PHP-在另一个名称空间中使用一个名称空间

Question

I'm trying to use some files from another namespace inside one of my own namespaces, however it's not recognising the exceptions from the Defuse\\Crypto namespace.

I've checked all the files, and everything is there stored perfectly in my directory. I can include the autoloader with no exceptions too.

What can I do to cleanly use both namespaces in the same file?

Here's my code:

namespace Defuse\Crypto;

$path = '/my/path/to/DefuseCrypto/autoloader';
require_once $path;

use \Defuse\Crypto\Crypto;
use \Defuse\Crypto\Exception as Ex;

namespace myNamespace;

class myClass
{
    static function encrypt_key($key)
    {
        try
        {
            $ciphertext = Crypto::encrypt($key, $privateKey);
            return $ciphertext;
        }
        catch (Ex\CryptoTestFailedException $ex)
        {
            return false;
        }
        catch (Ex\CannotPerformOperationException $ex)
        {
            return false;
        }
    }

    static function decrypt_key($key)
    {
        try
        {
            $decryptedKey = Crypto::decrypt($key, $privateKey);
            return $decryptedKey;
        }
        catch (Ex\InvalidCiphertextException $ex)
        {
            return false;
        }
        catch (Ex\CryptoTestFailedException $ex)
        {
            return false;
        }
        catch (Ex\CannotPerformOperationException $ex)
        {
            return false;
        }
    }
}

Answer 1

Of course you can use namespaces in classes. But you start from root with leading \\

Try this:

use Defuse\Crypto\Crypto;
use Defuse\Crypto\Exception as Ex;

After namespaces are included, you can use them. If you want to use a namespace often (more than 1 time), include namespaces in the top. Otherwise, you can use the full path at the place where you need.

Further, for maintainbility reasons use max. 1 namespace line.

Change your first line in:

namespace myNamespace;

And remove the second namespace line!

Answer 2

Three options: either you specify the fully qualified (so absolute) namespace directly:

catch (\Defuse\Crypto\Exception\CryptoTestFailedException $ex)

Or you use a relative namespace inside the currently active namespace:

catch (Exception\CryptoTestFailedException $ex)

Or you have to declare the namespace under an alias for internal usage just as @HenriS. suggested above:

use Defuse\Crypto\Exception as Ex;
[...]
catch (Ex\CryptoTestFailedException $ex)

In general nothing speaks against using multiple namespaces in one file, that is common. But I agree with @HenriS. here that it is not a good practice to create a separate namespace for exceptions.