Django：在序列化程序中查詢關系模型

Question

我有一個項目和成員資格 model，其中每個項目都有一個成員列表。 我需要從項目序列化程序中查明當前登錄的用戶是否被列為項目的成員，但我似乎無法在我的get_i_am_member方法中獲得正確的請求。 我需要將 Project model 中的項目 ID 傳遞給 Membership model 以過濾數據，然后檢查過濾后的成員資格 model 中的用戶是否與發出請求的用戶匹配。 有人可以幫忙嗎？ 這是我的代碼：

######################################################
# Serializer
######################################################

class ProjectSerializer(LightWeightSerializer):
    id = Field()
    name = Field()
    slug = Field()
    description = Field()
    created_date = Field()
    modified_date = Field()
    owner = MethodField()
    members = MethodField()
    is_private = Field()
    anon_permissions = Field()
    public_permissions = Field()
    is_looking_for_people = Field()
    looking_for_people_note = Field()
    i_am_member = MethodField()
    i_am_admin = MethodField()
    my_permissions = MethodField()

    def get_members(self, project):
        members = Membership.objects.filter(project_id=project.id).select_related()
        return MembershipSerializer(members, many=True, context=self.context).data

    def get_i_am_member(self, request):
        members_list = Membership.objects.filter(project_id=request.project.id).select_related('user')
        for member in members_list:
            if member.user == request.username:
                print(member.user)
                print("True")
                return True
            else:
                print(member.user)
                print("False")
            return False

######################################################
# Models
######################################################
class Project(models.Model):
    name = models.CharField(max_length=250, null=False, blank=False,
                            verbose_name=_("name"))
    slug = models.SlugField(max_length=250, unique=True, null=False, blank=True,
                            verbose_name=_("slug"))
    description = models.TextField(null=False, blank=False,
                                   verbose_name=_("description"))

    logo = models.FileField(upload_to=get_project_logo_file_path,
                            max_length=500, null=True, blank=True,
                            verbose_name=_("logo"))

    created_date = models.DateTimeField(null=False, blank=False,
                                        verbose_name=_("created date"),
                                        default=timezone.now)
    modified_date = models.DateTimeField(null=False, blank=False,
                                         verbose_name=_("modified date"))
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, blank=True,
                              related_name="owned_projects", verbose_name=_("owner"), on_delete=models.CASCADE)

    members = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name="projects",
                                     through="Membership", verbose_name=_("members"),
                                     through_fields=("project", "user"))

    is_private = models.BooleanField(default=True, null=False, blank=True,
                                     verbose_name=_("is private"))
    anon_permissions = ChoiceArrayField(
        models.TextField(null=False, blank=False, choices=ANON_PERMISSIONS),
        null=True,
        blank=True,
        default=list,
        verbose_name=_("anonymous permissions")
    )
    public_permissions = ChoiceArrayField(models.TextField(null=False, blank=False, choices=MEMBERS_PERMISSIONS),
                                    null=True, blank=True, default=list, verbose_name=_("user permissions"))

    is_featured = models.BooleanField(default=False, null=False, blank=True,
                                      verbose_name=_("is featured"))

    class Meta:
        db_table = "projects"
        verbose_name = "project"
        verbose_name_plural = "projects"
        ordering = ["name", "id"]
        index_together = [
            ["name", "id"],
        ]


class Membership(models.Model):
    # This model stores all project memberships. Also
    # stores invitations to memberships that do not have
    # assigned user.

    user = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, blank=True, default=None,
                             related_name="memberships", on_delete=models.CASCADE)
    project = models.ForeignKey(Project, null=False, blank=False,
                                related_name="memberships", on_delete=models.CASCADE)
    role = models.ForeignKey('core.Role', null=False, blank=False,
                             related_name="memberships", on_delete=models.CASCADE)
    is_admin = models.BooleanField(default=False, null=False, blank=False)

    user_order = models.BigIntegerField(default=timestamp_ms, null=False, blank=False,
                                        verbose_name=_("user order"))

    class Meta:
        db_table = "memberships"
        verbose_name = "membership"
        verbose_name_plural = "memberships"
        unique_together = ("user", "project",)
        ordering = ["project", "user__full_name", "user__username", "user__email"]

    def get_related_people(self):
        related_people = get_user_model().objects.filter(id=self.user.id)
        return related_people

    def clean(self):
        # TODO: Review and do it more robust
        memberships = Membership.objects.filter(user=self.user, project=self.project)
        if self.user and memberships.count() > 0 and memberships[0].id != self.id:
            raise ValidationError(_('The user is already member of the project'))

Answer 1

默認情況下，drf 使用上下文傳遞請求 object，因此修改應為：

def get_i_am_member(self, project):
    members_list = Membership.objects.filter(project_id=project.id).select_related('user')
    for member in members_list:
        if member.user == self.context['request'].user:
            print(member.user)
            print("True")
            return True
        else:
            print(member.user)
            print("False")
        return False

但是如果您手動調用序列化程序，則需要傳遞它：

ProjectSerializer(instance=project, context={'request': request})