How to send Slack api request to websocket without Bolt or other SDK?

I have the code below. It connects correctly to Slack, and authenticate correctly.

I want to sent a conversations.list request to list the channels. How can I do that without using Bolt or some other SDK? The system where this runs is locked down, so I'm not getting to install anything further than websockets.

I think the only missing part is figuring what to send on the websocket to request a channel list. Currently it outputs:

Opened connection
{"type":"hello","num_connections":1,"debug_info":{"host":"applink-11","build_number":105,"approximate_connection_time":18060},"connection_info":{"app_id":"Redacted"}}

The API I'm after is https://api.slack.com/methods/conversations.list

Code is

#!/usr/bin/env python2.6

import httplib
import requests
import websocket
import argparse

def on_message(ws, message):
    print(message)
    ws.send("list")

def on_error(ws, error):
    print(error)

def on_close(ws, close_status_code, close_msg):
    print("### closed ###")

def on_open(ws):
    print("Opened connection")

def run_with(url):
# websocket.enableTrace(True)
    ws = websocket.WebSocketApp(url,
    on_open=on_open,
    on_message=on_message,
    on_error=on_error,
    on_close=on_close)

    ws.run_forever()

def main():

    parser = argparse.ArgumentParser()
    parser.add_argument("token")
    args = parser.parse_args()

    url = 'https://slack.com/api/apps.connections.open'
    headers = {
'content-type': 'application/x-www-form-urlencoded',
'Authorization': 'Bearer ' + args.token}
    r = requests.post(url, headers=headers)

    if r.json()['ok']:
        url = r.json()['url']
        run_with(url)
    else:
        print(r.content)

if __name__ == '__main__':
    main()

Solution

You can’t get the channel list through the same WebSocket. Slack needs a normal HTTP request for conversations.list.

Usually, you'd use WebSocket for real-time events, but you can open the socket and still use normal HTTP calls to list the channels.



import requests
import websocket
import argparse

def on_message(ws, message):
    print("Got message:", message)

def on_error(ws, error):
    print("Error:", error)

def on_close(ws, close_status_code, close_msg):
    print("Socket closed")

def on_open(ws):
    print("Socket opened")

def run_socket(url):
    ws = websocket.WebSocketApp(
        url,
        on_open=on_open,
        on_message=on_message,
        on_error=on_error,
        on_close=on_close
    )
    ws.run_forever()

def list_channels(token):
    url = "https://slack.com/api/conversations.list"
    headers = {
        "Authorization": "Bearer " + token,
        "Content-Type": "application/x-www-form-urlencoded"
    }
    data = {
        "limit": "100"  # You can change this if you want more channels
    }
    response = requests.post(url, headers=headers, data=data)
    return response.json()

def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("token")
    args = parser.parse_args()
    token = args.token

    # 1. Open the Slack socket URL
    open_url = "https://slack.com/api/apps.connections.open"
    headers = {
        "Authorization": "Bearer " + token,
        "Content-Type": "application/x-www-form-urlencoded"
    }
    r = requests.post(open_url, headers=headers)
    data = r.json()

    # 2. If the socket opened okay, list channels using HTTP
    if data.get("ok"):
        channels = list_channels(token)
        print("Channels:", channels)

        # 3. Then connect to the socket
        socket_url = data["url"]
        run_socket(socket_url)
    else:
        print("Could not open socket:", r.text)

if __name__ == "__main__":
    main()