Django which submit button

It is also possible to have complete control over the rendering of each part of the form, by indexing its properties using dot notation. If you accepted the "challenge" in Django Tutorial Part 8: User authentication and permissions you'll have a list of all books on loan in the library, which is only visible to library staff. We can add a link to our renew page next to each item using the template code below. Note: Remember that your test login will need to have the permission " catalog. Creating a Form class using the approach described above is very flexible, allowing you to create whatever sort of form page you like and associate it with any model or models.

However, if you just need a form to map the fields of a single model then your model will already define most of the information that you need in your form: fields, labels, help text and so on. Rather than recreating the model definitions in your form, it is easier to use the ModelForm helper class to create the form from your model.

This ModelForm can then be used within your views in exactly the same way as an ordinary Form. All you need to do to create the form is add class Meta with the associated model BookInstance and a list of the model fields to include in the form.

Neither approach is recommended because new fields added to the model are then automatically included in the form without the developer necessarily considering possible security implications. Note: This might not look like all that much simpler than just using a Form and it isn't in this case, because we just have one field.

However, if you have a lot of fields, it can reduce the amount of code quite significantly! The rest of the information comes from the model field definitions e. If these aren't quite right, then we can override them in our class Meta , specifying a dictionary containing the field to change and its new value.

For example, in this form, we might want a label for our field of " Renewal date " rather than the default based on the field name: Due Back , and we also want our help text to be specific to this use case. The form handling algorithm we used in our function view example above represents an extremely common pattern in form editing views.

Django abstracts much of this "boilerplate" for you, by creating generic editing views for creating, editing, and deleting views based on models. Not only do these handle the "view" behavior, but they automatically create the form class a ModelForm for you from the model. Note: In addition to the editing views described here, there is also a FormView class, which lies somewhere between our function view and the other generic views in terms of "flexibility" vs "coding effort".

Using FormView , you still need to create your Form , but you don't have to implement all of the standard form-handling patterns. Instead, you just have to provide an implementation of the function that will be called once the submission is known to be valid.

In this section, we're going to use generic editing views to create pages to add functionality to create, edit, and delete Author records from our library — effectively providing a basic reimplementation of parts of the Admin site this could be useful if you need to offer admin functionality in a more flexible way than can be provided by the admin site.

As you can see, to create, update, or delete the views you need to derive from CreateView , UpdateView , and DeleteView respectively and then define the associated model. For the "create" and "update" cases you also need to specify the fields to display in the form using the same syntax as for ModelForm. In this case, we show how to list them individually and the syntax to list "all" fields. The AuthorDelete class doesn't need to display any of the fields, so these don't need to be specified.

This is similar to our previous forms and renders the fields using a table. There is nothing particularly new here! You can see that the views are classes, and must hence be called via. We must use pk as the name for our captured primary key value, as this is the parameter name expected by the view classes. The author create, update, and delete pages are now ready to test we won't bother hooking them into the site sidebar in this case, although you can do so if you wish.

Note: Observant users will have noticed that we didn't do anything to prevent unauthorized users from accessing the pages! First, log in to the site with an account that has whatever permissions you decided are needed to access the author editing pages. Enter values for the fields and then press Submit to save the author record. Finally, we can delete the page by appending delete to the end of the author detail-view URL e. Django should display the delete page shown below. Press " Yes, delete.

Create some forms to create, edit, and delete Book records. You can use exactly the same structure as for Authors. Creating and handling forms can be a complicated process! Django makes it much easier by providing programmatic mechanisms to declare, render, and validate forms. Furthermore, Django provides generic form editing views that can do almost all the work to define pages that can create, edit, and delete records associated with a single model instance.

There is a lot more that can be done with forms check out our See also list below , but you should now understand how to add basic forms and form-handling code to your own websites. Previous Overview: Django Next In this tutorial, we'll show you how to work with HTML Forms in Django, and, in particular, the easiest way to write forms to create, update, and delete model instances.

Prerequisites: Complete all previous tutorial topics, including Django Tutorial Part 8: User authentication and permissions. Objective: To understand how to write forms to get information from users and update the database. To understand how the generic class-based editing views can vastly simplify creating forms for working with a single model.

Based on the diagram above, the main things that Django's form handling does are: Display the default form the first time it is requested by the user. The form may contain blank fields e. Django provides a range of tools and libraries to help you build forms to accept input from site visitors, and then process and respond to the input. Some of these form interface elements - text input or checkboxes - are built into HTML itself. The URL contains the address where the data must be sent, as well as the data keys and values.

Any request that could be used to change the state of the system - for example, a request that makes changes in the database - should use POST. GET should be used only for requests that do not affect the state of the system.

