From 58f4658154a197a474740e28ba4f9506662ee88f Mon Sep 17 00:00:00 2001
From: Joseph Boiteau <josephboiteau@gmail.com>
Date: Wed, 11 Jan 2017 13:50:42 +1100
Subject: [PATCH] Fix code according to @jparise comments

- Refactor is_valid_request code
- Add "Facebot/1.0" User-Agent string
---
 snappass/main.py | 8 ++++----
 tests.py         | 1 +
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/snappass/main.py b/snappass/main.py
index 5f0f164..b6e530d 100644
--- a/snappass/main.py
+++ b/snappass/main.py
@@ -1,7 +1,7 @@
 import os
+import re
 import sys
 import uuid
-import re
 
 import redis
 from redis.exceptions import ConnectionError
@@ -9,6 +9,8 @@ from redis.exceptions import ConnectionError
 from flask import abort, Flask, render_template, request
 
 
+SNEAKY_USER_AGENTS = ('Slackbot', 'facebookexternalhit', 'Twitterbot', 'Facebot', 'WhatsApp')
+SNEAKY_USER_AGENTS_RE = re.compile('|'.join(SNEAKY_USER_AGENTS))
 NO_SSL = os.environ.get('NO_SSL', False)
 app = Flask(__name__)
 app.secret_key = os.environ.get('SECRET_KEY', 'Secret Key')
@@ -84,9 +86,7 @@ def request_is_valid(request):
     Ensure the request validates the following:
         - not made by some specific User-Agents (to avoid chat's preview feature issue)
     """
-    known_sneaky_user_agents = ['Slackbot', 'facebookexternalhit', 'Twitterbot', 'Facebot', 'WhatsApp']
-    user_agents_regexp = "|".join(known_sneaky_user_agents)
-    return not re.search(user_agents_regexp, request.headers.get('User-Agent', ''))
+    return not SNEAKY_USER_AGENTS_RE.search(request.headers.get('User-Agent', ''))
 
 
 @app.route('/', methods=['GET'])
diff --git a/tests.py b/tests.py
index 11c156a..bc5e709 100644
--- a/tests.py
+++ b/tests.py
@@ -82,6 +82,7 @@ class SnapPassRoutesTestCase(TestCase):
         a_few_sneaky_bots = [
             "Slackbot-LinkExpanding 1.0 (+https://api.slack.com/robots)",
             "facebookexternalhit/1.1",
+            "Facebot/1.0",
             "Twitterbot/1.0",
             "_WhatsApp/2.12.81 (Windows NT 6.1; U; es-ES) Presto/2.9.181 Version/12.00",
             "WhatsApp/2.16.6/i"