class Ghost(models.Model):
    create = models.DateTimeField(default=timezone.now, help_text='创建时间')
    update = models.DateTimeField(auto_now=True, help_text='修改时间')
    speed = models.IntegerField(default=0, help_text='速度')
    name = models.CharField(max_length=64, help_text='名称')


class InstanceTask(models.Model):
    create = models.DateTimeField(default=timezone.now, help_text='创建时间')
    update = models.DateTimeField(auto_now=True, help_text='修改时间')
    name = models.CharField(max_length=64, help_text='副本名称')

class InstanceTaskMap(models.Model):
    create = models.DateTimeField(default=timezone.now, help_text='创建时间')
    update = models.DateTimeField(auto_now=True, help_text='修改时间')
    name = models.CharField(max_length=64, help_text='地图名称')
    ghosts = models.ManyToManyField(Ghost, help_text='Ghost')
    instance_task = models.ForeignKey(InstanceTask, related_name='instancetask_instancetaskmap', blank=True, null=True,
                                      help_text='副本任务', on_delete=models.SET_NULL)

对于上面的model，如果要在django admin中展示ghosts信息，那么在list_display中直接加入’ghosts’ 会报下面的错误：The value of ‘list_display[1]’ must not be a ManyToManyField.

如果要解决这个问题可以使用下面的代码来展示：

class InstanceTaskMapAdmin(admin.ModelAdmin):
    list_display = ('name', 'instance_task', 'id', 'index', 'get_ghost_name', 'introduction')

    # https://blog.csdn.net/weixin_42134789/article/details/83686664
    def get_ghost_name(self, obj):
        ghost_list = []
        for g in obj.ghosts.all():
            ghost_list.append(g.ghost.name)
        return ','.join(ghost_list)

    get_ghost_name.short_description = "Ghosts" 

如果需要更丰富的信息可以参考上面代码注释中的链接。

Django REST framework is a powerful and flexible toolkit for building Web APIs.

Some reasons you might want to use REST framework:

• The Web browsable API is a huge usability win for your developers.

• Authentication policies including packages for OAuth1a and OAuth2.

• Serialization that supports both ORM and non-ORM data sources.

• Customizable all the way down – just use regular function-based views if you don’t need the more powerful features.

• Extensive documentation, and great community support.

• Used and trusted by internationally recognised companies including Mozilla, Red Hat, Heroku, and Eventbrite.

之前虽然也用了Django REST framework 但是序列化函数基本都是自己写的，并没有用框架带的序列化函数。这次不想在搞的那么麻烦，于是使用Django REST framework带的序列化函数。

但是在序列化foreignkey的时候却发现只有id，其余的数据没有。

model定义：

class PlayerGoodsItem(models.Model):
    create = models.DateTimeField(default=timezone.now, help_text='创建时间')
    update = models.DateTimeField(auto_now=True, help_text='修改时间')
    goods_item = models.ForeignKey(GoodsItem, related_name='goodsitem_playergoodsitem', help_text='商品信息',
                                   on_delete=models.CASCADE)

序列化代码：

class PlayerGoodsItemSerializer(serializers.ModelSerializer):
    class Meta:
        model = PlayerGoodsItem
        fields = "__all__"