CMB2 Dependency with Composer

Here is the short answer for how I installed CMB2 as a dependency with Composer for my plugin.

{
    "require": {
        "cmb2/cmb2": "^2.2"
    },
    "autoload"    : {
        "files": [
            "vendor/cmb2/cmb2/init.php"
        ]
    },
    "extra": {
        "installer-paths": {
            "vendor/cmb2/cmb2": ["cmb2/cmb2"]
        }
    }
}

Details of composer.json

Require

The require section, tells Composer the package (and version) we are installing. We are requiring cmb2/cmb2.

Autoload

We need to execute the CMB2 init.php code every time, so we specifically tell Composer it should load (and run) the code in vendor/cmb2/cmb2/init.php. This gets the plugin started for us.

Extra

Interestingly, on the first project where I installed CMB2 as a dependency I didn’t need this section. I was baffled when on the next project, CMB2 was installing in /wp-content/plugins instead of /vendor. The problem on the second project is that the package composer/installers was also being installed.

What does composer/installers do?

The package composer/installers looks for the value type in composer.json. In the case of CMB2, the value is

"type": "wordpress-plugin"

When a registered type (like wordpress-plugin) is found, the install path is modified. Since CMB2 is primarily a plugin, this makes sense. In my first project, since the package composer/installers was not included, the type value was ignored.

Override the Override

Since composer/installers overrides the install location for CMB2 because of "type": "wordpress-plugin", we have to override that override value to put it back in the original location.

Installed without installing

Troubleshooting this was even more complex because I’m not actually including composer/installers. Instead, I’m including johnbillion/extended-cpts, which in turn has composer/installers as a dependency therefore composer/installers was being installed.

Why Include CMB2 at All?

This is a valid question. Since CMB2 is a stand-alone plugin, I could add a note that this additional plugin is necessary to use the code. Alternatively, I could use something like TGM Plugin Activation to prompt the user to install CMB2 on activation of my plugin. However, CMB2 has a nice mechanism in place to load only the latest version of itself when it is included in multiple forms (i.e. as part of a plugin, part of a theme, or as a separate plugin). This coupled with the convenience of reducing the steps the user needs to complete (and coupled with the fact I’m only including a couple of extra lines in composer.json) makes this a practical decision for me.

Image Credit

Pixabay

Sal Ferrarello (@salcode)

Sal is a PHP developer with a focus on the WordPress platform. He is a conference speaker with a background including Piano Player, Radio DJ, Magician/Juggler, Beach Photographer, and High School Math Teacher. Sal can be found professionally at WebDevStudios, where he works as a senior backend engineer.