Python-Django/C2/Creating-Forms-in-Django/English

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Django/C2/Creating-Forms-in-Django/English

Title of script: Creating Forms in Django

Keywords: Video tutorial, Django views, Django Forms


Visual cue Narration
Slide: Creating Forms in Django Hello and Welcome to the spoken tutorial on “Creating Forms in Django”
Slide: Learning Objectives In this tutorial, we will learn to:
  • Create a Django form
  • Create views to handle form submission
Slide: System Requirements To record this tutorial, I am using
  • Ubuntu Linux 16.04 OS
  • Python 3.5
  • Python 3.4-venv or higher
  • gedit Text Editor and
  • Firefox web browser
Slide: Prerequisites To follow this tutorial, you need to know
  • How to create models and HTML templates in Django
  • If not, then please go through the prerequisite tutorials in this website.
Slide: Forms
  • Forms are used to get data from the user
  • The data is processed on the server side
  • Users can provide the data using form elements like text fields, options, etc.
  • Django has inbuilt libraries that build forms easily
Open a Terminal window


Press CTRl+ALT+T simultaneously

Let us open the terminal by pressing Ctrl, Alt and T keys simultaneously on the keyboard.
[Terminal]

cd my-django [Enter]

Now using the cd command, go to the folder my hyphen django which we created earlier.
[Terminal]

Type source myapp_env/bin/activate

and press Enter

Activate the virtual environment myapp underscore env
[Terminal] cd mysite [Enter] Then go to the mysite folder using the cd command.
Here onwards, please remember to press the Enter key after typing each command.
[Terminal]

Type gedit blog/forms.py & [Enter]

Let us now create a form in Django using models.

To do so, create a file forms dot py in the blog directory.

Type the command as shown.

[forms.py]Type:

from blog.models import Blog, Article

from django import forms


class BlogForm(forms.ModelForm):

class Meta:

model = Blog

fields = ['name']

class ArticleForm(forms.ModelForm):

class Meta:

model = Article

fields = ['title', 'body', 'draft']

We are now in forms.py file.

Type the code as shown here.

[forms.py] Highlight


class BlogForm(forms.ModelForm):

class ArticleForm(forms.ModelForm):

Django provides a class ModelForm to create a Form from a Model.


The Form is generated using the model definition.

[forms.py] Highlight

class Meta:

To provide data to the Form class, we are using an inner class Meta.
[forms.py] Highlight

model = Blog

We are assigning the Blog model which is used to generate Form.
[forms.py] Highlight

fields = ['name']

In Meta class, Fields attribute is used to select the fields to use in the form.
[forms.py] Highlight

class ArticleForm(forms.ModelForm):

class Meta:

model = Article fields = ['title', 'body', 'draft']

Similarly we have defined an inner class named Meta with fields for the Article Form.
[forms.py] Highlight

from blog.models import Blog, Article

Here, we have imported our models, Blog and Article.
[forms.py] Highlight

from django import forms

To create django forms, we need to import forms from Django.
[forms.py] Highlight the complete code Now, we have defined Django form using models.
Press Ctrl+S Save the file.
Switch to Terminal Switch back to the terminal to create a template file to call our Django form.
[Terminal]

Type gedit blog/templates/add_blog.html & [Enter]

Create an HTML file add underscore blog in templates directory.

Type the command as shown.

[add_blog.html]Type:


<html>

<body>

<form action="" method="POST">

{% csrf_token %}

{{ form }}

<input type="submit" value="Add Blog" />

</form>

</body>

</html>

We are now in add_blog.html,


Type the code as shown here.

[add_blog.html] Highlight

{% csrf_token %}

CSRF - Cross Site Request Forgery Protection

We have to use the csrf_token tag in a template which uses the form POST request.

Django provides built-in CSRF protection to protect the server from malicious websites.

[add_blog.html] Highlight

{{ form }}

Here we have included our context variable to display our Django Form.
[add_blog.html] Highlight

<input type="submit" value="Add Blog" />

Here, we have created a button to submit the form.
[add_blog.html] Highlight the complete code We have created a HTML template to use a form passed through context.
Press Ctrl+S Save the file.
Switch to Terminal Switch to the terminal.
[Terminal]

Type gedit blog/views.py & [Enter]

Open the file views.py to use this template.


Type the command as shown.

[views.py]:


from django.shortcuts import render

from django.http import HttpResponse

from .models import Blog, Article

from blog.forms import BlogForm, ArticleForm


# Create your views here.


def index(request):

return HttpResponse("Hello World")


def get_blogs(request):

blogs = Blog.objects.all()

context = {'blogs': blogs}

return render(request, 'blog/blogs.html', context)


def add_blog(request):

if request.method == 'POST':

form = BlogForm(request.POST)

if form.is_valid():

form.save()

return HttpResponse("Blog created")

else:

context = {'form': form}

return render(request, 'add_blog.html', context)

context = {'form': BlogForm()}

return render(request, 'add_blog.html', context)

We are now in views.py file.


Type the code as shown here.



Import the BlogForm and ArticleForm






Update the get_blogs function.






