Method compress

aiohttp/compression_utils.py:224–250

Compress the data and returned the compressed bytes. Note that flush() must be called after the last call to compress() If the data size is large than the max_sync_chunk_size, the compression will be done in the executor. Otherwise, the compression will be done in t

(self, data: Buffer)

        return self._compressor.compress(data)

    async def compress(self, data: Buffer) -> bytes:
        """Compress the data and returned the compressed bytes.

        Note that flush() must be called after the last call to compress()

        If the data size is large than the max_sync_chunk_size, the compression
        will be done in the executor. Otherwise, the compression will be done
        in the event loop.

        **WARNING: This method is NOT cancellation-safe when used with flush().**
        If this operation is cancelled, the compressor state may be corrupted.
        The connection MUST be closed after cancellation to avoid data corruption
        in subsequent compress operations.

        For cancellation-safe compression (e.g., WebSocket), the caller MUST wrap
        compress() + flush() + send operations in a shield and lock to ensure atomicity.
        """
        # For large payloads, offload compression to executor to avoid blocking event loop
        should_use_executor = (
            self._max_sync_chunk_size is not None
            and len(data) > self._max_sync_chunk_size
        )
        if should_use_executor:
            return await asyncio.get_running_loop().run_in_executor(
                self._executor, self._compressor.compress, data
            )
        return self.compress_sync(data)

    def flush(self, mode: int | None = None) -> bytes:
        """Flush the compressor synchronously.