134 lines
4.2 KiB
Python
134 lines
4.2 KiB
Python
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from functools import wraps
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from django.core.exceptions import FieldError
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from django.db import models, backends
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from django.db import connection
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from MySQLdb import OperationalError
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from MySQLdb.constants.ER import FT_MATCHING_KEY_NOT_FOUND
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def _get_indices(model):
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""" Return all of the FULLTEXT indices available for a given
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Django model."""
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cursor = connection.cursor()
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cursor.execute('show index from %s where index_type = "FULLTEXT"' %
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connection.ops.quote_name(model._meta.db_table))
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found = {}
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item = cursor.fetchone()
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while item:
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if not item:
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break
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(model_name, key_name, column_name) = (item[0], item[2], item[4])
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if not found.has_key(key_name):
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found[key_name] = []
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found[key_name].append(column_name)
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item = cursor.fetchone()
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return found.values()
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def _handle_oper(f):
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""" Specialized wrapper for methods of SearchQuerySet that will
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inform the user of what indices are available, should the user
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specify a list of fields on which to search."""
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def wrapper(self, *args, **kwargs):
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try:
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return f(self, *args, **kwargs)
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except OperationalError, e:
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if e.args[0] != FT_MATCHING_KEY_NOT_FOUND:
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raise
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idc = _get_indices(self.model)
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message = "No FULLTEXT indices found for this table."
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if len(idc) > 0:
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message = ("Index not found. Indices available include: %s" %
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str(tuple(idc)))
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raise FieldError, message
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return wraps(f)(wrapper)
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class SearchQuerySet(models.query.QuerySet):
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""" A QuerySet with a new method, search, and wrappers around the
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most common operations performed on a query set."""
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def __init__(self, model = None, query = None, using = None,
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aggregate_field_name = 'relevance'):
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super(SearchQuerySet, self).__init__(model, query, using)
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self._aggregate_field_name = aggregate_field_name
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def search(self, query, fields):
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meta = self.model._meta
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if not fields:
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found = _get_indices(self.model)
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if len(found) != 1:
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raise FieldError, "More than one index found for this table."
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fields = found[0]
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columns = [meta.get_field(name, many_to_many=False).column
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for name in fields]
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full_names = ["%s.%s" % (connection.ops.quote_name(meta.db_table),
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connection.ops.quote_name(column))
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for column in columns]
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match_expr = "MATCH(%s) AGAINST (%%s)" % (", ".join(full_names))
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return self.extra(select={self._aggregate_field_name: match_expr},
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where=[match_expr],
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params=[query],
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select_params = [query])
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# Python Magic Methods wrapped to provide useful information on exception.
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def __repr__(self):
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return super(SearchQuerySet, self).__repr__()
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__repr__ = _handle_oper(__repr__)
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def __len__(self):
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return super(SearchQuerySet, self).__len__()
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__len__ = _handle_oper(__len__)
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def __iter__(self):
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return super(SearchQuerySet, self).__iter__()
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__iter__ = _handle_oper(__iter__)
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def _result_iter(self):
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return super(SearchQuerySet, self)._result_iter()
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_result_iter = _handle_oper(_result_iter)
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def __nonzero__(self):
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return super(SearchQuerySet, self).__nonzero__()
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__nonzero__ = _handle_oper(__nonzero__)
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def __getitem__(self, k):
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return super(SearchQuerySet, self).__getitem__(k)
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__getitem__ = _handle_oper(__getitem__)
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# This is a private method of QuerySet. It's not guaranteed to even exist
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# after Django 1.2
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def _fill_cache(self, *args, **kwargs):
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return super(SearchQuerySet, self)._fill_cache(*args, **kwargs)
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_fill_cache = _handle_oper(_fill_cache)
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class SearchManager(models.Manager):
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def get_query_set(self, fields = []):
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return SearchQuerySet(self.model)
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def search(self, query, fields = []):
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return self.get_query_set().search(query, fields)
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