# Question Helper

## Asking the User for Confirmation

Suppose you want to confirm an action before actually executing it. Add the following to your command:

    def handle(self):
        if not self.confirm('Continue with this action?', False):
            return

In this case, the user will be asked “Continue with this action?”. If the user answers with `y` it returns `True` or `False` if they answer with `n`. The second argument to `confirm()` is the default value to return if the user doesn’t enter any valid input. If the second argument is not provided, `True` is assumed.

Tip

You can customize the regex used to check if the answer means “yes” in the third argument of the `customize()` method. For instance, to allow anything that starts with either `y` or `j`, you would set it to:

    self.confirm('Continue with this action?', False, '(?i)^(y|j)')

The regex defaults to `(?i)^y`.

## Asking the User for Information

You can also ask a question with more than a simple yes/no answer. For instance, if you want to know a user name, you can add this to your command:

    def handle(self):
        name = self.ask('Please enter your name', 'John Doe')

The user will be asked “Please enter your name”. They can type some name which will be returned by the `ask()` method. If they leave it empty, the default value (`John Doe` here) is returned.

### Let the User Choose from a List of Answers

If you have a predefined set of answers the user can choose from, you could use a `ChoiceQuestion` or the `choice()` method which makes sure that the user can only enter a valid string from a predefined list:

    def handle(self):
        color = self.choice(
            'Please select your favorite color (defaults to red)',
            ['red', 'blue', 'yellow'],
            0
        )

        self.line('You have just selected: %s' % color)

The option which should be selected by default is provided with the third argument. The default is `None`, which means that no option is the default one.

If the user enters an invalid string, an error message is shown and the user is asked to provide the answer another time, until they enter a valid string or reach the maximum number of attempts. The default value for the maximum number of attempts is `None`, which means infinite number of attempts.

### Multiple Choices

Sometimes, multiple answers can be given. The `ChoiceQuestion` or `choice()` method provides this feature using comma separated values. This is disabled by default, to enable this use the `multiple` keyword if using the `choice()` method or the `multiselect` attribute if using the `ChoiceQuestion` directly:

    def handle(self):
        colors = self.choice(
            'Please select your favorite color (defaults to red and blue),
            ['red', 'blue', 'yellow'],
            '0,1'
            multiple=True
        )

        self.line('You have just selected: %s' % ', '.join(colors))

Now, when the user enters `1,2`, the result will be: `You have just selected: blue, yellow`.

If the user does not enter anything, the result will be: `You have just selected: red, blue`.

### Autocompletion

You can also specify an array of potential answers for a given question. These will be autocompleted as the user types:

    def handle(self):
        names = ['John', 'Jane', 'Paul']
        question = self.create_question('Please enter a name', default='John')
        question.set_autocomplete_values(names)

        name = self.ask(question)

### Hiding the User’s Response

You can also ask a question and hide the response. This is particularly convenient for passwords:

    def handle(self):
        password = self.secret('What is the database password?')

## Validating the Answer

You can even validate the answer. For instance, you might only accept integers:

    def handle(self):
        question = self.create_question('Choose a number')
        question.set_validator(int)
        question.set_max_attempts(2)

        number = self.ask(question)

The `validator` a callback which handles the validation. It should throw an exception if there is something wrong. The exception message is displayed in the console, so it is a good practice to put some useful information in it. The validator or the callback function should also return the value of the user’s input if the validation was successful.

You can set the max number of times to ask with the `set_max_attempts()` method. If you reach this max number it will use the default value. Using `None` means the amount of attempts is infinite. The user will be asked as long as they provide an invalid answer and will only be able to proceed if their input is valid.

## Testing a Command that Expects Input

If you want to write a unit test for a command which expects some kind of input from the command line, you need to set the helper input stream:

    def test_execute_command(self):
        command_tester = CommandTester(command)
        # Equals to a user inputting "Test" and hitting ENTER
        # If you need to enter a confirmation, "yes\n" will work

        command_tester.execute(inputs="Test\n")