append link to result in wolframalpha_api (and the tests to validate that)

searx/engines/wolframalpha_api.py

@@ -10,15 +10,18 @@
 
 from urllib import urlencode
 from lxml import etree
+from re import search
 
 # search-url
 base_url = 'http://api.wolframalpha.com/v2/query'
 search_url = base_url + '?appid={api_key}&{query}&format=plaintext'
+site_url = 'http://www.wolframalpha.com/input/?{query}'
 api_key = ''  # defined in settings.yml
 
 # xpath variables
 failure_xpath = '/queryresult[attribute::success="false"]'
 answer_xpath = '//pod[attribute::primary="true"]/subpod/plaintext'
+input_xpath = '//pod[starts-with(attribute::title, "Input")]/subpod/plaintext'
 
 
 # do search-request
@@ -60,6 +63,15 @@ def response(resp):
 
             results.append({'answer': answer})
 
-    # TODO: append a result with title and link, like in the no api version
+    # if there's no input section in search_results, check if answer has the input embedded (before their "=" sign)
+    try:
+        query_input = search_results.xpath(input_xpath)[0].text
+    except IndexError:
+        query_input = search(u'([^\uf7d9]+)', answers[0].text).group(1)
+
+    # append link to site
+    result_url = site_url.format(query=urlencode({'i': query_input.encode('utf-8')}))
+    results.append({'url': result_url,
+                    'title': query_input + " - Wolfram|Alpha"})
 
     return results