我正在使用 GeoDjango 构建应用程序，但遇到以下问题：
我需要从 GPX 文件中读取轨道数据，这些数据应该存储在模型 MultiLineStringField 字段中。这应该发生在用户上传 GPX 文件的管理界面中
我试图实现这一点，即从文件中抓取的数据应该分配给 MultiLineStringField，而其他字段应该从表单中获取值。
我的模型是：
class GPXTrack(models.Model):
nome = models.CharField("Nome", blank = False, max_length = 255)
slug = models.SlugField("Slug", blank = True)
# sport natura arte/cultura
tipo = models.CharField("Tipologia", blank = False, max_length = 2, choices=TIPOLOGIA_CHOICES)
descrizione = models.TextField("Descrizione", blank = True)
gpx_file = models.FileField(upload_to = 'uploads/gpx/')
track = models.MultiLineStringField(blank = True)
objects = models.GeoManager()
published = models.BooleanField("Pubblicato")
rel_files = generic.GenericRelation(MyFiles)
#publish_on = models.DateTimeField("Pubblicare il", auto_now_add = True)
created = models.DateTimeField("Created", auto_now_add = True)
updated = models.DateTimeField("Updated", auto_now = True)
class Meta:
#verbose_name = "struttura'"
#verbose_name_plural = "strutture"
ordering = ['-created']
def __str__(self):
return str(self.nome)
def __unicode__(self):
return '%s' % (self.nome)
def put(self):
self.slug = sluggy(self.nome)
key = super(Foresta, self).put()
# do something after save
return key
在 admin.py 文件中，我已经覆盖了 save 方法，如下所示：
from django.contrib.gis import admin
from trails.models import GPXPoint, GPXTrack
from django.contrib.contenttypes import generic
from django.contrib.gis.gdal import DataSource
#from gpx_mapping import GPXMapping
from django.contrib.gis.utils import LayerMapping
from django.template import RequestContext
import tempfile
import os
import pprint
class GPXTrackAdmin(admin.OSMGeoAdmin):
list_filter = ( 'tipo', 'published')
search_fields = ['nome']
list_display = ('nome', 'tipo', 'published', 'gpx_file')
inlines = [TrackImagesInline, TrackFilesInline]
prepopulated_fields = {"slug": ("nome",)}
def save_model(self, request, obj, form, change):
"""When creating a new object, set the creator field.
"""
if 'gpx_file' in request.FILES:
# Get
gpxFile = request.FILES['gpx_file']
# Save
targetPath = tempfile.mkstemp()[1]
destination = open(targetPath, 'wt')
for chunk in gpxFile.chunks():
destination.write(chunk)
destination.close()
#define fields of interest for LayerMapping
track_point_mapping = {'timestamp' : 'time',
'point' : 'POINT',
}
track_mapping = {'track' : 'MULTILINESTRING'}
gpx_file = DataSource(targetPath)
mytrack = LayerMapping(GPXTrack, gpx_file, track_mapping, layer='tracks')
mytrack.save()
#remove the temp file saved
os.remove(targetPath)
orig = GPXTrack.objects.get(pk=mytrack.pk)
#assign the parsed values from LayerMapping to the appropriate Field
obj.track = orig.track
obj.save()
我所知道的：
- LayerMapping 不能用于更新字段，只能用于保存新字段
- 我无法访问 LayerMapping 对象的特定字段（即在上面的代码中：mytrack.track）并将其值分配给 model_save 方法中的模型字段（即obj.track）
- 我无法检索上次保存的 LayerMapping 对象的主键（即在上面的代码中：mytrack.pk），以便使用在表单中传递的值更新它，该字段未在 LayerMapping.mapping 中映射
那我该怎么办？！？！