If more than one person uses an application, which is usually the case in client-server architecture or Web interfaces, you need to control access or provide different features according to the connected users. It is also essential to provide security for sensitive data, even in single-user applications.
4D access control strategy depends on your deployment configuration:
- em aplicações multi-usuário, pode confiar nos usuários e grupos 4D,
- in single-user applications, user access is controlled through the system session, using commands such as
Current system user.
Para uma visão geral das funções de segurança de 4D, consulte o Guia de segurança de 4D.
Controlo de acesso em aplicações multi-usuário
Aplicações multi-usuário são implementadas com 4D Server. Incluem aplicações cliente-servidor, Web ou REST.
In multi-user applications, access control is done through 4D users and groups. You create users, assign passwords, create access groups that have different levels of privileges in the application.
You initiate the 4D password access control system with 4D Server by assigning a password to the Designer user. Until you give the Designer a password, all application access are done with the Designer's access rights, even if you have set up users and groups (when the application opens, no ID is required). Qualquer parte da aplicação pode ser aberta.
Quando uma senha for estabelecida para o Designer, todos os privilégios de acesso têm efeito. In order to connect to the application or to a server with protected access, remote users must enter a login/password.
Para desativar o sistema de acesso a senhas, precisa remover a senha Designer.
Controlo de acesso em aplicações usuário único
Single-user applications are desktop applications, deployed with 4D or merged with 4D Volume License. In single-user applications all users opening the application are Designers, they have all privileges and their name is "Designer". Access control is not based upon 4D users and groups, but upon user sessions.
Identificação de usuário
To identify the current user in a 4D single-user application, you can rely on the
Current system user command, which returns the user who opened the system session. Assim, a autenticação do usuário é delegada ao nível do SO.
You can then allow or deny access within your application by using code such as:
If(Current system user = $user) //you can store users in a database table
// give access to some features End if
If you want to use the system user name in 4D instead of "Designer" (e.g. in log files), you can call the
SET USER ALIAS command, for example:
SET USER ALIAS(Current system user)
Protecção do acesso
On a machine that is shared by several users, you can install the 4D application in a folder and give appropriate user access privileges to the folder at the OS level.
Encriptação de dados
If you want to protect access to the application data, we recommend to encrypt data and provide the encryption key to the authorized user(s).