[fix] wikipedia engine: don't raise an error when the query is not found

Add a new parameter "raise_for_status", set by default to True.
When True, any HTTP status code >= 300 raise an exception ( #2332 )
When False, the engine can manage the HTTP status code by itself.

docs/dev/engine_overview.rst

@@ -134,9 +134,9 @@ The function ``def request(query, params):`` always returns the ``params``
 variable.  Inside searx, the following paramters can be used to specify a search
 request:
 
-================== =========== ========================================================================
+================== =========== ==========================================================================
 argument           type        information
-================== =========== ========================================================================
+================== =========== ==========================================================================
 url                string      requested url
 method             string      HTTP request method
 headers            set         HTTP header information
@@ -145,7 +145,8 @@ cookies            set         HTTP cookies
 verify             boolean     Performing SSL-Validity check
 max_redirects      int         maximum redirects, hard limit
 soft_max_redirects int         maximum redirects, soft limit. Record an error but don't stop the engine
-================== =========== ========================================================================
+raise_for_status   bool        True by default: raise an exception if the HTTP code of response is >= 300
+================== =========== ==========================================================================
 
 
 example code

searx/engines/wikipedia.py

@@ -37,13 +37,15 @@ def request(query, params):
                                       language=url_lang(params['language']))
 
     params['headers']['User-Agent'] = searx_useragent()
+    params['raise_for_status'] = False
+    params['soft_max_redirects'] = 2
 
     return params
 
 
 # get response from search-request
 def response(resp):
-    if not resp.ok:
+    if resp.status_code == 404:
         return []
 
     results = []

searx/search.py

@@ -143,6 +143,7 @@ def send_http_request(engine, request_params):
     response = req(request_params['url'], **request_args)
 
     # check HTTP status
+    if request_params.get('raise_for_status'):
         response.raise_for_status()
 
     # check soft limit of the redirect count
@@ -340,7 +341,8 @@ def default_request_params():
         'url': '',
         'cookies': {},
         'verify': True,
-        'auth': None
+        'auth': None,
+        'raise_for_status': True
     }