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R3600/modules/websearch/lib/services/MathCalculatorService.py
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MathCalculatorService.py
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# -*- coding: utf-8 -*-
##
## This file is part of Invenio.
## Copyright (C) 2012 CERN.
##
## Invenio is free software; you can redistribute it and/or
## modify it under the terms of the GNU General Public License as
## published by the Free Software Foundation; either version 2 of the
## License, or (at your option) any later version.
##
## Invenio is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Invenio; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
"""
WebSearch service to do some basic math
"""
import re
import cgi
from invenio.config import CFG_SITE_LANG
from invenio.websearch_services import SearchService
numerics_and_operators_re = re.compile('[^\s\d\+\-\*/\.\(\)]')
integers_re = re.compile('([^\.\d]*|^)(\d*(\.)?\d*)([^\.\d]*|$)')
__plugin_version__ = "Search Service Plugin API 1.0"
class MathCalculatorService(SearchService):
"""
Do basic math
"""
def get_description(self, ln=CFG_SITE_LANG):
"Return service description"
return "Return evaluated math expression"
def answer(self, req, user_info, of, cc, colls_to_search, p, f, search_units, ln):
"""
Answer question given by context.
Return (relevance, html_string) where relevance is integer
from 0 to 100 indicating how relevant to the question the
answer is (see C{CFG_WEBSEARCH_SERVICE_MAX_SERVICE_ANSWER_RELEVANCE} for details) ,
and html_string being a formatted answer.
"""
if not p.strip():
return (0, '')
expression = numerics_and_operators_re.sub("", p)
if expression == p:
# That is safe expression
def make_float(matchobj):
prefix = matchobj.group(1) or ''
suffix = matchobj.group(4) or ''
middle = matchobj.group(2) or ''
if middle and not '.' in middle:
middle += '.0'
return prefix + middle + suffix
expression = integers_re.sub(make_float, expression)
try:
result = eval(expression)
if result.is_integer():
result = int(result)
return (100, '<strong>' + cgi.escape(p.strip()) + ' = ' + \
cgi.escape(str(result)) + \
'</strong>')
except Exception, e:
return (0, '')
else:
return (0, '')
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