters:

blobKey - Blob-key to serve in response.

byteRange - Byte range to serve in response.

response - HTTP response object.

Throws:

IOException - If an I/O error occurred.

IllegalStateException - If response was already committed.

serve

void serve(BlobKey blobKey,
           String rangeHeader,
           javax.servlet.http.HttpServletResponse response)
    throws IOException

Arrange for the specified blob to be served as the response content for the current request. response should be uncommitted before invoking this method, and should be assumed to be committed after invoking it. Any content written before calling this method will be ignored. You may, however, append custom headers before or after calling this method.

This method will set the App Engine blob range header to the content specified.

Parameters:

blobKey - Blob-key to serve in response.

rangeHeader - Content for range header to serve.

response - HTTP response object.

Throws:

IOException - If an I/O error occurred.

IllegalStateException - If response was already committed.

getByteRange

@Nullable ByteRange getByteRange(javax.servlet.http.HttpServletRequest request)

Get byte range from the request.

Parameters:

request - HTTP request object.

Returns:

Byte range as parsed from the HTTP range header. null if there is no header.

Throws:

RangeFormatException - Unable to parse header because of invalid format.

UnsupportedRangeFormatException - Header is a valid HTTP range header, the specific form is not supported by app engine. This includes unit types other than "bytes" and multiple ranges.

delete

void delete(BlobKey... blobKeys)

Permanently deletes the specified blobs. Deleting unknown blobs is a no-op.

Throws:

BlobstoreFailureException - If an error occurred while communicating with the blobstore.

getUploadedBlobs

@Deprecated
Map<String,BlobKey> getUploadedBlobs(javax.servlet.http.HttpServletRequest request)

Deprecated.

Use getUploads(javax.servlet.http.HttpServletRequest) instead. Note that getUploadedBlobs does not handle cases where blobs have been uploaded using the multiple="true" attribute of the file input form element.

Returns the BlobKey for any files that were uploaded, keyed by the upload form "name" field.

This method should only be called from within a request served by the destination of a createUploadUrl call.

Throws:

IllegalStateException - If not called from a blob upload callback request.

getUploads

Map<String,List<BlobKey>> getUploads(javax.servlet.http.HttpServletRequest request)

Returns the BlobKey for any files that were uploaded, keyed by the upload form "name" field. This method should only be called from within a request served by the destination of a createUploadUrl(java.lang.String) call.

Throws:

IllegalStateException - If not called from a blob upload callback request.

See Also:

getBlobInfos(javax.servlet.http.HttpServletRequest), getFileInfos(javax.servlet.http.HttpServletRequest)

getBlobInfos

Map<String,List<BlobInfo>> getBlobInfos(javax.servlet.http.HttpServletRequest request)

Returns the BlobInfo for any files that were uploaded, keyed by the upload form "name" field. This method should only be called from within a request served by the destination of a createUploadUrl(java.lang.String) call.

Throws:

IllegalStateException - If not called from a blob upload callback request.

Since:

1.7.5

See Also:

getFileInfos(javax.servlet.http.HttpServletRequest), getUploads(javax.servlet.http.HttpServletRequest)

getFileInfos

Map<String,List<FileInfo>> getFileInfos(javax.servlet.http.HttpServletRequest request)

Returns the FileInfo for any files that were uploaded, keyed by the upload form "name" field. This method should only be called from within a request served by the destination of a createUploadUrl(java.lang.String) call. Prefer this method over getBlobInfos(javax.servlet.http.HttpServletRequest) or getUploads(javax.servlet.http.HttpServletRequest) if uploading files to Cloud Storage, as the FileInfo contains the name of the created filename in Cloud Storage.

Throws:

IllegalStateException - If not called from a blob upload callback request.

Since:

1.7.5

See Also:

getBlobInfos(javax.servlet.http.HttpServletRequest), getUploads(javax.servlet.http.HttpServletRequest)

fetchData

byte[] fetchData(BlobKey blobKey,
                 long startIndex,
                 long endIndex)

Get fragment from specified blob.

Parameters:

blobKey - Blob-key from which to fetch data.

startIndex - Start index of data to fetch.

endIndex - End index (inclusive) of data to fetch.

Throws:

IllegalArgumentException - If blob not found, indexes are negative, indexes are inverted or fetch size is too large.

SecurityException - If the application does not have access to the blob.

BlobstoreFailureException - If an error occurred while communicating with the blobstore.

createGsBlobKey

BlobKey createGsBlobKey(String filename)

Create a BlobKey for a Google Storage File.

The existence of the file represented by filename is not checked, hence a BlobKey can be created for a file that does not currently exist.

You can safely persist the BlobKey generated by this function.

The created BlobKey can then be used as a parameter in API methods that can support objects in Google Storage, for example serve(com.google.appengine.api.blobstore.BlobKey,javax.servlet.http.HttpServletResponse).

Parameters:

filename - The Google Storage filename. The filename must be in the format "/gs/bucket_name/object_name".

Throws:

IllegalArgumentException - If the filename does not have the prefix "/gs/".