Script to archive Slack messages from a channel list.

slack_backup.py

'''
Script to archive Slack messages from a channel list.
You have to create a Slack Bot and invite him to private channels.
View https://github.com/docmarionum1/slack-archive-bot for how to configure your account.
Then provide the bot token to this script with the list of channels.
'''

TOKEN='xoxb-xxxxx-xxxxxx-xxxxxxxxxxx'

channels = {
    'général': 'CSNLXXXXXX',
    'veille': 'G01XXXXXX'
}

# Import WebClient from Python SDK (github.com/slackapi/python-slack-sdk)
from slack_sdk import WebClient
from slack_sdk.errors import SlackApiError
import json

# WebClient insantiates a client that can call API methods
# When using Bolt, you can use either `app.client` or the `client` passed to listeners.
client = WebClient(token=TOKEN)
# Store conversation history
conversation_history = []


def backup_channel(channel_name, channel_id):
    '''
    :channel_id: ID of the channel you want to send the message to
    '''
    try:
        print('Getting messages from', channel_name)
        # Call the conversations.history method using the WebClient
        # conversations.history returns the first 100 messages by default
        # These results are paginated
        result = client.conversations_history(channel=channel_id)
        all_message = []
        all_message += result["messages"]
        while result['has_more']:
            print("\tGetting more...")
            result = client.conversations_history(channel=channel_id, cursor=result['response_metadata']['next_cursor'])
            all_message += result["messages"]
        # Save to disk
        filename = f'{channel_name}.json'
        print(f'  We have downloaded {len(all_message)} messages from {channel_name}.')
        print('  Saving to', filename)
        with open(filename, 'w') as outfile:
            json.dump(all_message, outfile)
    except SlackApiError as e:
        print("Error using conversation: {}".format(e))


if __name__ == "__main__":
    # Iterate channels
    for chan_name, chan_id in channels.items():
        backup_channel(chan_name, chan_id)

Do you need slack admin rights for this?

You need to be able to create a "bot" to have a token. So I thing a normal user could not do it.

I suppose it not possible to use this for private messages since you cannot add apps to private messages under free version of slack?

You're probably right.

I did a little tweak in order to get the messages from a date onwards using the oldest parameter and the timestamp of the last message retrieved in the call. I needed to get all messages for the last 3 months essentially.

result = client.conversations_history(channel=channel_id,oldest='1621850176')
        all_message = []
        all_message += result["messages"]
        last_elem = result["messages"][-1]
        ts = last_elem["ts"]

       
        last_message_date = datetime.fromtimestamp(int(float(ts)))

        print(f'last message timestamp: {last_message_date}')

        while result['has_more']:
            print("\tGetting next 100 messages...")
            result = client.conversations_history(channel=channel_id, cursor=result['response_metadata']['next_cursor'],oldest=ts)
            all_message += result["messages"]

            last_elem = result["messages"][-1]
            ts = last_elem["ts"]

            last_message_date = datetime.fromtimestamp(int(float(ts)))
            print(f'Last message timestamp: {last_message_date}')

thanks for sharing

Thank you for this helpful starting point! Would you mind releasing this code under an open-source license such as MIT, or otherwise giving me permission to use it in https://github.com/edemaine/slack-backup (where I've added automatic channel listing, user listing, and making the output format compatible with https://github.com/pR0Ps/slack-to-discord)?

@edemaine I don't know how to set a license for a gist but I give permission to anyone to re-use and modify the code.

Thank you! I've added an MIT license to my fork.

(If you want to add a license to yours, you could probably just mention in a comment in the Python file.)

@benoit-cty , I might have a very simple question, but before testing your code, I would like to know if I have to invite the bot to every channel manually? I can, in the tester (on the API site) with the generated xbot token, get the list of channels, but when I want to read the channel history I get an error: "not in channel", and after inviting the bot this error is gone.

Yes, you have to invite him to private channels.