[enh] stackoverflow added

searx/engines/stackoverflow.py

@@ -0,0 +1,25 @@
+from urllib import quote
+from lxml import html
+from urlparse import urljoin
+
+base_url = 'http://stackoverflow.com/'
+search_url = base_url+'search?q='
+
+def request(query, params):
+    global search_url
+    query = quote(query.replace(' ', '+'), safe='+')
+    params['url'] = search_url + query
+    return params
+
+
+def response(resp):
+    global base_url
+    results = []
+    dom = html.fromstring(resp.text)
+    for result in dom.xpath('//div[@class="question-summary search-result"]'):
+        link = result.xpath('.//div[@class="result-link"]//a')[0]
+        url = urljoin(base_url, link.attrib.get('href'))
+        title = ' '.join(link.xpath('.//text()'))
+        content = ' '.join(result.xpath('.//div[@class="excerpt"]//text()'))
+        results.append({'url': url, 'title': title, 'content': content})
+    return results