searxng/searx/results.py

import re
from collections import defaultdict
from operator import itemgetter
from threading import RLock
from urllib.parse import urlparse, unquote
from searx import logger
from searx.engines import engines
from searx.metrics import histogram_observe, counter_add, count_error


CONTENT_LEN_IGNORED_CHARS_REGEX = re.compile(r'[,;:!?\./\\\\ ()-_]', re.M | re.U)
WHITESPACE_REGEX = re.compile('( |\t|\n)+', re.M | re.U)


# return the meaningful length of the content for a result
def result_content_len(content):
    if isinstance(content, str):
        return len(CONTENT_LEN_IGNORED_CHARS_REGEX.sub('', content))
    else:
        return 0


def compare_urls(url_a, url_b):
    """Lazy compare between two URL.
    "www.example.com" and "example.com" are equals.
    "www.example.com/path/" and "www.example.com/path" are equals.
    "https://www.example.com/" and "http://www.example.com/" are equals.

    Args:
        url_a (ParseResult): first URL
        url_b (ParseResult): second URL

    Returns:
        bool: True if url_a and url_b are equals
    """
    # ignore www. in comparison
    if url_a.netloc.startswith('www.'):
        host_a = url_a.netloc.replace('www.', '', 1)
    else:
        host_a = url_a.netloc
    if url_b.netloc.startswith('www.'):
        host_b = url_b.netloc.replace('www.', '', 1)
    else:
        host_b = url_b.netloc

    if host_a != host_b or url_a.query != url_b.query or url_a.fragment != url_b.fragment:
        return False

    # remove / from the end of the url if required
    path_a = url_a.path[:-1]\
        if url_a.path.endswith('/')\
        else url_a.path
    path_b = url_b.path[:-1]\
        if url_b.path.endswith('/')\
        else url_b.path

    return unquote(path_a) == unquote(path_b)


def merge_two_infoboxes(infobox1, infobox2):
    # get engines weights
    if hasattr(engines[infobox1['engine']], 'weight'):
        weight1 = engines[infobox1['engine']].weight
    else:
        weight1 = 1
    if hasattr(engines[infobox2['engine']], 'weight'):
        weight2 = engines[infobox2['engine']].weight
    else:
        weight2 = 1

    if weight2 > weight1:
        infobox1['engine'] = infobox2['engine']

    infobox1['engines'] |= infobox2['engines']

    if 'urls' in infobox2:
        urls1 = infobox1.get('urls', None)
        if urls1 is None:
            urls1 = []

        for url2 in infobox2.get('urls', []):
            unique_url = True
            parsed_url2 = urlparse(url2.get('url', ''))
            entity_url2 = url2.get('entity')
            for url1 in urls1:
                if (entity_url2 is not None and url1.get('entity') == entity_url2)\
                   or compare_urls(urlparse(url1.get('url', '')), parsed_url2):
                    unique_url = False
                    break
            if unique_url:
                urls1.append(url2)

        infobox1['urls'] = urls1

    if 'img_src' in infobox2:
        img1 = infobox1.get('img_src', None)
        img2 = infobox2.get('img_src')
        if img1 is None:
            infobox1['img_src'] = img2
        elif weight2 > weight1:
            infobox1['img_src'] = img2

    if 'attributes' in infobox2:
        attributes1 = infobox1.get('attributes')
        if attributes1 is None:
            infobox1['attributes'] = attributes1 = []

        attributeSet = set()
        for attribute in attributes1:
            label = attribute.get('label')
            if label not in attributeSet:
                attributeSet.add(label)
            entity = attribute.get('entity')
            if entity not in attributeSet:
                attributeSet.add(entity)

        for attribute in infobox2.get('attributes', []):
            if attribute.get('label') not in attributeSet\
               and attribute.get('entity') not in attributeSet:
                attributes1.append(attribute)

    if 'content' in infobox2:
        content1 = infobox1.get('content', None)
        content2 = infobox2.get('content', '')
        if content1 is not None:
            if result_content_len(content2) > result_content_len(content1):
                infobox1['content'] = content2
        else:
            infobox1['content'] = content2


def result_score(result):
    weight = 1.0

    for result_engine in result['engines']:
        if hasattr(engines[result_engine], 'weight'):
            weight *= float(engines[result_engine].weight)

    occurences = len(result['positions'])

    return sum((occurences * weight) / position for position in result['positions'])


class ResultContainer:
    """docstring for ResultContainer"""