GET would also be unsuitable for a password form, because the password would appear in the URL, and thus, also in browser history and server logs, all in plain text.

Neither would it be suitable for large quantities of data, or for binary data, such as an image. Handling forms is a complex business. It is possible to write code that does all of this manually, but Django can take care of it all for you.

In much the same way that a Django model describes the logical structure of an object, its behavior, and the way its parts are represented to us, a Form class describes a form and determines how it works and appears. A DateField and a FileField handle very different kinds of data and have to do different things with it. Each field type has an appropriate default Widget class , but these can be overridden as required.

Rendering a form in a template involves nearly the same work as rendering any other kind of object, but there are some key differences. In the case of a model instance that contained no data, it would rarely if ever be useful to do anything with it in a template. So when we handle a model instance in a view, we typically retrieve it from the database.

When the form is submitted, the POST request which is sent to the server will contain the form data. This is a very simple form. In practice, a form might contain dozens or hundreds of fields, many of which might need to be pre-populated, and we might expect the user to work through the edit-submit cycle several times before concluding the operation.

We might require some validation to occur in the browser, even before the form is submitted; we might want to use much more complex fields, that allow the user to do things like pick dates from a calendar and so on. We already know what we want our HTML form to look like. Our starting point for it in Django is this:. This does two things. It also means that when Django receives the form back from the browser, it will validate the length of the data.

When this method is called, if all fields contain valid data, it will:. Form data sent back to a Django website is processed by a view, generally the same view which published the form.

This allows us to reuse some of the same logic. To handle the form we need to instantiate it in the view for the URL where we want it to be published:. If we arrive at this view with a GET request, it will create an empty form instance and place it in the template context to be rendered.

This is what we can expect to happen the first time we visit the URL. This is because they are structural elements on your page, so they should remain in the template. You can see Django added the errors to the form as unordered lists. If you were to render this form in your browser, it would look something like Figure We will start with a simple form common to most websites—a contact form. To create our ContactForm class, we first create a new file called contact.

As the contact form is a part of the website, we will add it to the site app new file :. Now we have created our ContactForm class, we have a few tasks to complete to get it to render on our website:. To show our contact form, we start by creating a URL for it. We added a placeholder for the contact page in the top menu when we created the base template.

Now we will turn the placeholder into a link for our contact form changes in bold :. I have made one change to the base. For our contact form to render, it needs a template. Inside the new folder, create a file called contact. In the contact template, we are extending the base template, and replacing the title and content blocks with new content for our contact form. Some other things to note:. Our last step is to create the new contact view. Open your contact. To test the contact form, uncomment line 19, save the contact.

First, note there is a link to the contact form in the top menu. Next, submit the empty form to make sure the form validation is working. Django should show the error messages Figure Now, fill out the form with valid data and submit it again. You should get an assertion error triggered by the assert False statement in the view line With the assert False active in our view, we can check the contents of cd with the Django error page.

Scroll down to the assertion error and open the Local vars panel. You should see the cd variable containing a dictionary of the complete form submission Figure Figure Using the assert False statement allows us to check the contents of the submitted form.

Add the following to the end of your main. Once you have saved the changes to your CSS file, refresh the browser and submit the empty form. You may have to clear the browser cache to reload your CSS file. Not only should your form be better laid out, but showing pretty error messages too Figure Figure Adding some CSS changes our rather plain contact form into something to be proud of.

As this is a contact form, the most common way to deal with form submissions is to email them to a site administrator or some other contact person within the organization. Setting up an email server to test emails in development can be painful. Luckily, this is another problem for which the Django developers have provided a handy solution. Django provides several email backends, including a few designed for use during development.

We will use the console backend. The console backend sends email output to the terminal console. You can check this in your terminal window after you submit your form. There are other email backends for testing: filebased , locmem and dummy , which send your emails to a file on your local system, save it in an attribute in memory or send to a dummy backend respectively.

You can find more information in the Django documentation under Email Backends. This is all you need to send an email in Django.

To switch to production, you only need to change the backend and add your email server settings to settings. Test the view by filling out the form and submitting.

If you look in the console window PowerShell or command prompt you will see the view sent the coded email straight to the console. With submitted set to True , the contact. Figure Once a valid form has been submitted, the thank you message is shown instead of the form. The contact form is a common, but simple use of a website form. Another common use for forms is to collect information from the user and save the information in the database. Examples include entering your personal information for a membership application, your name and address details for a sales order, and filling out a survey.

Using forms for collecting and saving data from users is so common Django has a special form class to make creating forms from Django models much easier— model forms.