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We're going to install a totally new package into our app called the "security checker". The security checker is a tool that looks at your application's dependencies and tell you if any of them have known security vulnerabilities. But, full disclosure, as cool as that is... the real reason I want to install this library is because it's a great way to look at Symfony's all-important "recipe" system.
At your terminal, run:
composer require sec-checker
In a real app, you should probably pass
--dev to add this to your dev dependencies... but it won't matter for us.
There is, however, something weird here. Specifically...
sec-checker is not a valid package name! In the Composer world, every package must be
something/something-else: it can't just be
sec-checker. So what the heck is going on?
Back in PhpStorm, open up
composer.json. When we started the project, we had just a few dependencies in this file. One of them is
|... lines 2 - 3|
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This is a composer plugin that adds two special features to Composer itself. The first is called "aliases".
At your browser, go to http://flex.symfony.com to find and big page full of packages. Search for
security. Better, search for
sec-checker. Boom! This says that there is a package called
sensiolabs/security-checker and it has aliases of
security-checker and some more.
The alias system is simple: because Symfony Flex is in our app, we can say
composer require security-checker, and it will really download
You can see this in our terminal: we said
sec-checker, but ultimately it downloaded
sensiolabs/security-checker. That's also what Composer added to our
composer.json file. So... aliases are just a nice shortcut feature... but it's kinda cool! You can almost guess an alias when you want to install something. Want a logger? Run
composer require logger to get the recommended logger. Need to mail something?
composer require mailer. Need to eat a cake?
composer require cake!
The second feature that Flex adds to Composer is the really important one. It's the recipe system.
Back at the terminal, after installing the package, it said:
Symfony operations: 1 recipe configuring sensiolabs/security-checker.
Whoa! We expected
composer.lock to be modified... that's how composer works. But something also modified a
symfony.lock file... and added a totally new
symfony.lock is a file that's managed by Flex. You don't need to worry about it, but you should commit it. It keeps a big list of which recipes have been installed.
So, who created the other file? Open it up:
Each package you install may have a Flex "recipe". The idea is beautifully simple. Instead of telling people to install a package and then create this file, and update this other file in order to get things working, Flex executes a recipe which... just does that stuff for you! This file was added by the
You don't need to worry about the specifics of what's inside this file right now. The point is, thanks to this file, we have a new
bin/console command. Run:
security:check command? That wasn't there a second ago. It's there now thanks to the new YAML file. Try it:
php bin/console security:check
No packages have known vulnerabilities! Awesome!
Here is the big picture: thanks to the recipe system, whenever you install a package, Flex will check to see if that package has a recipe and, if it does, will install it. A recipe can do many things, like add files, create directories or even modify a few files, like adding new lines to your
The recipe system is a game-changer. I love it because anytime I need a new package, all I need to do is install it. I don't need to add configuration files or modify anything because the recipe automates all that boring work.
In fact, this recipe did something else we didn't notice. At the terminal, run:
git diff composer.json
We expected that Composer would add this new line to the
require section. But there is also a new line under the
scripts section. That was done by the recipe.
|... lines 2 - 3|
|... lines 5 - 8|
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|"security-checker security:check": "script"|
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Thanks to this, whenever you run:
After it finishes, it automatically runs the security checker.
The point is: to use the security checker, the only thing we needed to do was... install it. Its recipe took care of the rest of the setup.
Now... if you're wondering:
Hey! Where the heck does this recipe live? Can I see it?
That's a great question! Let's find out where these recipes live and what they look like next.