Struct GridFsUploadStream 

pub struct GridFsUploadStream { /* private fields */ }

Available on crate feature sync only.

A stream to which bytes can be written to be uploaded to a GridFS bucket.

Uploading to the Stream

The GridFsUploadStream type implements std::io::Write.

Bytes can be written to the stream using the write methods in the Write trait. When close is invoked on the stream, any remaining bytes in the buffer are written to the chunks collection and a corresponding FilesCollectionDocument is written to the files collection. It is an error to write to, abort, or close the stream after close has been called.

use std::io::Write;

let bytes = vec![0u8; 100];
let mut upload_stream = bucket.open_upload_stream("example_file").run()?;
upload_stream.write_all(&bytes[..])?;
upload_stream.close()?;

If the data is a local file (or other Read byte source), its contents can be efficiently written to the stream with std::io::copy.

Aborting the Stream

A stream can be aborted by calling the abort method. This will remove any chunks associated with the stream from the chunks collection. It is an error to write to, abort, or close the stream after abort has been called.

use std::io::Write;

let bytes = vec![0u8; 100];
let mut upload_stream = bucket.open_upload_stream("example_file").run()?;
upload_stream.write_all(&bytes[..])?;
upload_stream.abort()?;

In the event of an error during any operation on the GridFsUploadStream, any chunks associated with the stream will be removed from the chunks collection. Any subsequent attempts to write to, abort, or close the stream will return an error.

If a GridFsUploadStream is dropped prior to abort or close being called, its Drop implementation will remove any chunks associated with the stream from the chunks collection. Users should prefer calling abort explicitly to relying on the Drop implementation in order to inspect the result of the delete operation.

Flushing the Stream

Because all chunks besides the final chunk of a file must be exactly chunk_size_bytes, calling flush is not guaranteed to flush all bytes to the chunks collection. Any remaining buffered bytes will be written to the chunks collection upon a call to close.

Implementations

impl GridFsUploadStream

pub fn id(&self) -> &Bson

Gets the stream’s unique Bson identifier. This value will be the id field for the FilesCollectionDocument uploaded to the files collection when the stream is closed.

pub fn close(&mut self) -> Result<()>

Closes the stream, writing any buffered bytes to the chunks collection and a corresponding FilesCollectionDocument to the files collection. If an error occurs during either of these steps, the chunks associated with this stream are deleted. It is an error to write to, abort, or close the stream after this method has been called.

pub fn abort(&mut self) -> Result<()>

Aborts the stream, discarding any chunks that have already been written to the chunks collection. Once this method has been called, it is an error to attempt to write to, abort, or close the stream.

Trait Implementations

impl Write for GridFsUploadStream

fn write(&mut self, buf: &[u8]) -> Result<usize>

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.