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%Net.SSH.Session


class %Net.SSH.Session extends
%RegisteredObject

Represents an SSH session object. Each SSH session object must first be connected, then authenticated with the remote system. Note that there are multiple methods of authentication, this class supports password and publickey. Once connected and authenticated, the SSH object can be used to perform SCP (Secure Copy) operations of single files to and from the remote system, it can also be used to execute remote commands, tunnel TCP traffic and forms the base connection for SFTP operations (see %Net.SSH.SFTP).
The Test() method of this class illustrates some basic usage scenarios for this class.
NOTE: %Net.SSH is currently not supported on OpenVMS platforms.

Inventory


Parameters Properties Methods Queries Indices ForeignKeys Triggers
10 4 22


Summary


Properties
HostKey LocalCharset RemoteCharset

Methods
%AddToSaveSet %ClassIsLatestVersion %ClassName
%ConstructClone %DispatchClassMethod %DispatchGetModified
%DispatchGetProperty %DispatchMethod %DispatchSetModified
%DispatchSetMultidimProperty %DispatchSetProperty %Extends
%GetParameter %IsA %IsModified
%New %NormalizeObject %ObjectModified
%OnClose %OriginalNamespace %PackageName
%RemoveFromSaveSet %SerializeObject %SetModified
%ValidateObject AuthenticateWithKeyPair AuthenticateWithKeyboardInteractive
AuthenticateWithUsername Connect Disconnect
Execute ForwardPort GetAlgorithms
GetSupportedAlgorithms GetTimeout OpenSFTP
SetPreferredAlgorithms SetTimeout TestExecute
TestForwardPort VersionInfo


Parameters


• final parameter SSHPORT = 22;
Default SSH port
• final parameter SSHTRACEAUTH = 8;
Enables tracing of SSH authentication
• final parameter SSHTRACECONN = 16;
Enables tracing of SSH connections
• final parameter SSHTRACEERROR = 128;
Enables tracing of SSH error operations
• final parameter SSHTRACEKEX = 4;
Enables tracing of SSH key exchange
• final parameter SSHTRACEPUBLICKEY = 256;
Enables tracing of SSH public key operations
• final parameter SSHTRACESCP = 32;
Enables tracing of SSH/SCP operations
• final parameter SSHTRACESFTP = 64;
Enables tracing of SSH/SFTP operations
• final parameter SSHTRACESOCKET = 512;
Enables tracing of low level socket operations
• final parameter SSHTRACETRANS = 2;
Enables tracing of SSH transactions

Properties


• property HostKey as %String;
Remote host key
• property LocalCharset as %String [ InitialExpression = $CASE($system.Version.GetOS(),"Windows":"",:"UTF8") ];
Character set used by the local system. Defaults to UTF-8 for UNIX but likely should NOT BE SET for Windows (which means we'll use UCS-2 Unicode characters for local filenames).
• property RemoteCharset as %String [ InitialExpression = "UTF8" ];
Character set used by the remote server. Will almost certainly be UTF-8 for any SSH server.

Methods


• method %OnClose() as %Status
Clean up any resources
• method AuthenticateWithKeyPair(username As %String, publickeyfile As %String, privatekeyfile As %String, passphrase As %String) as %Status
Authenticate with the remote server using a public/private key pair and passphrase (for the private key). The private keys are PEM encoded and the public keys are in OpenSSH format.
If multiple forms of authentication are required by the server, for example /etc/ssh/sshd_config contains:
AuthenticationMethods publickey,password
Then in this case read the "," (comma) as AND; the server will require both forms of authentication.

