SSH to a Cisco Switch - Processing "More" Responses

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Demonstrates connecting to a Cisco switch, entering privileged mode with the ena command, and running a command whose response is paged. Each page ends with --More-- and requires a SPACE character to request the next page.

Note: QuickShell allocates a PTY, which is what a network device console expects. The device presents an interactive prompt, and each command's output is read up to the next prompt.

LOCAL nSuccess
LOCAL oSsh
LOCAL nPort
LOCAL cPassword
LOCAL nChannelNum
LOCAL nCaseSensitive
LOCAL cReceived
LOCAL cEnablePassword
LOCAL oSaMatch
LOCAL oSbReceived
LOCAL nMoreComing
LOCAL cPageText

nSuccess := 0

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  Demonstrates connecting to a Cisco switch, entering privileged mode, and running a command
//  whose response is paged -- each page ends with "--More--" and requires a SPACE character to
//  request the next page.

oSsh := CreateObject("Chilkat.Ssh")

nPort := 22
nSuccess := oSsh:Connect("172.16.16.100", nPort)
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
cPassword := "mySshPassword"

nSuccess := oSsh:AuthenticatePw("mySshLogin", cPassword)
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

nChannelNum := oSsh:QuickShell()
IF (nChannelNum < 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

//  IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
//  which means no limit -- without it, this call waits forever if the received data never
//  contains a match.
oSsh:ReadTimeoutMs := 15000

nCaseSensitive := 1

//  In unprivileged mode the switch prompt ends with ">".
nSuccess := oSsh:ChannelReceiveUntilMatch(nChannelNum, ">", "utf-8", nCaseSensitive)
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

cReceived := oSsh:GetReceivedText(nChannelNum, "utf-8")
IF (oSsh:LastMethodSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

? cReceived

//  Send "ena" to enter privileged mode.  Cisco devices expect a bare CR to terminate a command.
nSuccess := oSsh:ChannelSendString(nChannelNum, "ena" + Chr(13), "utf-8")
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

nSuccess := oSsh:ChannelReceiveUntilMatch(nChannelNum, "Password:", "utf-8", nCaseSensitive)
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

cReceived := oSsh:GetReceivedText(nChannelNum, "utf-8")
IF (oSsh:LastMethodSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

? cReceived

//  The enable password is separate from the login password, and likewise should come from a
//  secure source rather than being hard-coded.
cEnablePassword := "myEnablePassword"
nSuccess := oSsh:ChannelSendString(nChannelNum, cEnablePassword, "utf-8")
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

nSuccess := oSsh:ChannelSendString(nChannelNum, Chr(13), "utf-8")
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

//  In privileged mode the prompt ends with "#" instead of ">".
nSuccess := oSsh:ChannelReceiveUntilMatch(nChannelNum, "#", "utf-8", nCaseSensitive)
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

cReceived := oSsh:GetReceivedText(nChannelNum, "utf-8")
IF (oSsh:LastMethodSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

? cReceived

//  Run a command whose output is delivered a page at a time.
nSuccess := oSsh:ChannelSendString(nChannelNum, "show running-config" + Chr(13), "utf-8")
IF (nSuccess == 0)
    ? oSsh:LastErrorText
    oSsh:destroy()
    RETURN
ENDIF

//  Each read ends either at the device prompt (output complete) or at "--More--" (another page
//  is waiting).  Match the full prompt rather than a bare "#", because "#" also appears inside
//  configuration text and would match too early.
oSaMatch := CreateObject("Chilkat.StringArray")
oSaMatch:Append("MySwitchName#")
oSaMatch:Append("--More--")

oSbReceived := CreateObject("Chilkat.StringBuilder")
nMoreComing := 1

DO WHILE nMoreComing
    nSuccess := oSsh:ChannelReceiveUntilMatchN(nChannelNum, oSaMatch, "utf-8", nCaseSensitive)
    IF (nSuccess == 0)
        ? oSsh:LastErrorText
        oSsh:destroy()
        oSaMatch:destroy()
        oSbReceived:destroy()
        RETURN
    ENDIF

    oSbReceived:Clear()
    cPageText := oSsh:GetReceivedText(nChannelNum, "utf-8")
    IF (oSsh:LastMethodSuccess == 0)
        ? oSsh:LastErrorText
        oSsh:destroy()
        oSaMatch:destroy()
        oSbReceived:destroy()
        RETURN
    ENDIF

    oSbReceived:Append(cPageText)
    ? cPageText

    //  If this page ended with "--More--", send a SPACE to request the next page.
    nMoreComing := oSbReceived:Contains("--More--", nCaseSensitive)
    IF (nMoreComing)
        nSuccess := oSsh:ChannelSendString(nChannelNum, " ", "utf-8")
        IF (nSuccess == 0)
            ? oSsh:LastErrorText
            oSsh:destroy()
            oSaMatch:destroy()
            oSbReceived:destroy()
            RETURN
        ENDIF

    ENDIF

ENDDO

oSsh:Disconnect()

oSsh:destroy()
oSaMatch:destroy()
oSbReceived:destroy()