real time messaging with Slack

CodeChallenge/__init__.py

@@ -11,6 +11,7 @@
 from . import core
 from .api.eb import bp as eb_bp
 from .api.questions import bp as questions_bp
+from .api.slack import bp as slack_bp
 from .api.users import bp as users_bp
 from .api.vote import bp as vote_bp
 from .auth import jwt
@@ -62,6 +63,7 @@ def create_app(config):
     app.register_blueprint(q_cli_bp)
     app.register_blueprint(clock_cli_bp)
     app.register_blueprint(vote_bp)
+    app.register_blueprint(slack_bp)
 
     @app.errorhandler(429)
     def ratelimit_handler(e):

CodeChallenge/api/eb.py

@@ -1,5 +1,6 @@
 from hmac import compare_digest
 
+import requests
 from flask import Blueprint, request, current_app, render_template
 from flask_mail import Message
 
@@ -41,4 +42,10 @@ def worker():
 
         mail.send(msg)
 
+        webhook = current_app.config.get("SLACK_WEBHOOK")
+        if webhook is not None:
+            requests.post(webhook, json=dict(
+                text=f"*NEW RANK* {core.current_rank()}"
+            ))
+
     return "", 200

CodeChallenge/api/slack.py

@@ -0,0 +1,75 @@
+import hmac
+import re
+import time
+
+import requests
+from flask import Blueprint, request, jsonify, current_app, abort
+
+from .. import core
+
+bp = Blueprint("slackapi", __name__, url_prefix="/api/v1/slack")
+
+CMDRE = re.compile(r"^!([^ ]+)", re.I)
+
+
+@bp.before_request
+def slack_verify():
+    ts = request.headers.get("X-Slack-Request-Timestamp")
+    secret = bytes(current_app.config.get("SLACK_SIGNING_SECRET"), "utf8")
+    body = request.data
+
+    if abs(time.time() - int(ts)) > 60 * 5:
+        abort(401)
+
+    sig_basestring = bytes(f"v0:{ts}:", "utf8")
+    sig_basestring += body
+
+    my_sig = "v0=" + hmac.new(secret, sig_basestring, digestmod="SHA256").hexdigest()
+    slack_sig = request.headers.get("X-Slack-Signature")
+    if not hmac.compare_digest(my_sig, slack_sig):
+        abort(401)
+
+
+def post_message(channel, text):
+    rv = requests.post("https://slack.com/api/chat.postMessage",
+                       headers=dict(
+                           Authorization="Bearer " + current_app.config["SLACK_OAUTH_TOKEN"]
+                       ),
+                       json=dict(
+                           channel=channel,
+                           text=text
+                       ))
+
+    rv.raise_for_status()
+
+
+def handle_message(text, channel):
+    match = CMDRE.search(text)
+
+    if match is None:
+        return
+
+    command = match.group(1)
+
+    if command == "status":
+        rank = core.current_rank()
+        resp = f"*Current Rank:* {rank if rank != -1 else '(challenge not started)'}\n"
+        resp += f"*Max Rank:* {core.max_rank()}\n"
+        resp += f"*Next Rank:* {core.time_until_next_rank()}\n"
+        resp += f"*Total Users:* {core.user_count()}"
+
+        post_message(channel, resp)
+
+
+@bp.route("/event", methods=["POST"])
+def slack_event():
+    data = request.get_json()
+
+    if "challenge" in data:
+        return jsonify(challenge=data["challenge"])
+
+    event = data["event"]
+    if event["type"] == "message":
+        handle_message(event["text"], event["channel"])
+
+    return "", 200

CodeChallenge/config.py

@@ -31,6 +31,9 @@ class DefaultConfig:
     MG_LIST = "codechallenge@school.codewizardshq.com"
     WORKER_PASSWORD = os.getenv("WORKER_PASSWORD")
     SLACK_WEBHOOK = os.getenv("SLACK_WEBHOOK")
+    SLACK_SIGNING_SECRET = os.getenv("SLACK_SIGNING_SECRET")
+    SLACK_OAUTH_TOKEN = os.getenv("SLACK_OAUTH_TOKEN")
+    SLACK_CHANNEL = os.getenv("SLACK_CHANNEL")
 
     # no trailing /
     EXTERNAL_URL = "https://challenge.codewizardshq.com"

CodeChallenge/core.py

@@ -3,6 +3,7 @@
 from flask import current_app
 from sqlalchemy import func
 
+from .auth import Users
 from .models import Question, db
 
 
@@ -68,3 +69,7 @@ def challenge_ended() -> bool:
         return True
 
     return False
+
+
+def user_count() -> int:
+    return db.session.query(func.count(Users)).scalar()