Stdin

Interfacy can route piped stdin into command parameters.

from interfacy import Interfacy


def echo(message: str) -> str:
    """Echo a message."""
    return message


Interfacy(print_result=True, pipe_targets="message").run(echo)

$ echo "hello" | python app.py
hello

Per-command routing

Pipe targets can be configured on a single command.

parser = Interfacy(print_result=True)
parser.add_command(echo, pipe_targets="message")
parser.run()

Multiple targets

When more than one parameter is targeted, stdin is split into chunks. Newlines are the default delimiter.

def pair(left: str, right: str) -> tuple[str, str]:
    return left, right


parser.add_command(pair, pipe_targets=("left", "right"))

$ printf "one\ntwo" | python app.py

The command receives ("one", "two").

Custom delimiter

A dict configures delimiter and priority settings.

parser.add_command(
    pair,
    pipe_targets={"bindings": ("left", "right"), "delimiter": ","},
)

$ printf "one,two" | python app.py

parameters and bindings are both accepted as the target-key name.

Lists

If the target is a list, piped chunks become list elements.

def collect(items: list[int]) -> list[int]:
    return items


parser.add_command(collect, pipe_targets="items")

$ printf "1\n2\n3" | python app.py

The command receives [1, 2, 3].

Priority

CLI values win over stdin by default.

parser.add_command(echo, pipe_targets="message")

$ echo piped | python app.py cli

The command receives "cli".

priority="pipe" makes stdin override explicit CLI values.

parser.add_command(
    echo,
    pipe_targets={"bindings": "message", "priority": "pipe"},
)

Partial chunks

By default, Interfacy reports an error if fewer chunks are provided than required targets. With allow_partial=True, missing chunks become None and are ignored for optional parameters.

parser.add_command(
    pair,
    pipe_targets={"bindings": ("left", "right"), "allow_partial": True},
)