Why can't i import ciphersweet StringProvider - php

Question

I installed ciphersweet on my server using composer but when i try to import the library i'm getting this error.
Fatal error: Uncaught Error: Class 'ParagonIE\CipherSweet\KeyProvider\StringProvider' not found in index.php.
Seems like the dependency didn't install correcty, i'm lost can you help please.
It's a php error.
here's my code :
use ParagonIE\CipherSweet\EncryptedRow;
use ParagonIE\CipherSweet\Transformation\AlphaCharactersOnly;
use ParagonIE\CipherSweet\Transformation\FirstCharacter;
use ParagonIE\CipherSweet\Transformation\Lowercase;
use ParagonIE\CipherSweet\Backend\FIPSCrypto;
use ParagonIE\CipherSweet\KeyProvider\StringProvider;
$provider = new StringProvider('a981d3894b5884f6965baea64a09bb5b4b59c10e857008fc814923cf2f2de558');
$engine = new CipherSweet($provider, new FIPSCrypto());
/** #var CipherSweet $engine */
$row = (new EncryptedRow($engine, 'contacts'))
->addTextField('first_name')
->addTextField('last_name')
->addFloatField('latitude')
->addFloatField('longitude');
// Notice the ->addRowTransform() method:
$row->addCompoundIndex(
$row->createCompoundIndex(
'contact_first_init_last_name',
['first_name', 'last_name'],
64, // 64 bits = 8 bytes
true
)
->addTransform('first_name', new AlphaCharactersOnly())
->addTransform('first_name', new Lowercase())
->addTransform('first_name', new FirstCharacter())
->addTransform('last_name', new AlphaCharactersOnly())
->addTransform('last_name', new Lowercase())
);
$prepared = $row->prepareRowForStorage([
'first_name' => 'Jane',
'last_name' => 'Doe',
'latitude' => 52.52,
'longitude' => -33.106,
'extraneous' => true
]);
var_dump($prepared);
?>

Answer 1

You need to load the vendor/autoload.php in order for the installed packages to work.
For example, add require_once __DIR__ . '/vendor/autoload.php'; to the top of your file.
This will make php aware of the namespaces in your packages.
You might need to change this if your files are not in the root directory of your application. For example, if your files are in app/ directory, those files need to use require_once __DIR__ . '/../vendor/autoload.php'
See https://getcomposer.org/doc/01-basic-usage.md#autoloading for more details.