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# Source code for searx.engines.wikipedia

    # SPDX-License-Identifier: AGPL-3.0-or-later
    """This module implements the Wikipedia engine.  Some of this implementations
    are shared by other engines:

    - :ref:`wikidata engine`

    The list of supported languages is :py:obj:`fetched <fetch_wikimedia_traits>` from
    the article linked by :py:obj:`list_of_wikipedias`.

    Unlike traditional search engines, wikipedia does not support one Wikipedia for
    all languages, but there is one Wikipedia for each supported language. Some of
    these Wikipedias have a LanguageConverter_ enabled
    (:py:obj:`rest_v1_summary_url`).

    A LanguageConverter_ (LC) is a system based on language variants that
    automatically converts the content of a page into a different variant. A variant
    is mostly the same language in a different script.

    - `Wikipedias in multiple writing systems`_
    - `Automatic conversion between traditional and simplified Chinese characters`_

    PR-2554_:
      The Wikipedia link returned by the API is still the same in all cases
      (`https://zh.wikipedia.org/wiki/出租車`_) but if your browser's
      ``Accept-Language`` is set to any of ``zh``, ``zh-CN``, ``zh-TW``, ``zh-HK``
      or .. Wikipedia's LC automatically returns the desired script in their
      web-page.

      - You can test the API here: https://reqbin.com/gesg2kvx

    .. _https://zh.wikipedia.org/wiki/出租車:
       https://zh.wikipedia.org/wiki/%E5%87%BA%E7%A7%9F%E8%BB%8A

    To support Wikipedia's LanguageConverter_, a SearXNG request to Wikipedia uses
    :py:obj:`get_wiki_params` and :py:obj:`wiki_lc_locale_variants' in the
    :py:obj:`fetch_wikimedia_traits` function.

    To test in SearXNG, query for ``!wp 出租車`` with each of the available Chinese
    options:

    - ``!wp 出租車 :zh``    should show 出租車
    - ``!wp 出租車 :zh-CN`` should show 出租车
    - ``!wp 出租車 :zh-TW`` should show 計程車
    - ``!wp 出租車 :zh-HK`` should show 的士
    - ``!wp 出租車 :zh-SG`` should show 德士

    .. _LanguageConverter:
       https://www.mediawiki.org/wiki/Writing_systems#LanguageConverter
    .. _Wikipedias in multiple writing systems:
       https://meta.wikimedia.org/wiki/Wikipedias_in_multiple_writing_systems
    .. _Automatic conversion between traditional and simplified Chinese characters:
       https://en.wikipedia.org/wiki/Chinese_Wikipedia#Automatic_conversion_between_traditional_and_simplified_Chinese_characters
    .. _PR-2554: https://github.com/searx/searx/pull/2554

    """

    import urllib.parse

    import babel
    from lxml import html

    from searx import locales, utils
    from searx import network as _network
    from searx.enginelib.traits import EngineTraits

    # about
    about = {
        "website": "https://www.wikipedia.org/",
        "wikidata_id": "Q52",
        "official_api_documentation": "https://en.wikipedia.org/api/",
        "use_official_api": True,
        "require_api_key": False,
        "results": "JSON",
    }

    display_type = ["infobox"]
    """A list of display types composed from ``infobox`` and ``list``.  The latter
    one will add a hit to the result list.  The first one will show a hit in the
    info box.  Both values can be set, or one of the two can be set."""

    list_of_wikipedias = "https://meta.wikimedia.org/wiki/List_of_Wikipedias"
    """`List of all wikipedias <https://meta.wikimedia.org/wiki/List_of_Wikipedias>`_
    """

    wikipedia_article_depth = "https://meta.wikimedia.org/wiki/Wikipedia_article_depth"
    """The *editing depth* of Wikipedia is one of several possible rough indicators
    of the encyclopedia's collaborative quality, showing how frequently its articles
    are updated.  The measurement of depth was introduced after some limitations of
    the classic measurement of article count were realized.
    """

    rest_v1_summary_url = "https://{wiki_netloc}/api/rest_v1/page/summary/{title}"
    """
    `wikipedia rest_v1 summary API`_:
      The summary response includes an extract of the first paragraph of the page in
      plain text and HTML as well as the type of page. This is useful for page
      previews (fka. Hovercards, aka. Popups) on the web and link previews in the
      apps.

