Implements custom user authentication.

Parameters

In the following table, the description indicates the SQL data type. If you are writing your script in Java or .NET, you should use the appropriate corresponding data type. See SQL-Java data types and SQL-.NET data types.

In SQL scripts, you can specify event parameters by name or with a question mark, but you cannot mix names and question marks within a script. If you use question marks, the parameters must be in the order shown below and are optional only if no subsequent parameters are specified (for example, you must use parameter 1 if you want to use parameter 2). If you use named parameters, you can specify any subset of the parameters in any order.

Default action

Use MobiLink built-in user authentication mechanism.

Remarks

The MobiLink server executes this event upon starting each synchronization. It is executed in a transaction before the begin_synchronization transaction.

You can use this event to replace the built-in MobiLink authentication mechanism with a custom mechanism. You may want to call into the authentication mechanism of your DBMS, or you may want to implement features not present in the MobiLink built-in mechanism, such as password expiry or a minimum password length.

The parameters used in an authenticate_user event are as follows:

SQL scripts for the authenticate_user event must be implemented as stored procedures.

When the two authentication scripts are both defined, and both scripts return different authentication_status codes, the higher value is used.

The authenticate_user script is executed in a transaction along with all authentication scripts. This transaction always commits.

There are predefined scripts that you can use for the authenticate_user event to simplify authentication using LDAP, IMAP and POP3 servers.

See Authenticating to external servers.

See also

• Script parameters
• Adding and deleting scripts
• MobiLink users
• Using remote IDs and MobiLink user names in scripts
• Custom user authentication
• Authenticating to external servers
• authenticate_user_hashed connection event
• authenticate_parameters connection event
• modify_user connection event
• begin_synchronization connection event

SQL example

A typical authenticate_user script is a call to a stored procedure. The order of the parameters in the call must match the order above. The following example uses ml_add_connection_script to assign the event to a stored procedure called my_auth.

CALL ml_add_connection_script(
   'ver1', 'authenticate_user', 'call my_auth ( {ml s.username} )'
)

The following SQL Anywhere stored procedure uses only the user name to authenticate—it has no password check. The procedure ensures only that the supplied user name is one of the employee IDs listed in the ULEmployee table.

CREATE PROCEDURE my_auth( in @user_name varchar(128) )
BEGIN
  IF EXISTS
  ( SELECT * FROM ulemployee
    WHERE emp_id = @user_name )
  THEN
    MESSAGE 'OK' type info to client;
    RETURN 1000;
  ELSE
    MESSAGE 'Not OK' type info to client;
    RETURN 4000;
  END IF
END

Java example

The following call to a MobiLink system procedure registers a Java method called authenticateUser as the script for the authenticate_user event when synchronizing the script version ver1. This syntax is for SQL Anywhere consolidated databases.

CALL ml_add_java_connection_script(
   'ver1', 'authenticate_user',
   'ExamplePackage.ExampleClass.authenticateUser'
)

The following is the sample Java method authenticateUser. It calls Java methods that check and, if needed, change the user's password.

public String authenticateUser( 
  ianywhere.ml.script.InOutInteger authStatus,
  String user, 
  String pwd, 
  String newPwd )
  throws java.sql.sqlException {
  // A real authenticate_user handler would
  // handle more authentication code states.
  _curUser = user;
  if( checkPwd( user, pwd ) ) {  
    // Authentication successful.
    if( newPwd != null ) {  
      // Password is being changed.
      if( changePwd( user, pwd, newPwd ) ) {  
        // Authentication OK and password change OK.
        // Use custom code.
        authStatus.setValue( 1001 );
      } else {  
        // Authentication OK but password
        // change failed. Use custom code.
        java.lang.System.err.println( "user: "
         + user + " pwd change failed!" );
        authStatus.setValue( 1002 ); 
      } 
    } else {  
      authStatus.setValue( 1000 ); 
    } 
  } else {  
    // Authentication failed.
    authStatus.setValue( 4000 ); 
  }
  return ( null );
}

.NET example

The following call to a MobiLink system procedure registers a .NET method called AuthUser as the script for the authenticate_user connection event when synchronizing the script version ver1. This syntax is for SQL Anywhere consolidated databases.

CALL ml_add_dnet_connection_script(
   'ver1', 'authenticate_user',
   'TestScripts.Test.AuthUser'
)

The following is the sample .NET method AuthUser. It calls .NET methods that check and, if needed, change the user's password.

public string AuthUser( 
  ref int authStatus, 
  string user, 
  string pwd, 
  string newPwd ) {
  // A real authenticate_user handler would
  // handle more authentication code states.
  _curUser = user;
  if( CheckPwd( user, pwd ) ) {  
    // Authentication successful.
    if( newPwd != null ) {  
      // Password is being changed.
      if( ChangePwd( user, pwd, newPwd ) ) {  
        // Authentication OK and password change OK.
        // Use custom code.
        authStatus = 1001;
      } else {  
        // Authentication OK but password
        // change failed. Use custom code.
        System.Console.WriteLine( "user: "
         + user + " pwd change failed!" );
        authStatus = 1002; 
      } 
    } else {  
      authStatus = 1000 ; 
    } 
  } else {  
    // Authentication failed.
    authStatus = 4000; 
  }
  return ( null );
}

For a more detailed example of an authenticate_user script written in C# in .NET, see .NET synchronization example.