# searx.engines.duckduckgo — SearXNG Documentation (2024.5.4+dbed8da28)

# Source code for searx.engines.duckduckgo

    # SPDX-License-Identifier: AGPL-3.0-or-later
    """
    DuckDuckGo Lite
    ~~~~~~~~~~~~~~~
    """

    from typing import TYPE_CHECKING
    import re
    from urllib.parse import urlencode
    import json
    import babel
    import lxml.html

    from searx import (
        locales,
        redislib,
        external_bang,
    )
    from searx.utils import (
        eval_xpath,
        eval_xpath_getindex,
        extract_text,
    )
    from searx.network import get  # see https://github.com/searxng/searxng/issues/762
    from searx import redisdb
    from searx.enginelib.traits import EngineTraits

    if TYPE_CHECKING:
        import logging

        logger: logging.Logger

    traits: EngineTraits

    about = {
        "website": 'https://lite.duckduckgo.com/lite/',
        "wikidata_id": 'Q12805',
        "use_official_api": False,
        "require_api_key": False,
        "results": 'HTML',
    }

    send_accept_language_header = True
    """DuckDuckGo-Lite tries to guess user's prefered language from the HTTP
    ``Accept-Language``.  Optional the user can select a region filter (but not a
    language).
    """

    # engine dependent config
    categories = ['general', 'web']
    paging = True
    time_range_support = True
    safesearch = True  # user can't select but the results are filtered

    url = 'https://lite.duckduckgo.com/lite/'
    # url_ping = 'https://duckduckgo.com/t/sl_l'

    time_range_dict = {'day': 'd', 'week': 'w', 'month': 'm', 'year': 'y'}
    form_data = {'v': 'l', 'api': 'd.js', 'o': 'json'}

    def cache_vqd(query, value):
        """Caches a ``vqd`` value from a query."""
        c = redisdb.client()
        if c:
            logger.debug("cache vqd value: %s", value)
            key = 'SearXNG_ddg_web_vqd' + redislib.secret_hash(query)
            c.set(key, value, ex=600)

    def get_vqd(query):
        """Returns the ``vqd`` that fits to the *query*.  If there is no ``vqd`` cached
        (:py:obj:`cache_vqd`) the query is sent to DDG to get a vqd value from the
        response.

        .. hint::

           If an empty string is returned there are no results for the ``query`` and
           therefore no ``vqd`` value.

        DDG's bot detection is sensitive to the ``vqd`` value.  For some search terms
        (such as extremely long search terms that are often sent by bots), no ``vqd``
        value can be determined.

        If SearXNG cannot determine a ``vqd`` value, then no request should go out
        to DDG:

            A request with a wrong ``vqd`` value leads to DDG temporarily putting
            SearXNG's IP on a block list.

            Requests from IPs in this block list run into timeouts.

        Not sure, but it seems the block list is a sliding window: to get my IP rid
        from the bot list I had to cool down my IP for 1h (send no requests from
        that IP to DDG).

        TL;DR; the ``vqd`` value is needed to pass DDG's bot protection and is used
        by all request to DDG:

        - DuckDuckGo Lite: ``https://lite.duckduckgo.com/lite`` (POST form data)
        - DuckDuckGo Web: ``https://links.duckduckgo.com/d.js?q=...&vqd=...``
        - DuckDuckGo Images: ``https://duckduckgo.com/i.js??q=...&vqd=...``
        - DuckDuckGo Videos: ``https://duckduckgo.com/v.js??q=...&vqd=...``
        - DuckDuckGo News: ``https://duckduckgo.com/news.js??q=...&vqd=...``

        """
        value = None
        c = redisdb.client()
        if c:
            key = 'SearXNG_ddg_web_vqd' + redislib.secret_hash(query)
            value = c.get(key)
            if value or value == b'':
                value = value.decode('utf-8')
                logger.debug("re-use cached vqd value: %s", value)
                return value

        query_url = 'https://duckduckgo.com/?' + urlencode({'q': query})
        res = get(query_url)
        doc = lxml.html.fromstring(res.text)
        for script in doc.xpath("//script[@type='text/javascript']"):
            script = script.text
            if 'vqd="' in script:
                value = script[script.index('vqd="') + 5 :]
                value = value[: value.index('"')]
                break
        logger.debug("new vqd value: '%s'", value)
        if value is not None:
            cache_vqd(query, value)
        return value

    def get_ddg_lang(eng_traits: EngineTraits, sxng_locale, default='en_US'):
        """Get DuckDuckGo's language identifier from SearXNG's locale.

        DuckDuckGo defines its languages by region codes (see
        :py:obj:`fetch_traits`).

