django - GeoDjango 序列化 GeoJSON 跳过 'id' 字段

Question

我一直在使用 Geo-Django GeoJSON serializer这样我就可以从 PostGIS 数据库中检索一些对象并将它们显示在 OpenLayers map 上。

我正在通过以下方式获取要显示的对象:

gqs = self.model.objects.filter(point__distance_lte=(pnt, long(dist)))
type(gqs)
<class 'django.contrib.gis.db.models.query.GeoQuerySet'>

并且地理对象按预期包含所有模型字段:

self.model._meta.get_fields()
(<django.db.models.fields.AutoField: id>,
<django.db.models.fields.CharField: name>, 
<django.db.models.fields.SlugField: name_slug>, 
<django.db.models.fields.CharField: contact>, 
<django.db.models.fields.CharField: address>, 
<django.db.models.fields.CharField: postcode>, 
<django.db.models.fields.EmailField: email>, 
<django.db.models.fields.CharField: fax>, 
<django.db.models.fields.CharField: tel>, 
<django.db.models.fields.CharField: tel1>, 
<django.db.models.fields.CharField: tel_fax>, 
<django.db.models.fields.URLField: url>, 
<django.db.models.fields.CharField: wardlabel>, 
<django.db.models.fields.DecimalField: lon>, 
<django.db.models.fields.DecimalField: lat>, 
<django.db.models.fields.IntegerField: easting>, 
<django.db.models.fields.IntegerField: northing>, 
<django.db.models.fields.DateField: first_entered>, 
<django.db.models.fields.DateField: updated>, 
<django.contrib.gis.db.models.fields.PointField: point>)

包括id值...

(Pdb) gqs[0].id
5

然后我以最简单的方式将 GeoQuerySet 传递给 GeoJSON 序列化程序:

gqs_serialized = serialize('geojson', gqs)

并获得输出:

gqs_serialized
u'{"type": "FeatureCollection", 
  "crs": {
    "type": "name", 
    "properties": {"name": "EPSG:4326"}}, 
    "features": [
    {"geometry": {"type": "Point", "coordinates": [-0.19038, 51.490657]}, "type": "Feature", 
    "properties": {
      "tel1": null, 
      "fax": null, 
      "tel": null, 
      "name": "some club", 
      "url": null, 
      "wardlabel": "Redcliffe", 
      "lon": "-0.190380", 
      "updated": null, 
      "first_entered": "2013-12-01", 
      "contact": "some name", 
      "name_slug": "some club slug", 
      "postcode": "SW5 0JE", 
      "easting": 525732, 
      "address": "Some Address, London", 
      "lat": "51.490657", 
      "tel_fax": null, 
      "email": null, 
      "northing": 178409}},
     {"geometry": {"type": "Point", "coordinates": [-0.137183, 51.495597]}, "type": "Feature", 
    "properties": { etc...

除了模型中的“id”字段(AutoField)之外，所有内容都存在。我想将 id 值用作网页中的 div id 值，并且当我认为应该已经可用时，我真的不想创建另一个唯一 id(即组合 lon/lat 值)。

缺少的“id”字段发生了什么？

Answer 1

只要输出必须与 specs 兼容, stock 序列化器会忽略不支持的字段。但是，您可以制作自己的序列化程序:

# yourapp/geojson_serializer.py
from django.contrib.gis.serializers import Serializer as GeoJSONSerializer

class Serializer(GeoJSONSerializer):
    def get_dump_object(self, obj):
        data = super(Serializer, self).get_dump_object(obj)
        # Extend to your taste
        data.update(id=obj.pk)
        return data

在 settings.py 中启用新的序列化程序:

SERIALIZATION_MODULES = {
        "custom_geojson": "yourapp.geojson_serializer",
}

然后在你的代码中使用它:

from django.core import serializers
data = serializers.serialize('custom_geojson', some_model)