|
| 1 | +from django import forms |
| 2 | +from django.core.exceptions import ValidationError |
| 3 | +from django.forms import formset_factory, model_to_dict |
| 4 | +from django.forms.models import modelform_factory |
| 5 | +from django.utils.html import format_html, format_html_join |
| 6 | + |
| 7 | + |
| 8 | +class EmbeddedModelArrayField(forms.Field): |
| 9 | + def __init__(self, model, *, prefix, max_num=None, extra_forms=3, **kwargs): |
| 10 | + self.model = model |
| 11 | + self.prefix = prefix |
| 12 | + self.formset = formset_factory( |
| 13 | + form=modelform_factory(model, fields="__all__"), |
| 14 | + can_delete=True, |
| 15 | + max_num=max_num, |
| 16 | + extra=extra_forms, |
| 17 | + validate_max=True, |
| 18 | + ) |
| 19 | + kwargs["widget"] = EmbeddedModelArrayWidget() |
| 20 | + super().__init__(**kwargs) |
| 21 | + |
| 22 | + def clean(self, value): |
| 23 | + if not value: |
| 24 | + return [] |
| 25 | + formset = self.formset(value, prefix=self.prefix_override or self.prefix) |
| 26 | + if not formset.is_valid(): |
| 27 | + raise ValidationError(formset.errors + formset.non_form_errors()) |
| 28 | + cleaned_data = [] |
| 29 | + for data in formset.cleaned_data: |
| 30 | + # The "delete" checkbox isn't part of model data and must be |
| 31 | + # removed. The fallback to True skips empty forms. |
| 32 | + if data.pop("DELETE", True): |
| 33 | + continue |
| 34 | + cleaned_data.append(self.model(**data)) |
| 35 | + return cleaned_data |
| 36 | + |
| 37 | + def has_changed(self, initial, data): |
| 38 | + formset = self.formset(data, initial=models_to_dicts(initial), prefix=self.prefix) |
| 39 | + return formset.has_changed() |
| 40 | + |
| 41 | + def get_bound_field(self, form, field_name): |
| 42 | + # Nested embedded model form fields need a double prefix. |
| 43 | + # HACK: Setting self.prefix_override makes it available in clean() |
| 44 | + # which doesn't have access to the form. |
| 45 | + self.prefix_override = f"{form.prefix}-{self.prefix}" if form.prefix else None |
| 46 | + return EmbeddedModelArrayBoundField(form, self, field_name, self.prefix_override) |
| 47 | + |
| 48 | + |
| 49 | +class EmbeddedModelArrayBoundField(forms.BoundField): |
| 50 | + def __init__(self, form, field, name, prefix_override): |
| 51 | + super().__init__(form, field, name) |
| 52 | + self.formset = field.formset( |
| 53 | + self.data if form.is_bound else None, |
| 54 | + initial=models_to_dicts(self.initial), |
| 55 | + prefix=prefix_override if prefix_override else self.html_name, |
| 56 | + ) |
| 57 | + |
| 58 | + def __str__(self): |
| 59 | + body = format_html_join( |
| 60 | + "\n", "<tbody>{}</tbody>", ((form.as_table(),) for form in self.formset) |
| 61 | + ) |
| 62 | + return format_html("<table>\n{}\n</table>\n{}", body, self.formset.management_form) |
| 63 | + |
| 64 | + |
| 65 | +class EmbeddedModelArrayWidget(forms.Widget): |
| 66 | + """ |
| 67 | + Extract the data for EmbeddedModelArrayFormField's formset. |
| 68 | + This widget is never rendered. |
| 69 | + """ |
| 70 | + |
| 71 | + def value_from_datadict(self, data, files, name): |
| 72 | + return {field: value for field, value in data.items() if field.startswith(f"{name}-")} |
| 73 | + |
| 74 | + |
| 75 | +def models_to_dicts(models): |
| 76 | + """ |
| 77 | + Convert initial data (which is a list of model instances or None) to a |
| 78 | + list of dictionary data suitable for a formset. |
| 79 | + """ |
| 80 | + return [model_to_dict(model) for model in models or []] |
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