    __slots__ = '_merged_results', 'infoboxes', 'suggestions', 'answers', 'corrections', '_number_of_results',\
                '_closed', 'paging', 'unresponsive_engines', 'timings', 'redirect_url', 'engine_data', 'on_result'

    def __init__(self):
        super().__init__()
        self._merged_results = []
        self.infoboxes = []
        self.suggestions = set()
        self.answers = {}
        self.corrections = set()
        self._number_of_results = []
        self.engine_data = defaultdict(dict)
        self._closed = False
        self.paging = False
        self.unresponsive_engines = set()
        self.timings = []
        self.redirect_url = None
        self.on_result = lambda _: True

    def extend(self, engine_name, results):
        if self._closed:
            return

        standard_result_count = 0
        error_msgs = set()
        for result in list(results):
            result['engine'] = engine_name
            if 'suggestion' in result and self.on_result(result):
                self.suggestions.add(result['suggestion'])
            elif 'answer' in result and self.on_result(result):
                self.answers[result['answer']] = result
            elif 'correction' in result and self.on_result(result):
                self.corrections.add(result['correction'])
            elif 'infobox' in result and self.on_result(result):
                self._merge_infobox(result)
            elif 'number_of_results' in result and self.on_result(result):
                self._number_of_results.append(result['number_of_results'])
            elif 'engine_data' in result and self.on_result(result):
                self.engine_data[engine_name][result['key']] = result['engine_data']
            elif 'url' in result:
                # standard result (url, title, content)
                if not self._is_valid_url_result(result, error_msgs):
                    continue
                # normalize the result
                self._normalize_url_result(result)
                # call on_result call searx.search.SearchWithPlugins._on_result
                # which calls the plugins
                if not self.on_result(result):
                    continue
                self.__merge_url_result(result, standard_result_count + 1)
                standard_result_count += 1
            elif self.on_result(result):
                self.__merge_result_no_url(result, standard_result_count + 1)
                standard_result_count += 1

        if len(error_msgs) > 0:
            for msg in error_msgs:
                count_error(engine_name, 'some results are invalids: ' + msg, secondary=True)

        if engine_name in engines:
            histogram_observe(standard_result_count, 'engine', engine_name, 'result', 'count')

        if not self.paging and standard_result_count > 0 and engine_name in engines\
           and engines[engine_name].paging:
            self.paging = True

    def _merge_infobox(self, infobox):
        add_infobox = True
        infobox_id = infobox.get('id', None)
        infobox['engines'] = set([infobox['engine']])
        if infobox_id is not None:
            parsed_url_infobox_id = urlparse(infobox_id)
            for existingIndex in self.infoboxes:
                if compare_urls(urlparse(existingIndex.get('id', '')), parsed_url_infobox_id):
                    merge_two_infoboxes(existingIndex, infobox)
                    add_infobox = False

        if add_infobox:
            self.infoboxes.append(infobox)

    def _is_valid_url_result(self, result, error_msgs):
        if 'url' in result:
            if not isinstance(result['url'], str):
                logger.debug('result: invalid URL: %s', str(result))
                error_msgs.add('invalid URL')
                return False

        if 'title' in result and not isinstance(result['title'], str):
            logger.debug('result: invalid title: %s', str(result))
            error_msgs.add('invalid title')
            return False

        if 'content' in result:
            if not isinstance(result['content'], str):
                logger.debug('result: invalid content: %s', str(result))
                error_msgs.add('invalid content')
                return False

        return True

    def _normalize_url_result(self, result):
        """Return True if the result is valid
        """
        result['parsed_url'] = urlparse(result['url'])

        # if the result has no scheme, use http as default
        if not result['parsed_url'].scheme:
            result['parsed_url'] = result['parsed_url']._replace(scheme="http")
            result['url'] = result['parsed_url'].geturl()

