Access Control overview

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:

• in multi-user applications, you can rely on 4D users and groups,
• 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.

Access control in multi-user applications

Multi-user applications are deployed with 4D Server. They include client-server, Web, or REST applications.

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). Any part of the application can be opened.

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.

Access control in single-user applications

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. Thus user authentication is delegated to the OS level.

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

Privilégios

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).