#$language = "Python"
#$interface = "1.0"

# RevealNonPrintingCharacters.py
#
# Last Modified:
# 23 Dec, 2022
#   - Reviewed/Tested for Python 2/3 compatibility
#
# Description:
#   Shows one way to reveal what non-printing characters are in a string (for
#   example a string that was read in from the remote that might contain
#   CR, LF, and other non-printing characters and escape sequences)
#
#   This example illustrates running a command and revealing non-printing
#   characters in the command output received by SecureCRT.
#
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def RevealNonPrintingCharacters(strText):
    # Get a handle to a Dictionary object.
    colCharNames = dict()
    colCharNames[0] = '[NUL]'
    colCharNames[1] = '[SOH]'
    colCharNames[2] = '[STX]'
    colCharNames[3] = '[ETX]'
    colCharNames[4] = '[EOT]'
    colCharNames[5] = '[ENQ]'
    colCharNames[6] = '[ACK]'
    colCharNames[7] = '[BEL]'
    colCharNames[8] = '[BS]'
    colCharNames[9] = '[HT]'
    colCharNames[10] = '[LF]'
    colCharNames[11] = '[VT]'
    colCharNames[12] = '[FF]'
    colCharNames[13] = '[CR]'
    colCharNames[14] = '[SO]'
    colCharNames[15] = '[SI]'
    colCharNames[16] = '[DLE]'
    colCharNames[17] = '[DC1]'
    colCharNames[18] = '[DC2]'
    colCharNames[19] = '[DC3]'
    colCharNames[20] = '[DC4]'
    colCharNames[21] = '[NAK]'
    colCharNames[22] = '[SYN]'
    colCharNames[23] = '[ETB]'
    colCharNames[24] = '[CAN]'
    colCharNames[25] = '[EM]'
    colCharNames[26] = '[SUB]'
    colCharNames[27] = '[ESC]'
    colCharNames[28] = '[FS]'
    colCharNames[29] = '[GS]'
    colCharNames[30] = '[RS]'
    colCharNames[31] = '[US]'
    
    # The Range() function takes 3 arguments with the 2nd and 3rd arguments as
    # optional.  If you use two arguments, the range will begin with the first
    # argument and is not inclusive of the second argument.  In the statement
    # below we want 32 through 126, so we provide a second argument of 127.
    for nIndex in range(32, 127):
        colCharNames[nIndex] = chr(nIndex)
    
    # Delete is a special case:
    colCharNames[127] = '[DEL]'
    
    # Now, let's get to the "revealing"...
    strRevealingText = ''
    for nPos in range(0, len(strText)):
        # Get the current character (we're working left->right from the first
        # character of the string to the last character of the string):
        strCurrentChar = strText[nPos]
        
        # Map the current character to a printable sequence using either the
        # actual character (if printable), or a substitute as defined in the
        # colCharNames collection above:
        if ord(strCurrentChar) in colCharNames:
            strRevealingText += colCharNames[ord(strCurrentChar)]
        else:
            strRevealingText += strCurrentChar

    # Tidy things up a bit so that they'll appear more "normalized" in the
    # messagebox
    strRevealingText = strRevealingText.replace('[CR][LF]', '[CRLF]\r\n')
    strRevealingText = strRevealingText.replace('[CR]', '[CR]\r\n')
    strRevealingText = strRevealingText.replace('[LF]', '[LF]\r\n')
    strRevealingText = strRevealingText.replace('[HT]', '[HT]\r\n')
    
    # Return the data to the caller.
    return strRevealingText

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def Main():
    strPrompt = '$'
    crt.Screen.Synchronous = True
    crt.Screen.Send('ls -l --color\r')
    strReceivedData = crt.Screen.ReadString(strPrompt)
    crt.Dialog.MessageBox(RevealNonPrintingCharacters(strReceivedData))

Main()