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The Secure Shell (SSH) protocol enables an application to establish
a secure, interactive terminal session with a server, or execute
commands remotely on the server, with the output of the command
returned to the client. The SocketTools ActiveX control supports both
version 1.0 and 2.0 of the protocol.
The following methods are available for use by your application:
Initialize
Initialize the control and validate the runtime license key for the
current process. This method is normally not used if the control is
placed on a form in languages such as Visual Basic. However, if the
control is being created dynamically using a method similar to
CreateObject, then the application must call this method to
initialize the component before setting any properties or calling any
other methods in the control.
Connect
Establish a connection to the server. Once the connection has been
established, the other methods in the control may be used to interact
with the server.
Disconnect
Disconnect from the server and release any resources that have been
allocated for the client session. After this method is called, the
client session is no longer valid.
Uninitialize
Unload the Windows Sockets library and release any resources that
have been allocated for the current process. This is the last method
call that the application should make prior to terminating. This is
only necessary if the application has previously called the
Initialize method.
Input and Output
Once connected to the server, any output generated by the command
shell or a program executed on the server will be sent as data for the
client to read. Any input to the program is sent by the client and
received and processed by the server. The following methods are used:
Read
Reads any output that has been generated by the program executing on
the server. If the server closes the connection, this method
will return zero after all the data has been read. If the method is
successful, it will return the actual number of bytes read.
ReadLine
The ReadLine method reads data from the server up to the specified
number of bytes or until an end-of-line character sequence is
encountered. Unlike the Read method which reads arbitrary bytes of
data, this function is specifically designed to return a single line
of text data in a string variable.
Peek
The Peek method can be used to examine the data that is available to
be read from the internal receive buffer. If there is no data in the
receive buffer at that time, a value of zero is returned. The Peek
method will never cause the client to block, and so may be safely
used with asynchronous connections.
Write
Send data to the server which will be received as input to the
program. If the method succeeds, the return value is the number of
bytes actually written. This method should always be used when
sending binary data to the server.
WriteLine
The WriteLine method writes a line of text to the server and
terminates the line with a carriage-return and linefeed control
character sequence. Unlike the Write method which sends arbitrary
bytes of data to the server, this method is specifically designed to
send a single line of text data from a string.
Command Processing
The SSH protocol can be used to connect to a server, log in and
execute one or more commands, process the output from those commands
and display it to an end-user using a graphical interface. The user
never sees or interacts with the actual terminal session. The control
interface provides methods which can simplify this kind of application,
reducing the amount of code needed to process the data stream returned
by the server.
Execute
This method executes a command on a server and copies the output to a
user-specified buffer, with the exit code for the remote program as
the method's return value. This is a convenience method that enables
you to execute a remote command in a single call, without having to
write the code to establish the connection and read the output.
Search
This method is used to search for a specific character or sequence of
characters in the data stream returned by the server. The control
will accumulate all of the data received up to the point where the
character sequence is encountered. This can be used to capture all of
the output from a command, or search for specific results returned by
the command as it executes on the server.
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