Adds to Melange a tags framework based on taggable-mixin.
The taggable-mixin allowed only tag per Datastore model. This is extended
framework allows any arbitrary number of tags per Datastore model. Also,
now one can define different models for different Tag types which are all
inherited from the base Tag model provided by taggable-mixin.
The GHOPTask model makes use of 2 tags per model, one for difficulty and the
other for task_type, both using the tags framework.
Reviewed by: Paweł Sołyga
"""
This object provides quoting for GEOS geometries into PostgreSQL/PostGIS.
"""
from django.contrib.gis.db.backend.postgis.query import GEOM_FROM_WKB
from psycopg2 import Binary
from psycopg2.extensions import ISQLQuote
class PostGISAdaptor(object):
def __init__(self, geom):
"Initializes on the geometry."
# Getting the WKB (in string form, to allow easy pickling of
# the adaptor) and the SRID from the geometry.
self.wkb = str(geom.wkb)
self.srid = geom.srid
def __conform__(self, proto):
# Does the given protocol conform to what Psycopg2 expects?
if proto == ISQLQuote:
return self
else:
raise Exception('Error implementing psycopg2 protocol. Is psycopg2 installed?')
def __eq__(self, other):
return (self.wkb == other.wkb) and (self.srid == other.srid)
def __str__(self):
return self.getquoted()
def getquoted(self):
"Returns a properly quoted string for use in PostgreSQL/PostGIS."
# Want to use WKB, so wrap with psycopg2 Binary() to quote properly.
return "%s(%s, %s)" % (GEOM_FROM_WKB, Binary(self.wkb), self.srid or -1)