[mod] ADS engine: revision of the engine (Paper result)

Revision of the Astrophysics Data System (ADS) engine / use of the result type
Paper as well as other typifications.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

docs/dev/engines/online/astrophysics_data_system.rst

@@ -0,0 +1,8 @@
+.. _astrophysics_data_system engine:
+
+==============================
+Astrophysics Data System (ADS)
+==============================
+
+.. automodule:: searx.engines.astrophysics_data_system
+   :members:

searx/engines/astrophysics_data_system.py

@@ -1,93 +1,163 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
-""".. sidebar:: info
+"""The Astrophysics Data System (ADS_) is a digital library portal for
+researchers in astronomy and physics, operated by the Smithsonian Astrophysical
+Observatory (SAO) under a NASA grant.  The ADS_ is a solr instance, but not with
+the standard API paths.
 
-The Astrophysics Data System (ADS) is a digital library portal for researchers in astronomy and physics,
-operated by the Smithsonian Astrophysical Observatory (SAO) under a NASA grant.
-The engine is adapted from the solr engine.
+.. note::
 
+   The ADS_ engine requires an :py:obj:`API key <api_key>`.
+
+This engine uses the `search/query`_ API endpoint.  Since the user's search term
+is passed through, the `search syntax`_ of ADS can be used (at least to some
+extent).
+
+.. _ADS: https://ui.adsabs.harvard.edu
+.. _search/query: https://ui.adsabs.harvard.edu/help/api/api-docs.html#get-/search/query
+.. _search syntax: https://ui.adsabs.harvard.edu/help/search/search-syntax
+
+
+Configuration
+=============
+
+The engine has the following additional settings:
+
+- :py:obj:`api_key`
+- :py:obj:`ads_sort`
+
+.. code:: yaml
+
+  - name: astrophysics data system
+    api_key: "..."
+    inactive: false
+
+
+Implementations
+===============
 """
 
-# pylint: disable=global-statement
+import typing as t
 
 from datetime import datetime
-from json import loads
 from urllib.parse import urlencode
+
+from searx.utils import html_to_text
 from searx.exceptions import SearxEngineAPIException
+from searx.result_types import EngineResults
+
+if t.TYPE_CHECKING:
+    from searx.extended_types import SXNG_Response
+    from searx.search.processors import OnlineParams
 
 about = {
-    "website": 'https://ui.adsabs.harvard.edu/',
-    "wikidata_id": 'Q752099',
-    "official_api_documentation": 'https://ui.adsabs.harvard.edu/help/api/api-docs.html',
+    "website": "https://ui.adsabs.harvard.edu/",
+    "wikidata_id": "Q752099",
+    "official_api_documentation": "https://ui.adsabs.harvard.edu/help/api/api-docs.html",
     "use_official_api": True,
     "require_api_key": True,
-    "results": 'JSON',
+    "results": "JSON",
 }
 
-base_url = 'https://api.adsabs.harvard.edu/v1/search'
-result_base_url = 'https://ui.adsabs.harvard.edu/abs/'
-rows = 10
-sort = ''  # sorting: asc or desc
-field_list = ['bibcode', 'author', 'title', 'abstract', 'doi', 'date']  # list of field names to display on the UI
-default_fields = ''  # default field to query
-query_fields = ''  # query fields
+categories = ["science", "scientific publications"]
 paging = True
-api_key = 'unset'
+base_url = "https://api.adsabs.harvard.edu/v1/search/query"
+
+api_key = "unset"
+"""Get an API token as described in https://ui.adsabs.harvard.edu/help/api"""
+
+ads_field_list = [
+    "abstract",
+    "author",
+    "bibcode",
+    "comment",
+    "date",
+    "doi",
+    "isbn",
+    "issn",
+    "keyword",
+    "page",
+    "page_count",
+    "page_range",
+    "pub",
+    "pubdate",
+    "pubnote",
+    "read_count",
+    "title",
+    "volume",
+    "year",
+]
+"""Set of fields to return in the response from ADS."""
+
+ads_rows = 10
+"""How many records to return for the ADS request."""
+
+ads_sort = "read_count desc"
+"""The format is 'field' + 'direction' where direction is one of 'asc' or 'desc'
+and field is any of the valid indexes."""
 
