New class: SecurityData

Some secrets could be stored in a configuration file or in environment variables.

This allows to be compliant with http://12factor.net/config

How to use this class?

You can so define in the web server:
fastcgi_param CREDENTIAL_SECRET_ONE secret1value
fastcgi_param CREDENTIAL_SECRET_TWO secret2value
fastcgi_param CREDENTIAL_SECRET_THREE secret3value

Or you can instead:
fastcgi_param CREDENTIAL_PATH_DATASOURCES_SECURITYDATA /path/to/json/file;

This file must be a JSON object, each key the secret name:
{

"secret.one": "secret1value",
"secret.two": "secret2value",
"secret.three": "secret3value"

}

CREDENTIAL_ prefix and path.datasources.securitydata are customizable,
as they are class the constants ENV_PREFIX and SECRET_FILE.

Methods offered:

• getSecret recovers a secret;
• getSecretFromFile recovers a secret only from file;
• getSecretFromEnvironment recovers a secret only from env.

Helper methods offered:

• getSecretFromObject recovers a file from a PHP object;
• getSecretFilePath gets the path of the file containing secrets;
• getEnvironmentVariableName returns the name of the environment variable from the secret key.