Django Tastypie，多对多保存错误

Posted 2023-02-24

【中文标题】Django Tastypie，多对多保存错误

【英文标题】：Django Tastypie, ManyToMany Saving Error

【发布时间】：2012-07-01 19:55:13

【问题描述】：

我在保存项目时遇到了问题，通过美味派 api。 （POST 方法）

这是我的 api.py 代码。

from tastypie.resources import ModelResource, ALL, ALL_WITH_RELATIONS
from tastypie.authorization import DjangoAuthorization
from tastypie.authentication import BasicAuthentication
from tastypie import fields
from apps.clients.models import Client
from django.contrib.auth.models import User

class ClientAPI(ModelResource):
    users = fields.ToManyField('apps.clients.api.ClientUserAPI', 'users',related_name='entry',full=True)


    class Meta:
        queryset = Client.objects.all()
        resource_name="clients"
        authentication = BasicAuthentication()
        authorization = DjangoAuthorization()
        filtering=
            "users":ALL
        

    def hydrate_m2m(self,bundle):
        if bundle.data.get("users"):
            for user_id in bundle.data["users"]:
                new_user = User.objects.get(id=user_id)
                bundle.obj.users.add(new_user)


class ClientUserAPI(ModelResource):
    class Meta:
        queryset = User.objects.all()
        resource_name = 'users'
        fields = ['username', 'first_name', 'last_name', 'last_login']
        authentication = BasicAuthentication()
        authorization = DjangoAuthorization()

当我发布数据时，保存成功，但给我错误。

"error_message": "'NoneType' object has no attribute 'obj'", "traceback": "Traceback (most recent call last):\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 192, in wrapper\n response = callback(request, *args, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 397, in dispatch_list\n return self.dispatch('list', request, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 427, in dispatch\n response = method(request, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 1165, in post_list\n updated_bundle = self.obj_create(bundle, request=request, **self.remove_api_resource_names(kwargs))\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 1784, in obj_create\n self.save_m2m(m2m_bundle)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 1942, in save_m2m\n related_mngr = getattr(bundle.obj, field_object.attribute)\n\nAttributeError: 'NoneType' object has no attribute 'obj'\n"

当我将“return bundle”行添加到 hydrate_m2m 时，m2m 保存不成功（空白），仍然给我这样的错误。

"error_message": "'str' object has no attribute 'obj'", "traceback": "Traceback (most recent call last):\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 192, in wrapper\n response = callback(request, *args, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 397, in dispatch_list\n return self.dispatch('list', request, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 427, in dispatch\n response = method(request, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 1165, in post_list\n updated_bundle = self.obj_create(bundle, request=request, **self.remove_api_resource_names(kwargs))\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 1784, in obj_create\n self.save_m2m(m2m_bundle)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 1951, in save_m2m\n related_bundle.obj.save()\n\nAttributeError: 'str' object has no attribute 'obj'\n"

当我从代码中删除 hydrate_m2m 时，返回错误是：

"error_message": "The URL provided '1' was not a link to a valid resource.", "traceback": "Traceback (most recent call last):\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 192, in wrapper\n response = callback(request, *args, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 397, in dispatch_list\n return self.dispatch('list', request, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 427, in dispatch\n response = method(request, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 1165, in post_list\n updated_bundle = self.obj_create(bundle, request=request, **self.remove_api_resource_names(kwargs))\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 1783, in obj_create\n m2m_bundle = self.hydrate_m2m(bundle)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 743, in hydrate_m2m\n bundle.data[field_name] = field_object.hydrate_m2m(bundle)\n\n File \"/Library/Python/2.7/site-packages/tastypie/fields.py\", line 742, in hydrate_m2m\n m2m_hydrated.append(self.build_related_resource(value, **kwargs))\n\n File \"/Library/Python/2.7/site-packages/tastypie/fields.py\", line 588, in build_related_resource\n return self.resource_from_uri(self.fk_resource, value, **kwargs)\n\n File \"/Library/Python/2.7/site-packages/tastypie/fields.py\", line 522, in resource_from_uri\n obj = fk_resource.get_via_uri(uri, request=request)\n\n File \"/Library/Python/2.7/site-packages/tastypie/resources.py\", line 636, in get_via_uri\n raise NotFound(\"The URL provided '%s' was not a link to a valid resource.\" % uri)\n\nNotFound: The URL provided '1' was not a link to a valid resource.\n"

我认为提供“1”的 URL 是用户 ID。

请告诉我。我做错了什么？

顺便说一句，我英语不太好，对不起。

【问题讨论】：

您能否添加 POST 变量是什么以及将数据传递给模型的视图的相关部分

【参考方案1】：

我很确定，您将用户资源发布为逗号分隔的 id。这不是tastepie 默认处理相关资源的方式。您应该发布一个指向相关资源的 url 列表，在您的情况下 - 类似“/api/v1/users/1”。

或者，您可以将 hydrate_m2m 更改为 hydrate_users。通用 hydra_m2m 遍历资源中的每个字段，并尝试将其从 url-string 转换为相关资源的实例（这就是您收到有关“提供的 URL”的错误的原因）。 hydra_users 的代码可能如下所示：

def hydrate_users(self, bundle):
    try:
        user_ids = map(int, bundle.data.get('users', []))
    except ValueError:
        raise BadRequest("User ids must be ints") # from tastypie.exceptions
    bundle.data['users'] = User.objects.filter(id__in=user_ids)
    return bundle

希望对你有帮助

编辑：按照 Carson 的建议删除了 lambda 以支持 int

【讨论】：

map(int, bundle.data.get('users', [])) 也可以。为您节省 lambda。