 
-def init(_):
-    if api_key == 'unset':
-        raise SearxEngineAPIException('missing ADS API key')
+def setup(engine_settings: dict[str, t.Any]) -> bool:
+    """Initialization of the ADS_ engine, checks whether the :py:obj:`api_key`
+    is set, otherwise the engine is inactive.
+    """
+    key: str = engine_settings.get("api_key", "")
+    if key and key not in ("unset", "unknown", "..."):
+        return True
+    logger.error("Astrophysics Data System (ADS) API key is not set or invalid.")
+    return False
 
 
-def request(query, params):
-    query_params = {'q': query, 'rows': rows}
-    if field_list:
-        query_params['fl'] = ','.join(field_list)
-    if query_fields:
-        query_params['qf'] = ','.join(query_fields)
-    if default_fields:
-        query_params['df'] = default_fields
-    if sort:
-        query_params['sort'] = sort
+def request(query: str, params: "OnlineParams") -> None:
 
-    query_params['start'] = rows * (params['pageno'] - 1)
+    args: dict[str, str | int] = {
+        "q": query,
+        "fl": ",".join(ads_field_list),
+        "rows": ads_rows,
+        "start": ads_rows * (params["pageno"] - 1),
+    }
+    if ads_sort:
+        args["sort"] = ads_sort
 
-    params['headers']['Authorization'] = f'Bearer {api_key}'
-    params['url'] = f"{base_url}/query?{urlencode(query_params)}"
-
-    return params
+    params["headers"]["Authorization"] = f"Bearer {api_key}"
+    params["url"] = f"{base_url}?{urlencode(args)}"
 
 
-def response(resp):
-    try:
-        resp_json = loads(resp.text)
-    except Exception as e:
-        raise SearxEngineAPIException("failed to parse response") from e
+def response(resp: "SXNG_Response") -> EngineResults:
 
-    if 'error' in resp_json:
-        raise SearxEngineAPIException(resp_json['error']['msg'])
+    res = EngineResults()
+    json_data: dict[str, dict[str, t.Any]] = resp.json()
 
-    resp_json = resp_json["response"]
-    result_len = resp_json["numFound"]
-    results = []
+    if "error" in json_data:
+        raise SearxEngineAPIException(json_data["error"]["msg"])
 
-    for res in resp_json["docs"]:
-        author = res.get("author")
+    def _str(k: str) -> str:
+        return str(doc.get(k, ""))
 
-        if author:
-            author = author[0] + ' et al.'
+    def _list(k: str) -> list[str]:
+        return doc.get(k, [])
 
-        results.append(
-            {
-                'url': result_base_url + res.get("bibcode") + "/",
-                'title': res.get("title")[0],
-                'author': author,
-                'content': res.get("abstract"),
-                'doi': res.get("doi"),
-                'publishedDate': datetime.fromisoformat(res.get("date")),
-            }
+    for doc in json_data["response"]["docs"]:
+        authors: list[str] = doc["author"]
+        if len(authors) > 15:
+            # There are articles with hundreds of authors
+            authors = authors[:15] + ["et al."]
+
+        paper = res.types.Paper(
+            url=f"https://ui.adsabs.harvard.edu/abs/{doc.get('bibcode')}/",
+            title=html_to_text(_list("title")[0]),
+            authors=authors,
+            content=html_to_text(_str("abstract")),
+            doi=_list("doi")[0],
+            issn=_list("issn"),
+            isbn=_list("isbn"),
+            tags=_list("keyword"),
+            pages=",".join(_list("page")),
+            publisher=_str("pub") + " " + _str("year"),
+            publishedDate=datetime.fromisoformat(_str("date")),
+            volume=_str("volume"),
+            views=_str("read_count"),
+            comments=" / ".join(_list("pubnote")),
         )
+        res.add(paper)
 
-    results.append({'number_of_results': result_len})
-
-    return results
+    return res

searx/settings.yml

@@ -407,13 +407,12 @@ engines:
       require_api_key: false
       results: JSON
 
-  # - name: astrophysics data system
-  #   engine: astrophysics_data_system
-  #   sort: asc
-  #   weight: 5
-  #   categories: [science]
-  #   api_key: your-new-key
-  #   shortcut: ads
+  - name: astrophysics data system
+    engine: astrophysics_data_system
+    shortcut: ads
+    # read https://docs.searxng.org/dev/engines/online/astrophysics_data_system.html
+    api_key: ""
+    inactive: true
 
   - name: alpine linux packages
     engine: alpinelinux