Installing and Configuring the Natural Web I/O Interface Server

On Linux, the server part of the Natural Web I/O Interface runs in the background as a so-called daemon.

This document covers the following topics:

Installing the Natural Web I/O Interface Daemon

The Natural Web I/O Interface daemon is installed with Natural for Linux if the corresponding option is set during the installation. See the Installation documentation for further information.

Setting Up the Natural Web I/O Interface Components

Setting up the Natural Web I/O Interface on Linux consists of the following steps:

Step 1: Stop the Natural Web I/O Interface Daemons

This step is only required for an upgrade installation. It is not required when you install the Natural Web I/O Interface for the first time.

  1. Stop the nwosrvd process using the following command: 

    nwosrvd.sh portnumber stop

    Or use the script $NAT_HOME/INSTALL/nwosrvd.bsh which will be generated during the Natural Web I/O Interface installation for a specified port. 

    nwosrvd.bsh stop

  2. Repeat the above command (with an adapted port in script nwosrvd.bsh, if applicable) for each Natural Web I/O Interface service that is needed.

Step 2: Establish the Environment

  • Besides the settings for the Natural environment, additional settings for the Natural Web I/O Interface environment must be set. Ensure that the environment settings for Natural are set by the natenv environment script. The nwoenv environment script is called by the natenv environment script. Therefore, the Natural Web I/O Interface environment will be set with the Natural environment if it is set after the Natural Web I/O Interface installation.

    If the Natural Web I/O Interface environment is to be separate from the Natural environment, use the shell script nwoenv or nwoenv.csh by entering one of the following commands: 

    source nwoenv
    source nwoenv.csh

    These scripts can be found after the installation in $NAT_HOME/INSTALL.

Step 3: Install Natural and the Natural Web I/O Interface

  • The Natural Web I/O Interface can be selected in the Choose Packages screen during the Natural installation.

    Optionally, you may install a runlevel script to start/stop a Natural Web I/O Interface daemon when the machine starts/stops.

    After the Natural installation has finished, the Natural Web I/O Interface must be activated by starting Natural through a Natural Web I/O Interface client on Windows.

    When a runlevel script is used, the Natural Web I/O Interface daemon can only be administered by the user "root".

    When you install Natural with the Natural Web I/O Interface, the directory $NAT_HOME/nwo/$NWONODE is created. The template files located in $NAT_HOME/nwo/node-name are then copied to this new directory.

Step 4: Check the Environment Variables for the Natural Web I/O Interface

  • The Natural Web I/O Interface-specific settings are shown below:

    Environment Variable Description
    NWODIR The home directory for the product located at $NAT_HOME/nwo.
    NWONODE The name of the node (machine) on which the Natural Web I/O Interface is installed.
    NWO_SRVDCONF The configuration file $NAT_HOME/nwo/$NWONODE/nwosrvd.conf for the Natural Web I/O Interface daemon.
    NWO_TIMEOUT The maximum time, in seconds, that the Natural Web I/O Interface daemon will wait for a response. "0" means no timeout. The Natural Web I/O Interface daemon will terminate when it receives the timeout.

Step 5: Read the READ_NWO Files

  1. Access the directory $NAT_HOME/nwo and check the files READ_NWO.TXT and READ_NWO.FIX for any version-specific installation considerations concerning the particular platform.

  2. Add the services as described in the file READ_NWO.TXT.

Directories

The following directories are created when Natural is installed together with the Natural Web I/O Interface on a Linux system:

Directory Description
$NAT_HOME Top-level Natural directory.
$NATDIR Only used for compatibility with previous versions. Top-level Natural directory.
$NATDIR/$NATVERS Only used for compatibility with previous versions. The version subdirectory has been removed. Since $NATVERS is set to ".", it equals $NAT_HOME and $NATDIR.
$NWODIR Directory with the Natural Web I/O Interface components for the current version.
$NWONODE Contains the name of the machine (uname -n).
$NAT_HOME/INSTALL Shell scripts and environment files for the Natural Web I/O Interface (nwoenv, nwoenv.csh).
$NWODIR/bin Natural Web I/O Interface executable files (nwosrvd, nwosrvd.tr).
$NWODIR/node-name Contains the template files (nwosrvd.sh, nwo.sh, nwosrvd.conf).
$NWODIR/nwoexuex/userexit1 Contains the files for building the libnwouserexit1.
$NWODIR/nwoexuex/userexit2 Contains the files for building the libnwouserexit2.
$NAT_HOME/nwo/$NWONODE Work directory, contains the configuration files (nwosrvd.sh, nwo.sh, nwosrvd.conf).

