1 files changed, 76 insertions, 0 deletions
diff --git a/searx/plugins/unit_converter.py b/searx/plugins/unit_converter.py
new file mode 100644
index 000000000..dd515aa72
--- /dev/null
+++ b/searx/plugins/unit_converter.py
@@ -0,0 +1,76 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Calculate mathematical expressions using ack#eval
+"""
+
+from flask_babel import gettext
+
+from searx.data import WIKIDATA_UNITS
+
+name = "Unit converter plugin"
+description = gettext("Convert between units")
+default_on = True
+
+CONVERT_KEYWORDS = ["in", "to", "as"]
+
+
+def _convert(from_value, source_si_factor, target_si_factor):
+    return from_value * source_si_factor / target_si_factor
+
+
+def _parse_text_and_convert(search, splitted_query):
+    if len(splitted_query) != 2 or splitted_query[0].strip() == "" or splitted_query[1].strip() == "":
+        return
+
+    from_value = ""
+    from_unit_key = ""
+
+    # only parse digits as value that belong together
+    read_alpha = False
+    for c in splitted_query[0]:
+        if not read_alpha and (c in ("-", ".") or str.isdigit(c)):
+            from_value += c
+            read_alpha = True
+        elif c != " ":
+            from_unit_key += c
+
+    to_unit_key = splitted_query[1].strip()
+
+    from_unit = None
+    to_unit = None
+
+    for unit in WIKIDATA_UNITS.values():
+        if unit['symbol'] == from_unit_key:
+            from_unit = unit
+
+        if unit['symbol'] == to_unit_key:
+            to_unit = unit
+
+        if from_unit and to_unit:
+            break
+
+    if from_unit is None or to_unit is None or to_unit.get('si_name') != from_unit.get('si_name'):
+        return
+
+    result = _convert(float(from_value), from_unit['to_si_factor'], to_unit['to_si_factor'])
+    search.result_container.answers['conversion'] = {'answer': f"{result:g} {to_unit['symbol']}"}
+
+
+def post_search(_request, search):
+    # only convert between units on the first page
+    if search.search_query.pageno > 1:
+        return True
+
+    query = search.search_query.query
+    query_parts = query.split(" ")
+
+    if len(query_parts) < 3:
+        return True
+
+    for query_part in query_parts:
+        for keyword in CONVERT_KEYWORDS:
+            if query_part == keyword:
+                keyword_split = query.split(keyword, 1)
+                _parse_text_and_convert(search, keyword_split)
+                return True
+
+    return True