[mod] addition of various type hints / engine processors

Continuation of #5147 .. typification of the engine processors.

BTW:

- removed obsolete engine property https_support
- fixed & improved currency_convert
- engine instances can now implement a engine.setup method

[#5147] https://github.com/searxng/searxng/pull/5147

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

searx/engines/currency_convert.py

@@ -1,53 +1,58 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
-"""Currency convert (DuckDuckGo)
-"""
+"""Currency convert (DuckDuckGo)"""
 
+import typing as t
 import json
 from searx.result_types import EngineResults
 
+if t.TYPE_CHECKING:
+    from searx.search.processors import OnlineCurrenciesParams
+    from searx.extended_types import SXNG_Response
+
 # about
 about = {
-    "website": 'https://duckduckgo.com/',
-    "wikidata_id": 'Q12805',
-    "official_api_documentation": 'https://duckduckgo.com/api',
+    "website": "https://duckduckgo.com/",
+    "wikidata_id": "Q12805",
+    "official_api_documentation": "https://duckduckgo.com/api",
     "use_official_api": False,
     "require_api_key": False,
-    "results": 'JSONP',
+    "results": "JSONP",
     "description": "Service from DuckDuckGo.",
 }
 
-engine_type = 'online_currency'
-categories = []
-base_url = 'https://duckduckgo.com/js/spice/currency/1/{0}/{1}'
+engine_type = "online_currency"
+categories = ["currency", "general"]
+
+base_url = "https://duckduckgo.com/js/spice/currency/1/%(from_iso4217)s/%(to_iso4217)s"
+ddg_link_url = "https://duckduckgo.com/?q=%(from_iso4217)s+to+%(to_iso4217)s"
+
 weight = 100
 
-https_support = True
+
+def request(query: str, params: "OnlineCurrenciesParams") -> None:  # pylint: disable=unused-argument
+    params["url"] = base_url % params
 
 
-def request(_query, params):
-    params['url'] = base_url.format(params['from'], params['to'])
-    return params
-
-
-def response(resp) -> EngineResults:
+def response(resp: "SXNG_Response") -> EngineResults:
     res = EngineResults()
 
     # remove first and last lines to get only json
-    json_resp = resp.text[resp.text.find('\n') + 1 : resp.text.rfind('\n') - 2]
+    json_resp = resp.text[resp.text.find("\n") + 1 : resp.text.rfind("\n") - 2]
     try:
         conversion_rate = float(json.loads(json_resp)["to"][0]["mid"])
     except IndexError:
         return res
-    answer = '{0} {1} = {2} {3}, 1 {1} ({5}) = {4} {3} ({6})'.format(
-        resp.search_params['amount'],
-        resp.search_params['from'],
-        resp.search_params['amount'] * conversion_rate,
-        resp.search_params['to'],
-        conversion_rate,
-        resp.search_params['from_name'],
-        resp.search_params['to_name'],
-    )
 
-    url = f"https://duckduckgo.com/?q={resp.search_params['from']}+to+{resp.search_params['to']}"
+    params: OnlineCurrenciesParams = resp.search_params  # pyright: ignore[reportAssignmentType]
+    answer = "{0} {1} = {2} {3} (1 {5} : {4} {6})".format(
+        params["amount"],
+        params["from_iso4217"],
+        params["amount"] * conversion_rate,
+        params["to_iso4217"],
+        conversion_rate,
+        params["from_name"],
+        params["to_name"],
+    )
+    url = ddg_link_url % params
     res.add(res.types.Answer(answer=answer, url=url))
     return res