app/django/contrib/gis/db/backend/postgis/adaptor.py
author Sverre Rabbelier <srabbelier@gmail.com>
Fri, 13 Feb 2009 19:22:34 +0000
changeset 1298 a04ab9bd300a
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
Fixes as requested by Leslie on behalf of the Legal team Upped the copyright statement from 2008 to 2009, and link to the GAE Terms of Service instead of any custom ToS. Patch by: Sverre Rabbelier

"""
 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)