python - How to distinguish between multiple forms submitted in one form in Django?

Question

I have multiple forms of the same base class like this:

class DatabaseForm(forms.Form):
    active = forms.BooleanField(required=False)  # Determines, if username and password is required
    username = forms.CharField(label="Username", required=False)
    password = forms.CharField(label="Password", required=False)

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['active'].label = self.label

    def clean(self):
        cleaned_data = super(DatabaseForm, self).clean()
        active = cleaned_data.get("ative")
        username = cleaned_data.get("username")
        password = cleaned_data.get("password")
        if active and not (username and password):
            raise forms.ValidationError("Please fill in the required database configuration")

        return cleaned_data


class MySQLForm(DatabaseForm):
    label = "MySQL"


class PostgreSQLForm(DatabaseForm):
    label = "PostgreSQL"


class SqliteForm(DatabaseForm):
    label = "Sqlite3"

So only if the user chooses a database, he must fill in the username and password for it.

In my template, the form looks like this:

<form action="." method="post">
    {% csrf_token %}
    {{ mysql_form }}
    {{ postgres_form }}
    {{ sqlite_form }}
    <a id="database-submit-btn" href="#submit"
    class="btn btn-success submit-button">Submit</a>
</form>

Problem: When the user chooses a database by selecting the 'active' field, the 'active' fields of the other databases get set to True. It seems like I can't distinguish between the multiple fields, as they have the same key in the POST request (but I'm not sure that's the whole problem): 'username': ['mysql test', 'postgres test', 'sqlite test'], 'password': ['mysql password', 'postgres password', 'sqlite password']

How can I get this to work and keep the code extendable?

Answer 1

You can pass the prefix argument when you initialise your forms, this gives each field name a prefix and allows you to have multiple forms with the same field names

def foo(request):
    if request.method == 'POST':
        mysql_form = MySQLForm(request.POST, prefix='mysql')
        postgres_form = PostgreSQLForm(request.POST, prefix='postgres')
        sqlite_form = SqliteForm(request.POST, prefix='sqlite')
    else:
        mysql_form = MySQLForm(prefix='mysql')
        postgres_form = PostgreSQLForm(prefix='postgres')
        sqlite_form = SqliteForm(prefix='sqlite')

Or you can hardcode a prefix for each form in the class itself

class MySQLForm(DatabaseForm):
    label = "MySQL"
    prefix = "mysql"


class PostgreSQLForm(DatabaseForm):
    label = "PostgreSQL"
    prefix = "postgresql"


class SqliteForm(DatabaseForm):
    label = "Sqlite3"
    prefix = "sqlite3"