Extending Laravel Artisan Commands by@zachflower

Extending Laravel Artisan Commands

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Zachary Flower

Impostor.

I love Laravel.

As a PHP developer with a history of working in everything from WordPress to CodeIgniter, when Laravel came on the scene it was a revelation. From the design to the usability, it is an absolutely top-notch framework that contains untold depths of power.

That said, sometimes Laravel's own opinionated structure can get in the way of what can feel like pretty simple intentions, such as adding custom global arguments to all Artisan commands.

What do I mean by "custom global arguments?" As an example, all Artisan commands have the

same set of arguments and options that can be used during runtime:

    --raw             To output raw command list
    --format=FORMAT   The output format (txt, xml, json, or md) [default: "txt"]
    --short           To skip describing commands' arguments
-h, --help            Display help for the given command. When no command is given display help for the list command
-q, --quiet           Do not output any message
-V, --version         Display this application version
    --ansi|--no-ansi  Force (or disable --no-ansi) ANSI output
-n, --no-interaction  Do not ask any interactive question
    --env[=ENV]       The environment the command should run under
-v|vv|vvv, --verbose  Increase the verbosity of messages: 1 for normal output, 2 for more verbose output and 3 for debug

But, what if we wanted to add our own options and arguments?

A Wild Problem Has Appeared!

I've always been a pretty big fan of Heroku for both its power and ease-of-use—okay, maybe not so much lately thanks to how poorly they've communicated their most recent security incident, but historically I've been a fan.

One of Heroku's most frustrating drawbacks, though, is how limited the Scheduler is. A kind of half-assed cron, Heroku's Scheduler allows you to run any command on 10-minute, 1-hour, or 1-day intervals, which is kind of useful, but also woefully insufficient for many different types of jobs.

What if I only need something run weekly, monthly, or even yearly?

Scheduler says "no."

So, in order to work around this (within a typical Laravel application), I have traditionally added an additional argument to my Artisan commands that limits running on specific days. For example:

php artisan run:command --day=friday

Pretty simple design, right?

It gets the job done, but it's hardly scalable. Copying the same several lines of "if current day == --day parameter, then run, otherwise return 0" logic can get pretty tedious (not to mention nothing close to DRY), so I dug into Artisan to better understand how I could add additional global parameters that can be applied to all commands, rather than just the ones I specify.

Extending Artisan

Thankfully Laravel, being the object-oriented framework that it is, is pretty easy to extend. The challenge isn't so much in the extension as it is in properly writing said extension up into the rest of the application.

That said, before we can actually wire anything up, we first need to extend the Console\Application class and add our own custom --day argument. To do this, create a new file called ./app/Console/Application.php and paste the following code in:

<?php
namespace App\Console;

use Illuminate\Console\Application as Artisan;
use Illuminate\Support\Str;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;

class Application extends Artisan
{
    /**
     * Runs the current application.
     *
     * @return int 0 if everything went fine, or an error code
     */
    public function doRun(InputInterface $input, OutputInterface $output)
    {
      if ( !$this->checkDay($input) ) {
        $output->writeln(sprintf('<comment>This command can only be run on %s.</comment>', Str::plural(ucfirst($input->getParameterOption('--day')))), OutputInterface::VERBOSITY_QUIET);

        return 0;
      }

      return parent::doRun($input, $output);
    }

    protected function getDefaultInputDefinition()
    {
        $definition = parent::getDefaultInputDefinition();

        $definition->addOption(new InputOption('--day', null, InputOption::VALUE_OPTIONAL, "Only run the command on the specified day of the week"));

        return $definition;
    }

    public function checkDay(InputInterface $input)
    {
      $day = $input->getParameterOption('--day');

      if ( !$day ) {
        return true;
      }

      return strtolower(now()->englishDayOfWeek) === strtolower($day);
    }
}

What the above code is doing can be broken down into a few parts:

  1. It creates a new checkDay() method that gets our custom global parameter (--day) and checks the value against the current day of the week. If the two values are matched (or --day is not provided), then checkDay() will return true, otherwise it will return false.
  2. It extends the doRun() method and checks the value of checkDay() before running the rest of the command. If checkDay() returns false, the command will immediately return 0 and print a comment indicating that the command can only be run on the specified day.
  3. Finally, because we want anyone that types php artisan --help to know about this new argument, we extend getDefaultInputFunction() and add a new definition indicating that --day both exists, and how it works.

Wiring It Up

So, we've extended our console application, but if we were to run php artisan --help our new --day argument won't show up yet. That's because we need to tell Laravel about our new class, otherwise it will load the original Console\Application class by default.

To do this, open up ./app/Console/Kernel.php and add the following function to the Kernel class:

/**
 * Retrieve the artisan application instance.
 *
 * @return \Illuminate\Console\Application
 */
protected function getArtisan()
{
  if (is_null($this->artisan)) {
    return $this->artisan = (new \App\Console\Application($this->app, $this->events, $this->app->version()))->resolveCommands($this->commands);
  }

  return $this->artisan;
}

What the above function does is tell Laravel to load our newly defined \App\Console\Application class when setting Artisan up, rather than the default \Illuminate\Console\Application class. Because we extended the original Console\Application class, the existing functionality will still be maintained, but with the new functionality we just added.

Now, if we were to type php artisan --help, we would see a new argument listed in the response:

    --raw             To output raw command list
    --format=FORMAT   The output format (txt, xml, json, or md) [default: "txt"]
    --short           To skip describing commands' arguments
-h, --help            Display help for the given command. When no command is given display help for the list command
-q, --quiet           Do not output any message
-V, --version         Display this application version
    --ansi|--no-ansi  Force (or disable --no-ansi) ANSI output
-n, --no-interaction  Do not ask any interactive question
    --env[=ENV]       The environment the command should run under
    --day[=DAY]       Only run the command on the specified day of the week
-v|vv|vvv, --verbose  Increase the verbosity of messages: 1 for normal output, 2 for more verbose output and 3 for debug

Fin.

That's it!

All-in-all, it's a pretty straightforward change with some potentially powerful implications.


Also published at flower.codes

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