Merge [feat] engine: implementation of Anna's Archive

Anna's Archive [1] is a free non-profit online shadow library metasearch engine
providing access to a variety of book resources (also via IPFS), created by a
team of anonymous archivists [2].

[1] https://annas-archive.org/
[2] https://annas-software.org/AnnaArchivist/annas-archive

1 files changed, 200 insertions, 0 deletions

diff --git a/searx/engines/annas_archive.py b/searx/engines/annas_archive.py
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+# SPDX-License-Identifier: AGPL-3.0-or-later
+# lint: pylint
+""".. _annas_archive engine:
+
+==============
+Anna's Archive
+==============
+
+.. _Anna's Archive: https://annas-archive.org/
+.. _AnnaArchivist: https://annas-software.org/AnnaArchivist/annas-archive
+
+`Anna's Archive`_ is a free non-profit online shadow library metasearch engine
+providing access to a variety of book resources (also via IPFS), created by a
+team of anonymous archivists (AnnaArchivist_).
+
+.. contents:: Contents
+   :depth: 2
+   :local:
+   :backlinks: entry
+
+
+Configuration
+=============
+
+The engine has the following additional settings:
+
+- :py:obj:`aa_content`
+- :py:obj:`aa_ext`
+- :py:obj:`aa_sort`
+
+With this options a SearXNG maintainer is able to configure **additional**
+engines for specific searches in Anna's Archive.  For example a engine to search
+for *newest* articles and journals (PDF) / by shortcut ``!aaa <search-term>``.
+
+.. code:: yaml
+
+  - name: annas articles
+    engine: annas_archive
+    shortcut: aaa
+    aa_content: 'journal_article'
+    aa_ext: 'pdf'
+    aa_sort: 'newest'
+
+
+Implementations
+===============
+
+"""
+
+from typing import List, Dict, Any, Optional
+from urllib.parse import quote
+from lxml import html
+
+from searx.utils import extract_text, eval_xpath, eval_xpath_list
+from searx.enginelib.traits import EngineTraits
+from searx.data import ENGINE_TRAITS
+
+# about
+about: Dict[str, Any] = {
+    "website": "https://annas-archive.org/",
+    "wikidata_id": "Q115288326",
+    "official_api_documentation": None,
+    "use_official_api": False,
+    "require_api_key": False,
+    "results": "HTML",
+}
+
+# engine dependent config
+categories: List[str] = ["files"]
+paging: bool = False
+
+# search-url
+base_url: str = "https://annas-archive.org"
+aa_content: str = ""
+"""Anan's search form field **Content** / possible values::
+
+    journal_article, book_any, book_fiction, book_unknown, book_nonfiction,
+    book_comic, magazine, standards_document
+
+To not filter use an empty string (default).
+"""
+aa_sort: str = ''
+"""Sort Anna's results, possible values::
+
+    newest, oldest, largest, smallest
+
+To sort by *most relevant* use an empty string (default)."""
+
+aa_ext: str = ''
+"""Filter Anna's results by a file ending.  Common filters for example are
+``pdf`` and ``epub``.
+
+.. note::
+
+   Anna's Archive is a beta release: Filter results by file extension does not
+   really work on Anna's Archive.
+
+"""
+
+
+def init(engine_settings=None):  # pylint: disable=unused-argument
+    """Check of engine's settings."""
+    traits = EngineTraits(**ENGINE_TRAITS['annas archive'])
+
+    if aa_content and aa_content not in traits.custom['content']:
+        raise ValueError(f'invalid setting content: {aa_content}')
+
+    if aa_sort and aa_sort not in traits.custom['sort']:
+        raise ValueError(f'invalid setting sort: {aa_sort}')
+
+    if aa_ext and aa_ext not in traits.custom['ext']:
+        raise ValueError(f'invalid setting ext: {aa_ext}')
+
+
+def request(query, params: Dict[str, Any]) -> Dict[str, Any]:
+    q = quote(query)