Next to the get_blogs function, let us add add_blog function.


Type the code as shown here.




Here we have modified the function get_blog to get blog objects.


Also, we have defined a function add_blog.


[views.py] Highlight

if request.method == 'POST':

If this is a POST request, we need to process the form data.
[views.py] Highlight


form = BlogForm(request.POST)

We have created an instance of the BlogForm class object using the data from the POST request.


All the fields from the form are in request.POST

[views.py] Highlight

from blog.forms import BlogForm

We have imported the BlogForm from our blog’s form.
[views.py] Highlight


if form.is_valid():

Next, is_valid() method is used to check whether the entered data is valid or not.

If the data is valid then is_valid() function returns True.

Otherwise it returns False.

[views.py] Highlight

else part of def add_blog(request)

In the Else statement, when the data is empty or invalid, it will return the form with errors.
[views.py] Highlight

form.save()

When the form data is valid, we save a new Blog object from the form.
[views.py] Highlight

return HttpResponse("Blog created")

After successful addition of the blog, let’s return something.


So the return statement returns HttpResponse with the string “Blog created”.

[views.py] Highlight

context = {'form': BlogForm()}

If the request is GET_ request, then this will be executed.

An empty form instance of BlogForm is created.

Then, the form instance is added to context.

This context will be provided to the HTML template while rendering.

[views.py] Highlight

form = BlogForm(request.POST)

This is what will happen when a form is submitted using a POST request.

A form instance is created and data from the request is populated with it.

This is called “binding data to the form”.

It is now a bound form

[views.py] Highlight

from django.shortcuts import render

from django.http import HttpResponse

from .models import Blog, Article

Here we can see that, the necessary modules have already been imported.
[views.py] Highlight

def add_blog(request) section

We have added a function in our views to add Blog with use of Form data.
Press Ctrl+S Save the file.
Switch to Terminal Switch to the Terminal.
[Terminal]

Type gedit blog/urls.py & [Enter]

Now, we will insert the path in the URL configuration.

Type the command as shown.

[urls.py]

Type path('add_blog/', views.add_blog, name='add_blog'),

We are now in urls.py file in blog app.

Insert the new path as shown here.

[urls.py] We have added the path in blog app Urls.

And there are no changes in the root Urls.

Press Ctrl+S Save the file.
Switch to Terminal Switch to the Terminal.
[Terminal]

Press CTRL+SHIFT+T

For our convenience, let us run the Django server in a separate terminal.

Press Shift, Ctrl and T keys simultaneously.

[Terminal Tab 2]Type: cd ..

Type source myapp_env/bin/activate

and press Enter

In the new terminal tab, go to my-django directory using the cd command.

Activate the virtual environment.

[Terminal tab 2] type cd mysite

Type python manage.py runserver [Enter]

Now go to the mysite folder using cd command

Start the server.

Open a browser and type

http://localhost:8000/blogs/add_blog

Now we will call the view function add underscore blog.

Open the web browser, and type the URL as shown and press Enter.

[browser]

Point to the form

Here, we see a form with a labelled text Name.

Along with the input textbox and a Submit button.

[browser] (Cursor at text box)

press space key

Let us first try with some invalid data.

In the textbox enter spaces by pressing Space key multiple times.

[browser] Click Add Blog Click on the Add Blog button to save.
[browser]

(pointing to the error message)

Here, we see an error message “This field is required.”

So the blog is not created with invalid data.

[gedit] blog/views.py highlight

if form.is_valid():...

else:

context = {'form': form}

return render(request, 'add_blog.html', context)

In this way we can handle the invalid data.


We check if the form is valid or not and handle the request accordingly.

[browser] (Cursor at text box)

Type MY BLOG

Now, let us type MY BLOG in the text box.
[browser]

Click Add Blog

Click on the Add Blog button to save the Blog.
[browser]

(pointing to the web page)

Now, after submission, we get the response as Blog created.
Switch to views.py file from browser Let us now move to our views.py file to edit the existing Blog.
[views.py]Type:


def add_blog(request, blog_id=None):

if blog_id:

blog = Blog.objects.get(id=blog_id)

else:

blog = Blog()

if request.method == 'POST':

form = BlogForm(request.POST, instance=blog)

if form.is_valid():

form.save() return

get_blogs(request) else:

context = {'form': form}

return render(request, 'add_blog.html', context)

blog_form = BlogForm(instance=blog)

context = {'form': blog_form, 'blog': blog}

return render(request, 'add_blog.html', context)

Modify the function add_blog in the views.py file as shown here.



Pause the tutorial and update the code as shown.


[views.py] Highlight

if blog_id

blog = Blog.objects.get(id=blog_id)

When id matches with blog id, get function returns the corresponding blog object.
[views.py] Highlight

else:

blog = Blog()

In the Else statement, an unbound instance of the Blog is created.
[views.py] Highlight

if form.is_valid():

form.save()

return get_blogs(request)

When the form validation is done, the changes are saved.


Return statement contains our view function get_blogs.

