New in Symfony 3.3: A simpler way to get the project root directory

April 11, 2017 • Published by Javier Eguiluz

Warning: This post is about an unsupported Symfony version. Some of this information may be out of date. Read the most recent Symfony Docs.

Contributed by Fabien Potencier in #22315

In Symfony 3.3, we're introducing a lot of changes and simplifications to prepare us for the fascinating Symfony 4.0 release that will take place on November 2017.

Some of those changes are technically minor but will have a profound effect in your applications. In Symfony applications, the well-known getRootDir() method of the Kernel class and its counterpart kernel.root_dir parameter are misleading.

They return the path where the application kernel (usually AppKernel.php) is stored. In Symfony 2 and 3 this is usually the app/ directory, so it's common to use expressions like %kernel.root_dir%/../var/ or %kernel.root_dir%/../web/. In Symfony 4, the kernel class has been moved to the src/ directory, so the previous expressions won't break.

However, given that most of the times getRootDir() is used to get the project root directory, in Symfony 3.3 we've decided to add a new method to the Kernel class called getProjectDir() which will give you exactly that.

This new method finds the project root directory by looking for the first directory that contains a composer.json file starting from the directory where the kernel is stored and going up until composer.json is found.

In practice, this means that your application can simplify most or all the expressions that use %kernel.root_dir%. For example: use %kernel.project_dir%/web/ instead of %kernel.root_dir%/../web/.

Published in #Living on the edge

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Comments

Marius Balčytis said on Apr 11, 2017 at 11:42

Second `%` is missing in the examples

Alex Rock Certified said on Apr 11, 2017 at 12:26

This is absolutely awesome!

Javier Eguiluz Certified said on Apr 11, 2017 at 12:45

@Marius fixed! Thanks.

Tiago Farias da Silva said on Apr 11, 2017 at 12:49

Small changes, however, with very good impacts!

Dennis Smink said on Apr 11, 2017 at 16:42

So true. Most of the time a create a parameter in my projects with the name "project_dir" myself.

Looks like those days are almost over. :) Cannot wait for 3.3. I personally think this version has a few of the best features ever.

Nikolai Plath said on Apr 11, 2017 at 17:37

As a Symfony newcomer this was one of the things I found confusing.
Definitely a great addition ;)

Tommy Muehle said on Apr 12, 2017 at 05:10

@Javier
What is on production where maybe no composer.json are exist because this file are excluded from deployment?

James said on Apr 12, 2017 at 13:31

Why would you not use composer for production deployment ?

Javier Eguiluz Certified said on Apr 12, 2017 at 14:09

@Tommy if we look at the code here: https://github.com/symfony/symfony/pull/22315/files, if there's no composer.json I think it goes up and up until the root directory of the computer.

Maybe you can try it in some of your project to verify this and open an issue if there's a bug. We have time to fix it until the end of May, when Symfony 3.3 is released.

Fabien Potencier Certified said on Apr 12, 2017 at 18:44

#10

If you are not deploying the composer.json file, override the getProjectDir() method in your Kernel.

Oleksandr Savchenko said on Apr 13, 2017 at 05:30

#11

It's unusually to see static methods in Symfony and it's little bit confusing :|

Ignace Knops said on Apr 13, 2017 at 06:47

#12

It's not a static method:
https://github.com/symfony/http-kernel/blob/master/Kernel.php#L317

Javier Eguiluz Certified said on Apr 13, 2017 at 11:43

#13

@Oleksandr it's not static. We use the notation "ClassName::methodName" for any method, static or not. We even use that notation in the profiler and the debug toolbar.

Tommy Muehle said on Apr 13, 2017 at 13:31

#14

@James
We use composer on a CI server but transfer only the relevant files to production.
And there can the composer.json file are excluded.

@Javier
Thanks for the answer. I will try.

@fabien
Good point.

Matteo Contri said on Apr 18, 2017 at 07:05

#15

I don't think it's wise rely on a component that is not part of symfony framework itself, i suspect it's slower than a "%kernel.root_dir%/../web/" (compiled the difference will be near zero, of course), and i guess that more people than you think exclude composer.json in deploy phase. But -hey- your framework, your rules.
It's the first feature that i don't agree at 100% :-)

Thomas Dutrion said on Apr 19, 2017 at 08:37

#16

I may be stupid or too attached to th ZF way to do things, but ZF just uses a chdir(dirname(__DIR)) in public/index.php, which makes the default path from the project root.
Using this and some other __DIR__ related paths, I never encountered any problem. Wondering what use cases may not be covered with this solution...

Bruno Ziegler said on Jun 7, 2017 at 13:54

#17

Hey @Matteo Contri I am full of your opinion. I just stumbled upon deploying process.