Django很多关系都没有保存

Update:

For anyone curious, I figured out what and why and how to fix it. In my view I had: fields = ['html', 'tags', 'title', 'text', 'taken_date', 'image'] And am using {{ form.as_p }} in my template. Apparently once that gets posted from the form it really, really doesn't want anything else touching the form fields that wasn't already in the form. So I took out the 'tags' field from my view and it works.

对于任何好奇的人,我想出了什么,为什么以及如何解决它。在我看来,我有:fields = ['html','tags','title','text','taken_date','image']并且在我的模板中使用{{form.as_p}}。显然,一旦从表单中发布它真的,实际上不希望任何其他任何东西触及表单中尚未出现的表单字段。所以我从我的视图中取出了“标签”字段并且它有效。

Thanks to everyone that responded.

感谢所有回复的人。

Original Question:

Using Django 2.0.1 and PostgreSQL 9.2.18

使用Django 2.0.1和PostgreSQL 9.2.18

I'm writing a simple photogallery application. In it I have a photo object and PhotoTag object. The photo can have many tags and the tags can be associated with many photos, thus it needing to be a ManyToManyField.

我正在写一个简单的照相馆应用程序。在其中我有一个照片对象和PhotoTag对象。照片可以有许多标签,标签可以与许多照片相关联,因此它需要是ManyToManyField。

Upon save of the submitted photo, a post_save receiver calls functions to make thumbnails (which work fine) and a function to update tags.

保存提交的照片后,post_save接收器调用函数来制作缩略图(工作正常)和更新标签的函数。

The photo gets saved fine, update_tags gets called fine, tags get read from the photo fine, tags get saved into PhotoTag fine. But the manytomany table tying the two together does not get the new rows inserted. Unless the code exits abnormally during either the update_tags function or the post_save receiver function, thumbs after update_tags is called.

照片保存得很好,update_tags被称为正常,标签从照片中读取正常,标签保存到PhotoTag罚款。但是将两者捆绑在一起的多个表并没有插入新的行。除非代码在update_tags函数或post_save接收函数期间异常退出,否则调用update_tags之后的拇指。

I've even tried using a connection.cursor to write directly into the m2m table and it has the same behavior.

我甚至尝试使用connection.cursor直接写入m2m表,它具有相同的行为。

If I try to call save() on the Photo object again, I just get into an infinite loop due to the post_save signal.

如果我再次尝试在Photo对象上调用save(),由于post_save信号,我只是进入无限循环。

I'm baffled as to what is going on. Any clues?

我很困惑发生了什么事。有什么线索吗?

# models.py

def update_tags(instance):
    tags = get_tags(instance.image)

    # Set initial values
    pt = []
    tagid = ''
    photoid = instance.id

    # Loop through tag list and insert into PhotoTag and m2m relation
    for x in range(0, len(tags)):
        # Make sure this tag doesn't already exist
        if PhotoTag.objects.filter(tag_text=tags[x]).count() == 0:
            pt = PhotoTag.objects.create(tag_text=tags[x])
            tagid = PhotoTag.objects.latest('id').id
            instance.tags.add(pt)
        else:
            # Only working with new tags right now
            pass

    return


class Photo(models.Model):
    author = models.ForeignKey(settings.AUTH_USER_MODEL,
                               on_delete=models.CASCADE)
    title = models.CharField(max_length=200, null=True, blank=True)
    text = models.TextField(null=True, blank=True)
    html = models.BooleanField(default=False)
    filename = models.CharField(default='', max_length=100, blank=True,
                                null=True)
    image = models.ImageField(upload_to=upload_path)
    location = models.CharField(max_length=100, blank=True, null=True)
    entry_date = models.DateTimeField(default=timezone.now)
    taken_date = models.DateTimeField(blank=True, null=True)

    tags = models.ManyToManyField(PhotoTag, blank=True)


@receiver(post_save, sender=Photo)
def thumbs(sender, instance, **kwargs):
    """
    Upon photo save, create thumbnails and then
    update PhotoTag and m2m with any Exif/XMP tags
    in the photo.
    """

    mk_thumb(instance.image, 'mid')
    mk_thumb(instance.image, 'th')
    mk_thumb(instance.image, 'sm')

    update_tags(instance)

    return

-------------
From views.py
-------------

class PhotoCreate(LoginRequiredMixin, CreateView):
    model = Photo
    template_name = 'photogallery/photo_edit.html'
    fields = ['html', 'tags', 'title', 'text', 'taken_date', 'image']

    def get_initial(self):
        self.initial = {'entry_date': timezone.now()}
        return self.initial

    def form_valid(self, form):
        form.instance.author = self.request.user

        return super(PhotoCreate, self).form_valid(form)

Update:

def save(self, mkthumb='', *args, **kwargs):
      super(Photo, self).save(*args, **kwargs)
      if mkthumb != "thumbs":
          self.mk_thumb(self.image, 'mid')
          self.mk_thumb(self.image, 'th')
          self.mk_thumb(self.image, 'sm')

          self.update_tags()

          mkthumb = "thumbs"

      return

1 个解决方案

#1

override your save method like

覆盖你的保存方法,如

def save(self, *args, **kwargs):
    tags = get_tags(self.image)

    # Set initial values
    pt = None

    # Loop through tag list and insert into PhotoTag and m2m relation
    for x in range(0, len(tags)):
        # Make sure this tag doesn't already exist
        if PhotoTag.objects.filter(tag_text=tags[x]).count() == 0:
            pt = PhotoTag.objects.create(tag_text=tags[x])
            self.tags.add(pt)
        else:
            # Only working with new tags right now
            pass
      super(Photo, self).save(*args, **kwargs)