app/django/contrib/gis/db/backend/postgis/adaptor.py
author Lennard de Rijk <ljvderijk@gmail.com>
Mon, 30 Mar 2009 21:16:18 +0000
changeset 2034 59de158c936d
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Fixed the duplicate slots view. The script would not clear the screen upon recalculation also the list of duplicates would increase with every iteration because the variables weren't properly reset. Patch by: Merio Ferraro, Lennard de Rijk Reviewed by: to-be-reviewed

"""
 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)