Python script that reads GPS log files and sends values via OSC

This is the companion post to the one below, (Python script that sends live GPS values over OSC). It is for people who don’t have a GPS to attach but want to experiment with the kind of values you get from one. The script in the other post produces log files in the form of pickled OSC bundles which can then be sent out with this script.

It takes two arguments, the log file and the interval between sending bundles, there is one option, that is not to loop the file, but send it only once. Everything is documented in the comment at the top of the script.

#!/usr/bin/env python
# SatelliteLogReader.py
#
# takes a pickled file containing OSC bundles, made by
# PirateSatelliteServer.py and sends the bundles over OSC to a
# receiving programme, listening on port PORT (currently using 57120)
# at a regular interval of seconds
#
# Takes two arguments: location of log file and sending interval as a
# positive integer
#
# Example: python SatelliteLogReader.py data/test4.log 1 -n
#
# This reads from file test4.log and sends the bundles therein every
# (1) second. The '-n' option is 'no loop' which only sends the file
# contents once and then exits. If this option is not enabled, the
# default behaviour is to loop the file indefinately.
#
# TODO: sort out looping (re-sending the bundles from the beginning of
# the file again)

import pickle
try:
    import OSC
except ImportError:
    print """
Please install pyOSC from the following location:
https://trac.v2.nl/wiki/pyOSC
"""
import sys
from time import sleep
from optparse import OptionParser

# port number to send osc messages to
# set this in receiving programme too
PORT = 57120


def openPickle(logfile):
    """
    Tries to open the pickle file passed through logfile and handles
    errors if necessary
    """
    try:
        picklefile = open(logfile, 'rb')
    except IOError as err:
        print """
%s
There was a problem with the file you specified.
Did you type the name and location correctly?
""" % err
        sys.exit()
    return picklefile


def sendBundles(osc, logfile, secs):
    """
    Attempts to send osc bundles from pickle file and handle errors
    """
    picklefile = openPickle(logfile)
    while 1:
        try:
            message = pickle.load(picklefile)
            try:
                osc.send(message)
            except OSC.OSCClientError as err:
                print """
%s
Have you started the receiving programme?
""" % err
                return
            sleep(secs)
            print message, type(message)
            print
        except EOFError:
            return
        except KeyError:
            print """
There was a problem with the file you selected.
It seems to be of the wrong type for this script.
Please select another file.
"""
            sys.exit()


def main():
    """
    """
    usage = "usage: %prog filename seconds"
    parser = OptionParser(usage, version="%prog 0.1")
    parser.add_option("-n", "--noloop", dest="noloop",
                      help="don't loop the log file", action="store_true",
                      default=False)
    (options, args) = parser.parse_args()
    if len(args) != 2:
        parser.error("specify a file path and sending interval in seconds")
    logfile = args[0]
    try:
        secs = float(args[1])
    except ValueError as err:
        print """
%s
Please enter a positive integer for the seconds
""" % err
        return
    # localhost and port settings - remember to set this in the
    # receiving programmpe too
    send_address = ("127.0.0.1", PORT)
    # OSC basic client
    osc = OSC.OSCClient()
    osc.connect(send_address) # set the address for all following messages
    if options.noloop == False:
        while 1:
            sendBundles(osc, logfile, secs)
    else:
        sendBundles(osc, logfile, secs)
        print """'no loop' selected, script ends here
"""
        return


if __name__ == '__main__':
    sys.exit(main())

You can download some test log files and another copy of the script here.

An example of evoking the script:
$ python SatelliteLogReader.py data/test4.log 1