ipworks
Class Rexec

java.lang.Object
  |
  +--ipworks.Rexec

public class Rexec

extends java.lang.Object

The Rexec bean is used to execute commands on a remote UNIX machine using the rexec mechanism.

The Rexec bean allows remote execution of commands on UNIX hosts, or any other system with the rexec interface. Using the bean is very simple. The destination is specified by the RemoteHost property, the login information is given by the RemoteUser and RemotePassword properties. Then call the Execute method with the Command to execute as a parameter. You can also set the Command property to the command that you would like to execute for identical results. Further input can be supplied to the command by assigning data to the Text parameter of the Send method, or via the Stdin property.

The output of the command is returned through the Stdout event. If an error happens on the protocol level, the error message can be found in the ErrorMessage property. Errors during command execution (the stderr stream) are given by the Stderr event.

To be able to successfully use the bean, the remote host must be set up to allow execution of commands via rexec from the machine the bean runs on.

Constructor Summary

Rexec()

Method Summary

void	addRexecEventListener(ipworks.RexecEventListener l)
java.lang.String	config(java.lang.String configurationString) Sets or retrieves a beanconfiguration setting.
void	disconnect() Disconnect from the RemoteHost .
void	doEvents() Processes events from the internal message queue.
void	execute(java.lang.String command) Execute a Command on the remote host.
int	getBytesSent() The number of bytes actually sent after an assignment to Stdin.
java.lang.String	getCommand() The command to be sent to the remote host.
byte[]	getEOL() Used to break the stdout data stream into chunks separated by its value.
byte[]	getErrEOL() Used to break the stderr data stream into chunks separated by its value.
java.lang.String	getErrorMessage() The error message returned when any of the steps prior to command execution fail.
ipworks.Firewall	getFirewall() A set of properties related to firewall access.
java.lang.String	getLocalHost() The name of the local host or user-assigned IP interface through which connections are initiated or accepted.
int	getLocalPort() The TCP port in the local host where the bean binds.
java.lang.String	getRemoteHost() The address of the remote host.
java.lang.String	getRemotePassword() The password of the user on the remote host.
int	getRemotePort() The remote exec service port (default is 512).
java.lang.String	getRemoteUser() The id of the user on the remote host.
byte[]	getStderr() Returns the standard error output (stderr) from the remote application.
byte[]	getStdout() Provides the standard output (stdout) from the remote application.
int	getTimeout() A timeout for the bean.
void	interrupt() Interrupt the current method.
boolean	isConnected() Shows whether the bean is connected.
boolean	isEOF() If True, the connection has closed, and there is no buffered data available.
void	removeRexecEventListener(ipworks.RexecEventListener l)
void	send(byte[] text) Execute a Command on the remote host.
void	setCommand(java.lang.String command) The command to be sent to the remote host.
void	setConnected(boolean connected) Shows whether the bean is connected.
void	setEOL(byte[] EOL) Used to break the stdout data stream into chunks separated by its value.
void	setErrEOL(byte[] errEOL) Used to break the stderr data stream into chunks separated by its value.
void	setFirewall(ipworks.Firewall firewall) A set of properties related to firewall access.
void	setLocalHost(java.lang.String localHost) The name of the local host or user-assigned IP interface through which connections are initiated or accepted.
void	setLocalPort(int localPort) The TCP port in the local host where the bean binds.
void	setRemoteHost(java.lang.String remoteHost) The address of the remote host.
void	setRemotePassword(java.lang.String remotePassword) The password of the user on the remote host.
void	setRemotePort(int remotePort) The remote exec service port (default is 512).
void	setRemoteUser(java.lang.String remoteUser) The id of the user on the remote host.
void	setStdin(byte[] stdin) A string of data to be sent to the remote host while connected.
void	setTimeout(int timeout) A timeout for the bean.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Rexec

public Rexec()

Method Detail

getBytesSent

public int getBytesSent()

The number of bytes actually sent after an assignment to Stdin.

The BytesSent property shows how many bytes were sent after the last assignment to Stdin . Please check the Stdin property for more information.

getCommand

public java.lang.String getCommand()

The command to be sent to the remote host.

Assigning a UNIX command to this property makes the bean attempt to connect to the RemoteHost and execute the command using the rexec protocol. There is no need to append an end-of-line character to the command.

If "" (empty string) is assigned to the Command property, the current connection is broken.

Example (Execute a Command)

 RexecControl.Command = "cd /home/username/; ls -al; cd/; ls" 

setCommand

public void setCommand(java.lang.String command)
                throws IPWorksException

The command to be sent to the remote host.

Assigning a UNIX command to this property makes the bean attempt to connect to the RemoteHost and execute the command using the rexec protocol. There is no need to append an end-of-line character to the command.

If "" (empty string) is assigned to the Command property, the current connection is broken.

Example (Execute a Command)

 RexecControl.Command = "cd /home/username/; ls -al; cd/; ls" 

IPWorksException

isConnected

public boolean isConnected()

Shows whether the bean is connected.