+    lang = traits.get_language(params["language"], traits.all_locale)  # type: ignore
+    params["url"] = base_url + f"/search?lang={lang or ''}&content={aa_content}&ext={aa_ext}&sort={aa_sort}&q={q}"
+    return params
+
+
+def response(resp) -> List[Dict[str, Optional[str]]]:
+    results: List[Dict[str, Optional[str]]] = []
+    dom = html.fromstring(resp.text)
+
+    for item in eval_xpath_list(dom, '//main//div[contains(@class, "h-[125]")]/a'):
+        results.append(_get_result(item))
+
+    # The rendering of the WEB page is very strange; except the first position
+    # all other positions of Anna's result page are enclosed in SGML comments.
+    # These comments are *uncommented* by some JS code, see query of class
+    # '.js-scroll-hidden' in Anna's HTML template:
+    #   https://annas-software.org/AnnaArchivist/annas-archive/-/blob/main/allthethings/templates/macros/md5_list.html
+
+    for item in eval_xpath_list(dom, '//main//div[contains(@class, "js-scroll-hidden")]'):
+        item = html.fromstring(item.xpath('./comment()')[0].text)
+        results.append(_get_result(item))
+
+    return results
+
+
+def _get_result(item):
+    return {
+        'template': 'paper.html',
+        'url': base_url + item.xpath('./@href')[0],
+        'title': extract_text(eval_xpath(item, './/h3/text()[1]')),
+        'publisher': extract_text(eval_xpath(item, './/div[contains(@class, "text-sm")]')),
+        'authors': [extract_text(eval_xpath(item, './/div[contains(@class, "italic")]'))],
+        'content': extract_text(eval_xpath(item, './/div[contains(@class, "text-xs")]')),
+        'img_src': item.xpath('.//img/@src')[0],
+    }
+
+
+def fetch_traits(engine_traits: EngineTraits):
+    """Fetch languages and other search arguments from Anna's search form."""
+    # pylint: disable=import-outside-toplevel
+
+    import babel
+    from searx.network import get  # see https://github.com/searxng/searxng/issues/762
+    from searx.locales import language_tag
+
+    engine_traits.all_locale = ''
+    engine_traits.custom['content'] = []
+    engine_traits.custom['ext'] = []
+    engine_traits.custom['sort'] = []
+
+    resp = get(base_url + '/search')
+    if not resp.ok:  # type: ignore
+        raise RuntimeError("Response from Anna's search page is not OK.")
+    dom = html.fromstring(resp.text)  # type: ignore
+
+    # supported language codes
+
+    lang_map = {}
+    for x in eval_xpath_list(dom, "//form//select[@name='lang']//option"):
+        eng_lang = x.get("value")
+        if eng_lang in ('', '_empty', 'nl-BE', 'und'):
+            continue
+        try:
+            locale = babel.Locale.parse(lang_map.get(eng_lang, eng_lang), sep='-')
+        except babel.UnknownLocaleError:
+            # silently ignore unknown languages
+            # print("ERROR: %s -> %s is unknown by babel" % (x.get("data-name"), eng_lang))
+            continue
+        sxng_lang = language_tag(locale)
+        conflict = engine_traits.languages.get(sxng_lang)
+        if conflict:
+            if conflict != eng_lang:
+                print("CONFLICT: babel %s --> %s, %s" % (sxng_lang, conflict, eng_lang))
+            continue
+        engine_traits.languages[sxng_lang] = eng_lang
+
+    for x in eval_xpath_list(dom, "//form//select[@name='content']//option"):
+        engine_traits.custom['content'].append(x.get("value"))
+
+    for x in eval_xpath_list(dom, "//form//select[@name='ext']//option"):
+        engine_traits.custom['ext'].append(x.get("value"))
+
+    for x in eval_xpath_list(dom, "//form//select[@name='sort']//option"):
+        engine_traits.custom['sort'].append(x.get("value"))