[views.py] Highlight

get_blogs(request)

The view function get_blogs is used to get the blog objects that we have created.
[views.py] Highlight

blog_form = BlogForm(instance=blog)

Here, we create a form instance BlogForm.
[views.py] Highlight

instance=blog

instance equal to blog will initialize the values of the form fields.

These values are provided by the blog object.

[views.py] Highlight

context = {'form': blog_form, 'blog': blog}

Here, we set the context variable as "form" and "blog".
[views.py] Highlight

'blog': blog

blog is the context variable that contains Blog objects as key value.
Press Ctrl+S Save the file.
Switch to templates/add_blog.html file Now, switch to add_blog.html file under templates.
[add_blog.html]Type:


<html>

<body>

<form action="/blogs/add_blog/{{ blog.id }}/" method="POST">

{% csrf_token %}

{{ form }}

<input type="submit" value="Submit" />

</form>

</body>

</html>



Replace the code as shown here.




[add_blog.html] Highlight

<form action="/blogs/add_blog/{{ blog.id }}/" method="POST">

In form action, include the reference path to the existing blog object.
[add_blog.html]

Highlight the complete code

So now we can edit our existing blog object using id.
Press Ctrl+S Save the file.
Switch to blog/urls.py Switch to urls.py file in the blog directory to include the path.
[urls.py] Type

path('add_blog/<int:blog_id>/', views.add_blog, name='edit_blog'),

Add a new URL path as shown here.
[urls.py] Highlight


path('add_blog/<int:blog_id>/', views.add_blog, name='edit_blog'),

Here, we have included add_blog path with int blog_id.


So that we can edit the existing blog object using blog id.

[urls.py] Highlight


path('add_blog/', views.add_blog, name='add_blog'),

path('add_blog/<int:blog_id>/', views.add_blog, name='edit_blog'),

The two URL paths, "add blog" and "edit blog" are different.


But handled by the same view function.

Press Ctrl+S Save the file.
Switch to Terminal Let us now edit blogs.html
[Terminal Tab 1]


Type gedit blog/templates/blog/blogs.html & [Enter]

Switch to the first terminal.

Type the command as shown.

[blogs.html] Type:


<!DOCTYPE html>

<html>

<body>

<h3>Edit Blog: </h3> <nowiki> {% if blogs %} <nowiki> <ul>

{% for blog in blogs %}

<li>{{blog.name}}<a href='/blogs/add_blog/{{blog.id}}'> [Edit]</a></li>

{% endfor %}

{% else %}

<p>No Blog articles are available.</p>

</ul>

{% endif %}

</body>

</html>



Update the code as shown here.



[blogs.html] Highlight

<li>{{blog.name}}<a href='/blogs/add_blog/{{blog.id}}'> [Edit]</a></li>

Here we have added the link that redirect to edit existing blog.
[blogs.html] Highlight

{{ blog.name }}

blog.name will display the particular blog object that matches with its blog id.
[blogs.html] Highlight

<p>No Blogs are available.</p>

If there is no blogs available, else statement returns "No Blogs are available".
Press Ctrl+S Save the file.
We have now set everything to edit the existing Blog title.
Switch to browser Now, switch to the browser.
[browser] Open a browser and type


http://localhost:8000/blogs/get_blogs/ [Enter]

In the address bar, type the URL as shown and press Enter.
[browser]

(pointing to the web page)

Here, we see the Blogs which we have created earlier in this series with an edit option.


Blog models which we have created in this tutorial are also available.

[browser]


Click Edit (beside blog name MY BLOG)

Beside blog name MY BLOG, click on Edit.


It will redirect to the edit form page.

[browser]

Type Newly Edited Blog (in Text Box)

Now, change the blog name into “Newly Edited Blog”.
[browser]

Click Submit

Then click on the Submit button.

We see the blog name has been changed from My Blog to Newly Edited Blog.

Switch to the terminal. This is how we create and edit a blog using Django Form.

Switch to the second terminal.

Terminal] Press Ctrl+C keys

Type deactivate [Enter]

Stop the server.

And deactivate the virtual environment.

Switch to Slide With this, we come to the end of this tutorial.

Let us summarize.

Slide: Summary In this tutorial, we have learnt to
  • Create a Django form
  • Create views to handle form submission
Slide: Assignment As an assignment,
  • Create and edit Article using Django Form
Slide: About Spoken Tutorial project The video at the following link summarises the Spoken Tutorial project.

Please download and watch it.

Slide: Spoken Tutorial workshops The Spoken Tutorial Project team conducts workshops and gives certificates.

For more details, please write to us.

Slide: Forum for specific questions: Please post your timed queries in this Forum.
Slide: FOSSEE to answer questions Please post your general or technical questions in this Forum.
Slide: Acknowledgement Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.

More information on this mission is available at this link.

Slide: Thanks Slide This script has been contributed by Thiagarajar College of Engineering and the FOSSEE Project, IIT Bombay.

The video has been recorded by Praveen from Spoken Tutorial Project, IIT Bombay.

Thanks for watching.

Contributors and Content Editors

Nancyvarkey, Pravin1389

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