butler.py

#!/usr/bin/env python3

#
# Dump all the messages from a given Slack channel since a certain
# timestamp, one line per message with timestamp and user name.
#


from datetime import datetime
from pytz import timezone, utc
from urllib.parse import urlencode
import json
import re
import requests
import sys

def load_config(file):
    with open(file) as f:
        return json.load(f)

config = load_config('secret.json')


def api_url(method, args):
    args['token'] = config['client']['oauth']
    return 'https://slack.com/api/{method}?{args}'.format(method=method, args=urlencode(args))


def api_request(method, **args):
    r = requests.get(api_url(method, args))
    if r.status_code == 200:
        resp = json.loads(r.text)
        if resp['ok']:
            return resp
        else:
            raise Exception("Not ok: {}".format(resp))
    else:
        raise Exception("Error on request: {}".format(r))


def all_channels(cursor=None):
    args = {}
    if cursor is not None: args['cursor'] = cursor
    resp = api_request('channels.list', **args)

    yield from resp['channels']
    if 'response_metadata' in resp and 'next_cursor' in resp['response_metadata']:
        yield from all_channels(resp['response_metadata']['next_cursor'])

def all_messages(channel, oldest):
    # N.B. this depends on the contract that if we only past oldest
    # (and not latest as well) the API returns the messages nearest
    # oldest rather than nearest latest.
    resp = api_request('channels.history', channel=channel, oldest=oldest, count=1000)
    messages = resp['messages']
    if len(messages) > 0:
        yield from reversed(messages)
        if resp['has_more']:
            yield from all_messages(channel, float(messages[0]['ts']))


def channel_ids():
    return { c['name'] : c['id'] for c in all_channels() }


def get_user(id, cache):
    if id not in cache:
        cache[id] = api_request('users.info', user=id)['user']['real_name']
    return cache[id]


if __name__ == '__main__':

    users = dict()
    eastern = timezone('US/Eastern')

    channel_id = channel_ids()[sys.argv[1]]
    start = float(sys.argv[2])

    for m in all_messages(channel_id, start):
        time = datetime.fromtimestamp(float(m['ts']), utc).astimezone(eastern).strftime('%a %I:%M %p')
        user = get_user(m['user'], users)
        text = re.sub('<@(.*?)>', lambda m: get_user(m.group(1), users), m['text'])

        if 'subtype' in m and m['subtype'] == 'channel_join':
            print('[{}] {}'.format(time, text))
        else:
            print('[{}] {}: {}'.format(time, user, text))