Use this property to determine whether the bean is connected to the remote host or not.

setConnected

public void setConnected(boolean connected)
                  throws IPWorksException

Shows whether the bean is connected.

Use this property to determine whether the bean is connected to the remote host or not.

IPWorksException

isEOF

public boolean isEOF()

If True, the connection has closed, and there is no buffered data available.

EOF is an acronym for "End Of File".

getEOL

public byte[] getEOL()

Used to break the stdout data stream into chunks separated by its value.

The EOL property is used to define boundaries in the Stdout stream using the value of the property.

setEOL

public void setEOL(byte[] EOL)
            throws IPWorksException

Used to break the stdout data stream into chunks separated by its value.

The EOL property is used to define boundaries in the Stdout stream using the value of the property.

IPWorksException

getErrEOL

public byte[] getErrEOL()

Used to break the stderr data stream into chunks separated by its value.

The ErrEOL property is used to define boundaries in the Stderr stream using the value of the property.

setErrEOL

public void setErrEOL(byte[] errEOL)
               throws IPWorksException

Used to break the stderr data stream into chunks separated by its value.

The ErrEOL property is used to define boundaries in the Stderr stream using the value of the property.

IPWorksException

getErrorMessage

public java.lang.String getErrorMessage()

The error message returned when any of the steps prior to command execution fail.

This error message is returned on a separate connection associated with error messages.

getFirewall

public ipworks.Firewall getFirewall()

A set of properties related to firewall access.

This is a FIREWALL type property which contains fields describing the firewall through which the bean will attempt to connect.

setFirewall

public void setFirewall(ipworks.Firewall firewall)
                 throws IPWorksException

A set of properties related to firewall access.

This is a FIREWALL type property which contains fields describing the firewall through which the bean will attempt to connect.

IPWorksException

getLocalHost

public java.lang.String getLocalHost()

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the bean initiate connections (or accept in the case of server beans) only through that interface.

If the bean is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

setLocalHost

public void setLocalHost(java.lang.String localHost)
                  throws IPWorksException

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

The LocalHost property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the bean initiate connections (or accept in the case of server beans) only through that interface.

If the bean is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

IPWorksException

getLocalPort

public int getLocalPort()

The TCP port in the local host where the bean binds.

The LocalPort property must be set before a connection is attempted. It instructs the bean to bind to a specific port (or communication endpoint) in the local machine.

Setting it to 0 (default) enables the bean to choose a port at random. The chosen port will be shown by the LocalPort property after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set the LocalPort property when a connection is active will generate an error.

Use this property with caution. If you supply a value, it must be an available port on the system, or an error will be returned. Furthermore, the bean always attempts to bind to a secure (sub 1000) port when the value of LocalPort is the default (0). If you supply your own value, make sure the remote system is configured to allow that particular value.

setLocalPort

public void setLocalPort(int localPort)
                  throws IPWorksException

The TCP port in the local host where the bean binds.

The LocalPort property must be set before a connection is attempted. It instructs the bean to bind to a specific port (or communication endpoint) in the local machine.

Setting it to 0 (default) enables the bean to choose a port at random. The chosen port will be shown by the LocalPort property after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set the LocalPort property when a connection is active will generate an error.

Use this property with caution. If you supply a value, it must be an available port on the system, or an error will be returned. Furthermore, the bean always attempts to bind to a secure (sub 1000) port when the value of LocalPort is the default (0). If you supply your own value, make sure the remote system is configured to allow that particular value.

IPWorksException

getRemoteHost

public java.lang.String getRemoteHost()

The address of the remote host. Domain names are resolved to IP addresses.

The RemoteHost property specifies the IP address (IP number in dotted internet format) or Domain Name of the remote host. It is set before a connection is attempted and cannot be changed once a connection is established.

If the RemoteHost property is set to a Domain Name, a DNS request is initiated, and upon successful termination of the request, the RemoteHost property is set to the corresponding address. If the search is not successful, an error is returned.

If the bean is configured to use a SOCKS firewall, the value assigned to this property may be preceeded with a "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

Example (Connecting)

 IPPortControl.RemoteHost = "MyHostNameOrIP"
 IPPortControl.RemotePort = 777
 IPPortControl.Connected = true 

setRemoteHost

public void setRemoteHost(java.lang.String remoteHost)
                   throws IPWorksException

The address of the remote host. Domain names are resolved to IP addresses.

The RemoteHost property specifies the IP address (IP number in dotted internet format) or Domain Name of the remote host. It is set before a connection is attempted and cannot be changed once a connection is established.

If the RemoteHost property is set to a Domain Name, a DNS request is initiated, and upon successful termination of the request, the RemoteHost property is set to the corresponding address. If the search is not successful, an error is returned.

If the bean is configured to use a SOCKS firewall, the value assigned to this property may be preceeded with a "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

Example (Connecting)

 IPPortControl.RemoteHost = "MyHostNameOrIP"
 IPPortControl.RemotePort = 777
 IPPortControl.Connected = true 

IPWorksException

getRemotePassword

public java.lang.String getRemotePassword()

The password of the user on the remote host.

