Check for updates using 24 hour time delta

Rather than only checking for an available update on app init, the check
for updates now performs the check once every 24 hours on the first
request sent after that period.

This also now catches the requests.exceptions.ConnectionError that is
thrown if the app is initialized without an active internet connection.

Fixes #649

app/__init__.py

@@ -3,6 +3,7 @@ from app.request import send_tor_signal
 from app.utils.session import generate_user_key
 from app.utils.bangs import gen_bangs_json
 from app.utils.misc import gen_file_hash, read_config_bool
+from datetime import datetime, timedelta
 from flask import Flask
 from flask_session import Session
 import json
@@ -71,8 +72,12 @@ app.config['BANG_PATH'] = os.getenv(
 app.config['BANG_FILE'] = os.path.join(
     app.config['BANG_PATH'],
     'bangs.json')
+
+# Config fields that are used to check for updates
 app.config['RELEASES_URL'] = 'https://github.com/' \
                              'benbusby/whoogle-search/releases'
+app.config['LAST_UPDATE_CHECK'] = datetime.now() - timedelta(hours=24)
+app.config['HAS_UPDATE'] = ''
 
 # The alternative to Google Translate is treated a bit differently than other
 # social media site alternatives, in that it is used for any translation

app/routes.py

@@ -7,7 +7,7 @@ import os
 import pickle
 import urllib.parse as urlparse
 import uuid
-from datetime import timedelta
+from datetime import datetime, timedelta
 from functools import wraps
 
 import waitress
@@ -16,7 +16,8 @@ from app.models.config import Config
 from app.models.endpoint import Endpoint
 from app.request import Request, TorError
 from app.utils.bangs import resolve_bang
-from app.utils.misc import read_config_bool, get_client_ip, get_request_url
+from app.utils.misc import read_config_bool, get_client_ip, get_request_url, \
+    check_for_update
 from app.utils.results import add_ip_card, bold_search_terms,\
     add_currency_card, check_currency, get_tabs_content
 from app.utils.search import Search, needs_https, has_captcha
@@ -31,15 +32,6 @@ from cryptography.fernet import Fernet
 # Load DDG bang json files only on init
 bang_json = json.load(open(app.config['BANG_FILE'])) or {}
 
-# Check the newest version of WHOOGLE
-update = bsoup(get(app.config['RELEASES_URL']).text, 'html.parser')
-newest_version = update.select_one('[class="Link--primary"]').string[1:]
-current_version = int(''.join(filter(str.isdigit,
-                                     app.config['VERSION_NUMBER'])))
-newest_version = int(''.join(filter(str.isdigit, newest_version)))
-newest_version = '' if current_version >= newest_version \
-    else newest_version
-
 ac_var = 'WHOOGLE_AUTOCOMPLETE'
 autocomplete_enabled = os.getenv(ac_var, '1')
 
@@ -106,6 +98,14 @@ def session_required(f):
 def before_request_func():
     global bang_json
 
+    # Check for latest version if needed
+    now = datetime.now()
+    if now - timedelta(hours=24) > app.config['LAST_UPDATE_CHECK']:
+        app.config['LAST_UPDATE_CHECK'] = now
+        app.config['HAS_UPDATE'] = check_for_update(
+            app.config['RELEASES_URL'],
+            app.config['VERSION_NUMBER'])
+
     g.request_params = (
         request.args if request.method == 'GET' else request.form
     )
@@ -214,7 +214,7 @@ def index():
         return render_template('error.html', error_message=error_message)
 
     return render_template('index.html',
-                           newest_version=newest_version,
+                           has_update=app.config['HAS_UPDATE'],
                            languages=app.config['LANGUAGES'],
                            countries=app.config['COUNTRIES'],
                            themes=app.config['THEMES'],
@@ -363,7 +363,7 @@ def search():
 
     return render_template(
         'display.html',
-        newest_version=newest_version,
+        has_update=app.config['HAS_UPDATE'],
         query=urlparse.unquote(query),
         search_type=search_util.search_type,
         config=g.user_config,

app/templates/footer.html

@@ -2,7 +2,7 @@
     <p class="footer">
         Whoogle Search v{{ version_number }} ||
         <a class="link" href="https://github.com/benbusby/whoogle-search">{{ translation['github-link'] }}</a>
-        {% if newest_version %}
+        {% if has_update %}
              || <span class="update_available">Update Available 🟢</span>
         {% endif %}
     </p>

app/utils/misc.py

@@ -1,6 +1,8 @@
+from bs4 import BeautifulSoup as bsoup
 from flask import Request
 import hashlib
 import os
+from requests import exceptions, get
 
 
 def gen_file_hash(path: str, static_file: str) -> str:
@@ -30,3 +32,18 @@ def get_request_url(url: str) -> str:
         return url.replace('http://', 'https://', 1)
 
     return url
+
+
+def check_for_update(version_url: str, current: str) -> int:
+    # Check for the latest version of Whoogle
+    try:
+        update = bsoup(get(version_url).text, 'html.parser')
+        latest = update.select_one('[class="Link--primary"]').string[1:]
+        current = int(''.join(filter(str.isdigit, current)))
+        latest = int(''.join(filter(str.isdigit, latest)))
+        has_update = '' if current >= latest else latest
+    except (exceptions.ConnectionError, AttributeError):
+        # Ignore failures, assume current version is up to date
+        has_update = ''
+
+    return has_update