用 curl 检测端口是否可连接 - http 返回码 - 证书有效期 - Shell

#!/bin/bash

# refer: https://www.baeldung.com/linux/check-website-availablilty and https://curl.se/mail/archive-2022-04/0027.html

trap "exit 1" TERM
export TOP_PID=$$
STDOUTFILE=".tempCurlStdOut" # temp file to store stdout
> $STDOUTFILE # cleans the file content

# Argument parsing follows our specification
for i in "$@"; do
  case $i in
#    http*)
#      WEBPAGE="${i#*=}"
#      shift
#      ;;
    -n=*|--notWantedContent=*)
      NOTWANTEDCONTENT="${i#*=}"
      shift
      ;;
    -r=*|--requiredContent=*)
      REQUIREDCONTENT="${i#*=}"
      shift
      ;;
    -e=*|--email=*)
      EMAIL="${i#*=}"
      shift
      ;;
    -s|--silent)
      SILENT=true
      shift
      ;;
    -t|--testTcpPortOnly)
      TESTTCPPORTONLY=true
      shift
      ;;      
#    *)
#      >&2 echo "Unknown option: $i" # stderr
#      exit 1
#      ;;
    *)
      WEBPAGE="${i#*=}"
      shift      
      ;;
    *)
      ;;
  esac
done

if test -z "$WEBPAGE"; then
    >&2 echo "Missing required URL" # stderr
    exit 1;
fi

function tcp_port_is_open {
  local exit_status_code
#   curl -t '' --connect-timeout 2 -s telnet://"$1:$2" </dev/null
   URL=${WEBPAGE#*//*}
   curl -t '' --connect-timeout 2 -s telnet://"$URL" </dev/null
   exit_status_code=$?
   case $exit_status_code in
     49) return 0 ;;
     *) return "$exit_status_code" ;;
   esac
}

function stdOutput { 
    if ! test "$SILENT" = true; then
        echo "$1"
    fi
}

function stdError { 
    if ! test "$SILENT" = true; then
        >&2 echo "$1" # stderr
    fi
    if ! test -z "$EMAIL"; then
        echo -e "Subject: $WEBPAGE is not working\n\nThe error is: $1" | msmtp $EMAIL
    fi
    kill -s TERM $TOP_PID # abort the script execution
}

if tcp_port_is_open > /dev/null 2>&1 ; then
    if test "$TESTTCPPORTONLY" = true; then
        stdOutput "TCP port is open -> OK"
    else
#            stdOutput "Internet connectivity OK"
    HTTPCODE=$(curl --max-time 5 --silent --write-out %{response_code} --output "$STDOUTFILE" "$WEBPAGE")
    CONTENT=$(<$STDOUTFILE) # if there are no errors, this is the HTML code of the web page
        if test $HTTPCODE -eq 200; then
            stdOutput "HTTP STATUS CODE $HTTPCODE -> OK"
        else
            stdError "HTTP STATUS CODE $HTTPCODE -> Has something gone wrong?"
        fi
        if ! test -z "$NOTWANTEDCONTENT"; then
            if echo "$CONTENT" | grep -iq "$NOTWANTEDCONTENT"; then # case insensitive check
                stdError "Not wanted content '$NOTWANTEDCONTENT'"
            fi
        fi
        if ! test -z "$REQUIREDCONTENT"; then
            if ! echo "$CONTENT" | grep -iq "$REQUIREDCONTENT"; then # case insensitive check
                stdError "Required content '$REQUIREDCONTENT' is absent"
            fi
        fi
        if echo "$WEBPAGE" | grep -iq "https"; then # case insensitive check
            EXPIREDATE=$(curl --max-time 5 --verbose --head --stderr - "$WEBPAGE" | grep "expire date" | cut -d":" -f 2- | date -f - "+%s")
            DAYS=$(( ($EXPIREDATE - $(date "+%s")) / (60*60*24) )) # days remaining to expiration
            if test $DAYS -gt 7; then
                stdOutput "No need to renew the SSL certificate. It will expire in $DAYS days."
            else
                if test $DAYS -gt 0; then
                    stdError "The SSL certificate should be renewed as soon as possible ($DAYS remaining days)."
                else
                    stdError "The SSL certificate IS ALREADY EXPIRED!"
                fi
            fi
        fi
    fi    
else
    stdError "TCP port is close -> Has something gone wrong?"
    exit 1
fi

例子：

liujia@moni:~/check$ ./c.sh anqun.org:3389 -t
TCP port is close -> Has something gone wrong?
liujia@moni:~/check$ ./c.sh anqun.org:3390 -t
TCP port is open -> OK
liujia@moni:~/check$ ./c.sh http://anqun.org:80
HTTP STATUS CODE 200 -> OK
liujia@moni:~/check$ ./c.sh https://anqun.org:443
TCP port is close -> Has something gone wrong?
liujia@moni:~/check$ ./c.sh https://liujia.anqun.org:443
HTTP STATUS CODE 200 -> OK
No need to renew the SSL certificate. It will expire in 59 days.
liujia@moni:~/check$ ./c.sh https://hy.anqun.org:443 -e=i@liujia.anqun.org
TCP port is close -> Has something gone wrong?