MessageBody

class MessageBody(**kwargs)

MessageBody represents the request or response body of a Message.

Note that while length always reflects the full length of the message body, data is normally None, and will only be filled in after flatten is called. For client-side messages, this automatically happens for the response body after it has been fully read. Likewise, for server-side messages, the request body is automatically filled in after being read.

As an added bonus, when data is filled in, it is always terminated with a \0 byte (which is not reflected in length).

Constructors

class MessageBody

classmethod new() → MessageBody

Creates a new MessageBody.

Message uses this internally; you will not normally need to call it yourself.

Methods

class MessageBody

append(data: Sequence[int]) → None

Appends length bytes from data to body according to use.

Parameters:: data – data to append

append_bytes(buffer: Bytes) → None

Appends the data from buffer to body.

Parameters:: buffer – a Bytes

complete() → None

Tags body as being complete.

Call this when using chunked encoding after you have appended the last chunk.

flatten() → Bytes

Fills in body’s data field with a buffer containing all of the data in body.

Adds an additional \0 byte not counted by body’s length field.

get_accumulate() → bool

Gets the accumulate flag on body.

See [method``MessageBody``.set_accumulate. for details.

get_chunk(offset: int) → Bytes | None

Gets a Bytes containing data from body starting at offset.

The size of the returned chunk is unspecified. You can iterate through the entire body by first calling get_chunk with an offset of 0, and then on each successive call, increment the offset by the length of the previously-returned chunk.

If offset is greater than or equal to the total length of body, then the return value depends on whether or not complete has been called or not; if it has, then get_chunk will return a 0-length chunk (indicating the end of body). If it has not, then get_chunk will return None (indicating that body may still potentially have more data, but that data is not currently available).

Parameters:: offset – an offset

got_chunk(chunk: Bytes) → None

Handles the MessageBody part of receiving a chunk of data from the network.

Normally this means appending chunk to body, exactly as with append_bytes, but if you have set body’s accumulate flag to False, then that will not happen.

This is a low-level method which you should not normally need to use.

Parameters:: chunk – a Bytes received from the network

set_accumulate(accumulate: bool) → None

Sets or clears the accumulate flag on body.

(The default value is True.) If set to False, body’s data field will not be filled in after the body is fully sent/received, and the chunks that make up body may be discarded when they are no longer needed.

If you set the flag to False on the Message request_body of a client-side message, it will block the accumulation of chunks into body’s data field, but it will not normally cause the chunks to be discarded after being written like in the server-side Message response_body case, because the request body needs to be kept around in case the request needs to be sent a second time due to redirection or authentication.

Parameters:: accumulate – whether or not to accumulate body chunks in body

truncate() → None: Deletes all of the data in body.

wrote_chunk(chunk: Bytes) → None

Handles the MessageBody part of writing a chunk of data to the network.

Normally this is a no-op, but if you have set body’s accumulate flag to False, then this will cause chunk to be discarded to free up memory.

This is a low-level method which you should not need to use, and there are further restrictions on its proper use which are not documented here.

Parameters:: chunk – a Bytes returned from get_chunk

Fields

class MessageBody

data: The data

length: Length of data