How to access Slack's Interactive Message request payload parameter?

Question

I would like to access the payload parameter sent by Slack to Interactive Message Request Url when a user clicks on a button in one of these messages.

How do I do this?

Answer 1

On your server side, check your request url route is allowed to receive POST. As said in theirs docs ( https://api.slack.com/docs/message-buttons ) :

Your Action URL will receive a HTTP POST request, including a payload body parameter, itself containing an application/x-www-form-urlencoded JSON string.

You first have to decode the x-www-form-urlencoded format of the request, then json decode it.

In python, I end up with this line of code :

payload = json.loads(urlparse.parse_qs(request.get_data())['payload'][0])

Hope it helps someone else one day !

Answer 2

If you are using AWS lamdba as backend, use following. (python3)

import json
from urllib.parse import parse_qs

payload = json.loads(parse_qs(event['body'])['payload'][0])

Answer 3

I managed getting the info this way:

data = request.form.to_dict()
payload = json.loads(data['payload'])
print(payload["actions"][0]["name"])

Hope it helps someone in the future.

The first line converts the ImmutableDict to a mutable dictionary.

The second line is necessary because the payload is still JSON.

The third line is simply accessing the payload action details as seen in the Block Link Builder , often most people will only have one relevant action to process.