Choose Options with the new DialogHelper::select¶

Suppose that we want to make sure that one of a few things is chosen. We’re already using the DialogHelper to ask for a thing. Now, let’s create an array of our favorite items and use the select function:

protected function execute(InputInterface $input, OutputInterface $output)
{
    /** @var $dialog \Symfony\Component\Console\Helper\DialogHelper */
    $dialog = $this->getHelper('dialog');

    $favoriteItems = array(
        'Symfony',
        'Ice Cream',
        'Documentation',
    );

    $index = $dialog->select(
        $output,
        'What do you want more of? ',
        $favoriteItems
    );
    $favoriteThing = $favoriteItems[$index];

    $output->writeln(sprintf(
        'I heard you liked <comment>%s</comment>, so I put more <comment>%s</comment> in your <comment>%s</comment>',
        $favoriteThing,
        $favoriteThing,
        $favoriteThing
    ));
}

When we try it, we get more of your favorite thing!

Command-Line Auto-completion¶

Let’s keep going. Another function on the dialog helper is askAndValidate, which has actually always existed. First, create a simple validation function that makes sure the value is one of our things. Next, use the askAndValidate function instead of select:

$validation = function($thing) use ($favoriteItems) {
    if (!in_array($thing, $favoriteItems)) {
        throw new \InvalidArgumentException(sprintf(
            '"%s" is not one of my favorite things!',
            $thing
        ));
    }

    return $thing;
};

$favoriteThing = $dialog->askAndValidate(
    $output,
    'What do you want more of?',
    $validation,
);

When we try it, it’s pretty simple - we type anything, and it keeps asking us until we enter a valid value. This is actually a bit worse than using select, but stay with me!

Change the askAndValidate method slightly - passing false and null to the default max tries and default value arguments and then finally the array of $favoriteItems next:

$favoriteThing = $dialog->askAndValidate(
    $output,
    'What do you want more of?',
    $validation,
    false,
    null,
    $favoriteItems
);

Try this again. At first, it looks the same. But as soon as we type anything, it starts auto-completing our answer. How cool is that!

Showing a Progress Bar¶

Let’s add just one more fancy thing. A lot of times, I write console tasks to handle long-running processes. I normally wouldn’t admit this but, I can be a bit impatient, I always want to know how far through the process I am. Normally I set some variables and print out a status message. Now there’s a much better way.

First, setup a loop that pauses in the middle randomly - this will be our “fake” long-running process:

foreach (str_split($favoriteThing) as $char) {
    usleep(rand(100000, 1000000));
}

Next, grab the ProgressHelper by using the getHelper function. This is brand new to Symfony 2.2 and it works by showing details about how far along the process is. Start it with, well the start function, which takes the number of “steps” as its second argument. If you were looping through 1000 database records, you’ll probably set this to 1000:

/** @var $progressHelper \Symfony\Component\Console\Helper\ProgressHelper */
$progressHelper = $this->getHelper('progress');
$progressHelper->start($output, strlen($favoriteThing));
foreach (str_split($favoriteThing) as $char) {
    // ...
}

Now, on each loop, simply call advance to move the progress bar through one step:

foreach (str_split($favoriteThing) as $char) {
    usleep(rand(100000, 1000000));

    $progressHelper->advance();
}

That’s it, let’s run this and see what happens! This time, we get a really cool progress bar that shows us exactly where things are.

You can even control how this looks, using a number of different functions on the ProgressHelper class. The easiest is setFormat, which let’s you choose how “verbose” the progress bar should be. Let’s choose FORMAT_VERBOSE to see the most details possible:

$progressHelper->setFormat(
    \Symfony\Component\Console\Helper\ProgressHelper::FORMAT_VERBOSE
);

If you’re not used to building your own custom console commands, they’re easy and powerful! And even if you’re not using Symfony, you can use just the Console component to create single-file, standalone command-line applications.