fix yahoo engines and add comments

searx/engines/yahoo.py

-#!/usr/bin/env python
+## Yahoo (Web)
+# 
+# @website     https://search.yahoo.com/web
+# @provide-api yes (https://developer.yahoo.com/boss/search/), $0.80/1000 queries
+# 
+# @using-api   no (because pricing)
+# @results     HTML (using search portal)
+# @stable      no (HTML can change)
+# @parse       url, title, content, suggestion
 
 from urllib import urlencode
 from urlparse import unquote
 from lxml import html
 from searx.engines.xpath import extract_text, extract_url
 
+# engine dependent config
 categories = ['general']
-search_url = 'http://search.yahoo.com/search?{query}&b={offset}'
+paging = True
+language_support = True
+
+# search-url
+search_url = 'https://search.yahoo.com/search?{query}&b={offset}&fl=1&vl=lang_{lang}'
+
+# specific xpath variables
 results_xpath = '//div[@class="res"]'
 url_xpath = './/h3/a/@href'
 title_xpath = './/h3/a'
 content_xpath = './/div[@class="abstr"]'
 suggestion_xpath = '//div[@id="satat"]//a'
 
-paging = True
-
 
+# remove yahoo-specific tracking-url
 def parse_url(url_string):
     endings = ['/RS', '/RK']
     endpositions = []
     start = url_string.find('http', url_string.find('/RU=')+1)
+
     for ending in endings:
         endpos = url_string.rfind(ending)
         if endpos > -1:
             endpositions.append(endpos)
 
     end = min(endpositions)
+
     return unquote(url_string[start:end])
 
 
+# do search-request
 def request(query, params):
     offset = (params['pageno'] - 1) * 10 + 1
+
     if params['language'] == 'all':
         language = 'en'
     else:
         language = params['language'].split('_')[0]
+
     params['url'] = search_url.format(offset=offset,
-                                      query=urlencode({'p': query}))
+                                      query=urlencode({'p': query}),
+                                      lang=language)
+
+    # TODO required?
     params['cookies']['sB'] = 'fl=1&vl=lang_{lang}&sh=1&rw=new&v=1'\
         .format(lang=language)
+
     return params
 
 
+# get response from search-request
 def response(resp):
     results = []
+
     dom = html.fromstring(resp.text)
 
+    # parse results
     for result in dom.xpath(results_xpath):
         try:
             url = parse_url(extract_url(result.xpath(url_xpath), search_url))
             title = extract_text(result.xpath(title_xpath)[0])
         except:
             continue
+
         content = extract_text(result.xpath(content_xpath)[0])
-        results.append({'url': url, 'title': title, 'content': content})
 
+        # append result
+        results.append({'url': url, 
+                        'title': title, 
+                        'content': content})
+
+    # if no suggestion found, return results
     if not suggestion_xpath:
         return results
 
+    # parse suggestion
     for suggestion in dom.xpath(suggestion_xpath):
+        # append suggestion
         results.append({'suggestion': extract_text(suggestion)})
 
+    # return results
     return results

searx/engines/yahoo_news.py

-#!/usr/bin/env python
+## Yahoo (News)
+# 
+# @website     https://news.yahoo.com
+# @provide-api yes (https://developer.yahoo.com/boss/search/), $0.80/1000 queries
+# 
+# @using-api   no (because pricing)
+# @results     HTML (using search portal)
+# @stable      no (HTML can change)
+# @parse       url, title, content, publishedDate
 
 from urllib import urlencode
 from lxml import html
 import re
 from dateutil import parser
 
+# engine dependent config
 categories = ['news']
-search_url = 'http://news.search.yahoo.com/search?{query}&b={offset}'
+paging = True
+language_support = True
+
+# search-url
+search_url = 'https://news.search.yahoo.com/search?{query}&b={offset}&fl=1&vl=lang_{lang}'
+
+# specific xpath variables
 results_xpath = '//div[@class="res"]'
 url_xpath = './/h3/a/@href'
 title_xpath = './/h3/a'
 publishedDate_xpath = './/span[@class="timestamp"]'
 suggestion_xpath = '//div[@id="satat"]//a'
 
-paging = True
-
 
+# do search-request
 def request(query, params):
     offset = (params['pageno'] - 1) * 10 + 1
+
     if params['language'] == 'all':
         language = 'en'
     else:
         language = params['language'].split('_')[0]
+    
     params['url'] = search_url.format(offset=offset,
-                                      query=urlencode({'p': query}))
+                                      query=urlencode({'p': query}),
+                                      lang=language)
+
+    # TODO required?
     params['cookies']['sB'] = 'fl=1&vl=lang_{lang}&sh=1&rw=new&v=1'\
         .format(lang=language)
     return params
 
 
+# get response from search-request
 def response(resp):
     results = []
+
     dom = html.fromstring(resp.text)
 
+    # parse results
     for result in dom.xpath(results_xpath):
         url = parse_url(extract_url(result.xpath(url_xpath), search_url))
         title = extract_text(result.xpath(title_xpath)[0])
         content = extract_text(result.xpath(content_xpath)[0])
+
+        # parse publishedDate
         publishedDate = extract_text(result.xpath(publishedDate_xpath)[0])
 
         if re.match("^[0-9]+ minute(s|) ago$", publishedDate):
         if publishedDate.year == 1900:
             publishedDate = publishedDate.replace(year=datetime.now().year)
 
+        # append result
         results.append({'url': url,
                         'title': title,
                         'content': content,
                         'publishedDate': publishedDate})
 
-    if not suggestion_xpath:
-        return results
-
-    for suggestion in dom.xpath(suggestion_xpath):
-        results.append({'suggestion': extract_text(suggestion)})
-
+    # return results
     return results