Asynchronously fetches data for a blob.
View aliases
Main aliases
`google.appengine.ext.blobstore.blobstore.fetch_data_async`
google.appengine.ext.blobstore.fetch_data_async(
blob, start_index, end_index, rpc=None
)
Fetches a fragment of a blob up to MAX_BLOB_FETCH_SIZE
in length. Attempting
to fetch a fragment that extends beyond the boundaries of the blob will return
the amount of data from start_index
until the end of the blob, which will be
a smaller size than requested. Requesting a fragment that is entirely outside
the boundaries of the blob will return an empty string. Attempting to fetch a
negative index will raise an exception.
Args |
blob
|
A BlobInfo , BlobKey , string, or Unicode representation of
the BlobKey of the blob from which you want to fetch data.
|
start_index
|
The start index of blob data to fetch. This value must not be
negative.
|
end_index
|
The end index (inclusive) of the blob data to fetch. This value
must be greater than or equal to start_index .
|
rpc
|
Optional UserRPC object.
|
Returns |
A UserRPC whose result will be a string as returned by fetch_data() .
|
Raises |
TypeError
|
If start_index or end_index are not indexes, or if blob is
not a string, BlobKey or BlobInfo .
|
DataIndexOutOfRangeError
|
If start_index is set to a value that is less
than 0 or end_index is less than start_index when calling
rpc.get_result() .
|
BlobFetchSizeTooLargeError
|
If the requested blob fragment is larger than
MAX_BLOB_FETCH_SIZE when calling rpc.get_result() .
|
BlobNotFoundError
|
If the blob does not exist when calling
rpc.get_result() .
|