i3wttr

i3wttr

#!/usr/bin/python3
# -*- coding: utf-8 -*-

import json
import logging
import signal
import socket
import sys
import threading
import time
import urllib.parse
import urllib.request


class WttrClient(object):
    UPDATE_INTERVAL = 3600
    URL = 'https://wttr.in/'
    LINE_FORMAT = '1'

    def __init__(self):
        self._weather_data = {}
        self._running = True
        self._lock = threading.Lock()
        self._cond = threading.Condition(self._lock)

        self._thread = threading.Thread(target=self._run, name='WeatherUpdater')
        self._thread.start()

    def __enter__(self):
        return self

    def __exit__(self, *args):
        self.close()

    def get_local_weather(self):
        with self._lock:
            return self._weather_data.get('local', None)

    def close(self):
        with self._lock:
            self._running = False
            self._cond.notify_all()
        self._thread.join()

    @property
    def _is_running(self):
        return self._running and self._thread.is_alive()

    def _run(self):
        try:
            while self._is_running:
                try:
                    logging.debug('Entering read loop...')
                    with urllib.request.urlopen(self.URL + '?' + urllib.parse.urlencode({'format': self.LINE_FORMAT})) as f:
                        line = f.read().decode('utf-8').strip()
                    with self._lock:
                        self._weather_data['local'] = line
                    delay = self.UPDATE_INTERVAL
                except Exception as ex:
                    logging.warning('Request failed: %s', ex)
                    delay = self.UPDATE_INTERVAL * 0.1
                with self._lock:
                    while self._is_running:
                        if self._cond.wait(delay):
                            break
        except BaseException as ex:
            logging.exception('Receive thread failed: %s', ex)
            raise


def get_weather(client):
    line = client.get_local_weather()
    if not line: return []
    return [{
        'full_text': client.get_local_weather(),
        'name': 'wttr',
        'markup': 'none',
        'instance': 'local',
    }]


if __name__ == '__main__':
    logging.basicConfig(stream=sys.stderr, level=logging.DEBUG)

    # websocket-client causes SIGPIPE.
    signal.signal(signal.SIGPIPE, signal.SIG_IGN)

    with WttrClient() as wttr:
        # Skip the first line which contains the version header.
        print(sys.stdin.readline().strip(), flush=True)

        # The second line contains the start of the infinite array.
        print(sys.stdin.readline().strip(), flush=True)

        for line in sys.stdin:
            line = line.strip()
            prefix = ''
            # ignore comma at start of lines
            if line.startswith(','):
                line, prefix = line[1:], ','

            j = json.loads(line)
            try:
                j = list(get_weather(wttr)) + j
            except BaseException as ex:
                logging.exception('Failed to generate content (ignored): %s',
                                  ex)

            print(prefix + json.dumps(j), flush=True)