从管理表单中的 Django 验证中排除字段

Question

I am working on project with a lot of legacy code base ( Django 2.2 ). I have a custom model field for price that goes like this

class PriceField(PositiveIntegerField):

    def get_prep_value(self, value: float) -> Optional[int]:
        return int(value * 100) if value else self.default

    def from_db_value(self, value: int, expression, connection) -> Optional[float]:
        return value / 100 if value else value


class Expertise(models.Model):
    price = PriceField(blank=True, default=0, help_text='Price per min.')
    ...

Prices are stored in db multiplied by 100, eg 9.90 is stored as 990 , and values are obtained from db in human readable way ( 990 as 9.90 ).

Now I am facing a problem with default PositiveIntegerField Django admin form validation for that field. Because this value represented as float every time I click "Save" I get a PositiveIntegerField 's ValidationError . Is there any way to exclude this field from admin form validation or to send this field value multiplied by 100?

Answer 1

If you setup a custom form you can manipulate the data entry of the form before actually save it to the DB, as well as determine the data type for the input.

Edit: to do what i said you may as well end up removing the custom input and just doing the *100 thing on the custom form, anyway i think if you wanna ignore validations the anwser may be in a custom form.

I used to have custom form like this:

class ArticleModelForm(forms.ModelForm):
    project = forms.ModelChoiceField(
        queryset=Project.objects.order_by('title'),
        label="Proyecto",
        empty_label="Seleccionar proyecto",
        widget=forms.Select(
            attrs={
                "class": "basic-single form-control w-100",
                "id": "id-select-project-article"
            }))
    //lot more inputs

    def __init__(self, *args, **kwargs):
        super(ArticleModelForm, self).__init__(*args, **kwargs)
        self.fields['image'].widget.attrs['class'] = 'form-control-file'
        self.fields['image'].widget.attrs['accept'] = 'image/*'
        self.fields['file'].widget.attrs['class'] = 'form-control-file'
        self.fields['file'].widget.attrs['accept'] = 'application/pdf'
        for field in self.fields.values():
            field.error_messages = {
                'required':
                'El campo {fieldname} es requerido'.format(
                    fieldname=field.label)
            }

    def clean_file(self):
        file = self.cleaned_data.get("file")
        if not (file.name.endswith(".pdf")):
            raise forms.ValidationError(
                "Favor de ingresar un archivo en formato pdf")
        return file

    def clean_project(self):
        project = self.cleaned_data.get("project")
        user = self.cleaned_data.get("user")
        if project:
            projectObj = Project.objects.get(id=project.id)
            if not user in projectObj.participants.all():
                raise forms.ValidationError(
                    "Usted no es participante en este proyecto.")
        return project

    class Meta:
        model = Article
        fields = [
            'user', 'project', 'journal', 'authors', 'title', 'indexed',
            'indexInfo', 'arbitration', 'publicationYear', 'pages', 'file',
            'image', 'programTribute', 'academyTribute', 'eventPublication',
            'tags'
        ]

You can do your logic to *100 your number on the clean method for the field and return that value to be saved.

I don't remember excatly how to setup custom forms on admin but i know for sure you can do it.

I know i did this to setup custom usermodel and had to import my custom user forms on the admin.py of my users app:

from django.contrib import admin
from django.contrib.auth import get_user_model
from django.contrib.auth.admin import UserAdmin

from .forms import UserSapCreationForm, UserSapChangeForm //my custom forms 
from .models import UserSap

class UserSapAdmin(UserAdmin):
    add_form = UserSapCreationForm
    form = UserSapChangeForm
    model = UserSap
    verbose_name = 'Usuario Sap'
    list_display = (
        'email',
        'account',
        'rol',
        'is_staff',
        'is_active',
    )
    list_filter = (
        'rol',
        'is_staff',
        'is_active',
    )

    fieldsets = (
        ('Usuario Sap', {
            'fields': (
                'email',
                'password',
                'rol',
            )
        }),
        ('Informacion personal', {
            'fields': ('account', )
        }),
        ('Grupos', {
            'classes': ('wide', ),
            'fields': ('groups', )
        }),
        ('Permisos', {
            'classes': ('wide', ),
            'fields': ('user_permissions', )
        }),
        ('Login', {
            'fields': ('is_active', )
        }),
        ('Staff', {
            'fields': ('is_staff', )
        }),
    )
    """
    add_fieldsets = (
        ('add', {
            'classes': ('wide',),
            'fields': ('email', 'account', 'rol', 'password1', 'password2', 'is_staff', 'is_active')}
         ),
    )
"""
    ordering = ('email', )

    search_fields = ('email', )

    filter_horizontal = ()


admin.site.register(UserSap, UserSapAdmin)

sorry i can't develop a full answer for you case but hopefully this examples will help you start searching for solutions.