[mod] plugin limiter: improve the log messages

In debug mode more detailed logging is needed to evaluate if an access should
have been blocked by the limiter.

BTW: remove duplicate code checking bot signature ``re_bot.match(user_agent)``

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/plugins/limiter.py

@@ -17,13 +17,14 @@ import re
 from flask import request
 
 from searx import redisdb
+from searx.plugins import logger
 from searx.redislib import incr_sliding_window
 
 name = "Request limiter"
 description = "Limit the number of request"
 default_on = False
 preference_section = 'service'
-
+logger = logger.getChild('limiter')
 
 re_bot = re.compile(
     r'('
@@ -42,44 +43,52 @@ def is_accepted_request() -> bool:
     user_agent = request.headers.get('User-Agent', '')
     x_forwarded_for = request.headers.get('X-Forwarded-For', '')
 
-    if request.path == '/image_proxy':
     if re_bot.match(user_agent):
+        logger.debug("BLOCK %s: detected bot", x_forwarded_for)
         return False
-        return True
 
     if request.path == '/search':
         c_burst = incr_sliding_window(redis_client, 'IP limit, burst' + x_forwarded_for, 20)
         c_10min = incr_sliding_window(redis_client, 'IP limit, 10 minutes' + x_forwarded_for, 600)
         if c_burst > 15 or c_10min > 150:
-            logger.debug("to many request")  # pylint: disable=undefined-variable
+            logger.debug("BLOCK %s: to many request", x_forwarded_for)
-            return False
-
-        if re_bot.match(user_agent):
-            logger.debug("detected bot")  # pylint: disable=undefined-variable
             return False
 
         if len(request.headers.get('Accept-Language', '').strip()) == '':
-            logger.debug("missing Accept-Language")  # pylint: disable=undefined-variable
+            logger.debug("BLOCK %s: missing Accept-Language", x_forwarded_for)
             return False
 
         if request.headers.get('Connection') == 'close':
-            logger.debug("got Connection=close")  # pylint: disable=undefined-variable
+            logger.debug("BLOCK %s: got Connection=close", x_forwarded_for)
             return False
 
         accept_encoding_list = [l.strip() for l in request.headers.get('Accept-Encoding', '').split(',')]
         if 'gzip' not in accept_encoding_list and 'deflate' not in accept_encoding_list:
-            logger.debug("suspicious Accept-Encoding")  # pylint: disable=undefined-variable
+            logger.debug("BLOCK %s: suspicious Accept-Encoding", x_forwarded_for)
             return False
 
         if 'text/html' not in request.accept_mimetypes:
-            logger.debug("Accept-Encoding misses text/html")  # pylint: disable=undefined-variable
+            logger.debug("BLOCK %s: Accept-Encoding misses text/html", x_forwarded_for)
             return False
 
         if request.args.get('format', 'html') != 'html':
             c = incr_sliding_window(redis_client, 'API limit' + x_forwarded_for, 3600)
             if c > 4:
-                logger.debug("API limit exceeded")  # pylint: disable=undefined-variable
+                logger.debug("BLOCK %s: API limit exceeded", x_forwarded_for)
                 return False
+
+    logger.debug(
+        "OK %s: '%s'" % (x_forwarded_for, request.path)
+        + " || form: %s" % request.form
+        + " || Accept: %s" % request.headers.get('Accept', '')
+        + " || Accept-Language: %s" % request.headers.get('Accept-Language', '')
+        + " || Accept-Encoding: %s" % request.headers.get('Accept-Encoding', '')
+        + " || Content-Type: %s" % request.headers.get('Content-Type', '')
+        + " || Content-Length: %s" % request.headers.get('Content-Length', '')
+        + " || Connection: %s" % request.headers.get('Connection', '')
+        + " || User-Agent: %s" % user_agent
+    )
+
     return True