        To get region and language of a DDG service use:

        .. code: python

           eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
           eng_lang = get_ddg_lang(traits, params['searxng_locale'])

        It might confuse, but the ``l`` value of the cookie is what SearXNG calls
        the *region*:

        .. code:: python

            # !ddi paris :es-AR --> {'ad': 'es_AR', 'ah': 'ar-es', 'l': 'ar-es'}
            params['cookies']['ad'] = eng_lang
            params['cookies']['ah'] = eng_region
            params['cookies']['l'] = eng_region

        .. hint::

           `DDG-lite <https://lite.duckduckgo.com/lite>`__ does not offer a language
           selection to the user, only a region can be selected by the user
           (``eng_region`` from the example above).  DDG-lite stores the selected
           region in a cookie::

             params['cookies']['kl'] = eng_region  # 'ar-es'

        """
        return eng_traits.custom['lang_region'].get(  # type: ignore
            sxng_locale, eng_traits.get_language(sxng_locale, default)
        )

    ddg_reg_map = {
        'tw-tzh': 'zh_TW',
        'hk-tzh': 'zh_HK',
        'ct-ca': 'skip',  # ct-ca and es-ca both map to ca_ES
        'es-ca': 'ca_ES',
        'id-en': 'id_ID',
        'no-no': 'nb_NO',
        'jp-jp': 'ja_JP',
        'kr-kr': 'ko_KR',
        'xa-ar': 'ar_SA',
        'sl-sl': 'sl_SI',
        'th-en': 'th_TH',
        'vn-en': 'vi_VN',
    }

    ddg_lang_map = {
        # use ar --> ar_EG (Egypt's arabic)
        "ar_DZ": 'lang_region',
        "ar_JO": 'lang_region',
        "ar_SA": 'lang_region',
        # use bn --> bn_BD
        'bn_IN': 'lang_region',
        # use de --> de_DE
        'de_CH': 'lang_region',
        # use en --> en_US,
        'en_AU': 'lang_region',
        'en_CA': 'lang_region',
        'en_GB': 'lang_region',
        # Esperanto
        'eo_XX': 'eo',
        # use es --> es_ES,
        'es_AR': 'lang_region',
        'es_CL': 'lang_region',
        'es_CO': 'lang_region',
        'es_CR': 'lang_region',
        'es_EC': 'lang_region',
        'es_MX': 'lang_region',
        'es_PE': 'lang_region',
        'es_UY': 'lang_region',
        'es_VE': 'lang_region',
        # use fr --> rf_FR
        'fr_CA': 'lang_region',
        'fr_CH': 'lang_region',
        'fr_BE': 'lang_region',
        # use nl --> nl_NL
        'nl_BE': 'lang_region',
        # use pt --> pt_PT
        'pt_BR': 'lang_region',
        # skip these languages
        'od_IN': 'skip',
        'io_XX': 'skip',
        'tokipona_XX': 'skip',
    }

    def quote_ddg_bangs(query):
        # quote ddg bangs
        query_parts = []

        # for val in re.split(r'(\s+)', query):
        for val in re.split(r'(\s+)', query):
            if not val.strip():
                continue
            if val.startswith('!') and external_bang.get_node(external_bang.EXTERNAL_BANGS, val[1:]):
                val = f"'{val}'"
            query_parts.append(val)
        return ' '.join(query_parts)

    def request(query, params):

        query = quote_ddg_bangs(query)

        # request needs a vqd argument
        vqd = get_vqd(query)

        eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
        # eng_lang = get_ddg_lang(traits, params['searxng_locale'])

        params['url'] = url
        params['method'] = 'POST'
        params['data']['q'] = query

        # The API is not documented, so we do some reverse engineering and emulate
        # what https://lite.duckduckgo.com/lite/ does when you press "next Page"
        # link again and again ..

        params['headers']['Content-Type'] = 'application/x-www-form-urlencoded'
        params['data']['vqd'] = vqd

        # initial page does not have an offset
        if params['pageno'] == 2:
            # second page does have an offset of 20
            offset = (params['pageno'] - 1) * 20
            params['data']['s'] = offset
            params['data']['dc'] = offset + 1

        elif params['pageno'] > 2:
            # third and following pages do have an offset of 20 + n*50
            offset = 20 + (params['pageno'] - 2) * 50
            params['data']['s'] = offset
            params['data']['dc'] = offset + 1

        # initial page does not have additional data in the input form
        if params['pageno'] > 1:

            params['data']['o'] = form_data.get('o', 'json')
            params['data']['api'] = form_data.get('api', 'd.js')
            params['data']['nextParams'] = form_data.get('nextParams', '')
            params['data']['v'] = form_data.get('v', 'l')
            params['headers']['Referer'] = 'https://lite.duckduckgo.com/'

        params['data']['kl'] = eng_region
        params['cookies']['kl'] = eng_region

        params['data']['df'] = ''
        if params['time_range'] in time_range_dict:
            params['data']['df'] = time_range_dict[params['time_range']]
            params['cookies']['df'] = time_range_dict[params['time_range']]

        logger.debug("param data: %s", params['data'])
        logger.debug("param cookies: %s", params['cookies'])
        return params

    def response(resp):

        if resp.status_code == 303:
            return []

        results = []
        doc = lxml.html.fromstring(resp.text)

        result_table = eval_xpath(doc, '//html/body/form/div[@class="filters"]/table')

        if len(result_table) == 2:
            # some locales (at least China) does not have a "next page" button and
            # the layout of the HTML tables is different.
            result_table = result_table[1]
        elif not len(result_table) >= 3:
            # no more results
            return []
        else:
            result_table = result_table[2]
            # update form data from response
            form = eval_xpath(doc, '//html/body/form/div[@class="filters"]/table//input/..')
            if len(form):

                form = form[0]
                form_data['v'] = eval_xpath(form, '//input[@name="v"]/@value')[0]
                form_data['api'] = eval_xpath(form, '//input[@name="api"]/@value')[0]
                form_data['o'] = eval_xpath(form, '//input[@name="o"]/@value')[0]
                logger.debug('form_data: %s', form_data)

        tr_rows = eval_xpath(result_table, './/tr')
        # In the last <tr> is the form of the 'previous/next page' links
        tr_rows = tr_rows[:-1]

        len_tr_rows = len(tr_rows)
        offset = 0

        while len_tr_rows >= offset + 4:

            # assemble table rows we need to scrap
            tr_title = tr_rows[offset]
            tr_content = tr_rows[offset + 1]
            offset += 4

            # ignore sponsored Adds <tr class="result-sponsored">
            if tr_content.get('class') == 'result-sponsored':
                continue

            a_tag = eval_xpath_getindex(tr_title, './/td//a[@class="result-link"]', 0, None)
            if a_tag is None:
                continue

            td_content = eval_xpath_getindex(tr_content, './/td[@class="result-snippet"]', 0, None)
            if td_content is None:
                continue

            results.append(
                {
                    'title': a_tag.text_content(),
                    'content': extract_text(td_content),
                    'url': a_tag.get('href'),
                }
            )

        return results

    def fetch_traits(engine_traits: EngineTraits):
        """Fetch languages & regions from DuckDuckGo.

        SearXNG's ``all`` locale maps DuckDuckGo's "Alle regions" (``wt-wt``).
        DuckDuckGo's language "Browsers prefered language" (``wt_WT``) makes no
        sense in a SearXNG request since SearXNG's ``all`` will not add a
        ``Accept-Language`` HTTP header.  The value in ``engine_traits.all_locale``
        is ``wt-wt`` (the region).

        Beside regions DuckDuckGo also defines its languages by region codes.  By
        example these are the english languages in DuckDuckGo:

        - en_US
        - en_AU
        - en_CA
        - en_GB

        The function :py:obj:`get_ddg_lang` evaluates DuckDuckGo's language from
        SearXNG's locale.

        """
        # pylint: disable=too-many-branches, too-many-statements
        # fetch regions

        engine_traits.all_locale = 'wt-wt'

        # updated from u661.js to u.7669f071a13a7daa57cb / should be updated automatically?
        resp = get('https://duckduckgo.com/dist/util/u.7669f071a13a7daa57cb.js')

        if not resp.ok:  # type: ignore
            print("ERROR: response from DuckDuckGo is not OK.")

        pos = resp.text.find('regions:{') + 8  # type: ignore
        js_code = resp.text[pos:]  # type: ignore
        pos = js_code.find('}') + 1
        regions = json.loads(js_code[:pos])

        for eng_tag, name in regions.items():

            if eng_tag == 'wt-wt':
                engine_traits.all_locale = 'wt-wt'
                continue

            region = ddg_reg_map.get(eng_tag)
            if region == 'skip':
                continue

            if not region:
                eng_territory, eng_lang = eng_tag.split('-')
                region = eng_lang + '_' + eng_territory.upper()

            try:
                sxng_tag = locales.region_tag(babel.Locale.parse(region))
            except babel.UnknownLocaleError:
                print("ERROR: %s (%s) -> %s is unknown by babel" % (name, eng_tag, region))
                continue

            conflict = engine_traits.regions.get(sxng_tag)
            if conflict:
                if conflict != eng_tag:
                    print("CONFLICT: babel %s --> %s, %s" % (sxng_tag, conflict, eng_tag))
                continue
            engine_traits.regions[sxng_tag] = eng_tag

        # fetch languages

        engine_traits.custom['lang_region'] = {}

        pos = resp.text.find('languages:{') + 10  # type: ignore
        js_code = resp.text[pos:]  # type: ignore
        pos = js_code.find('}') + 1
        js_code = '{"' + js_code[1:pos].replace(':', '":').replace(',', ',"')
        languages = json.loads(js_code)

        for eng_lang, name in languages.items():

            if eng_lang == 'wt_WT':
                continue

            babel_tag = ddg_lang_map.get(eng_lang, eng_lang)
            if babel_tag == 'skip':
                continue

            try:

                if babel_tag == 'lang_region':
                    sxng_tag = locales.region_tag(babel.Locale.parse(eng_lang))
                    engine_traits.custom['lang_region'][sxng_tag] = eng_lang
                    continue

                sxng_tag = locales.language_tag(babel.Locale.parse(babel_tag))

            except babel.UnknownLocaleError:
                print("ERROR: language %s (%s) is unknown by babel" % (name, eng_lang))
                continue

            conflict = engine_traits.languages.get(sxng_tag)
            if conflict:
                if conflict != eng_lang:
                    print("CONFLICT: babel %s --> %s, %s" % (sxng_tag, conflict, eng_lang))
                continue
            engine_traits.languages[sxng_tag] = eng_lang