        # strip multiple spaces and cariage returns from content
        result['content'] = WHITESPACE_REGEX.sub(' ', result['content'])

        return True

    def __merge_url_result(self, result, position):
        result['engines'] = set([result['engine']])
        duplicated = self.__find_duplicated_http_result(result)
        if duplicated:
            self.__merge_duplicated_http_result(duplicated, result, position)
            return

        # if there is no duplicate found, append result
        result['positions'] = [position]
        with RLock():
            self._merged_results.append(result)

    def __find_duplicated_http_result(self, result):
        result_template = result.get('template')
        for merged_result in self._merged_results:
            if 'parsed_url' not in merged_result:
                continue
            if compare_urls(result['parsed_url'], merged_result['parsed_url'])\
               and result_template == merged_result.get('template'):
                if result_template != 'images.html':
                    # not an image, same template, same url : it's a duplicate
                    return merged_result
                else:
                    # it's an image
                    # it's a duplicate if the parsed_url, template and img_src are differents
                    if result.get('img_src', '') == merged_result.get('img_src', ''):
                        return merged_result
        return None

    def __merge_duplicated_http_result(self, duplicated, result, position):
        # using content with more text
        if result_content_len(result.get('content', '')) >\
                result_content_len(duplicated.get('content', '')):
            duplicated['content'] = result['content']

        # merge all result's parameters not found in duplicate
        for key in result.keys():
            if not duplicated.get(key):
                duplicated[key] = result.get(key)

        # add the new position
        duplicated['positions'].append(position)

        # add engine to list of result-engines
        duplicated['engines'].add(result['engine'])

        # using https if possible
        if duplicated['parsed_url'].scheme != 'https' and result['parsed_url'].scheme == 'https':
            duplicated['url'] = result['parsed_url'].geturl()
            duplicated['parsed_url'] = result['parsed_url']

    def __merge_result_no_url(self, result, position):
        result['engines'] = set([result['engine']])
        result['positions'] = [position]
        with RLock():
            self._merged_results.append(result)

    def close(self):
        self._closed = True

        for result in self._merged_results:
            score = result_score(result)
            result['score'] = score
            for result_engine in result['engines']:
                counter_add(score, 'engine', result_engine, 'score')

        results = sorted(self._merged_results, key=itemgetter('score'), reverse=True)

        # pass 2 : group results by category and template
        gresults = []
        categoryPositions = {}

        for res in results:
            # FIXME : handle more than one category per engine
            engine = engines[res['engine']]
            res['category'] = engine.categories[0] if len(engine.categories) > 0 else ''

            # FIXME : handle more than one category per engine
            category = res['category']\
                + ':' + res.get('template', '')\
                + ':' + ('img_src' if 'img_src' in res or 'thumbnail' in res else '')

            current = None if category not in categoryPositions\
                else categoryPositions[category]

            # group with previous results using the same category
            # if the group can accept more result and is not too far
            # from the current position
            if current is not None and (current['count'] > 0)\
                    and (len(gresults) - current['index'] < 20):
                # group with the previous results using
                # the same category with this one
                index = current['index']
                gresults.insert(index, res)

                # update every index after the current one
                # (including the current one)
                for k in categoryPositions:
                    v = categoryPositions[k]['index']
                    if v >= index:
                        categoryPositions[k]['index'] = v + 1

                # update this category
                current['count'] -= 1

            else:
                # same category
                gresults.append(res)

                # update categoryIndex
                categoryPositions[category] = {'index': len(gresults), 'count': 8}

        # update _merged_results
        self._merged_results = gresults

    def get_ordered_results(self):
        if not self._closed:
            self.close()
        return self._merged_results

    def results_length(self):
        return len(self._merged_results)

    def results_number(self):
        resultnum_sum = sum(self._number_of_results)
        if not resultnum_sum or not self._number_of_results:
            return 0
        return resultnum_sum / len(self._number_of_results)

    def add_unresponsive_engine(self, engine_name, error_type, error_message=None, suspended=False):
        if engines[engine_name].display_error_messages:
            self.unresponsive_engines.add((engine_name, error_type, error_message, suspended))

    def add_timing(self, engine_name, engine_time, page_load_time):
        timing = {
            'engine': engines[engine_name].shortcut,
            'total': engine_time,
            'load': page_load_time,
        }
        self.timings.append(timing)

    def get_timings(self):
        return self.timings