SAJ Solar Inverter query tool

power.py

import xmltodict
import requests
import argparse
import urlparse
import sys

__version__ = "1.0.0"
__description__ = "Query tool for SAJ solar inverters"


def parse_arguments():
    """
    Parse commandline arguments.
    """

    parser = argparse.ArgumentParser()

    # Add options
    parser.add_argument(
        "--host", action="store", required=True, help="remote host")
    parser.add_argument(
        "--query", action="store", help="field to query")

    # Parse command line
    return parser.parse_args(), parser


def main():
    """
    Read a single value, using the first command line argument as query.
    """

    # Parse arguments and configure application instance.
    arguments, parser = parse_arguments()

    # Fix the host URL.
    url = arguments.host

    if not url.startswith("http://"):
        url = "http://" + url

    url = urlparse.urljoin(url, "real_time_data.xml")

    # Make request to read data.
    try:
        response = requests.get(url)
    except requests.ConnectionError:
        sys.stderr.write("Cannot connect to inverter.\n")
        sys.exit(1)

    # Parse data.
    data = xmltodict.parse(response.content)

    if arguments.query:
        try:
            sys.stdout.write("%s\n" % data["real_time_data"][arguments.query])
        except KeyError:
            sys.stderr.write("Cannot query field.\n")
            sys.exit(2)
    else:
        for key, value in data["real_time_data"].iteritems():
            sys.stdout.write("%s: %s\n" % (key, value))

# E.g. `python power.py --host 192.168.2.1 --query `
if __name__ == "__main__":
    sys.exit(main())