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1 from django import forms |
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2 from django.contrib.gis.db.backend import SpatialBackend |
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3 from django.utils.translation import ugettext_lazy as _ |
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4 |
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5 class GeometryField(forms.Field): |
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6 """ |
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7 This is the basic form field for a Geometry. Any textual input that is |
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8 accepted by SpatialBackend.Geometry is accepted by this form. By default, |
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9 this is GEOSGeometry, which accepts WKT, HEXEWKB, WKB, and GeoJSON. |
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10 """ |
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11 widget = forms.Textarea |
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12 |
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13 default_error_messages = { |
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14 'no_geom' : _(u'No geometry value provided.'), |
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15 'invalid_geom' : _(u'Invalid geometry value.'), |
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16 'invalid_geom_type' : _(u'Invalid geometry type.'), |
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17 } |
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18 |
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19 def __init__(self, **kwargs): |
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20 self.null = kwargs.pop('null') |
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21 self.geom_type = kwargs.pop('geom_type') |
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22 super(GeometryField, self).__init__(**kwargs) |
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23 |
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24 def clean(self, value): |
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25 """ |
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26 Validates that the input value can be converted to a Geometry |
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27 object (which is returned). A ValidationError is raised if |
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28 the value cannot be instantiated as a Geometry. |
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29 """ |
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30 if not value: |
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31 if self.null: |
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32 # The geometry column allows NULL, return None. |
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33 return None |
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34 else: |
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35 raise forms.ValidationError(self.error_messages['no_geom']) |
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36 |
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37 try: |
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38 # Trying to create a Geometry object from the form value. |
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39 geom = SpatialBackend.Geometry(value) |
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40 except: |
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41 raise forms.ValidationError(self.error_messages['invalid_geom']) |
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42 |
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43 # Ensuring that the geometry is of the correct type (indicated |
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44 # using the OGC string label). |
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45 if str(geom.geom_type).upper() != self.geom_type and not self.geom_type == 'GEOMETRY': |
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46 raise forms.ValidationError(self.error_messages['invalid_geom_type']) |
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47 |
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48 return geom |