import argparse
from django.contrib.gis import gdal
from django.core.management.base import BaseCommand, CommandError
from django.utils.inspect import get_func_args
class LayerOptionAction(argparse.Action):
"""
Custom argparse action for the `ogrinspect` `layer_key` keyword option
which may be an integer or a string.
"""
def __call__(self, parser, namespace, value, option_string=None):
try:
setattr(namespace, self.dest, int(value))
except ValueError:
setattr(namespace, self.dest, value)
class ListOptionAction(argparse.Action):
"""
Custom argparse action for `ogrinspect` keywords that require
a string list. If the string is 'True'/'true' then the option
value will be a boolean instead.
"""
def __call__(self, parser, namespace, value, option_string=None):
if value.lower() == 'true':
setattr(namespace, self.dest, True)
else:
setattr(namespace, self.dest, value.split(','))
class Command(BaseCommand):
help = (
'Inspects the given OGR-compatible data source (e.g., a shapefile) and outputs\n'
'a GeoDjango model with the given model name. For example:\n'
' ./manage.py ogrinspect zipcode.shp Zipcode'
)
requires_system_checks = False
def add_arguments(self, parser):
parser.add_argument('data_source', help='Path to the data source.')
parser.add_argument('model_name', help='Name of the model to create.')
parser.add_argument(
'--blank',
action=ListOptionAction, default=False,
help='Use a comma separated list of OGR field names to add '
'the `blank=True` option to the field definition. Set to `true` '
'to apply to all applicable fields.',
)
parser.add_argument(
'--decimal',
action=ListOptionAction, default=False,
help='Use a comma separated list of OGR float fields to '
'generate `DecimalField` instead of the default '
'`FloatField`. Set to `true` to apply to all OGR float fields.',
)
parser.add_argument(
'--geom-name', default='geom',
help='Specifies the model name for the Geometry Field (defaults to `geom`)'
)
parser.add_argument(
'--layer', dest='layer_key',
action=LayerOptionAction, default=0,
help='The key for specifying which layer in the OGR data '
'source to use. Defaults to 0 (the first layer). May be '
'an integer or a string identifier for the layer.',
)
parser.add_argument(
'--multi-geom', action='store_true',
help='Treat the geometry in the data source as a geometry collection.',
)
parser.add_argument(
'--name-field',
help='Specifies a field name to return for the __str__() method.',
)
parser.add_argument(
'--no-imports', action='store_false', dest='imports',
help='Do not include `from django.contrib.gis.db import models` statement.',
)
parser.add_argument(
'--null', action=ListOptionAction, default=False,
help='Use a comma separated list of OGR field names to add '
'the `null=True` option to the field definition. Set to `true` '
'to apply to all applicable fields.',
)
parser.add_argument(
'--srid',
help='The SRID to use for the Geometry Field. If it can be '
'determined, the SRID of the data source is used.',
)
parser.add_argument(
'--mapping', action='store_true',
help='Generate mapping dictionary for use with `LayerMapping`.',
)
def handle(self, *args, **options):
data_source, model_name = options.pop('data_source'), options.pop('model_name')
# Getting the OGR DataSource from the string parameter.
try:
ds = gdal.DataSource(data_source)
except gdal.GDALException as msg:
raise CommandError(msg)
# Returning the output of ogrinspect with the given arguments
# and options.
from django.contrib.gis.utils.ogrinspect import _ogrinspect, mapping
# Filter options to params accepted by `_ogrinspect`
ogr_options = {k: v for k, v in options.items()
if k in get_func_args(_ogrinspect) and v is not None}
output = [s for s in _ogrinspect(ds, model_name, **ogr_options)]
if options['mapping']:
# Constructing the keyword arguments for `mapping`, and
# calling it on the data source.
kwargs = {
'geom_name': options['geom_name'],
'layer_key': options['layer_key'],
'multi_geom': options['multi_geom'],
}
mapping_dict = mapping(ds, **kwargs)
# This extra legwork is so that the dictionary definition comes
# out in the same order as the fields in the model definition.
rev_mapping = {v: k for k, v in mapping_dict.items()}
output.extend(['', '', '# Auto-generated `LayerMapping` dictionary for %s model' % model_name,
'%s_mapping = {' % model_name.lower()])
output.extend(" '%s': '%s'," % (
rev_mapping[ogr_fld], ogr_fld) for ogr_fld in ds[options['layer_key']].fields
)
output.extend([" '%s': '%s'," % (options['geom_name'], mapping_dict[options['geom_name']]), '}'])
return '\n'.join(output) + '\n'