[enh] opensearch/rss support part I.

searx/templates/opensearch_response_rss.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<rss version="2.0"
+     xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/"
+     xmlns:atom="http://www.w3.org/2005/Atom">
+  <channel>
+    <title>Searx search: {{ q }}</title>
+    <link>{{ base_url }}?q={{ q }}</link>
+    <description>Search results for "{{ q }}" - searx</description>
+    <opensearch:totalResults>{{ number_of_results }}</opensearch:totalResults>
+    <opensearch:startIndex>1</opensearch:startIndex>
+    <opensearch:itemsPerPage>{{ number_of_results }}</opensearch:itemsPerPage>
+    <atom:link rel="search" type="application/opensearchdescription+xml" href="{{ base_url }}opensearch.xml"/>
+    <opensearch:Query role="request" searchTerms="{{ q }}" startPage="1" />
+    {% for r in results %}
+    <item>
+      <title>{{ r.title }}</title>
+      <link>{{ r.url }}</link>
+      <description>{{ r.content }}</description>
+    </item>
+    {% endfor %}
+  </channel>
+</rss>

searx/webapp.py

 app = Flask(__name__)
 app.secret_key = settings.secret_key
 
+
 opensearch_xml = '''<?xml version="1.0" encoding="utf-8"?>
 <OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/">
   <ShortName>searx</ShortName>
 </OpenSearchDescription>
 '''
 
+
+def get_base_url():
+    if settings.base_url:
+        hostname = settings.base_url
+    else:
+        scheme = 'http'
+        if request.is_secure:
+            scheme = 'https'
+        hostname = url_for('index', _external=True, _scheme=scheme)
+    return hostname
+
+
 def render(template_name, **kwargs):
     global categories
     kwargs['categories'] = sorted(categories.keys())
         query = query.replace(query_parts[0], '', 1).strip()
     return query, query_engines
 
-@app.route('/', methods=['GET', 'POST'])
+
+@APp.route('/', methods=['GET', 'POST'])
 def index():
     global categories
 
         response = Response(csv.stream.read(), mimetype='application/csv')
         response.headers.add('Content-Disposition', 'attachment;Filename=searx_-_{0}.csv'.format('_'.join(query.split())))
         return response
+    elif request_data.get('format') == 'rss':
+        response_rss = render('opensearch_response_rss.xml'
+                              ,results=results
+                              ,q=request_data['q']
+                              ,number_of_results=len(results)
+                              ,base_url=get_base_url()
+                              )
+        response = Response(response_rss, mimetype='application/xml')
+        response.headers.add('Content-Disposition', 'attachment;Filename=searx_-_{0}.xml'.format('_'.join(query.split())))
+        return response
+
 
     return render('results.html'
                  ,results=results
 def opensearch():
     global opensearch_xml
     method = 'post'
-    scheme = 'http'
     # chrome/chromium only supports HTTP GET....
     if request.headers.get('User-Agent', '').lower().find('webkit') >= 0:
         method = 'get'
-    if request.is_secure:
-        scheme = 'https'
-    if settings.base_url:
-        hostname = settings.base_url
-    else:
-        hostname = url_for('index', _external=True, _scheme=scheme)
-    ret = opensearch_xml.format(method=method, host=hostname)
+    base_url = get_base_url()
+    ret = opensearch_xml.format(method=method, host=base_url)
     resp = Response(response=ret,
                 status=200,
                 mimetype="application/xml")