Flow to complete Slack authentication with Flask (Python)

I implemented Slack authentication in Flask. Generally, you can see it by looking at the official document, but there are some parts that are a little confusing when you want to acquire user information at the same time as authenticating, so I will leave it as a memorandum.

Premise

I wrote about the registration of the Slack app in detail last time. https://qiita.com/svfreerider/items/0e1fe74c70e2047f0ce9

Most are just the code in the official documentation below. https://slack.dev/python-slackclient/auth.html

Source code

auth.py

import functools
import pdb
import slack

from flask import (
    Blueprint, flash, g, redirect, render_template, request, session, url_for
)

from app.db import (
    search_user, register_user, search_team, register_team, search_team_user, register_team_user
)

bp = Blueprint('auth', __name__, url_prefix='/auth')
client_id = 'XXXXXXXXXXXXXXX'
client_secret = 'XXXXXXXXXXXXXXX'
oauth_scope = 'channels:read,chat:write:bot,users:read,users:read.email'

Prepare ʻauth.pyto implement the authentication function. Define theclient_id and client_secretthat you got when you registered your Slack app. In addition to this, definescope`. scope specifies the range of permissions required of the user to create this app. It is also necessary to set it on the application side. Also, when applying, you must state the reason for "why you need this scope".

In my case, I created a bot and sent notifications from it, so I added channels: read and chat: write: bot to specify the channels. I also included ʻusers: read and ʻusers: read.email because I would like to have the user's personal information and email address later.

auth.py

@bp.route('/redirect', methods=['GET'])
def authorize():
    authorize_url = f"https://slack.com/oauth/authorize?scope={ oauth_scope }&client_id={ client_id }"

    return redirect(authorize_url)

If you do this, you will be redirected to the Slack authentication screen by going to / auth / redirect.

auth.py

@bp.route('/callback', methods=["GET", "POST"])
def callback():
    auth_code = request.args['code']
    client = slack.WebClient(token="")
    oauth_info = client.oauth_access(
        client_id=client_id,
        client_secret=client_secret,
        code=auth_code
    )

After callback, use the code at the end of the URL to get the user's information. User acquisition is done with ʻoauth_access`.

However, at this time, the user's name and e-mail address information have not been obtained yet. This time, we will call the user's detailed information separately using the acquired ʻoauth_token`.

auth.py

    access_token = oauth_info['access_token']
    client = slack.WebClient(token=access_token)
    user_id = oauth_info['user_id']
    response = client.users_info(user=user_id)

With ʻusers_info`, you can get all the information you want, such as the user's email address and name, as well as the icon image and time zone.

This is not limited to Flask, but I think that Python can be used as it is. I put Flask in just two weeks ago, but as a longtime Rails player, I can't find any literature at all.

From now on, I think that the number of cases of making apps with machine learning + Flask will surely increase, so I will share it as needed.