Django：在序列化程序中查询关系模型

Question

I have a Project and Memberships model where each project has a list of members. I need to find out if the current logged in user is listed as a member on the project from the project serializer, but I can't seem to get the request correct in my get_i_am_member method. I need to pass the project id from the Project model to the Membership model to filter the data, then check if the user in the filtered memberships model matches the user making the request. Can someone please assist? Here is my code:

######################################################
# 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

By default drf passes request object using context, so modification should be:

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

But in case you manually call serializer, you need to pass it:

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