    HTTP ``Accept-Language`` header (``send_accept_language_header``):
      The desired language variant code for wikis where LanguageConverter_ is
      enabled.

    .. _wikipedia rest_v1 summary API:
       https://en.wikipedia.org/api/rest_v1/#/Page%20content/get_page_summary__title_

    """

    wiki_lc_locale_variants = {
        "zh": (
            "zh-CN",
            "zh-HK",
            "zh-MO",
            "zh-MY",
            "zh-SG",
            "zh-TW",
        ),
        "zh-classical": ("zh-classical",),
    }
    """Mapping rule of the LanguageConverter_ to map a language and its variants to
    a Locale (used in the HTTP ``Accept-Language`` header). For example see `LC
    Chinese`_.

    .. _LC Chinese:
       https://meta.wikimedia.org/wiki/Wikipedias_in_multiple_writing_systems#Chinese
    """

    wikipedia_script_variants = {
        "zh": (
            "zh_Hant",
            "zh_Hans",
        )
    }

    def get_wiki_params(sxng_locale, eng_traits):
        """Returns the Wikipedia language tag and the netloc that fits to the
        ``sxng_locale``.  To support LanguageConverter_ this function rates a locale
        (region) higher than a language (compare :py:obj:`wiki_lc_locale_variants`).

        """
        eng_tag = eng_traits.get_region(sxng_locale, eng_traits.get_language(sxng_locale, "en"))
        wiki_netloc = eng_traits.custom["wiki_netloc"].get(eng_tag, "en.wikipedia.org")
        return eng_tag, wiki_netloc

    def request(query, params):
        """Assemble a request (`wikipedia rest_v1 summary API`_)."""
        if query.islower():
            query = query.title()

        _eng_tag, wiki_netloc = get_wiki_params(params["searxng_locale"], traits)
        title = urllib.parse.quote(query)
        params["url"] = rest_v1_summary_url.format(wiki_netloc=wiki_netloc, title=title)

        params["raise_for_httperror"] = False
        params["soft_max_redirects"] = 2

        return params

    # get response from search-request
    def response(resp):

        results = []
        if resp.status_code == 404:
            return []
        if resp.status_code == 400:
            try:
                api_result = resp.json()
            except Exception:  # pylint: disable=broad-except
                pass
            else:
                if (
                    api_result["type"] == "https://mediawiki.org/wiki/HyperSwitch/errors/bad_request"
                    and api_result["detail"] == "title-invalid-characters"
                ):
                    return []

        _network.raise_for_httperror(resp)

        api_result = resp.json()
        title = utils.html_to_text(api_result.get("titles", {}).get("display") or api_result.get("title"))
        wikipedia_link = api_result["content_urls"]["desktop"]["page"]

        if "list" in display_type or api_result.get("type") != "standard":
            # show item in the result list if 'list' is in the display options or it
            # is a item that can't be displayed in a infobox.
            results.append(
                {
                    "url": wikipedia_link,
                    "title": title,
                    "content": api_result.get("description", ""),
                }
            )

        if "infobox" in display_type:
            if api_result.get("type") == "standard":
                results.append(
                    {
                        "infobox": title,
                        "id": wikipedia_link,
                        "content": api_result.get("extract", ""),
                        "img_src": api_result.get("thumbnail", {}).get("source"),
                        "urls": [{"title": "Wikipedia", "url": wikipedia_link}],
                    }
                )

        return results

    # Nonstandard language codes
    #
    # These Wikipedias use language codes that do not conform to the ISO 639
    # standard (which is how wiki subdomains are chosen nowadays).

