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Diffstat (limited to 'gstudio/search.py')
-rw-r--r-- | gstudio/search.py | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/gstudio/search.py b/gstudio/search.py new file mode 100644 index 0000000..adbb037 --- /dev/null +++ b/gstudio/search.py @@ -0,0 +1,181 @@ +# Copyright (c) 2011, 2012 Free Software Foundation + +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU Affero General Public License as +# published by the Free Software Foundation, either version 3 of the +# License, or (at your option) any later version. + +# This program 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 Affero General Public License for more details. + +# You should have received a copy of the GNU Affero General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + + +# This project incorporates work covered by the following copyright and permission notice: + +# Copyright (c) 2009, Julien Fache +# All rights reserved. + +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions +# are met: + +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in +# the documentation and/or other materials provided with the +# distribution. +# * Neither the name of the author nor the names of other +# contributors may be used to endorse or promote products derived +# from this software without specific prior written permission. + +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED +# OF THE POSSIBILITY OF SUCH DAMAGE. + +"""Search module with complex query parsing for Gstudio""" +from pyparsing import Word +from pyparsing import alphas +from pyparsing import WordEnd +from pyparsing import Combine +from pyparsing import opAssoc +from pyparsing import Optional +from pyparsing import OneOrMore +from pyparsing import StringEnd +from pyparsing import printables +from pyparsing import quotedString +from pyparsing import removeQuotes +from pyparsing import ParseResults +from pyparsing import CaselessLiteral +from pyparsing import operatorPrecedence + +from django.db.models import Q + +from gstudio.models import Nodetype +from gstudio.settings import STOP_WORDS + + +def createQ(token): + """Creates the Q() object""" + meta = getattr(token, 'meta', None) + query = getattr(token, 'query', '') + wildcards = None + + if isinstance(query, basestring): # Unicode -> Quoted string + search = query + else: # List -> No quoted string (possible wildcards) + if len(query) == 1: + search = query[0] + elif len(query) == 3: + wildcards = 'BOTH' + search = query[1] + elif len(query) == 2: + if query[0] == '*': + wildcards = 'START' + search = query[1] + else: + wildcards = 'END' + search = query[0] + + # Ignore connective words (of, a, an...) and STOP_WORDS + if (len(search) < 3 and not search.isdigit()) or \ + search in STOP_WORDS: + return Q() + + if not meta: + return Q(content__icontains=search) | \ + Q(excerpt__icontains=search) | \ + Q(title__icontains=search) + + if meta == 'metatype': + if wildcards == 'BOTH': + return Q(metatypes__title__icontains=search) | \ + Q(metatypes__slug__icontains=search) + elif wildcards == 'START': + return Q(metatypes__title__iendswith=search) | \ + Q(metatypes__slug__iendswith=search) + elif wildcards == 'END': + return Q(metatypes__title__istartswith=search) | \ + Q(metatypes__slug__istartswith=search) + else: + return Q(metatypes__title__iexact=search) | \ + Q(metatypes__slug__iexact=search) + elif meta == 'author': + if wildcards == 'BOTH': + return Q(authors__username__icontains=search) + elif wildcards == 'START': + return Q(authors__username__iendswith=search) + elif wildcards == 'END': + return Q(authors__username__istartswith=search) + else: + return Q(authors__username__iexact=search) + elif meta == 'tag': # TODO: tags ignore wildcards + return Q(tags__icontains=search) + + +def unionQ(token): + """Appends all the Q() objects""" + query = Q() + operation = 'and' + negation = False + + for t in token: + if type(t) is ParseResults: # See tokens recursively + query &= unionQ(t) + else: + if t in ('or', 'and'): # Set the new op and go to next token + operation = t + elif t == '-': # Next tokens needs to be negated + negation = True + else: # Append to query the token + if negation: + t = ~t + if operation == 'or': + query |= t + else: + query &= t + return query + + +NO_BRTS = printables.replace('(', '').replace(')', '') +SINGLE = Word(NO_BRTS.replace('*', '')) +WILDCARDS = Optional('*') + SINGLE + Optional('*') + WordEnd(wordChars=NO_BRTS) +QUOTED = quotedString.setParseAction(removeQuotes) + +OPER_AND = CaselessLiteral('and') +OPER_OR = CaselessLiteral('or') +OPER_NOT = '-' + +TERM = Combine(Optional(Word(alphas).setResultsName('meta') + ':') + + (QUOTED.setResultsName('query') | + WILDCARDS.setResultsName('query'))) +TERM.setParseAction(createQ) + +EXPRESSION = operatorPrecedence(TERM, [ + (OPER_NOT, 1, opAssoc.RIGHT), + (OPER_OR, 2, opAssoc.LEFT), + (Optional(OPER_AND, default='and'), 2, opAssoc.LEFT)]) +EXPRESSION.setParseAction(unionQ) + +QUERY = OneOrMore(EXPRESSION) + StringEnd() +QUERY.setParseAction(unionQ) + + +def advanced_search(pattern): + """Parse the grammar of a pattern + and build a queryset with it""" + query_parsed = QUERY.parseString(pattern) + return Nodetype.published.filter(query_parsed[0]).distinct() |