master trunk of gnowsys-studio

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()