authenticate_user connection event

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

In SQL scripts, you can specify event parameters by name or with a question mark. Using question marks has been deprecated. Use named parameters instead. 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 are going to use parameter 2). If you use named parameters, you can specify any subset of the parameters in any order.

Use MobiLink built-in user authentication mechanism.

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:

• authentication_status

  The authentication_status parameter is required. It indicates the overall success of the authentication, and can be set to one of the following values:

  Returned Value	authentication_status	Description
  V <= 1999	1000	Authentication succeeded.
  2000 <= V <= 2999	2000	Authentication succeeded: password expiring soon.
  3000 <= V <= 3999	3000	Authentication failed: password expired.
  4000 <= V <= 4999	4000	Authentication failed.
  5000 <= V <= 5999	5000	Unable to authenticate because the remote ID is already in use. Try the synchronization again later.
  6000 <= V	4000	If the returned value is greater than 5999, MobiLink interprets it as a returned value of 4000.

  The value is sent to the client so it can be used to customize authentication behavior at the client.

• authentication_message

  This optional parameter provides an authentication message.

  This named parameter is initialized to NULL before its first use by a user authentication script. Its returning message is then passed into the next user authentication script, if the script takes this named parameter. The final message is translated into the character set of the remote database.

  If no error occurred during execution of the user authentication scripts, this message is then sent to the client by the MobiLink server before precessing the upload stream, regardless of the user authentication status.

  This message is sent to the client, even if the user authentication failed.

• username

  This optional parameter is the MobiLink user name.

• remote_id

  The MobiLink remote ID. You can only reference the remote ID if you are using named parameters.

• password

  This optional parameter indicates the password for authentication purposes. If the user does not supply a password, this is null.

• new_password

  This optional parameter indicates a new password. If the user does not change their password, this is null.

• new_remote_id

  This optional parameter indicates a new remote ID. If the remote ID is not new, this is null.

• new_username

  This optional parameter indicates a new user name. If the user name is not new, this is null.

• script_version

  This optional parameter specifies that the MobiLink server passes the script version string used for the current synchronization to this parameter. Question marks cannot be used to specify this parameter.

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.

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.authentication_status}, {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( inout @auth_status int, in @user_name varchar(128) )
BEGIN
  IF EXISTS
  ( SELECT * FROM ulemployee
    WHERE emp_id = @user_name )
  THEN
    MESSAGE 'OK' type info to client;
    SET @auth_status = 1000;
  ELSE
    MESSAGE 'Not OK' type info to client;
    SET @auth_status = 4000;
  END IF
END

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 void authenticateUser( 
  com.sap.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 ); 
  }
  }

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.

namespace TestScripts {
public class Test {
    string _curUser = null;
public void 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; 
  }
  }}}