Question

我发现了一些关于this one或this other one或多或少相同情况的帖子，但我无法适应我的情况。我想要的是，如果用户尝试创建另一个与他自己已经存储在db中的名称相同的模型，则返回我的表单并发出警告。我想使用Django内置的设施here，但我需要一些建议来改变我的代码：请问你帮我吗？我的代码如下：

models.py

class ShapeFile(models.Model):
    name = models.CharField(max_length=100)
    srid = models.ForeignKey(SpatialRefSys)
    model_definition = models.OneToOneField(ModelDefinition)
    user = models.ForeignKey(User)
    color_table = models.ManyToManyField(ColorTable)
    file = models.FileField(upload_to=get_upload_path)
    class Meta:
        unique_together = ('name', 'user')

forms.py

class UploadForm(ModelForm):
    class Meta:
        model = ShapeFile
        fields = ('name','srid','file','color_table')
        widgets = {'srid': TextInput()}

views.py

@login_required
def index(request):
    if request.method == 'POST':
        form = UploadForm(request.POST, request.FILES)
        if form.is_valid():
            req = request.POST
            sridVal = form.cleaned_data['srid'].pk
            shpVal = form.cleaned_data['name']

            # The final table name is something like 'mutant_celeryPy2_123_salzburg_lc'
            end_table_name = request.user.username + "_" + shpVal + '_lc'

            # Creates a table, otherwise return the retrieved one
            model_def, created = ModelDefinition.objects.get_or_create(
                app_label='celeryPy2',
                object_name=end_table_name,
                defaults=dict(
                   bases=(BaseDefinition(base=GeoModel),),
                   fields=(GeometryFieldDefinition(name='the_geom', srid=sridVal),
                           SmallIntegerFieldDefinition(name='cat'),)
                )
            )
            obj = form.save(commit=False)
            obj.user = request.user
            obj.model_definition = model_def
            obj.save()
            messages.success(request, 'Shapefile upload succesful!')
            return HttpResponse('Stored!')
        else:
            print "Upload shapefile form is invalid!!!"
    else:
        form = UploadForm()

    return render_to_response('celeryPy2/index.html',
                              {'form': form,},
                              context_instance=RequestContext(request))

如果我以user1身份登录并填写表单，请假设名称为'myshape'，当我提交时，我会收到“存储！”消息：一切正常，模型user1_myshape_lc已创建。如果我使用相同的user1重新登录并尝试存储其他数据，其字段名称设置为'myshape'，就像之前一样，我正确地获得了异常：

    Exception Type: IntegrityError at /celeryPy2/main
    Exception Value: duplicate key value violates unique constraint "celeryPy2_shapefile_model_definition_id_key"
    DETAIL:  Key (model_definition_id)=(154) already exists.

如何使用警告取回我的表单而不是获取Django异常错误消息？谢谢。

Answer 1

模型表单验证应该处理此问题并引发验证错误。但是您已从表单中排除user字段，这是unique_together约束的一部分，因此无法验证。参考validate_unique

您可以尝试更改视图代码，在已发布的数据中添加user字段，然后实例化该表单。

或者更好的方法是在表单中添加隐藏的用户字段，以便在request.POST中可用，并且验证可以根据需要运行。

Answer 2

感谢Rohan，我发现隐藏的字段解决方案是最好的：现在我正确地找回了我的表单，并显示错误消息：Shape file with this Name and User already exists。这是我修改过的代码，可以让事情顺利进行：

<强> forms.py

class UploadForm(ModelForm):
    class Meta:
        model = ShapeFile
        fields = ('name','user','srid','file','color_table')
        widgets = {'srid': TextInput(), 'user': HiddenInput()}

<强> views.py

@login_required
def index(request):
    if request.method == 'POST':
        form = UploadForm(request.POST, request.FILES)
        if form.is_valid():
            req = request.POST
            sridVal = form.cleaned_data['srid'].pk
            shpVal = form.cleaned_data['name']

            # The final table name is something like 'mutant_celeryPy2_123_salzburg_lc'
            end_table_name = request.user.username + "_" + shpVal + '_lc'

            # Creates a table, otherwise return the retrieved one
            model_def, created = ModelDefinition.objects.get_or_create(
                app_label='celeryPy2',
                object_name=end_table_name,
                defaults=dict(
                   bases=(BaseDefinition(base=GeoModel),),
                   fields=(GeometryFieldDefinition(name='the_geom', srid=sridVal),
                           SmallIntegerFieldDefinition(name='cat'),)
                )
            )
            obj = form.save(commit=False)
            obj.model_definition = model_def
            obj.save()
            messages.success(request, 'Shapefile upload succesful!')
            return HttpResponse('Stored!')
        else:
            print "Upload shapefile form is invalid!!!"
    else:
        form = UploadForm(initial={'user': request.user})

    return render_to_response('celeryPy2/index.html',
                              {'form': form,},
                              context_instance=RequestContext(request))

在ModelForm中是唯一的，如何返回带有错误消息的表单？

2 个答案: