Django用户外键在View vs中，在model.save（）方法中 [英] Django User foreign key in View vs in model.save() method

问题描述

我有以下模型（简化）：

I have the following model (simplified):

class Candidate(models.Model):
    """ Model for candidate clients """

    # fields
    general_category = models.ForeignKey('GeneralCategory',
                                         related_name='candidate',
                                         null=True,
                                         blank=True,
                                         # default=1,
                                         verbose_name='Γενική Κατηγορία',)

    brand_name = models.CharField(max_length=160,
                                  blank=True,
                                  verbose_name='Επωνυμία')

    creation_date = models.DateTimeField(null=True, blank=True, verbose_name='Πρώτη καταχώρηση')
    last_edited = models.DateTimeField(null=True, blank=True, verbose_name='Τελευταία επεξεργασία')

    first_edited_by = models.ForeignKey(User,
                                        related_name='first_edited_candidates',
                                        blank=True,
                                        null=True,
                                        verbose_name='Πρώτη επεξεργασία από',)

    last_edited_by = models.ForeignKey(User,
                                       related_name='last_edited_candidates',
                                       blank=True,
                                       null=True,
                                       verbose_name='Τελευταία επεξεργασία από',)

    def save(self, *args, **kwargs):
        """ On save, update timestamps and user fields """
        if 'request' in kwargs:
            request = kwargs.pop('request')
        else:
            request = None

        if not self.id:
            self.creation_date = timezone.now()
        self.last_edited = timezone.now()

        if request is not None:
            if not self.first_edited_by:
                self.first_edited_by = request.user
            self.last_edited_by = request.user

        log.info(self)
        return super(Candidate, self).save(*args, **kwargs)

    def __str__(self):
        return self.brand_name + '[' + str(self.__dict__) + ']'

如果我在PyCharm中启动调试器，我可以看到两个用户外键在我的详细视图中按预期填充，但在 model.save（）方法是无。另一个外键（ general_category ）按预期填充。

If I fire up the debugger in PyCharm I can see that the two User foreign keys are populated as expected in my detail view, but inside the model.save() method they are None. The other foreign key (general_category) is populated as expected.

为什么？这是否与 self 关键字有关？

Why is that? Does it have something to do with the self keyword?

我的观点（再次简化）是这样的： / p>

My view (again, simplified) is this:

@login_required
@require_http_methods(["GET", "POST"])
def candidate_detail(request, candidate_id):
    candidate = get_object_or_404(Candidate, pk=candidate_id)
    original_http_referrer = request.GET.get('next')
    if request.method == 'GET':
        form = CandidateForm(instance=candidate)
    elif request.method == 'POST':
        form = CandidateForm(request.POST, instance=candidate)
        if form.is_valid():
            candidate.save(request=request)
            return HttpResponseRedirect(original_http_referrer)
        # else:
            # TODO: show some error message ?

    context = {'candidate': candidate,
               'form': form,
               'original_http_referrer': original_http_referrer}
    return render(request, 'candidates/candidate_detail.html', context)

我正在使用 Django 1.8 em> Python 3.4 。

I'm using Django 1.8 with Python 3.4.

更新：外键的价值似乎丢失了

UPDATE: It seems that the value of the foreign keys is lost in the line

form = CandidateForm(request.POST, instance=candidate)

奇怪的是，如果我和调试器一步一步地走下去，我的程序最终会按预期工作！ （我也尝试使用 manage.py runserver ，以确保它不是PyCharm的服务器实现中的错误，而不是）

The weird thing is that, if I step-in and go line-by-line with the debugger, my program ends up working as expected! (I have also tried this using manage.py runserver to make sure it is not a bug in the PyCharm's server implementation and it's not)

我将在明天的每一步尝试登录我的模型，以缩小违规代码。只是为了确保，这里是我的表单的代码（不是简化）：

I'll try logging my model at each step tomorrow to narrow down the offending code. Just to make sure, here is my form's code (not simplified):

from django.forms import ModelForm
from candidates.models import Candidate


class CandidateForm(ModelForm):
    class Meta:
        model = Candidate
        fields = '__all__'

推荐答案

您没有保存表单。

    if form.is_valid():
        candidate = form.save(commit=False)
        candidate.save(request=request)

请注意，保存方法的前四行可以简化为一个：

Note that the first four lines of the save method can be simplified to one:

request = kwargs.pop('request', None)

这篇关于Django用户外键在View vs中，在model.save（）方法中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！