#!/usr/bin/ksh93.att
#################################################################
#### !!! Download the latest version of ksh93 to run this script.
#################################################################
function usagemsg_ckhttp_k93 {
  print -u 2 -- "
Program: ckhttp_k93

Determine if a Web page is accessible by specifying a host name,
port number, and web page location.

Usage: ${1##*/} [-?] [-vV] [-u url]
                           [-t type] [-c class] [-l logFile]
  Where:
    -u url        = http://nodeName:port/path/to/page
    -t type       = Log Message type: ERROR, WARN (Default:ERROR)
    -c class      = Log Message class: O, S, U (Default:O)
    -l logFile    = Log file name (Default:/var/log/ckhttp.log)
    -s            = Log successful responses (Default:only log errors)
    -v            = Verbose Mode
    -V            = Very Verbose Mode

Author: Dana French (dfrench@mtxia.com)
        Copyright 2009 by Dana French: All Rights Reserved

\"AutoContent\" enabled
"
}
################################################################
#### 
#### Description:
#### 
#### Determine if a Web page is accessible by specifying a host name,
#### port number, and web page location.
#### 
#### Assumptions:
#### 
#### The user specified URL must be in one of the following format:
#### 
####     http://hostname.domain:PortNumber/web/page/location/index.html
####     https://hostname.domain:PortNumber/web/page/location/index.html
#### 
####     Example URLs:
#### 
####         http://www.mtxia.com:80/js/index.shtml
####         https://www.mtxia.com:443/secure/index.php
#### 
#### The URL must begin with "http://" or "https://".
#### Only "http" and "https" protocols are currently supported.
#### The hostname must be resolvable to an IP address.
#### The port number must be one or more digits.
#### If no port number is specified, port number "80" is assumed.
#### 
#### Dependencies:
#### 
#### This function requires a recent version of ksh93.  The version
#### shipped with AIX is INSUFFICIENT to run this script.  Download
#### the latest ksh93 AIX binary from http://www.kornshell.com
#### 
#### If you download the latest ksh93 AIX binary, place it on your
#### system at the location /usr/bin/ksh93.att.  Do not overwrite
#### the existing /usr/bin/ksh93.  Then modify the shebang line
#### to use #!/usr/bin/ksh93.att
#### 
#### Products:
#### 
#### This function records error messages to a default or
#### user specified log file.  The return code from this
#### function can be used to indicate success or failure to
#### resolve the user specified hostname.
#### 
#### Configured Usage:
#### 
#### This function may be executed from the command line or
#### included in a script function library.
#### 
#### Details:
#### 
################################################################
function ckhttp_k93 {
  typeset VERSION="1.1"
  typeset TRUE="0"
  typeset FALSE="1"
  typeset VERBOSE="${FALSE}"
  typeset VERYVERB="${FALSE}"
  typeset PORTNUM="80"
  typeset PORTCHK="${PORTNUM}"
  typeset NODENAME=""
  typeset TORF=""
  typeset DATETIME=$( date +"%m/%d/%Y %H:%M:%S" )
  typeset SYSTEM="$( hostname )"
  typeset TYPE="${TYPE:-ERROR}"
  typeset CLASS="${CLASS:-O}"
  typeset SOURCE
  typeset DESCRIPTION
  typeset MSG
  typeset LINE
  typeset RESPONSE
  typeset LOGFILE="/var/log/ckhttp.log"
  typeset HTTPVER="HTTP/1.1"
  typeset HTTPOK
  typeset PROTOCOL="http"
  typeset URL=""
  typeset LOGSUCCESS="${FALSE}"

#### HTTP HEAD Success codes, any other HEAD response is considered unsuccessful.
  HTTPOK=( 200 301 302 )

  while getopts ":vVu:t:c:l:s" OPTION
  do
    case "${OPTION}" in
        'u') URL="${OPTARG}";;
        't') TYPE="${OPTARG}";;
        'c') CLASS="${OPTARG}";;
        'l') LOGFILE="${OPTARG}";;
        's') LOGSUCCESS="${TRUE}";;
        'v') VERBOSE="${TRUE}";;
        'V') VERYVERB="${TRUE}";;
      [?:#]) usagemsg_ckhttp_k93 "${0}" && return 1 ;;
    esac
  done
 
  shift $(( ${OPTIND} - 1 ))

