1 """

     2  This object provides quoting for GEOS geometries into PostgreSQL/PostGIS.

     3 """

     4 

     5 from django.contrib.gis.db.backend.postgis.query import GEOM_FROM_WKB

     6 from psycopg2 import Binary

     7 from psycopg2.extensions import ISQLQuote

     8 

     9 class PostGISAdaptor(object):

    10     def __init__(self, geom):

    11         "Initializes on the geometry."

    12         # Getting the WKB (in string form, to allow easy pickling of

    13         # the adaptor) and the SRID from the geometry.

    14         self.wkb = str(geom.wkb)

    15         self.srid = geom.srid

    16 

    17     def __conform__(self, proto):

    18         # Does the given protocol conform to what Psycopg2 expects?

    19         if proto == ISQLQuote:

    20             return self

    21         else:

    22             raise Exception('Error implementing psycopg2 protocol. Is psycopg2 installed?')

    23 

    24     def __eq__(self, other):

    25         return (self.wkb == other.wkb) and (self.srid == other.srid)

    26 

    27     def __str__(self):

    28         return self.getquoted()

    29 

    30     def getquoted(self):

    31         "Returns a properly quoted string for use in PostgreSQL/PostGIS."

    32         # Want to use WKB, so wrap with psycopg2 Binary() to quote properly.

    33         return "%s(%s, %s)" % (GEOM_FROM_WKB, Binary(self.wkb), self.srid or -1)