85 lines
2.5 KiB
Python
85 lines
2.5 KiB
Python
from logging import getLogger
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from sqlalchemy import types, Column, Table
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from geoalchemy import Geometry, GeometryColumn, GeometryDDL, GeometryExtensionColumn
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from geoalchemy.postgis import PGComparator
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from ckan.lib.base import config
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from ckan import model
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from ckan.model import Session
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from ckan.model import meta
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from ckan.model.domain_object import DomainObject
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log = getLogger(__name__)
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package_extent_table = None
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DEFAULT_SRID = 4326 #(WGS 84)
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def setup(srid=None):
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if package_extent_table is None:
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define_spatial_tables(srid)
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log.debug('Spatial tables defined in memory')
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if model.repo.are_tables_created():
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if not Table('geometry_columns',meta.metadata).exists() or \
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not Table('spatial_ref_sys',meta.metadata).exists():
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raise Exception('The spatial extension is enabled, but PostGIS ' + \
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'has not been set up in the database. ' + \
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'Please refer to the "Setting up PostGIS" section in the README.')
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if not package_extent_table.exists():
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try:
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package_extent_table.create()
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except Exception,e:
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# Make sure the table does not remain incorrectly created
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# (eg without geom column or constraints)
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if package_extent_table.exists():
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Session.execute('DROP TABLE package_extent')
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Session.commit()
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raise e
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log.debug('Spatial tables created')
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else:
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log.debug('Spatial tables already exist')
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# Future migrations go here
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else:
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log.debug('Spatial tables creation deferred')
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class PackageExtent(DomainObject):
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def __init__(self, package_id=None, the_geom=None):
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self.package_id = package_id
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self.the_geom = the_geom
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def define_spatial_tables(db_srid=None):
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global package_extent_table
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if not db_srid:
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db_srid = int(config.get('ckan.spatial.srid', DEFAULT_SRID))
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else:
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db_srid = int(db_srid)
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package_extent_table = Table('package_extent', meta.metadata,
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Column('package_id', types.UnicodeText, primary_key=True),
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GeometryExtensionColumn('the_geom', Geometry(2,srid=db_srid)))
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meta.mapper(PackageExtent, package_extent_table, properties={
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'the_geom': GeometryColumn(package_extent_table.c.the_geom,
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comparator=PGComparator)})
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# enable the DDL extension
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GeometryDDL(package_extent_table)
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