flask_server.py

"""Minimal Flask receiver for EveryPage webhooks.

The one gotcha: verification needs the RAW body bytes. Use
request.get_data() - request.json parses (and can re-order) them.
"""

import json
import os

from flask import Flask, request

from verify import verify

# The full secret from webhook creation, whsec_ prefix included.
SECRET = os.environ["EVERYPAGE_WEBHOOK_SECRET"]

app = Flask(__name__)


@app.post("/webhooks/everypage")
def everypage_webhook():
    body = request.get_data()  # raw bytes, before any parsing
    header = request.headers.get("X-Everypage-Signature", "")
    if not verify(SECRET, body, header):
        return "invalid signature", 400

    # Safe to parse now: {event, timestamp, data:{fileUuid, fileName, ...}}.
    envelope = json.loads(body)
    data = envelope["data"]
    print(f"{envelope['event']} at {envelope['timestamp']}: "
          f"{data['fileName']} ({data['fileUuid']})")

    # Any 2xx counts as delivered. Respond fast; do slow work async.
    return "", 204


if __name__ == "__main__":
    app.run(port=3000)