Note:
The above table lists the most important directories and files.

Configuring the Natural Web I/O Interface Daemon on Linux

When the Natural installation has finished, the directory $NAT_HOME/nwo/$NWONODE contains the files nwosrvd.conf, nwosrvd.sh and nwo.sh.

The configuration of the Natural Web I/O Interface daemon can be done using the Natural Web I/O Interface daemon commands or by editing the configuration file nwosrvd.conf.

The following topics are covered below:

Natural Web I/O Interface Daemon Commands

The following commands can be specified at the Linux command prompt:

Command Description
nwosrvd –help

Shows all available Natural Web I/O Interface daemon commands and subcommands.

nwosrvd –v

Shows the version of the Natural Web I/O Interface daemon.

nwosrvd nnnn

Defines the listening port number.

nwosrvd –show

Shows the configuration of the Natural Web I/O Interface daemon.

nwosrvd -config keys

Changes the configuration of the Natural Web I/O Interface daemon. The following keys can be specified:

–host=hostname

The host name used.

-userexit1=pathname

The message defined with this key is saved in the UserExit1 key of the configuration file nwosrvd.conf, section [UserExits].

–userexit2=pathname

The message defined with this key is saved in the UserExit2 key of the configuration file nwosrvd.conf, section [UserExits].

–passparam=parameters

The message defined with this key is saved in the Parameters key of the configuration file nwosrvd.conf, section [PasswdArguments].

–passold=message

The message defined with this key is saved in the EnterOldPassword key of the configuration file nwosrvd.conf, section [PasswdMessages].

–passnew=message

The message defined with this key is saved in the NewPassword key of the configuration file nwosrvd.conf, section [PasswdMessages].

–passreenter=message

The message defined with this key is saved in the ReEnterNewPassword key of the configuration file nwosrvd.conf, section [PasswdMessages].

–passsuccess=message

The message defined with this key is saved in the PasswordSuccessful key of the configuration file nwosrvd.conf, section [PasswdMessages].

–logging=option

The option defined with this key is saved in the Logging key of the configuration file nwosrvd.conf, section [Miscellaneous].

-ssl=[yes|no]

The option defined with this key is saved in the ssl key of the configuration file nwosrvd.conf, section [SSL].

-pam=[yes|no]

The option defined with this key is saved in the pam key of the configuration file nwosrvd.conf, section [PAM]. PAM itself also has a configuration file or section (depends on the PAM implementation); the PAM configuration name must be nwosrvd.

To remove any user exits from the configuration, enter the following command:

nwosrvd –config –userexit1=

Once the configuration was changed, the Natural Web I/O Interface daemon must be restarted.

nwosrvd.conf - Configuration File for the Natural Web I/O Interface Daemon

The configuration file nwosrvd.conf contains information that the user exits need for the Natural Web I/O Interface daemon. It has the following content: 

[Miscellaneous]
Logging=I

[UserExits]
; UserExit1=/FS/sag/nat/nwoexuex/userexit1/libnwouserexit1.so
; UserExit2=/FS/sag/nat/nwoexuex/userexit2/libnwouserexit2.so

[PasswdArguments]
Parameters=

[PasswdMessages]
EnterOldPassword=Enter existing login password:
NewPassword=New Password:
ReEnterNewPassword=Re-enter new Password:
PasswordSuccessful=passwd: password successfully changed for*

[SSL]
ssl=no

[PAM]
pam=no
Section in Configuration File Description
[Miscellaneous]

The key Logging is used to define the amount of logging information that is to be reported. One of the following options can be specified:

E for errors.
W for warnings.
I for information.

See also Logging Information.

[Host]

The hostname used. (optional)
[UserExits]

Two user exits can be defined:

UserExit1

The library that is defined by UserExit1 contains the following function:

int nwo_CheckUsernameAndPassword(const char *pUsername, const char *pPassword, const char *pNewPassword, char *pErrorMessage)

If the key UserExit1 is defined in the configuration file, the function nwo_CheckUsernameAndPassword is responsible for checking the user name and password. If a new password is received, user exit 1 is also responsible for changing the password.

In the case of an error, the return code of the function must be "0"; in this case, the pErrorMessage is returned to the client.

