Framing

iso8583sim.net.framing

`Framing`

Framing(
    header: str = '2b',
    tpdu: bytes | None = None,
    header_includes_self: bool = False,
)

How messages are delimited on a TCP stream. Attributes

str

Length header: “2b” / “4b” (2 or 4 byte big-endian binary) or “2a” / “4a” (2 or 4 ASCII digits). The length covers everything after the header.

bytes | None

Optional TPDU sent after the length header, e.g. bytes.fromhex(“6000010000”). On responses the destination and source addresses are swapped.

bool

Some hosts count the header bytes in the length. Off by default.

`frame()`

def frame(message: bytes, tpdu: bytes | None = None) -> bytes

Add the TPDU (if configured) and the length header to an encoded message.

`read()`

async def read(reader: asyncio.StreamReader) -> tuple[bytes | None, bytes]

Read one framed message. Returns (tpdu, message). Raises asyncio.IncompleteReadError if the connection closes mid-frame, and EOFError when it closes cleanly between frames.

`split()`

def split(buffer: bytes) -> tuple[list[tuple[bytes | None, bytes]], bytes]

Split a byte buffer into complete frames. Returns (frames, leftover bytes).

Functions

`swap_tpdu()`

def swap_tpdu(tpdu: bytes | None) -> bytes | None

Swap a TPDU’s destination and source addresses, as a response does.

Core

Security

Wire formats

Networking

LLM

Servers

Demo

`Framing`

`frame()`

`read()`

`split()`

Functions

`swap_tpdu()`

​Framing

​frame()

​read()

​split()

​Functions

​swap_tpdu()

`Framing`

`frame()`

`read()`

`split()`

Functions

`swap_tpdu()`