add comments to search.py

* add comments
* add licence-header

searx/search.py

+'''
+searx is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+searx is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with searx. If not, see < http://www.gnu.org/licenses/ >.
+
+(C) 2013- by Adam Tauber, <asciimoo@gmail.com>
+'''
+
 import grequests
 from itertools import izip_longest, chain
 from datetime import datetime
 from searx.languages import language_codes
 from searx.utils import gen_useragent
 
+
 number_of_searches = 0
 
 
+# get default reqest parameter
 def default_request_params():
     return {
         'method': 'GET', 'headers': {}, 'data': {}, 'url': '', 'cookies': {}}
 
 
+# create a callback wrapper for the search engine results
 def make_callback(engine_name, results, suggestions, callback, params):
+
     # creating a callback wrapper for the search engine results
     def process_callback(response, **kwargs):
         cb_res = []
         response.search_params = params
+
+        # update stats with current page-load-time
         engines[engine_name].stats['page_load_time'] += \
             (datetime.now() - params['started']).total_seconds()
+
         try:
             search_results = callback(response)
         except Exception, e:
+            # increase errors stats
             engines[engine_name].stats['errors'] += 1
             results[engine_name] = cb_res
+
+            # print engine name and specific error message
             print '[E] Error with engine "{0}":\n\t{1}'.format(
                 engine_name, str(e))
             return
+            
         for result in search_results:
             result['engine'] = engine_name
+
+            # if it is a suggestion, add it to list of suggestions
             if 'suggestion' in result:
                 # TODO type checks
                 suggestions.add(result['suggestion'])
                 continue
+
+            # append result
             cb_res.append(result)
+
         results[engine_name] = cb_res
+
     return process_callback
 
 
+# score results and remove duplications
 def score_results(results):
+    # calculate scoring parameters
     flat_res = filter(
         None, chain.from_iterable(izip_longest(*results.values())))
     flat_len = len(flat_res)
     engines_len = len(results)
+
     results = []
+
     # deduplication + scoring
     for i, res in enumerate(flat_res):
 
         res['engines'] = [res['engine']]
         weight = 1.0
 
+        # get weight of this engine if possible
         if hasattr(engines[res['engine']], 'weight'):
             weight = float(engines[res['engine']].weight)
 
+        # calculate score for that engine
         score = int((flat_len - i) / engines_len) * weight + 1
+
         duplicated = False
 
+        # check for duplicates
         for new_res in results:
+            # remove / from the end of the url if required
             p1 = res['parsed_url'].path[:-1] if res['parsed_url'].path.endswith('/') else res['parsed_url'].path  # noqa
             p2 = new_res['parsed_url'].path[:-1] if new_res['parsed_url'].path.endswith('/') else new_res['parsed_url'].path  # noqa
+
+            # check if that result is a duplicate
             if res['host'] == new_res['host'] and\
                unquote(p1) == unquote(p2) and\
                res['parsed_url'].query == new_res['parsed_url'].query and\
                res.get('template') == new_res.get('template'):
                 duplicated = new_res
                 break
+
+        # merge duplicates together
         if duplicated:
+            # using content with more text
             if res.get('content') > duplicated.get('content'):
                 duplicated['content'] = res['content']
+
+            # increase result-score
             duplicated['score'] += score
+
+            # add engine to list of result-engines
             duplicated['engines'].append(res['engine'])
+
+            # using https if possible
             if duplicated['parsed_url'].scheme == 'https':
                 continue
             elif res['parsed_url'].scheme == 'https':
                 duplicated['url'] = res['parsed_url'].geturl()
                 duplicated['parsed_url'] = res['parsed_url']
+
+        # if there is no duplicate found, append result
         else:
             res['score'] = score
             results.append(res)
+
+    # return results sorted by score
     return sorted(results, key=itemgetter('score'), reverse=True)
 
 
     """Search information container"""
 
     def __init__(self, request):
+        # init vars
         super(Search, self).__init__()
         self.query = None
         self.engines = []
         self.paging = False
         self.pageno = 1
         self.lang = 'all'
+
+        # set blocked engines
         if request.cookies.get('blocked_engines'):
             self.blocked_engines = request.cookies['blocked_engines'].split(',')  # noqa
         else:
             self.blocked_engines = []
+
         self.results = []
         self.suggestions = []
         self.request_data = {}
 
+        # set specific language if set
         if request.cookies.get('language')\
            and request.cookies['language'] in (x[0] for x in language_codes):
             self.lang = request.cookies['language']
 
+        # set request method
         if request.method == 'POST':
             self.request_data = request.form
         else:
         if not self.request_data.get('q'):
             raise Exception('noquery')
 
+        # set query
         self.query = self.request_data['q']
 
+        # set pagenumber
         pageno_param = self.request_data.get('pageno', '1')
         if not pageno_param.isdigit() or int(pageno_param) < 1:
             raise Exception('wrong pagenumber')
 
         self.pageno = int(pageno_param)
 
+        # parse query, if tags are set, which change the serch engine or search-language
         self.parse_query()
 
         self.categories = []
 
