Provider dependencies detection

[cedricalfonsi]

In order to be able to deploy the library in various environments, it would be better to check if the primitive functions/classes of the different providers are present instead of checking if the package has been deployed in a specific vendor directory.

Even if it's a best practice to put external libraries in a vendor directory, all projects don't respect it and can't deploy your great library.

I created a pull request for the DonatjUAParser Provider : #60

Let me know if it makes sense to you

[ThaDafinser]

@cedricalfonsi the check was done that way when i started with the package (but it was not testable)

UserAgentParser/src/Provider/DonatjUAParser.php

Lines 43 to 45 in 8318722

	if (! function_exists('parse_user_agent')) {
	throw new Exception\PackageNotLoadedException('You need to install ' . $this->getComposerPackageName() . ' to use this provider');
	}

But since this package only supports composer for installation, i wasn't seeing a problem with it (expect the performance of a single file call)

In the next major version (which only support PHP7), the check will be hopefully done by this awesome package https://github.com/Ocramius/PackageVersions#package-versions

@cedricalfonsi if you find a (clean) way to test function_exists() we can probably change it.
Otherwise i suggest you to uncomment that check by hand

[ThaDafinser]

@cedricalfonsi any idea? I'm pretty sure we could do this better somehow

I'll close the PR in the meantime

[cedricalfonsi]

@ThaDafinser as composer is required to install the lib it makes sense.

I checked the composer API without any success. But we can do something by our own, knowing that the lib will be installed itself in the vendor-dir, we can find it easily.

in AbstractProvider.php

    /**
     * Get vendor dir
     *
     * @return string
     */
    protected function getVendorDir() {
        return dirname(dirname(dirname(dirname(__DIR__))));
    }

and in the providers constructs, by instance here for DonatjUAParser

    public function __construct()
    {
        if (! file_exists($this->getVendorDir() . '/' . $this->getPackageName() . '/composer.json')) {
            throw new PackageNotLoadedException('You need to install the package ' . $this->getPackageName() . ' to use this provider');
        }
    }

What do you think about that ? If ok I'll send a PR.

[ThaDafinser]

@cedricalfonsi i was thinking about this a while (that's why i reply so late, sorry about that)

By doing dirname(dirname(dirname(dirname(__DIR__)))) we limit ourself again to a fixed structure.
So that will work for no composer installation in some cases, but not for composer installation anymore.

There are two possible solutions and ways after them

• check if a package is installed over function_exists() or class_exists()
  • package can be used by none composer users
  • hard to test / mock
• leave the current file_exists()check and do it later maybe with ocramius/package-versions package
  • only composer is supported
  • easy to test

Since i know currently no reason to not use composer, i'll leave it as is for now.
If someone wants to use "modern" software, a package manager is required anyway - since the dependency cant be handled manually anymore.

_Still want to use the package without composer? Comment out the check in the __construct() method_

[cedricalfonsi]

@ThaDafinser Actually, we also use composer in our project, but the vendor-dir has a different name, that's why we need to locate it.

dirname(dirname(dirname(dirname(__DIR__)))) does the job, as the structure of the UserAgentParser is well known.

What do you mean by it "limit ourself again to a fixed structure" ? If the structure of the UserAgentParser lib will change, we will also change the getVendorDir function.

We are few in this case we renamed the vendor-dir of composer, and I agree it will be more simple to manage this case with future lib such as the one you mentioned.

[ThaDafinser]

Now i get you. You use this option? https://getcomposer.org/doc/03-cli.md#composer-vendor-dir