[Python] Slack sdk OAuth 2 redirect url not working

I created a Slack app and I'm trying to get OAuth 2.0 to work. I'm using Python with flask to try and exchange tokens but I can't seem to get the redirect url to open properly.

Slack requires the redirect to be https, and I'm using localhost to redirect at http://127.0.0.1:5000/slack/oauth/callback. It seems like Slack won't accept an http url, and flask doesn't work with https. Is there something I'm missing to get this working?

I saw some other solutions to try and apply a proxy fix, but that didn't work for me.

Thanks in advance and let me know if you need any other details.

Here's what I'm currently doing right now:

import html
from slack_sdk.oauth import AuthorizeUrlGenerator
from slack_sdk.oauth.installation_store import FileInstallationStore
from slack_sdk.oauth.state_store import FileOAuthStateStore
from flask import Flask


SLACK_CLIENT_ID = "MY_CLIENT_ID"


state_store = FileOAuthStateStore(expiration_seconds=300, base_dir="./data")
installation_store = FileInstallationStore(base_dir="./data")

# Build https://slack.com/oauth/v2/authorize with sufficient query parameters
authorize_url_generator = AuthorizeUrlGenerator(
client_id=SLACK_CLIENT_ID,
scopes=["app_mentions:read", "chat:write"],
user_scopes=["bookmarks:read", "bookmarks:write", "canvases:read", "canvases:write", "chat:write", "groups:history",
"groups:read", "groups:write", "groups:write.invites", "groups:write.topic", "pins:read", "pins:write"],
)


app = Flask(__name__)


@app.route("/slack/install", methods=["GET"])
def oauth_start():
state = state_store.issue()
url = authorize_url_generator.generate(state)
return f'<a href="{html.escape(url)}">' \
f'<img alt=""Add to Slack"" height="40" width="139" src="https://platform.slack-edge.com/img/add_to_slack.png" srcset="https://platform.slack-edge.com/img/add_to_slack.png 1x, https://platform.slack-edge.com/img/add_to_slack@2x.png 2x" /></a>'


from slack_sdk.web import WebClient
@app.route("/slack/oauth/callback", methods=["GET"])
def oauth_callback():
print("Hello world!") # Doesn't reach this


# Redirect is https://127.0.0.1:5000/slack/oauth/callback
if __name__ == "__main__":
print("install at 'http://127.0.0.1:5000/slack/install'") # Opens ok
app.run()

Continue reading...