+++ /dev/null
-from types import StringTypes
-import pgdb
-
-from sfa.util.faults import SfaInvalidArgument
-
-from sfa.storage.parameter import Parameter, Mixed, python_type
-
-class Filter(Parameter, dict):
- """
- A type of parameter that represents a filter on one or more
- columns of a database table.
- Special features provide support for negation, upper and lower bounds,
- as well as sorting and clipping.
-
-
- fields should be a dictionary of field names and types
- Only filters on non-sequence type fields are supported.
- example : fields = {'node_id': Parameter(int, "Node identifier"),
- 'hostname': Parameter(int, "Fully qualified hostname", max = 255),
- ...}
-
-
- filter should be a dictionary of field names and values
- representing the criteria for filtering.
- example : filter = { 'hostname' : '*.edu' , site_id : [34,54] }
- Whether the filter represents an intersection (AND) or a union (OR)
- of these criteria is determined by the join_with argument
- provided to the sql method below
-
- Special features:
-
- * a field starting with the ~ character means negation.
- example : filter = { '~peer_id' : None }
-
- * a field starting with < [ ] or > means lower than or greater than
- < > uses strict comparison
- [ ] is for using <= or >= instead
- example : filter = { ']event_id' : 2305 }
- example : filter = { '>time' : 1178531418 }
- in this example the integer value denotes a unix timestamp
-
- * if a value is a sequence type, then it should represent
- a list of possible values for that field
- example : filter = { 'node_id' : [12,34,56] }
-
- * a (string) value containing either a * or a % character is
- treated as a (sql) pattern; * are replaced with % that is the
- SQL wildcard character.
- example : filter = { 'hostname' : '*.jp' }
-
- * fields starting with - are special and relate to row selection, i.e. sorting and clipping
- * '-SORT' : a field name, or an ordered list of field names that are used for sorting
- these fields may start with + (default) or - for denoting increasing or decreasing order
- example : filter = { '-SORT' : [ '+node_id', '-hostname' ] }
- * '-OFFSET' : the number of first rows to be ommitted
- * '-LIMIT' : the amount of rows to be returned
- example : filter = { '-OFFSET' : 100, '-LIMIT':25}
-
- A realistic example would read
- GetNodes ( { 'node_type' : 'regular' , 'hostname' : '*.edu' , '-SORT' : 'hostname' , '-OFFSET' : 30 , '-LIMIT' : 25 } )
- and that would return regular (usual) nodes matching '*.edu' in alphabetical order from 31th to 55th
- """
-
- def __init__(self, fields = {}, filter = {}, doc = "Attribute filter"):
- # Store the filter in our dict instance
- valid_fields = {}
- for field in filter:
- if field in fields:
- valid_fields[field] = filter[field]
- dict.__init__(self, valid_fields)
-
- # Declare ourselves as a type of parameter that can take
- # either a value or a list of values for each of the specified
- # fields.
- self.fields = dict ( [ ( field, Mixed (expected, [expected]))
- for (field,expected) in fields.iteritems()
- if python_type(expected) not in (list, tuple, set) ] )
-
- # Null filter means no filter
- Parameter.__init__(self, self.fields, doc = doc, nullok = True)
-
- def quote(self, value):
- """
- Returns quoted version of the specified value.
- """
-
- # The pgdb._quote function is good enough for general SQL
- # quoting, except for array types.
- if isinstance(value, (list, tuple, set)):
- return "ARRAY[%s]" % ", ".join(map(self.quote, value))
- else:
- return pgdb._quote(value)
-
- def sql(self, join_with = "AND"):
- """
- Returns a SQL conditional that represents this filter.
- """
-
- # So that we always return something
- if join_with == "AND":
- conditionals = ["True"]
- elif join_with == "OR":
- conditionals = ["False"]
- else:
- assert join_with in ("AND", "OR")
-
- # init
- sorts = []
- clips = []
-
- for field, value in self.iteritems():
- # handle negation, numeric comparisons
- # simple, 1-depth only mechanism
-
- modifiers={'~' : False,
- '<' : False, '>' : False,
- '[' : False, ']' : False,
- '-' : False,
- }
-
- for char in modifiers.keys():
- if field[0] == char:
- modifiers[char]=True
- field = field[1:]
- break
-
- # filter on fields
- if not modifiers['-']:
- if field not in self.fields:
- raise SfaInvalidArgument, "Invalid filter field '%s'" % field
-
- if isinstance(value, (list, tuple, set)):
- # handling filters like '~slice_id':[]
- # this should return true, as it's the opposite of 'slice_id':[] which is false
- # prior to this fix, 'slice_id':[] would have returned ``slice_id IN (NULL) '' which is unknown
- # so it worked by coincidence, but the negation '~slice_ids':[] would return false too
- if not value:
- field=""
- operator=""
- value = "FALSE"
- else:
- operator = "IN"
- value = map(str, map(self.quote, value))
- value = "(%s)" % ", ".join(value)
- else:
- if value is None:
- operator = "IS"
- value = "NULL"
- elif isinstance(value, StringTypes) and \
- (value.find("*") > -1 or value.find("%") > -1):
- operator = "LIKE"
- # insert *** in pattern instead of either * or %
- # we dont use % as requests are likely to %-expansion later on
- # actual replacement to % done in PostgreSQL.py
- value = value.replace ('*','***')
- value = value.replace ('%','***')
- value = str(self.quote(value))
- else:
- operator = "="
- if modifiers['<']:
- operator='<'
- if modifiers['>']:
- operator='>'
- if modifiers['[']:
- operator='<='
- if modifiers[']']:
- operator='>='
- else:
- value = str(self.quote(value))
-
- clause = "%s %s %s" % (field, operator, value)
-
- if modifiers['~']:
- clause = " ( NOT %s ) " % (clause)
-
- conditionals.append(clause)
- # sorting and clipping
- else:
- if field not in ('SORT','OFFSET','LIMIT'):
- raise SfaInvalidArgument, "Invalid filter, unknown sort and clip field %r"%field
- # sorting
- if field == 'SORT':
- if not isinstance(value,(list,tuple,set)):
- value=[value]
- for field in value:
- order = 'ASC'
- if field[0] == '+':
- field = field[1:]
- elif field[0] == '-':
- field = field[1:]
- order = 'DESC'
- if field not in self.fields:
- raise SfaInvalidArgument, "Invalid field %r in SORT filter"%field
- sorts.append("%s %s"%(field,order))
- # clipping
- elif field == 'OFFSET':
- clips.append("OFFSET %d"%value)
- # clipping continued
- elif field == 'LIMIT' :
- clips.append("LIMIT %d"%value)
-
- where_part = (" %s " % join_with).join(conditionals)
- clip_part = ""
- if sorts:
- clip_part += " ORDER BY " + ",".join(sorts)
- if clips:
- clip_part += " " + " ".join(clips)
- return (where_part,clip_part)
git://git.onelab.eu / sfa.git / commitdiff