GeoDjango序列化GeoJSON跳过'id'字段 [英] GeoDjango serialize GeoJSON skipping 'id' field

问题描述

我一直在使用Geo-Django GeoJSON serializer ，以便我可以从PostGIS数据库检索一些对象并将其显示在OpenLayers地图上。

I've been using the Geo-Django GeoJSON serializer so that I can retrieve some objects from a PostGIS database and display them on an OpenLayers map.

我正在获取在以下方式：

I'm obtaining the objects for display in the following way:

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

，地理对象包括所有模型字段如下：

and the Geo-Objects include all the model fields as expected:

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>)

包含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：

I then pass the GeoQuerySet to the GeoJSON serializer in the simplest possible way:

gqs_serialized = serialize('geojson', gqs)

并获取输出：

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...

一切都存在，但'id'字段（AutoField）从模型。我想在网页中使用id值作为div id值，而当我认为应该已经可以使用时，我真的不希望创建另一个唯一的id（即组合lon / lat值）。

Everything is present but the 'id' field (AutoField) from the model. I want to use the id values as div id values in a webpage and I don't really want to have to create another unique id (ie. combining lon/lat values) when I think one should already be available.

失踪的id字段发生了什么？

What happened to the missing 'id' field?

推荐答案

输出必须与规格兼容，库存序列化程序将忽略不受支持的字段。但是，您可以制作自己的序列化程序：

As far as the output must be compatible with the specs, the stock serializer omits unsupported fields. However, you could craft your own serializer:

# 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：

Enable your new serializer in settings.py:

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

然后在代码中使用它：

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

这篇关于GeoDjango序列化GeoJSON跳过'id'字段的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！