I try to render a django-simple-history queryset in a django-tables2 table. At the moment I pass the raw queryset to the template inside the context. Further I want to pass the Queryset to a Table object to use the features of the table like linkyfy columns or exclude columns. For this I have to specify a model inside the tables meta. The problem here is, that the model for the history is generated automatically.
Actually code:
#views.py
from .tables import HistoryTable
class HistoryView(LoginRequiredMixin, SingleTableView):
template_name = "funkwerkstatt/history.html"
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context["table"] = Device.history.filter(id=self.kwargs["pk"])
## futur code
#context["table"] = HistoryTable(Device.history.filter(id=self.kwargs["pk"]))
return context
#tables.py
import django_tables2 as tables
class HistoryTable(tables.Table):
device = tables.Column(accessor="device", linkify=True)
class Meta:
model = # HistoryModel?!
empty_text = "No entry"
exclude = ["id",]
Is there a way to referent the auto generated HistoryModel
Reading the docs helps some times.
https://django-simple-history.readthedocs.io/en/latest/common_issues.html#pointing-to-the-model
class PollHistoryListView(ListView): # or PollHistorySerializer(ModelSerializer):
class Meta:
model = Poll.history.model
# ...
Is there any good way that I can make modifications to individual fields of data in a list view? For example, I have a blog post model that looks like
class Blog(models.Model):
create_time = models.DateTimeField(auto_now_add=True)
title = models.CharField(max_length=250)
document = models.TextField(blank=True)
and my list view looks like this:
class BlogPostListView(ListView):
model = Blog
template_name = 'blog/posts.html'
context_object_name = 'posts'
ordering = ['-create_time']
Obviously I want to display a list of blog posts in a table format, and I want to modify how the create_time looks (currently showing 'March 7, 2020, 10:16 a.m.', but I only want 2020-3-7 10:16); and the post document can be too long to display in a cell, I want to truncate it into only 150 words.
so what are the better ways to achieve this in a listview view?
(I read some sort-of similar questions in StackOverflow, but it is either done in the template such as reformating the time which does not solve my second requirement, or too vague to understand).
If you want to customise the representation between model and view. A faster way to do that is to use serializer and RetrieveAPIView of DRF. Check out installation link. Then, you can make the use of serializer to customise representations of model's fields.
Here is pseudo code:
from rest_framework import serializers
from rest_framework.generics import RetrieveAPIView
class BlogSerializer(serializers.ModelSerializer)
def get_create_time(self, blog):
return self.create_time..strftime("%m/%d/%Y, %H:%M)
def get_document(self, blog):
return self.document[:151]
class BlogPostListView(RetrieveAPIView):
queryset = Blog.objects.all()
serializer_class = BlogSerializer
template_name = 'blog/posts.html'
As Chouvic suggested that I should use ModelSerializer, I managed to get it work in the listView. Here is my solution:
serializer:
class BlogListSerializer(serializers.ModelSerializer):
create_time_str = serializers.SerializerMethodField()
short_document_str = serializers.SerializerMethodField()
class Meta:
model = Blog
fields = '__all__'
def get_create_time_str(self, obj):
return obj.create_time.strftime("%Y/%m/%d")
def get_short_document_str(self, obj):
return obj.document[0:150]
as for the ListView:
class BlogListView(ListView):
model = Blog
template_name = 'blog/posts.html'
context_object_name = 'posts'
ordering = ['-create_time']
queryset = Blog.objects.all()
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
posts = context['posts']
mod_posts = BlogListSerializer(posts, many=True)
context['posts'] = mod_posts.data
return context
BlogListSerializer(posts, many=True) takes in posts (a list of post) and return a new list of post each with the new 'attributes' of create_time_str and short_document_str.
In the template, I just need to refer it as <td>{{ post.create_time_str }}</td>.
I am trying to understand the process of generating generic form views in django. I have a generic view class with just
class BookUpdate(UpdateView):
model = Book
fields = [ 'name',
'pages',
'categorys'
]
which automatically generates a working html form from my model data. But now, I want to modify the field that is shown for categorys, is there any way to do this, or do I have to create a complete working BookForm class and custom BookUpdate class? Here its just 3 fields, but in my real case there are maybe 15 fields that I would need to code by myself, just because of a tiny change in the category field.
Cant I just overwrite the single field, using any class method?
You can either specify fields or form_class in your generic class-based view. With fields, Django will use a modelform_factory to generate the form. There's not much you can customise then.