This must be the password of a user in the remote host for whom remote execution of commands is permitted.

setRemotePassword

public void setRemotePassword(java.lang.String remotePassword)
                       throws IPWorksException

The password of the user on the remote host.

This must be the password of a user in the remote host for whom remote execution of commands is permitted.

IPWorksException

getRemotePort

public int getRemotePort()

The remote exec service port (default is 512).

The RemotePort property specifies the rexec service port on the remote host.

A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before command execution is attempted.

setRemotePort

public void setRemotePort(int remotePort)
                   throws IPWorksException

The remote exec service port (default is 512).

The RemotePort property specifies the rexec service port on the remote host.

A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before command execution is attempted.

IPWorksException

getRemoteUser

public java.lang.String getRemoteUser()

The id of the user on the remote host.

This must be the id of a user in the remote host for whom remote execution of commands is permitted.

setRemoteUser

public void setRemoteUser(java.lang.String remoteUser)
                   throws IPWorksException

The id of the user on the remote host.

This must be the id of a user in the remote host for whom remote execution of commands is permitted.

IPWorksException

getStderr

public byte[] getStderr()

Returns the standard error output (stderr) from the remote application.

The property is set to an empty string before each new request.

setStdin

public void setStdin(byte[] stdin)
              throws IPWorksException

A string of data to be sent to the remote host while connected.

This property is used to provide input for the process in the remote host.

If you are sending data to the remote host faster than it can process it, or faster than the network bandwidth allows, the outgoing queue might fill up. When this happens, Stdin fails with exception 10035: "[10035] Operation would block" (WSAEWOULDBLOCK). You can check this error, and then try to send the data again.

IPWorksException

getStdout

public byte[] getStdout()

Provides the standard output (stdout) from the remote application.

The property is set to an empty string before each new request.

getTimeout

public int getTimeout()

A timeout for the bean.

If the Timeout property is set to 0, all operations return immediately, potentially failing with an error if they can't be completed immediately.

If Timeout is set to a positive value, the bean will wait for the operation to complete before returning control.

The bean will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the bean throws an IPWorksException raises an IPWorksException exception .

Please note that by default, all timeouts are inactivity timeouts , i.e. the timeout period is extended by Timeout seconds when data is successfully sent or received.

Optionally, the behaviour of the bean may be changed to absolute timeouts , i.e. the bean will wait for a maximum of Timeout seconds since the beginning of the operation, without extending the timeout period during communications.

This behavior is controlled by theAbsoluteTimeoutconfiguration setting.

The default value for the Timeout property is 60 seconds.

setTimeout

public void setTimeout(int timeout)
                throws IPWorksException

A timeout for the bean.

If the Timeout property is set to 0, all operations return immediately, potentially failing with an error if they can't be completed immediately.

If Timeout is set to a positive value, the bean will wait for the operation to complete before returning control.

The bean will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the operation is not yet complete, the bean throws an IPWorksException raises an IPWorksException exception .

Please note that by default, all timeouts are inactivity timeouts , i.e. the timeout period is extended by Timeout seconds when data is successfully sent or received.

Optionally, the behaviour of the bean may be changed to absolute timeouts , i.e. the bean will wait for a maximum of Timeout seconds since the beginning of the operation, without extending the timeout period during communications.

This behavior is controlled by theAbsoluteTimeoutconfiguration setting.

The default value for the Timeout property is 60 seconds.

IPWorksException

config

public java.lang.String config(java.lang.String configurationString)
                        throws IPWorksException

Sets or retrieves a beanconfiguration setting.

Config is a generic method available in every bean. It is used to set and retrieveconfiguration settingsfor the bean.

Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the bean, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY , you must call Config("PROPERTY=VALUE") , where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY") . The value will be returned as a string.

IPWorksException

disconnect

public void disconnect()
                throws IPWorksException

Disconnect from the RemoteHost .

Calling this method is normally unneccessary, unless you wish to interrupt the remote program, or the remote program is waiting for standard input to end before terminating.

IPWorksException

doEvents

public void doEvents()
              throws IPWorksException

Processes events from the internal message queue.

When DoEvents is called, the bean processes any available events. If no events are available, it waits for a preset period of time, and then returns.

IPWorksException

execute

public void execute(java.lang.String command)
             throws IPWorksException

Execute a Command on the remote host.

Calling this method is equivalent to setting the Command property to Command .

Example (Execute a Command)

 RexecControl.Execute("cd /home/username/; ls -al; cd/; ls") 

IPWorksException

interrupt

public void interrupt()
               throws IPWorksException

Interrupt the current method.

If there is no method in progress, Interrupt simply returns doing nothing.

IPWorksException

send

public void send(byte[] text)
          throws IPWorksException

Execute a Command on the remote host.

The bean attempts to connect to the RemoteHost and execute the Command using the rexec protocol. There is no need to append an end-of-line character to the command.

IPWorksException

addRexecEventListener

public void addRexecEventListener(ipworks.RexecEventListener l)
                           throws java.util.TooManyListenersException

java.util.TooManyListenersException

removeRexecEventListener

public void removeRexecEventListener(ipworks.RexecEventListener l)