  (( VERYVERB == TRUE )) && set -x

#### Extract the protocol from the URL specified by the user.
  PROTOCOL="${URL%%://*}"

#### Extract the full path file name to the web page specified by the user.
  PAGE="${URL#${PROTOCOL}://}"
  PAGE="/${PAGE#*/}"

#### Extract the node name from the URL specified by the user.
  NODENAME="${URL#${PROTOCOL}://}"
  NODENAME="${NODENAME%%/*}"

#### Extract the network port number from the URL specified by the user.
  [[ "_${NODENAME}" == _*:+([0-9]) ]] && PORTNUM="${NODENAME##*:}"
  [[ "_${NODENAME}" == _*:* ]] && PORTCHK="${NODENAME##*:}"

#### Remove the network port number from the nodename specified by the user.
  NODENAME="${NODENAME%%:*}"

  (( VERBOSE == TRUE )) && print -u 2 -- "#\n# Function Name..........................: ${0}"
  (( VERBOSE == TRUE )) && print -u 2 -- "# Version................................: ${VERSION}"

################################################################

  trap "usagemsg_ckhttp_k93 ${0}" EXIT

  if [[ "_${NODENAME}" == "_" ]] || [[ "_${PORTNUM}" == "_" ]]
  then
    (( VERBOSE == TRUE )) && print -u 2 -- "# ERROR: specify node name and port......: ${PROTOCOL}://${NODENAME}:${PORTNUM}"
    return 2
  fi 

  if [[ "_${PORTCHK}" != _+([0-9]) ]]
  then
    (( VERBOSE == TRUE )) && print -u 2 -- "# ERROR: Invalid port number.............: ${PORTCHK}"
    return 3
  fi 

  if ! [[ "_${TYPE}" == _@(ERROR|WARN) ]]
  then
    (( VERBOSE == TRUE )) && print -u 2 -- "# ERROR: Invalid log message type........: ${TYPE}"
    return 4
  fi 

  if ! [[ "_${CLASS}" == _@(O|S|U) ]]
  then
    (( VERBOSE == TRUE )) && print -u 2 -- "# ERROR: Invalid log message class.......: ${CLASS}"
    return 5
  fi 

  if ! [[ -d "${LOGFILE%/*}" ]]
  then
    (( VERBOSE == TRUE )) && print -u 2 -- "# ERROR: Invalid log file directory......: ${LOGFILE%/*}"
    return 6
  fi 

  if [[ "_${PROTOCOL}" != _@(http|https) ]]
  then
    (( VERBOSE == TRUE )) && print -u 2 -- "# ERROR: Invalid protocol specified......: ${PROTOCOL}"
    return 7
  fi 

  trap "-" EXIT

################################################################

#### 
#### If verbose mode was specified by the user on the command
#### line, output the configuration information to the
#### standard error stream STDERR.

  (( VERBOSE == TRUE )) && print -u 2 -- "# HTTP Protocol..........................: ${PROTOCOL}"

  [[ "_${NODENAME}" == "_" ]] && TORF="Not Specified" || TORF="${NODENAME}"
  (( VERBOSE == TRUE )) && print -u 2 -- "# Network Service Name...................: ${TORF}"

  [[ "_${PORTNUM}" == "_" ]] && TORF="Not Specified" || TORF="${PORTNUM}"
  (( VERBOSE == TRUE )) && print -u 2 -- "# Network Port Number....................: ${TORF}"

  (( VERBOSE == TRUE )) && print -u 2 -- "# HTTP Page location.....................: ${PAGE}"
  (( VERBOSE == TRUE )) && print -u 2 -- "# Log file...............................: ${LOGFILE}"
  (( VERBOSE == TRUE )) && print -u 2 -- "# Log message class......................: ${CLASS}"
  (( VERBOSE == TRUE )) && print -u 2 -- "# Log message type.......................: ${TYPE}"