When user name and password are correct, the return code must be a value other than "0". "1" indicates that the Natural session runs under the user who started the daemon (authentication). "2" indicates that the Natural session runs under the login user (authentication and impersonation).

UserExit2

The library that is defined by UserExit2 contains the following functions:

  • int nwo_Messages(int *iNumberOfMessages, char *pMessage[])

    iNumberOfMessages: Number of messages returned in the array.

    pMessage: Array of messages.

    If the key UserExit2 is defined in the configuration file, the function nwo_Messages is called when a new connection (client) is accepted and the messages returned by this function are sent to the client. User exit 2 may be used, for example, to send a message such as the following: "For maintenance reasons, the Natural application XXXXX will be down next monday, from 18:00 until 19:00".

    In the case of an error, the return code of the function must be "0".

    After the function nwo_Messages has been called, the function nwo_FreeMessages is called.

  • int nwo_FreeMessages(int iNumberOfMessages, char *pMessage[])

    iNumberOfMessages: Number of messages.

    pMessage: Array of messages.

    If the key UserExit2 is defined, the function nwo_FreeMessages is called to free any resources (normally memory) allocated in the function nwo_Messages.

    In the case of an error, the return code of the function must be "0".

[PasswdArguments]

The key Parameters is used to define any additional parameter(s) that have to be passed to the passwd command.

[PasswdMessages]

The keys in this section define the messages that are to be returned by the system (passwd command) when a user changes the password. If any of these messages is not identified by the daemon, an error will be returned to the client.

Password Mechanism

The password and new password are encrypted on the client side and decrypted on the Linux side. A maximum of 8 characters is allowed.

If user exit 1 is active, user name, password and new password are passed to the user exit.

If user exit 1 is not active, the daemon checks whether user name and password are correct for the system. If a new password is sent, the daemon changes the password by calling the Linux command passwd.

[SSL]

The key ssl is used to define whether the SSL protocol is to be used. One of the following values can be specified: "yes" or "no".

See also SSL Support.

[PAM]

The key pam is used to define whether the PAM (Pluggable Authentication Modules) mechanism is to be used. One of the following values can be specified: "yes" or "no".

PAM itself also has a configuration file or section (depends on the PAM implementation); the PAM configuration name must be nwosrvd.

Note:
On Red Hat Enterprise Linux, only PAM authentication is possible.

nwosrvd.sh - Shell Script for Starting and Stopping the Natural Web I/O Interface Daemon

The shell script nwosrvd.sh is used to start and stop the Natural Web I/O Interface daemon. For further information, see Starting and Stopping the Natural Web I/O Interface Daemon.

nwo.sh - Shell Script for Starting Natural

In order to start a Natural session, the Natural Web I/O Interface service executes a shell script. The shell script prepares the environment for the Natural session and eventually starts Natural. It must therefore contain all environment settings needed to run the Natural session.

The shell script receives certain parameters from the Natural Web I/O Interface client. The parameters can either be evaluated by the shell script itself or passed on to Natural. A client who wants to start a Natural session can specify the shell script to be used.

The shell script nwo.sh is called from the Natural Web I/O Interface daemon in order to start a Natural session. It has the following content: 

#!/bin/sh
 
echo "Number of arguments $#" > nwo.log

IPAddress=""
ClientId=""
CodePage=""
CustomParameters=""
NaturalParameters=""

if [ "$1" != "null" ]
then
  IPAddress="$1"
fi

if [ "$2" != "null" ]
then
  ClientId="$2"
fi

if [ "$3" != "null" ]
then
  CodePage="$3"
fi

if [ "$4" != "null" ]
then
  CustomParameters="$4"
fi

if [ "$5" != "null" ]
then
  NaturalParameters="$5"
fi

#echo "IP Address="$IPAddress >> nwo.log
#echo "Client Id="$ClientId >> nwo.log
#echo "Code Page="$CodePage >> nwo.log
#echo "Custom Parameters="$CustomParameters >> nwo.log
#echo "Natural Parameters="$NaturalParameters >> nwo.log
#echo "NWO_BROWSER_IO="$NWO_BROWSER_IO >> nwo.log

$NAT_HOME/bin/natural $NaturalParameters etid=$$ > /dev/null 2>&1

You have to create such a shell script for each Natural application. It can have any name and it must be located in a directory which is defined in the environment variable PATH.

The name of the shell script is taken from the configuration file for the session. It is taken from the configuration file section that is defined for the session that the user has selected in the logon page. For further information, see Configuring the Client.

