first commit

searx/plugins/unit_converter.py

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+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""A plugin for converting measured values from one unit to another unit (a
+unit converter).
+
+The plugin looks up the symbols (given in the query term) in a list of
+converters, each converter is one item in the list (compare
+:py:obj:`ADDITIONAL_UNITS`).  If the symbols are ambiguous, the matching units
+of measurement are evaluated.  The weighting in the evaluation results from the
+sorting of the :py:obj:`list of unit converters<symbol_to_si>`.
+"""
+from __future__ import annotations
+import typing
+import re
+import babel.numbers
+
+from flask_babel import gettext, get_locale
+
+from searx.wikidata_units import symbol_to_si
+from searx.plugins import Plugin, PluginInfo
+from searx.result_types import EngineResults
+
+if typing.TYPE_CHECKING:
+    from searx.search import SearchWithPlugins
+    from searx.extended_types import SXNG_Request
+    from searx.plugins import PluginCfg
+
+
+name = ""
+description = gettext("")
+
+plugin_id = ""
+preference_section = ""
+
+CONVERT_KEYWORDS = ["in", "to", "as"]
+
+
+class SXNGPlugin(Plugin):
+    """Convert between units.  The result is displayed in area for the
+    "answers".
+    """
+
+    id = "unit_converter"
+
+    def __init__(self, plg_cfg: "PluginCfg") -> None:
+        super().__init__(plg_cfg)
+
+        self.info = PluginInfo(
+            id=self.id,
+            name=gettext("Unit converter plugin"),
+            description=gettext("Convert between units"),
+            preference_section="general",
+        )
+
+    def post_search(self, request: "SXNG_Request", search: "SearchWithPlugins") -> EngineResults:
+        results = EngineResults()
+
+        # only convert between units on the first page
+        if search.search_query.pageno > 1:
+            return results
+
+        query = search.search_query.query
+        query_parts = query.split(" ")
+
+        if len(query_parts) < 3:
+            return results
+
+        for query_part in query_parts:
+            for keyword in CONVERT_KEYWORDS:
+                if query_part == keyword:
+                    from_query, to_query = query.split(keyword, 1)
+                    target_val = _parse_text_and_convert(from_query.strip(), to_query.strip())
+                    if target_val:
+                        results.add(results.types.Answer(answer=target_val))
+
+        return results
+
+
+# inspired from https://stackoverflow.com/a/42475086
+RE_MEASURE = r'''
+(?P<sign>[-+]?)         # +/- or nothing for positive
+(\s*)                   # separator: white space or nothing
+(?P<number>[\d\.,]*)    # number: 1,000.00 (en) or 1.000,00 (de)
+(?P<E>[eE][-+]?\d+)?    # scientific notation: e(+/-)2 (*10^2)
+(\s*)                   # separator: white space or nothing
+(?P<unit>\S+)           # unit of measure
+'''
+
+
+def _parse_text_and_convert(from_query, to_query) -> str | None:
+
+    # pylint: disable=too-many-branches, too-many-locals
+
+    if not (from_query and to_query):
+        return None
+
+    measured = re.match(RE_MEASURE, from_query, re.VERBOSE)
+    if not (measured and measured.group('number'), measured.group('unit')):
+        return None
+
+    # Symbols are not unique, if there are several hits for the from-unit, then
+    # the correct one must be determined by comparing it with the to-unit
+    # https://github.com/searxng/searxng/pull/3378#issuecomment-2080974863
+
+    # first: collecting possible units
+
+    source_list, target_list = [], []
+
+    for symbol, si_name, from_si, to_si, orig_symbol in symbol_to_si():
+
+        if symbol == measured.group('unit'):
+            source_list.append((si_name, to_si))
+        if symbol == to_query:
+            target_list.append((si_name, from_si, orig_symbol))
+
+    if not (source_list and target_list):
+        return None
+
+    source_to_si = target_from_si = target_symbol = None
+
+    # second: find the right unit by comparing list of from-units with list of to-units
+
+    for source in source_list:
+        for target in target_list:
+            if source[0] == target[0]:  # compare si_name
+                source_to_si = source[1]
+                target_from_si = target[1]
+                target_symbol = target[2]
+
+    if not (source_to_si and target_from_si):
+        return None
+
+    _locale = get_locale() or 'en_US'
+
+    value = measured.group('sign') + measured.group('number') + (measured.group('E') or '')
+    value = babel.numbers.parse_decimal(value, locale=_locale)
+
+    # convert value to SI unit
+
+    if isinstance(source_to_si, (float, int)):
+        value = float(value) * source_to_si
+    else:
+        value = source_to_si(float(value))
+
+    # convert value from SI unit to target unit
+
+    if isinstance(target_from_si, (float, int)):
+        value = float(value) * target_from_si
+    else:
+        value = target_from_si(float(value))
+
+    if measured.group('E'):
+        # when incoming notation is scientific, outgoing notation is scientific
+        result = babel.numbers.format_scientific(value, locale=_locale)
+    else:
+        result = babel.numbers.format_decimal(value, locale=_locale, format='#,##0.##########;-#')
+
+    return f'{result} {target_symbol}'