    lang_map = locales.LOCALE_BEST_MATCH.copy()
    lang_map.update(
        {
            "be-tarask": "bel",
            "ak": "aka",
            "als": "gsw",
            "bat-smg": "sgs",
            "cbk-zam": "cbk",
            "fiu-vro": "vro",
            "map-bms": "map",
            "no": "nb-NO",
            "nrm": "nrf",
            "roa-rup": "rup",
            "nds-nl": "nds",
            #'simple: – invented code used for the Simple English Wikipedia (not the official IETF code en-simple)
            "zh-min-nan": "nan",
            "zh-yue": "yue",
            "an": "arg",
        }
    )

    def fetch_traits(engine_traits: EngineTraits):
        fetch_wikimedia_traits(engine_traits)
        print("WIKIPEDIA_LANGUAGES: %s" % len(engine_traits.custom["WIKIPEDIA_LANGUAGES"]))

    def fetch_wikimedia_traits(engine_traits: EngineTraits):
        """Fetch languages from Wikipedia.  Not all languages from the
        :py:obj:`list_of_wikipedias` are supported by SearXNG locales, only those
        known from :py:obj:`searx.locales.LOCALE_NAMES` or those with a minimal
        :py:obj:`editing depth <wikipedia_article_depth>`.

        The location of the Wikipedia address of a language is mapped in a
        :py:obj:`custom field <searx.enginelib.traits.EngineTraits.custom>`
        (``wiki_netloc``).  Here is a reduced example:

        .. code:: python

           traits.custom['wiki_netloc'] = {
               "en": "en.wikipedia.org",
               ..
               "gsw": "als.wikipedia.org",
               ..
               "zh": "zh.wikipedia.org",
               "zh-classical": "zh-classical.wikipedia.org"
           }
        """
        # pylint: disable=import-outside-toplevel, too-many-branches

        from searx.network import get  # see https://github.com/searxng/searxng/issues/762
        from searx.utils import searxng_useragent

        engine_traits.custom["wiki_netloc"] = {}
        engine_traits.custom["WIKIPEDIA_LANGUAGES"] = []

        # insert alias to map from a script or region to a wikipedia variant

        for eng_tag, sxng_tag_list in wikipedia_script_variants.items():
            for sxng_tag in sxng_tag_list:
                engine_traits.languages[sxng_tag] = eng_tag
        for eng_tag, sxng_tag_list in wiki_lc_locale_variants.items():
            for sxng_tag in sxng_tag_list:
                engine_traits.regions[sxng_tag] = eng_tag

        headers = {"Accept": "*/*", "User-Agent": searxng_useragent()}
        resp = get(list_of_wikipedias, timeout=5, headers=headers)
        if not resp.ok:
            raise RuntimeError("Response from Wikipedia is not OK.")

        dom = html.fromstring(resp.text)
        for row in dom.xpath('//table[contains(@class,"sortable")]//tbody/tr'):
            cols = row.xpath("./td")
            if not cols:
                continue
            cols = [c.text_content().strip() for c in cols]

            depth = float(cols[11].replace("-", "0").replace(",", ""))
            articles = int(cols[4].replace(",", "").replace(",", ""))

            eng_tag = cols[3]
            wiki_url = row.xpath("./td[4]/a/@href")[0]
            wiki_url = urllib.parse.urlparse(wiki_url)

            try:
                sxng_tag = locales.language_tag(babel.Locale.parse(lang_map.get(eng_tag, eng_tag), sep="-"))
            except babel.UnknownLocaleError:
                # print("ERROR: %s [%s] is unknown by babel" % (cols[0], eng_tag))
                continue
            finally:
                engine_traits.custom["WIKIPEDIA_LANGUAGES"].append(eng_tag)

            if sxng_tag not in locales.LOCALE_NAMES:
                if articles < 10000:
                    # exclude languages with too few articles
                    continue

                if int(depth) < 20:
                    # Rough indicator of a Wikipedia’s quality, showing how
                    # frequently its articles are updated.
                    continue

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

            engine_traits.languages[sxng_tag] = eng_tag
            engine_traits.custom["wiki_netloc"][eng_tag] = wiki_url.netloc

        engine_traits.custom["WIKIPEDIA_LANGUAGES"].sort()