You should create a BookForm class so that you can customise the fields. In your BookUpdate view, you only need to remove fields and add form_class = BookForm. Here I'm customising the widget for categorys and overriding the form field for pages:
def BookUpdate(UpdateView):
model = Book
form_class = BookForm
def BookForm(ModelForm):
pages = MyCustomPagesField()
class Meta:
model = Book
fields = '__all__'
widgets = {'categorys': MyCustomWidget()}
Note that you don't have to specify all fields, you can use "__all__" to have all fields or you can set exclude = [<list fields to exclude>] to just exclude a couple.
You don't have to code the fields yourself. But there is a small amount of work to do, as there isn't a method to override.
What you need to do is define a custom form. Since that will be a ModelForm, it will use the same logic to automatically create its fields based on the model. You can then override the definition of one of them.
class BookForm(forms.ModelForm):
categorys = forms.ModelMultipleChoiceField(custom_attributes_here...)
class Meta:
model = Book
fields = ["name", "pages", "categorys"]
And now tell your view to use that form:
class BookUpdate(UpdateView):
form_class = BookForm
I have a model registered on the admin site. One of its fields is a long string expression. I'd like to add custom form fields to the add/update pages of this model in the admin. Based on the values of these fields I will build the long string expression and save it in the relevant model field.
How can I do this?
I'm building a mathematical or string expression from symbols. The user chooses symbols (these are the custom fields that are not part of the model) and when they click save then I create a string expression representation from the list of symbols and store it in the DB. I don't want the symbols to be part of the model and DB, only the final expression.
Either in your admin.py or in a separate forms.py you can add a ModelForm class and then declare your extra fields inside that as you normally would. I've also given an example of how you might use these values in form.save():
from django import forms
from yourapp.models import YourModel
class YourModelForm(forms.ModelForm):
extra_field = forms.CharField()
def save(self, commit=True):
extra_field = self.cleaned_data.get('extra_field', None)
# ...do something with extra_field here...
return super(YourModelForm, self).save(commit=commit)
class Meta:
model = YourModel
To have the extra fields appearing in the admin just:
Edit your admin.py and set the form property to refer to the form you created above.
Include your new fields in your fields or fieldsets declaration.
Like this:
class YourModelAdmin(admin.ModelAdmin):
form = YourModelForm
fieldsets = (
(None, {
'fields': ('name', 'description', 'extra_field',),
}),
)
UPDATE:
In Django 1.8 you need to add fields = '__all__' to the metaclass of YourModelForm.
It it possible to do in the admin, but there is not a very straightforward way to it. Also, I would like to advice to keep most business logic in your models, so you won't be dependent on the Django Admin.
Maybe it would be easier (and maybe even better) if you have the two seperate fields on your model. Then add a method on your model that combines them.
For example:
class MyModel(models.model):
field1 = models.CharField(max_length=10)
field2 = models.CharField(max_length=10)
def combined_fields(self):
return '{} {}'.format(self.field1, self.field2)
Then in the admin you can add the combined_fields() as a readonly field:
class MyModelAdmin(models.ModelAdmin):
list_display = ('field1', 'field2', 'combined_fields')
readonly_fields = ('combined_fields',)
def combined_fields(self, obj):
return obj.combined_fields()
If you want to store the combined_fields in the database you could also save it when you save the model:
def save(self, *args, **kwargs):
self.field3 = self.combined_fields()
super(MyModel, self).save(*args, **kwargs)
Django 2.1.1
The primary answer got me halfway to answering my question. It did not help me save the result to a field in my actual model. In my case I wanted a textfield that a user could enter data into, then when a save occurred the data would be processed and the result put into a field in the model and saved. While the original answer showed how to get the value from the extra field, it did not show how to save it back to the model at least in Django 2.1.1
This takes the value from an unbound custom field, processes, and saves it into my real description field:
class WidgetForm(forms.ModelForm):
extra_field = forms.CharField(required=False)
def processData(self, input):
# example of error handling
if False:
raise forms.ValidationError('Processing failed!')
return input + " has been processed"
def save(self, commit=True):
extra_field = self.cleaned_data.get('extra_field', None)
# self.description = "my result" note that this does not work
# Get the form instance so I can write to its fields
instance = super(WidgetForm, self).save(commit=commit)
# this writes the processed data to the description field
instance.description = self.processData(extra_field)
if commit:
instance.save()
return instance
class Meta:
model = Widget
fields = "__all__"
You can always create new admin template, and do what you need in your admin_view (override the admin add URL to your admin_view):
url(r'^admin/mymodel/mymodel/add/$','admin_views.add_my_special_model')
If you absolutely only want to store the combined field on the model and not the two seperate fields, you could do something like this:
Create a custom form using the form attribute on your ModelAdmin. ModelAdmin.form
Parse the custom fields in the save_formset method on your ModelAdmin. ModelAdmin.save_model(request, obj, form, change)
I never done something like this so I'm not completely sure how it will work out.
