[fix] opensearch on chromium for android (#2132)

searx/templates/__common__/opensearch.xml

@@ -6,7 +6,7 @@
   <Image>{{ urljoin(host, url_for('static', filename='img/favicon.png')) }}</Image>
   <LongName>searx metasearch</LongName>
   {% if opensearch_method == 'get' %}
-    <Url rel="results" type="text/html" method="get" template="{{ host }}search?q={searchTerms}"/>
+    <Url rel="results" type="text/html" method="get" template="{{ host }}?q={searchTerms}"/>
   {% else %}
     <Url rel="results" type="text/html" method="post" template="{{ host }}">
         <Param name="q" value="{searchTerms}" />

searx/webapp.py

@@ -463,6 +463,9 @@ def pre_request():
     request.errors = []
 
     preferences = Preferences(themes, list(categories.keys()), engines, plugins)
+    user_agent = request.headers.get('User-Agent', '').lower()
+    if 'webkit' in user_agent and 'android' in user_agent:
+        preferences.key_value_settings['method'].value = 'GET'
     request.preferences = preferences
     try:
         preferences.parse_dict(request.cookies)