MDS Lesson 5

Forms

What are they for?

Pass user input to server

• search queries
• login
• add/update records

Processing a form

1. Enter Data
2. Submit Data
3. Validate Data
4. Act on Data

A Form in HTML

<form method="GET" action="/search/">
    <fieldset>
        <caption> Search </caption>
        <input type="text" name="q">
        <button type="submit">Search</button>
    </fieldset>
</form>

A Login Form

<form method="POST" action="/login/">
    <formset>
        <caption> Log In </caption>
        <input type="text" name="username">
        <input type="password" name="password">
        <button type="submit">Log In</button>
    </formset>
</form>

GET versus POST ?

GET

POST

• Data show in URL
• Idempotent
• Cachable

• Data sent in body
• Changes state of server
• Not cahable

Django Forms

• Declarative - document fields
• Validation
• HTML generation

The Login Form

from django import forms

class LoginForm(forms.Form):
    username = forms.TextField()
    password = forms.PasswordField()

The Form View

from .forms import SearchForm

def login(request):
    if request.method == 'POST':

        form = SearchForm(request.POST)
        if form.valid():
            ...
            return redirect(request.user)
    else:
        form = SearchForm()

    return render(request, 'login.html', {'form': form})

What about Validation?

• Field
• Custom per field
• Custom per form