Arguments

The shell script will receive the following arguments:

Order Argument Description
1 IPAddress The client IP address from where the session is opened.

Note:
If there is a proxy, this will not be the IP address of the client workstation. Instead, it will be the IP address of the proxy.

2 ClientId The user name from the logon page is passed as the client ID.
3 CodePage The encoding that is defined in the configuration file for the session. This value can be used to set the Natural system variable *CODEPAGE.
4 CustomParameters From the logon page, it is possible to pass any values to the script in order to execute any desired action.

Example: you pass a small text to the script which describes an error. When the script receives this error text, it sends it as an e-mail to the administrator.

5 NaturalParameters These can be any Natural parameters. The parameters are either defined in the configuration file for the session, or they are entered in the logon page. The following is an example of the corresponding entry in the configuration file:

<natural_parameter>parm=nwoparm\ stack=(logon\ mylib;start-program;fin)<natural_parameter>

The language that is selected in the logon page is added as the first element to the Natural parameters in the form "ulang=x".

Arguments 1 to 4 can be used to audit the client, to allow to run an application from a specific PC (identifying the IP address), to build statistics, to do special actions, etc.

Environment Variables

In the shell script, several environment variables can be set for the Natural session that is started by the daemon:

NWO_ENABLE_ACK=["YES"|"NO"]

This environment variable is used for asynchronous screens (SET CONTROL N).

YES When asynchronous screens are sent to the client, Natural will wait to receive an ACK package before the next screen can be sent.
NO No waiting between asynchronous screens. Default value.
NWO_PF_MSG_LINES_NATIVE_FORMAT=["YES"|"NO"]

This environment variable defines how the PF keys and the message line are to be shown.

YES The PF key prompting lines and the message line are shown as output text, as in the native Linux environment.
NO The PF keys are rendered as buttons and the message line is rendered as a special message line element. Default value.
NWO_TIMEOUT=[number-of-seconds]

The maximum time, in seconds, that Natural waits to receive any input from the client before it closes the session. If the number of seconds is "0", Natural waits infinitely (no timeout). The default value is "0".

Error NAT5466 is returned at timeout. In Natural, the application can handle this error and decide how to continue or terminate.

Logging Information

The logging information system reports errors, warnings and/or session information, depending on the option that has been defined with the following Natural Web I/O Interface daemon command: 

nwosrvd -config -logging=option

option can be one of the following:

Option Description
E

Error.

When this option is specified, the Natural Web I/O Interface daemon reports only errors.

In the case of an error, the daemon usually exits immediately.

W

Warning.

When this option is specified, the Natural Web I/O Interface daemon reports errors and warnings for uncritical errors.

In the case of a warning, the daemon continues to run.

I

Information.

When this option is specified, the Natural Web I/O Interface daemon reports errors, warnings and information.

The information messages allow to check the session parameters, IP address, etc.

Help information, for example, on how to run, configure and install the Natural Web I/O Interface daemon is always provided. The messages which inform you when the daemon has been started or stopped are also part of the help information.

To find out which logging option is currently active, enter the following Natural Web I/O Interface daemon command: 

nwosrvd -show

The logging messages are shown directly for the standard output. The format of the messages is as in the following example: 

%NWOSRVD-E: 18.01.2008 14:55:20 NWO_SRVDCONF is not established.

The following information is provided:

  • %NWOSRVD is the internal name of the Natural Web I/O Interface daemon.

  • The message type is shown directly after %NWOSRVD. It can be one of the following: -E (error), -W (warning), -I (information), or -H (help).

  • Date and time when the message was reported.

  • Any text or message which pertains to the error, warning, information or help.

If you want to save these messages, you have to redirect the standard output to a file.

Example for csh:

nwosrvd 5454 >& nwosrvd_5454.log

Example for sh, ksh and bsh:

nwosrvd 5454 >& nwosrvd_5454.log 2>&1

SSL Support

SSL is used for a secure connection between the Natural Web I/O Interface server and the Natural Web I/O Interface client or Natural for Ajax. Server authentication cannot be switched off. A certificate and a private key is always required on the server.

To establish an SSL connection, you have to proceed as described in the following topics:

Creating an SSL Certificate and a Private Key

To create and use an SSL certificate and a private key on the server, proceed as described below.

