UI - Always use UTC timezone for storing data, show local timezone (#2799)

Author: dgtlmoon

changedetectionio/flask_app.py

@@ -38,6 +38,8 @@
 from flask_cors import CORS
 from flask_wtf import CSRFProtect
 from loguru import logger
+from zoneinfo import ZoneInfo
+
 
 from changedetectionio import html_tools, __version__
 from changedetectionio import queuedWatchMetaData
@@ -159,21 +161,6 @@ def _jinja2_filter_pagination_slice(arr, skip):
 
     return arr
 
-def app_get_system_time():
-    from zoneinfo import ZoneInfo  # Built-in timezone support in Python 3.9+
-
-    system_timezone = datastore.data['settings']['application'].get('timezone')
-    if not system_timezone:
-        system_timezone = os.environ.get("TZ")
-
-    try:
-        system_zone = ZoneInfo(system_timezone)
-    except Exception as e:
-        logger.warning(f'Warning, unable to use timezone "{system_timezone}" defaulting to UTC- {str(e)}')
-        system_zone = ZoneInfo("UTC")  # Fallback to UTC if the timezone is invalid
-
-    return system_zone
-
 @app.template_filter('format_seconds_ago')
 def _jinja2_filter_seconds_precise(timestamp):
     if timestamp == False:
@@ -258,9 +245,6 @@ def changedetection_app(config=None, datastore_o=None):
     # (instead of the global var)
     app.config['DATASTORE'] = datastore_o
 
-    # Just to check (it will output some debug if not)
-    app_get_system_time()
-
     login_manager = flask_login.LoginManager(app)
     login_manager.login_view = 'login'
     app.secret_key = init_app_secret(config['datastore_path'])
@@ -968,12 +952,8 @@ def settings_page():
             else:
                 flash("An error occurred, please see below.", "error")
 
-
-        system_timezone = app_get_system_time()
-        system_time = datetime.now(system_timezone)
-
-        # Fallback for locale formatting
-        formatted_system_time = system_time.strftime("%Y-%m-%d %H:%M:%S %Z%z")  # Locale-aware time
+        # Convert to ISO 8601 format, all date/time relative events stored as UTC time
+        utc_time = datetime.now(ZoneInfo("UTC")).isoformat()
 
         output = render_template("settings.html",
                                  api_key=datastore.data['settings']['application'].get('api_access_token'),
@@ -983,8 +963,7 @@ def settings_page():
                                  hide_remove_pass=os.getenv("SALTED_PASS", False),
                                  min_system_recheck_seconds=int(os.getenv('MINIMUM_SECONDS_RECHECK_TIME', 3)),
                                  settings_application=datastore.data['settings']['application'],
-                                 system_time=formatted_system_time,
-                                 timezone_name=system_timezone
+                                 utc_time=utc_time,
                                  )
 
         return output

changedetectionio/static/js/global-settings.js

@@ -24,5 +24,8 @@ $(document).ready(function () {
         $(target).toggle();
     });
 
+    $(".local-time").each(function (e) {
+        $(this).text(new Date($(this).data("utc")).toLocaleString());
+    })
 });
 

changedetectionio/templates/settings.html

@@ -79,8 +79,8 @@
                         <span class="pure-form-message-inline">When a request returns no content, or the HTML does not contain any text, is this considered a change?</span>
                     </div>
                     <div class="pure-control-group">
-                        <p><strong>Local Time:</strong> {{ system_time }}</p>
-                        <p><strong>Timezone:</strong> {{ timezone_name }}</p>
+                        <p><strong>UTC Time from Server:</strong> <span id="utc-time" >{{ utc_time }}</span></p>
+                        <p><strong>Local Time in Browser:</strong> <span class="local-time" data-utc="{{ utc_time }}"></span></p>
                     </div>
                 {% if form.requests.proxy %}
                     <div class="pure-control-group inline-radio">