  (( LOGSUCCESS == TRUE )) && TORF="TRUE" || TORF="FALSE"
  (( VERBOSE == TRUE )) && print -u 2 -- "# Log successful requests................: ${TORF}"

################################################################

  SOURCE="${NODENAME}"
  DESCRIPTION="${PROTOCOL} test failed for page rendering ${NODENAME}:${PORTNUM}${PAGE}"
  MSG="${DATETIME} ${SYSTEM} ${SOURCE} ${TYPE} ${CLASS} ${DESCRIPTION}"

#### 
#### Open a network connection to the remote node on the user
#### specified network port.  If the connection is successful, 
#### send an HTTP HEAD request, and read the first line of the
#### response into an array, then close the network connection.
#### 

  if exec 3<>/dev/tcp/${NODENAME}/${PORTNUM}
  then
    print -u 3 -- "HEAD ${PAGE} ${HTTPVER}\r"
    print -u 3 -- "Host:${NODENAME}\r"
    print -u 3 -- "\r\n\r"
    IFS=$' \t\n'
    read -u 3 -A -- RESPONSE
#     while read -u 3 -- LINE
#     do
#       [[ "_${LINE}" == _HTTP* ]] && RESPONSE=( ${LINE} ) && continue
#       [[ "_${LINE}" == _Location:* ]] && LOCATION=( "${LINE#*:}" ) && break
#     done
    exec 3>&-
    exec 3<&-

#### 
#### Determine if the response received from the HTTP HEAD
#### request contains a successful return code.
#### The successful return codes are contained in an array
#### called HTTPOK.
#### 

    (( VERBOSE == TRUE )) && print -u 2 -- "# Response from http server..............: ${RESPONSE[@]}"
    IFS="|"
    if [[ "_${RESPONSE[1]}" == _@(${HTTPOK[*]}) ]]
    then
      (( VERBOSE == TRUE )) && print -u 2 -- "# Success: HTTP return code..............: ${RESPONSE[1]}"

#### 
#### If the "-s" command line option was specifed by the
#### user, then create a log message consistent with normal
#### Unix log formats, and append the SUCCESSFUL message to the
#### log file.
#### 

      if (( LOGSUCCESS == TRUE ))
      then
        DESCRIPTION="Successful response received: ${RESPONSE[1]} : ${PROTOCOL}://${NODENAME}:${PORTNUM}${PAGE}"
        TYPE="SUCCESS"
        MSG="${DATETIME} ${SYSTEM} ${SOURCE} ${TYPE} ${CLASS} ${DESCRIPTION}"
        print -- "${MSG}" >> "${LOGFILE}"
      fi
      return 0

#### 
#### If the HTTP HEAD return code is unsuccessful, create a
#### log message consistent with normal Unix log formats, and
#### append the error message to the log file.
#### 

    else
      DESCRIPTION="Invalid HTTP return code:${RESPONSE[1]} : ${PROTOCOL}://${NODENAME}:${PORTNUM}${PAGE}"
      (( VERBOSE == TRUE )) && print -u 2 -- "# ERROR: ${DESCRIPTION}"
      MSG="${DATETIME} ${SYSTEM} ${SOURCE} ${TYPE} ${CLASS} ${DESCRIPTION}"
      print -- "${MSG}" >> "${LOGFILE}"
      return 8
    fi
    IFS=$' \t\n'

#### 
#### If network connection attempt fails, create a log
#### message consistent with normal Unix log formats, and
#### append the error message to the log file.
#### 

  else
    DESCRIPTION="Unable to open ${PROTOCOL} connection..: ${PROTOCOL}://${NODENAME}:${PORTNUM}${PAGE}"
    (( VERBOSE == TRUE )) && print -u 2 -- "# ERROR: ${DESCRIPTION}"
    MSG="${DATETIME} ${SYSTEM} ${SOURCE} ${TYPE} ${CLASS} ${DESCRIPTION}"
    print -- "${MSG}" >> "${LOGFILE}"
    return 9
  fi
  exec 3>&-
  exec 3<&-

  return 10
}

################################################################

ckhttp_k93 "${@}"