expect - Programmed dialogue with interactive streams

Installation

pip install xpect

Example usage

See the test suite: https://github.com/eerimoq/expect/blob/master/tests/test_expect.py

A basic login example using pyserial:

>>> import pyserial
>>> import expect
>>> serial_linux = pyserial.Serial("/dev/ttyS0")
>>> linux = expect.Handler(serial_linux)
>>> linux.send("")
>>> linux.expect(r"username: ")
>>> linux.send("root")
>>> linux.expect(r"password: ")
>>> linux.send("root")
>>> linux.expect(r"/home/root $ ")

Classes

class expect.Handler(iostream, eol='n', break_conditions=None, print_input=True, print_output=False, split_pattern='n')

Class wrapping an io object.

__init__(iostream, eol='\n', break_conditions=None, print_input=True, print_output=False, split_pattern='\n')

Initialize object with given parameters.

Parameters:

• iostream – Io stream to read data from and write data data to. The class of this object must implement two functions, read(count) and write(string). read() must return a string.
• eol – ‘end of line’ string to send after the ‘send string’.
• break_conditions – expect() throws an exception if the returned value from iostream.read() is in this iterable.
• print_input – Print input on stdout.
• print_output – Print output on stdout.
• split_pattern – Split read data using this regexp before sreaching for a match.

expect(pattern, timeout=None, print_input=True)

Returns when regular expression pattern matches the data read from the output stream.

Parameters:pattern – Regular expression to match. Returns:The matched string.

send(string, send_eol=True)

Writes a string to the iostream.

Parameters:

• string – String to send.
• send_eol – Send ‘end of line’ after string.

Returns:

Return value of iostream.write().