52 lines
1.7 KiB
Python
52 lines
1.7 KiB
Python
"""
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This object provides quoting for GEOS geometries into PostgreSQL/PostGIS.
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"""
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from __future__ import unicode_literals
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from psycopg2 import Binary
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from psycopg2.extensions import ISQLQuote
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class PostGISAdapter(object):
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def __init__(self, geom, geography=False):
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"Initializes on the geometry."
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# Getting the WKB (in string form, to allow easy pickling of
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# the adaptor) and the SRID from the geometry.
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self.ewkb = bytes(geom.ewkb)
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self.srid = geom.srid
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self.geography = geography
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self._adapter = Binary(self.ewkb)
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def __conform__(self, proto):
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# Does the given protocol conform to what Psycopg2 expects?
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if proto == ISQLQuote:
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return self
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else:
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raise Exception('Error implementing psycopg2 protocol. Is psycopg2 installed?')
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def __eq__(self, other):
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if not isinstance(other, PostGISAdapter):
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return False
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return (self.ewkb == other.ewkb) and (self.srid == other.srid)
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def __hash__(self):
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return hash((self.ewkb, self.srid))
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def __str__(self):
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return self.getquoted()
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def prepare(self, conn):
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"""
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This method allows escaping the binary in the style required by the
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server's `standard_conforming_string` setting.
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"""
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self._adapter.prepare(conn)
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def getquoted(self):
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"Returns a properly quoted string for use in PostgreSQL/PostGIS."
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# psycopg will figure out whether to use E'\\000' or '\000'
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return str('%s(%s)' % (
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'ST_GeogFromWKB' if self.geography else 'ST_GeomFromEWKB',
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self._adapter.getquoted().decode())
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)
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