python/lib/django_1_4/django/contrib/gis/management/commands/ogrinspect.py

   1 import os
   2 from optparse import make_option
   3 from django.contrib.gis import gdal
   4 from django.core.management.base import LabelCommand, CommandError
   5
   6 def layer_option(option, opt, value, parser):
   7     """
   8     Callback for `make_option` for the `ogrinspect` `layer_key`
   9     keyword option which may be an integer or a string.
  10     """
  11     try:
  12         dest = int(value)
  13     except ValueError:
  14         dest = value
  15     setattr(parser.values, option.dest, dest)
  16
  17 def list_option(option, opt, value, parser):
  18     """
  19     Callback for `make_option` for `ogrinspect` keywords that require
  20     a string list.  If the string is 'True'/'true' then the option
  21     value will be a boolean instead.
  22     """
  23     if value.lower() == 'true':
  24         dest = True
  25     else:
  26         dest = [s for s in value.split(',')]
  27     setattr(parser.values, option.dest, dest)
  28
  29 class Command(LabelCommand):
  30     help = ('Inspects the given OGR-compatible data source (e.g., a shapefile) and outputs\n'
  31             'a GeoDjango model with the given model name. For example:\n'
  32             ' ./manage.py ogrinspect zipcode.shp Zipcode')
  33     args = '[data_source] [model_name]'
  34
  35     option_list = LabelCommand.option_list + (
  36         make_option('--blank', dest='blank', type='string', action='callback',
  37                     callback=list_option, default=False,
  38                     help='Use a comma separated list of OGR field names to add '
  39                     'the `blank=True` option to the field definition.  Set with'
  40                     '`true` to apply to all applicable fields.'),
  41         make_option('--decimal', dest='decimal', type='string', action='callback',
  42                     callback=list_option, default=False,
  43                     help='Use a comma separated list of OGR float fields to '
  44                     'generate `DecimalField` instead of the default '
  45                     '`FloatField`. Set to `true` to apply to all OGR float fields.'),
  46         make_option('--geom-name', dest='geom_name', type='string', default='geom',
  47                     help='Specifies the model name for the Geometry Field '
  48                     '(defaults to `geom`)'),
  49         make_option('--layer', dest='layer_key', type='string', action='callback',
  50                     callback=layer_option, default=0,
  51                     help='The key for specifying which layer in the OGR data '
  52                     'source to use. Defaults to 0 (the first layer). May be '
  53                     'an integer or a string identifier for the layer.'),
  54         make_option('--multi-geom', action='store_true', dest='multi_geom', default=False,
  55                     help='Treat the geometry in the data source as a geometry collection.'),
  56         make_option('--name-field', dest='name_field',
  57                     help='Specifies a field name to return for the `__unicode__` function.'),
  58         make_option('--no-imports', action='store_false', dest='imports', default=True,
  59                     help='Do not include `from django.contrib.gis.db import models` '
  60                     'statement.'),
  61         make_option('--null', dest='null', type='string', action='callback',
  62                     callback=list_option, default=False,
  63                     help='Use a comma separated list of OGR field names to add '
  64                     'the `null=True` option to the field definition.  Set with'
  65                     '`true` to apply to all applicable fields.'),
  66         make_option('--srid', dest='srid',
  67                     help='The SRID to use for the Geometry Field.  If it can be '
  68                     'determined, the SRID of the data source is used.'),
  69         make_option('--mapping', action='store_true', dest='mapping',
  70                     help='Generate mapping dictionary for use with `LayerMapping`.')
  71         )
  72
  73     requires_model_validation = False
  74
  75     def handle(self, *args, **options):
  76         try:
  77             data_source, model_name = args
  78         except ValueError:
  79             raise CommandError('Invalid arguments, must provide: %s' % self.args)
  80
  81         if not gdal.HAS_GDAL:
  82             raise CommandError('GDAL is required to inspect geospatial data sources.')
  83
  84         # Removing options with `None` values.
  85         options = dict([(k, v) for k, v in options.items() if not v is None])
  86
  87         # Getting the OGR DataSource from the string parameter.
  88         try:
  89             ds = gdal.DataSource(data_source)
  90         except gdal.OGRException, msg:
  91             raise CommandError(msg)
  92
  93         # Whether the user wants to generate the LayerMapping dictionary as well.
  94         show_mapping = options.pop('mapping', False)
  95
  96         # Getting rid of settings that `_ogrinspect` doesn't like.
  97         verbosity = options.pop('verbosity', False)
  98         settings = options.pop('settings', False)
  99
 100         # Returning the output of ogrinspect with the given arguments
 101         # and options.
 102         from django.contrib.gis.utils.ogrinspect import _ogrinspect, mapping
 103         output = [s for s in _ogrinspect(ds, model_name, **options)]
 104         if show_mapping:
 105             # Constructing the keyword arguments for `mapping`, and
 106             # calling it on the data source.
 107             kwargs = {'geom_name' : options['geom_name'],
 108                       'layer_key' : options['layer_key'],
 109                       'multi_geom' : options['multi_geom'],
 110                       }
 111             mapping_dict = mapping(ds, **kwargs)
 112             # This extra legwork is so that the dictionary definition comes
 113             # out in the same order as the fields in the model definition.
 114             rev_mapping = dict([(v, k) for k, v in mapping_dict.items()])
 115             output.extend(['', '# Auto-generated `LayerMapping` dictionary for %s model' % model_name,
 116                            '%s_mapping = {' % model_name.lower()])
 117             output.extend(["    '%s' : '%s'," % (rev_mapping[ogr_fld], ogr_fld) for ogr_fld in ds[options['layer_key']].fields])
 118             output.extend(["    '%s' : '%s'," % (options['geom_name'], mapping_dict[options['geom_name']]), '}'])
 119         return '\n'.join(output) + '\n'