Calling AuthenticateWithKeyPair fails with LIBSSH2_ERROR_PUBLICKEY_UNVERIFIED which is a bit misleading ... it's really "authenticated with partial success" so we can then try then authenticating with a password which should then succeed (or keyboard-interactive).
• method AuthenticateWithKeyboardInteractive(username As %String, lambda As %String, ByRef context) as %Status
Authenticate with the remote server using the "keyboard-interactive" authentication scheme. This requires a callback lambda/function that will be called with a list of one or challenges to which the lambda will return the responses to the challenge(s). The lambda is invoked with the following arguments:
  • username As %String Username being authenticated
  • instructions As %String Instructions from the server (optional)
  • prompts As %List A $LIST of challenge prompt(s)
  • promptflags As %List A $LIST of flags for each of the challenge prompt(s)
  • ByRef context A pass-by-ref context value
  • The lambda must return a $LIST of responses, with each Nth element in the $LIST corresponding to the Nth challenge prompt. If there is no response for a prompt, then that Nth $LIST element should be empty. The allowed values for promptflags are as follows:
  • E Echo on. If E is missing DO NOT ECHO! (e.g. password entry)
  • NOTE: The context can be anything of your choosing (an array, object or whatever) and it is passed by reference.
    See notes in AuthenticateWithKeyPair() when using multiple forms of authentication.
    • method AuthenticateWithUsername(username As %String, password As %String) as %Status
    Authenticate with the remote server using a username/password via the "password" authentication scheme. Note that this is NOT the same as keyboard-interactive which is typically what login sessions use.
    See notes in AuthenticateWithKeyPair() when using multiple forms of authentication.
    • method Connect(hostname As %String, port As %Integer = ..#SSHPORT, hostkey As %String = "") as %Status
    Connect to a remote host, specifying the hostname, and optionally the port and remote hostkey to match. The hostkey helps prevent impersonation attacks, it is a hash of the remote hosts' public key.
    • method Disconnect() as %Status
    Disconnect from the remote host
    • method Execute(pCommand As %String, ByRef pDevice As %String, ByRef pEnv) as %Status
    Execute a remote command on the remote system. In order to do I/O with the remote command, an XDEV device instance is passed back via the pDevice parameter. This is a normal device and can be used with the USE/READ/WRITE/CLOSE commands. Note that environment variables for the remote command can be passed as an array of name/value pairs.
    • method ForwardPort(pRemoteHost As %String, pRemotePort As %Integer, ByRef pDevice As %String) as %Status
    Forwards traffic via the SSH connection to a remote host/port. The traffic is sent via an XDEV device that is opened by ForwardPort() and passed back by reference via the pDevice parameter.
    • method GetAlgorithms(ByRef preferences As %String) as %Status
    Called to retrieve the current set of negotiated algorithms/methods for various categories. Format of the result string is as follows:
    <category>=<option>[:<category1>=<option1>[:...]]
    Where <category> is one of:
  • KEX Key Exchange Methods
  • HOSTKEY Hostkey public key algorithms
  • CRYPT Encryption algorithms
  • MAC MAC algorithms
  • COMPCompression Algorithms
  • NOTE: The allowed values can be found here:
    http://libssh2.sourceforge.net/doc/#libssh2sessionmethodpref And <option> is a comma delimited list of one or more values.
    • method GetSupportedAlgorithms(ByRef algs As %String) as %Status
    Called to retrieve the set of supported algorithms for various categories. Format of the string is as follows:
    <category>=<option>[:<category1>=<option1>[:...]]
    Where <category> is one of:
  • KEX Key Exchange Methods
  • HOSTKEY Hostkey public key algorithms
  • CRYPT Encryption algorithms
  • MAC MAC algorithms
  • COMP Compression Algorithms
  • NOTE: The allowed values can be found here:
    http://libssh2.sourceforge.net/doc/#libssh2sessionmethodpref
    • method GetTimeout(ByRef pTimeoutMS As %Integer = -1) as %Status
    Gets the timeout for SSH operations in milliseconds. An infinite timeout is represented by the value of -1; the default timeout is set to 30 seconds.
    • method OpenSFTP(ByRef sftp As %Net.SSH.SFTP) as %Status
    Open up an SFTP session for SFTP activity.
    • method SetPreferredAlgorithms(preferences As %String) as %Status
    Called before connecting to a remote host to specify various preferred algorithms and methods that should be used. Format of the preferences string is as follows:
    <category>=<option>[:<category1>=<option1>[:...]]
    Where <category> is one of:
  • KEX Key Exchange Methods
  • HOSTKEY Hostkey public key algorithms
  • CRYPT Encryption algorithms
  • MAC MAC algorithms
  • COMPCompression Algorithms
  • NOTE: The allowed values can be found here:
    http://libssh2.sourceforge.net/doc/#libssh2sessionmethodpref And <option> is a comma delimited list of one or more values.
    • method SetTimeout(pTimeoutMS As %Integer = -1) as %Status
    Sets the timeout for SSH operations in milliseconds. An infinite timeout can be set by passing -1 to this methods; the default timeout is set to 30 seconds.
    • classmethod TestExecute(host As %String, username As %String, password As %String, command As %String = "uname -a", pTimeout As %Integer = -1) as %Status
    Demonstrates the execution of a remote command (by default, uname -a).
    • classmethod TestForwardPort(host As %String, username As %String, password As %String, remotehost As %String = "whatismyipaddress.com", remoteport As %Integer = 80) as %Status
    Demonstrates the use of port forwarding to whatismyipaddress.com via the remote SSH server.
    • method VersionInfo(ByRef pClientVersion As %String, ByRef pServerVersion As %String) as %Status
    Retrieves the client and server SSH versions. If the server version is not available, or if the session is not connected, then pServerVersion will be undefined. Note that the client version refers to the release of libssh2 being used.