The first (highest score) solution (https://stackoverflow.com/a/23337009/10843740) was accurate, but I have more.
If you declare fields by code, that solution works perfectly, but what if you want to build those dynamically?
In this case, creating fields in the __init__ function for the ModelForm won't work. You will need to pass a custom metaclass and override the declared_fields in the __new__ function!
Here is a sample:
class YourCustomMetaClass(forms.models.ModelFormMetaclass):
"""
For dynamically creating fields in ModelForm to be shown on the admin panel,
you must override the `declared_fields` property of the metaclass.
"""
def __new__(mcs, name, bases, attrs):
new_class = super(NamedTimingMetaClass, mcs).__new__(
mcs, name, bases, attrs)
# Adding fields dynamically.
new_class.declared_fields.update(...)
return new_class
# don't forget to pass the metaclass
class YourModelForm(forms.ModelForm, metaclass=YourCustomMetaClass):
"""
`metaclass=YourCustomMetaClass` is where the magic happens!
"""
# delcare static fields here
class Meta:
model = YourModel
fields = '__all__'
This is what I did to add the custom form field "extra_field" which is not the part of the model "MyModel" as shown below:
# "admin.py"
from django.contrib import admin
from django import forms
from .models import MyModel
class MyModelForm(forms.ModelForm):
extra_field = forms.CharField()
def save(self, commit=True):
extra_field = self.cleaned_data.get('extra_field', None)
# Do something with extra_field here
return super().save(commit=commit)
#admin.register(MyModel)
class MyModelAdmin(admin.ModelAdmin):
form = MyModelForm
You might get help from my answer at :
my response previous on multicheckchoice custom field
You can also extend multiple forms having different custom fields and then assigning them to your inlines class like stackedinline or tabularinline:
form =
This way you can avoid formset complication where you need to add multiple custom fields from multiple models.
so your modeladmin looks like:
inlines = [form1inline, form2inline,...]
In my previous response to the link here, you will find init and save methods.
init will load when you view the page and save will send it to database.
in these two methods you can do your logic to add strings and then save thereafter view it back in Django admin change_form or change_list depending where you want.
list_display will show your fields on change_list.
Let me know if it helps ...
....
class CohortDetailInline3(admin.StackedInline):
model = CohortDetails
form = DisabilityTypesForm
...
class CohortDetailInline2(admin.StackedInline):
model = CohortDetails
form = StudentRPLForm
...
...
#admin.register(Cohort)
class CohortAdmin(admin.ModelAdmin):
form = CityInlineForm
inlines = [uploadInline, cohortDetailInline1,
CohortDetailInline2, CohortDetailInline3]
list_select_related = True
list_display = ['rto_student_code', 'first_name', 'family_name',]
...
Suppose I have two models:
class Topic(models.Model):
title = models.CharField()
# other stuff
class Post(models.Model):
topic = models.ForeignKey(Topic)
body = models.TextField()
# other stuff
And I want to create a form contains two fields: Topic.title and Post.body. Of course, I can create the following form:
class TopicForm(Form):
title = forms.CharField()
body = forms.TextField()
# and so on
But I don't want to duplicate code, since I already have title and body in models. I'm looking for something like this:
class TopicForm(MagicForm):
class Meta:
models = (Topic, Post)
fields = {
Topic: ('title', ),
Post: ('body', )
}
# and so on
Also, I want to use it in class based views. I mean, I would like to write view as:
class TopicCreate(CreateView):
form_class = TopicForm
# ...
def form_valid(self, form):
# some things before creating objects
As suggested in comments, I could use two forms. But I don't see any simple way to use two forms in my TopicCreate view - I should reimplement all methods belongs to getting form(at least).
So, my question is:
Is there something already implemented in Django for my requirements? Or is there a better(simpler) way?
or
Do you know a simple way with using two forms in class based view? If so, tell me, it could solve my issue too.
You can create two separate forms having the required fields, for each model. Then show both forms in the template inside one html element. Both forms will get rendered and then submitted individually. You can then process the forms separately in the view.
class TopicForm(ModelForm):
class Meta:
model = Topic
fields = ("title", ..)
class PostForm(ModelForm):
class Meta:
model = Post
fields = ("body", ..)
In view:
form1 = TopicForm()
form2 = PostForm()
In template:
<form ...>
{{ form1 }}
{{ form2 }}
</form>
You can easily use form.save() and all other functions, without doing it all yourself.