Make it possible to disable ratelimiter

Update APScheduler
Error message on missing flask-limiter

cps/__init__.py

@@ -28,7 +28,6 @@ import mimetypes
 from flask import Flask
 from .MyLoginManager import MyLoginManager
 from flask_principal import Principal
-from flask_limiter import Limiter
 
 from . import logger
 from .cli import CliParameter
@@ -42,6 +41,11 @@ from . import config_sql
 from . import cache_buster
 from . import ub, db
 
+try:
+    from flask_limiter import Limiter
+    limiter_present = True
+except ImportError:
+    limiter_present = False
 try:
     from flask_wtf.csrf import CSRFProtect
     wtf_present = True
@@ -97,7 +101,10 @@ web_server = WebServer()
 
 updater_thread = Updater()
 
-limiter = Limiter(key_func=True, headers_enabled=True, auto_check=False, swallow_errors=True)
+if limiter_present:
+    limiter = Limiter(key_func=True, headers_enabled=True, auto_check=False, swallow_errors=True)
+else:
+    limiter = None
 
 def create_app():
     if csrf:
@@ -115,21 +122,13 @@ def create_app():
     if error:
         log.error(error)
 
-    lm.login_view = 'web.login'
-    lm.anonymous_user = ub.Anonymous
-    lm.session_protection = 'strong' if config.config_session == 1 else "basic"
-
-    db.CalibreDB.update_config(config)
-    db.CalibreDB.setup_db(config.config_calibre_dir, cli_param.settings_path)
-    calibre_db.init_db()
-
-    updater_thread.init_updater(config, web_server)
-    # Perform dry run of updater and exit afterwards
-    if cli_param.dry_run:
-        updater_thread.dry_run()
-        sys.exit(0)
-    updater_thread.start()
-
+    if not limiter:
+        log.info('*** "flask-limiter" is needed for calibre-web to run. '
+                 'Please install it using pip: "pip install flask-limiter" ***')
+        print('*** "flask-limiter" is needed for calibre-web to run. '
+              'Please install it using pip: "pip install flask-limiter" ***')
+        web_server.stop(True)
+        sys.exit(8)
     if sys.version_info < (3, 0):
         log.info(
             '*** Python2 is EOL since end of 2019, this version of Calibre-Web is no longer supporting Python2, '
@@ -146,6 +145,22 @@ def create_app():
               'Please install it using pip: "pip install flask-WTF" ***')
         web_server.stop(True)
         sys.exit(7)
+
+    lm.login_view = 'web.login'
+    lm.anonymous_user = ub.Anonymous
+    lm.session_protection = 'strong' if config.config_session == 1 else "basic"
+
+    db.CalibreDB.update_config(config)
+    db.CalibreDB.setup_db(config.config_calibre_dir, cli_param.settings_path)
+    calibre_db.init_db()
+
+    updater_thread.init_updater(config, web_server)
+    # Perform dry run of updater and exit afterwards
+    if cli_param.dry_run:
+        updater_thread.dry_run()
+        sys.exit(0)
+    updater_thread.start()
+
     for res in dependency_check() + dependency_check(True):
         log.info('*** "{}" version does not meet the requirements. '
                  'Should: {}, Found: {}, please consider installing required version ***'
@@ -157,8 +172,6 @@ def create_app():
     if os.environ.get('FLASK_DEBUG'):
         cache_buster.init_cache_busting(app)
     log.info('Starting Calibre Web...')
-    limiter.init_app(app)
-    # limiter.limit("2/minute")(parent)
     Principal(app)
     lm.init_app(app)
     app.secret_key = os.getenv('SECRET_KEY', config_sql.get_flask_session_key(ub.session))
@@ -179,6 +192,10 @@ def create_app():
                                            config.config_goodreads_api_secret_e,
                                            config.config_use_goodreads)
     config.store_calibre_uuid(calibre_db, db.Library_Id)
+    # Configure rate limiter
+    app.config.update(RATELIMIT_ENABLED=config.config_ratelimiter)
+    limiter.init_app(app)
+
     # Register scheduled tasks
     from .schedule import register_scheduled_tasks, register_startup_tasks
     register_scheduled_tasks(config.schedule_reconnect)