+        # if engines are calculated from query, set categories by using that informations
         if self.engines:
             self.categories = list(set(engine['category']
                                        for engine in self.engines))
+
+        # otherwise, using defined categories to calculate which engines should be used
         else:
+            # set used categories
             for pd_name, pd in self.request_data.items():
                 if pd_name.startswith('category_'):
                     category = pd_name[9:]
+                    # if category is not found in list, skip
                     if not category in categories:
                         continue
+
+                    # add category to list
                     self.categories.append(category)
+
+            # if no category is specified for this search, using user-defined default-configuration which (is stored in cookie)
             if not self.categories:
                 cookie_categories = request.cookies.get('categories', '')
                 cookie_categories = cookie_categories.split(',')
                 for ccateg in cookie_categories:
                     if ccateg in categories:
                         self.categories.append(ccateg)
+
+            # if still no category is specified, using general as default-category
             if not self.categories:
                 self.categories = ['general']
 
+            # using all engines for that search, which are declared under the specific categories
             for categ in self.categories:
                 self.engines.extend({'category': categ,
                                      'name': x.name}
                                     for x in categories[categ]
                                     if not x.name in self.blocked_engines)
 
+    # parse query, if tags are set, which change the serch engine or search-language
     def parse_query(self):
         query_parts = self.query.split()
         modified = False
+
+        # check if language-prefix is set
         if query_parts[0].startswith(':'):
             lang = query_parts[0][1:].lower()
 
+            # check if any language-code equal with declared language-codes
             for lc in language_codes:
                 lang_id, lang_name, country = map(str.lower, lc)
+
+                # if correct language-code is found, set it as new search-language
                 if lang == lang_id\
                    or lang_id.startswith(lang)\
                    or lang == lang_name\
                     modified = True
                     break
 
+        # check if category/engine prefix is set
         elif query_parts[0].startswith('!'):
             prefix = query_parts[0][1:].replace('_', ' ')
 
+            # check if prefix equal with engine shortcut
             if prefix in engine_shortcuts\
                and not engine_shortcuts[prefix] in self.blocked_engines:
                 modified = True
                 self.engines.append({'category': 'none',
                                      'name': engine_shortcuts[prefix]})
+
+            # check if prefix equal with engine name
             elif prefix in engines\
                     and not prefix in self.blocked_engines:
                 modified = True
                 self.engines.append({'category': 'none',
                                     'name': prefix})
+
+            # check if prefix equal with categorie name
             elif prefix in categories:
                 modified = True
+                # using all engines for that search, which are declared under that categorie name
                 self.engines.extend({'category': prefix,
                                     'name': engine.name}
                                     for engine in categories[prefix]
                                     if not engine in self.blocked_engines)
+
+        # if language, category or engine were specificed in this query, search for more tags which does the same
         if modified:
             self.query = self.query.replace(query_parts[0], '', 1).strip()
             self.parse_query()
 
+    # do search-request
     def search(self, request):
         global number_of_searches
+
+        # init vars
         requests = []
         results = {}
         suggestions = set()
+
+        # increase number of active searches
         number_of_searches += 1
+
+        # set default useragent
         #user_agent = request.headers.get('User-Agent', '')
         user_agent = gen_useragent()
 
+        # start search-reqest for all selected engines
         for selected_engine in self.engines:
             if selected_engine['name'] not in engines:
                 continue
 
             engine = engines[selected_engine['name']]
 
+            # if paging is not supported, skip
             if self.pageno > 1 and not engine.paging:
                 continue
 
+            # if search-language is set and engine does not provide language-support, skip
             if self.lang != 'all' and not engine.language_support:
                 continue
 
+            # set default request parameters
             request_params = default_request_params()
             request_params['headers']['User-Agent'] = user_agent
             request_params['category'] = selected_engine['category']
             request_params['started'] = datetime.now()
             request_params['pageno'] = self.pageno
             request_params['language'] = self.lang
+
+            # update request parameters dependent on search-engine (contained in engines folder)
             request_params = engine.request(self.query.encode('utf-8'),
                                             request_params)
 
                 # TODO add support of offline engines
                 pass
 
+            # create a callback wrapper for the search engine results
             callback = make_callback(
                 selected_engine['name'],
                 results,
                 request_params
             )
 
+            # create dictionary which contain all informations about the request
             request_args = dict(
                 headers=request_params['headers'],
                 hooks=dict(response=callback),
                 timeout=engine.timeout
             )
 
+            # specific type of request (GET or POST)
             if request_params['method'] == 'GET':
                 req = grequests.get
             else:
             if not request_params['url']:
                 continue
 
+            # append request to list
             requests.append(req(request_params['url'], **request_args))
+
+        # send all search-request
         grequests.map(requests)
+
+        # update engine-specific stats
         for engine_name, engine_results in results.items():
             engines[engine_name].stats['search_count'] += 1
             engines[engine_name].stats['result_count'] += len(engine_results)
 
+        # score results and remove duplications
         results = score_results(results)
 
+        # update engine stats, using calculated score
         for result in results:
             for res_engine in result['engines']:
                 engines[result['engine']]\
                     .stats['score_count'] += result['score']
 
+        # return results and suggestions
         return results, suggestions