[enh] wikipedia infobox

creates simple multilingual infobox using wikipedia's api

searx/engines/wikipedia.py

@@ -0,0 +1,114 @@
+"""
+ Wikipedia (Web)
+
+ @website     https://{language}.wikipedia.org
+ @provide-api yes
+
+ @using-api   yes
+ @results     JSON
+ @stable      yes
+ @parse       url, infobox
+"""
+
+from json import loads
+from urllib import urlencode, quote
+
+# search-url
+base_url = 'https://{language}.wikipedia.org/'
+search_postfix = 'w/api.php?'\
+    'action=query'\
+    '&format=json'\
+    '&{query}'\
+    '&prop=extracts|pageimages'\
+    '&exintro'\
+    '&explaintext'\
+    '&pithumbsize=300'\
+    '&redirects'
+
+
+# set language in base_url
+def url_lang(lang):
+    if lang == 'all':
+        language = 'en'
+    else:
+        language = lang.split('_')[0]
+
+    return base_url.format(language=language)
+
+
+# do search-request
+def request(query, params):
+    if query.islower():
+        query += '|' + query.title()
+
+    params['url'] = url_lang(params['language']) \
+        + search_postfix.format(query=urlencode({'titles': query}))
+
+    return params
+
+
+# get first meaningful paragraph
+# this should filter out disambiguation pages and notes above first paragraph
+# "magic numbers" were obtained by fine tuning
+def extract_first_paragraph(content, title, image):
+    first_paragraph = None
+
+    failed_attempts = 0
+    for paragraph in content.split('\n'):
+
+        starts_with_title = paragraph.lower().find(title.lower(), 0, len(title) + 35)
+        length = len(paragraph)
+
+        if length >= 200 or (starts_with_title >= 0 and (image or length >= 150)):
+            first_paragraph = paragraph
+            break
+
+        failed_attempts += 1
+        if failed_attempts > 3:
+            return None
+
+    return first_paragraph
+
+
+# get response from search-request
+def response(resp):
+    results = []
+
+    search_result = loads(resp.content)
+
+    # wikipedia article's unique id
+    # first valid id is assumed to be the requested article
+    for article_id in search_result['query']['pages']:
+        page = search_result['query']['pages'][article_id]
+        if int(article_id) > 0:
+            break
+
+    if int(article_id) < 0:
+        return []
+
+    title = page.get('title')
+
+    image = page.get('thumbnail')
+    if image:
+        image = image.get('source')
+
+    extract = page.get('extract')
+
+    summary = extract_first_paragraph(extract, title, image)
+    if not summary:
+        return []
+
+    # link to wikipedia article
+    # parenthesis are not quoted to make infobox mergeable with wikidata's
+    wikipedia_link = url_lang(resp.search_params['language']) \
+        + 'wiki/' + quote(title.replace(' ', '_').encode('utf8')).replace('%28', '(').replace('%29', ')')
+
+    results.append({'url': wikipedia_link, 'title': title})
+
+    results.append({'infobox': title,
+                    'id': wikipedia_link,
+                    'content': summary,
+                    'img_src': image,
+                    'urls': [{'title': 'Wikipedia', 'url': wikipedia_link}]})
+
+    return results