FTP From PL/SQL

Sometimes it's preferable to trigger FTP jobs directly from PL/SQL rather than rely on CRON or AT. This article contains a brief description of the two methods I use.

The first method relies on a java stored procedure, described in Shell Commands From PL/SQL, which can be used to trigger a shell script to perform the transfer. The shell script may look like the following:

#! /bin/ksh

# Move to appropriate directory on local server
cd /extracts

# FTP all files in directory
ftp -inv ftp.company.com <<EOF
user ftpuser ftppassword
# Move to appropriate directory on remote server.
cd /loads
ascii
mput *.*
bye
EOF

The second approach uses a combination of the UTL_TCP and UTL_FILE packages to create a simple FTP API (ftp.pks, ftp.pkb). Once the API is loaded into the appropriate schema simple FTP commands can be initiated as follows:

CREATE OR REPLACE DIRECTORY my_docs AS '/u01/app/oracle/';
SET SERVEROUTPUT ON SIZE 1000000
@c:\ftp.pks
@c:\ftp.pkb

-- Retrieve an ASCII file from a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.ascii(p_conn => l_conn);
  ftp.get(p_conn      => l_conn,
          p_from_file => '/u01/app/oracle/test.txt',
          p_to_dir    => 'MY_DOCS',
          p_to_file   => 'test_get.txt');
  ftp.logout(l_conn);
END;
/

-- Send an ASCII file to a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.ascii(p_conn => l_conn);
  ftp.put(p_conn      => l_conn,
          p_from_dir  => 'MY_DOCS',
          p_from_file => 'test_get.txt',
          p_to_file   => '/u01/app/oracle/test_put.txt');
  ftp.logout(l_conn);
END;
/

-- Retrieve a binary file from a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.binary(p_conn => l_conn);
  ftp.get(p_conn      => l_conn,
          p_from_file => '/u01/app/oracle/product/9.2.0.1.0/sysman/reporting/gif/jobs.gif',
          p_to_dir    => 'MY_DOCS',
          p_to_file   => 'jobs_get.gif');
  ftp.logout(l_conn);
END;
/

-- Send a binary file to a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.binary(p_conn => l_conn);
  ftp.put(p_conn      => l_conn,
          p_from_dir  => 'MY_DOCS',
          p_from_file => 'jobs_get.gif',
          p_to_file   => '/u01/app/oracle/jobs_put.gif');
  ftp.logout(l_conn);
END;
/

-- Get a directory listing from a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
  l_list  ftp.t_string_table;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.list(p_conn   => l_conn,
           p_dir   => '/u01/app/oracle',
           p_list  => l_list);
  ftp.logout(l_conn);
  
  IF l_list.COUNT > 0 THEN
    FOR i IN l_list.first .. l_list.last LOOP
      DBMS_OUTPUT.put_line(i || ': ' || l_list(i));
    END LOOP;
  END IF;
END;
/

-- Get a directory listing (file names only) from a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
  l_list  ftp.t_string_table;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.nlst(p_conn   => l_conn,
           p_dir   => '/u01/app/oracle',
           p_list  => l_list);
  ftp.logout(l_conn);
  
  IF l_list.COUNT > 0 THEN
    FOR i IN l_list.first .. l_list.last LOOP
      DBMS_OUTPUT.put_line(i || ': ' || l_list(i));
    END LOOP;
  END IF;
END;
/

-- Rename a file on a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.rename(p_conn => l_conn,
             p_from => '/u01/app/oracle/dba/shutdown',
             p_to   => '/u01/app/oracle/dba/shutdown.old');
  ftp.logout(l_conn);
END;
/

-- Delete a file on a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.delete(p_conn => l_conn,
             p_file => '/u01/app/oracle/dba/temp.txt');
  ftp.logout(l_conn);
END;
/

-- Create a directory on a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.mkdir(p_conn => l_conn,
            p_dir => '/u01/app/oracle/test');
  ftp.logout(l_conn);
END;
/

-- Remove a directory from a remote FTP server.
DECLARE
  l_conn  UTL_TCP.connection;
BEGIN
  l_conn := ftp.login('ftp.company.com', '21', 'ftpuser', 'ftppassword');
  ftp.rmdir(p_conn => l_conn,
            p_dir  => '/u01/app/oracle/test');
  ftp.logout(l_conn);
END;
/

The basic functions are implemented using LOBs to allow FTP without having to access files on the local filesystem. The get and put procedures string these together to form a complete job using all the functions. If a straight forward FTP to, or from, the local filesystem is required it is more efficient to use the GET_DIRECT and PUT_DIRECT procedures as they avoid the temporary LOBs.

The current implementation has the following issues:

The mput and mget operations are not supported directly, but can be implemented using a combination of the list/nlst and get/put operations.
The implementation of binary transfers relies on UTL_FILE features only available in Oracle9i Release 2 upwards.
There is no support for ASCII mode in the PUT_DIRECT procedure.

Thanks to Hans van Doormalen for noticing I wasn't closing my passive connections. I do now :)

If you are using Oracle 11g you will need to configure an access control list (ACL) to allow UTL_TCP to access the network. The examples above work correctly with the following basic ACL. You will need to amend the FTP server and username details to match your FTP server address and the Oracle username running the FTP API.

DECLARE
  l_acl_name    VARCHAR2(30) := 'utl_tcp.xml';
  l_ftp_server  VARCHAR2(20) := '192.168.2.131';
  l_username    VARCHAR2(30) := 'TEST';
BEGIN
  DBMS_NETWORK_ACL_ADMIN.create_acl (
    acl          => l_acl_name, 
    description  => 'Allow connections using UTL_TCP',
    principal    => l_username,
    is_grant     => TRUE, 
    privilege    => 'connect',
    start_date   => SYSTIMESTAMP,
    end_date     => NULL);

  COMMIT;

  DBMS_NETWORK_ACL_ADMIN.add_privilege ( 
    acl         => l_acl_name, 
    principal   => l_username,
    is_grant    => FALSE, 
    privilege   => 'connect', 
    position    => NULL, 
    start_date  => NULL,
    end_date    => NULL);

  COMMIT;

  DBMS_NETWORK_ACL_ADMIN.assign_acl (
    acl         => l_acl_name,
    host        => l_ftp_server, 
    lower_port  => NULL,
    upper_port  => NULL);

  COMMIT;
END;
/

For more information see:

Hope this helps. Regards Tim...

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