  1. Adapt the example configuration file openssl.cnf to your needs.

    Note:
    openssl.cnf is delivered in <install-dir>/common/security/openssl and openssl is delivered in <install-dir>/common/security/openssl/bin.

  2. Set the environment variable so that it points to the file openssl.cnf: 

    set OPENSSL_CONF=<install-dir>/common/security/openssl/openssl.cnf
export OPENSSL_CONF;

  3. Generate a certificate signing request:

    openssl req –new > server.cert.csr

  4. Generate a private RSA key:

    openssl rsa –in privkey.pem –out server.cert.key

  5. Generate a self-signed certificate:

    openssl x509 –in server.cert.csr –out server.cert.crt –req –signkey server.cert.key –days 365

    It is important that the name of the generated certificate is server.cert.crt and that the name of the generated private key is server.cert.key.

    Note:
    The certificate can be self-signed or it can be signed by a CA (Certificate Authority) such as VeriSign.

  6. Put the generated files into the same directory as the scripts which start the Natural Web I/O Interface server.

Configuring the Daemon

After you have created an SSL certificate and a private key as described above, proceed as follows:

  1. Change the configuration of the Natural Web I/O Interface daemon using the following command: 

    nwosrvd -config -ssl yes

  2. Restart the Natural Web I/O Interface daemon.

See also Configuring the Natural Web I/O Interface Daemon on Linux.

Configuring the Client

After you have configured the daemon as described above, you have to import the generated server.cert.crt file to a truststore on the client. For information on how to do this for the Natural Web I/O Interface client, see Configuring SSL. If you are using Natural for Ajax as the client, see Configuring SSL in the Natural for Ajax documentation.

Working with the Linux Components of the Natural Web I/O Interface

The Linux components of the Natural Web I/O Interface are used to start the Natural applications linked with the Natural Web I/O Interface library.

The following topics are covered below:

Starting and Stopping the Natural Web I/O Interface Daemon

The Natural Web I/O Interface daemons are responsible for accepting new sessions.

Since the daemon checks the user name and password, the following permissions must be set as follows (for setting the permissions, you must be super-user): 

chmod 6755 nwosrvd.sh
chown root nwosrvd.sh

The Natural installation attempts to set permissions and owner. However, you have to verify this before you start the Natural Web I/O Interface daemon.

The daemon can be started and stopped using the following command: 

cd $NAT_HOME/nwo/$NWONODE
nwosrvd.sh portnumber [start|stop]

Alternatively:

cd $NAT_HOME/INSTALL
nwosrvd.bsh  [start|stop]

Note:
The daemon must be started on a port which is not yet used.

The shell script you have created must be in the same directory as the nwosrvd.sh script. It will be used by the Natural Web I/O Interface (configuration file for the session; see Configuring the Client). The following is an example of the corresponding entry in the configuration file: 

<natural_program>your-shell-script.sh</natural_program>

Starting a Natural Application

Almost any Natural application can be used with the Natural Web I/O Interface. See also Differences between the Natural Web I/O Interface Client and Terminal Emulation.

To start a new Natural application with the Natural Web I/O Interface, proceed as follows:

  1. Create a new parameter file from NWOPARM using the Configuration Utility.

  2. In this new parameter file, modify the STACK command as follows: 

    logon library; startprogram; fin

    Note:
    Only "real" Natural applications can be used. The Natural Main Menu cannot be used as a Natural application.

Add the new service as follows:

  1. Look for a port number which is not yet used.

  2. Create a new shell script (similar to nwo.sh) for starting the Natural application: 

    cd $NAT_HOME/nwo/$NWONODE
copy nwo.sh your-shell-script.sh
vi your-shell-script.sh

    You have to decide which (last) line you will use in the script. Use one of the following: 

    $NAT_HOME/bin/natural parm=parameter-file etid=$$ >output-file 2>&1
    $NAT_HOME/bin/natural $5 etid=$$ >output-file 2>&1

    When using the line with parm=parameter-file, the above step in which you modify the STACK command is mandatory.

    When using $5, the Natural parameter (parameter-file and STACK command) is taken from the configuration file for the session (see Configuring the Client). The following is an example of the corresponding entry in the configuration file: 

    <natural_parameter>parm=myparm stack=(logon mylib;menu;fin)<natural_parameter>

  3. If you want to define special settings for the Natural session, you can set the environment variables in your shell script. See above.

  4. Set the permissions for the shell script which starts the service as follows: 

    chmod 775 script-name

The service is now available for use with a PC.