server

#! env bash

while getopts "n:c:e:" OPT; do
    case $OPT in
        n) name=$OPTARG ;;
        c) capture_file=$OPTARG ;;
        e) handler=$OPTARG ;;
    esac
done
shift $((OPTIND-1))

[[ -z $name ]] && echo "Must provide -n <name> option" >&2 && exit 1

function log {
    # Log to syslog since stdout is used for response content
    logger -t xinetd.webhook-${name} -p user.info "$@" &>/dev/null
}

capture_file=${capture_file:-/tmp/webhook-${name}.http}

function read-http {
    # Read in the full HTTP request

    # We look for the Content-Length because the client
    # may not send an EOF on the input so we have to be
    # precise about how we read from stdin.
    while IFS=$'\r\n' read -r line; do
        echo -en "$line\r\n"
        case $line in
            Content-Length:*) content_length=$(cut -d ' ' -f 2 <<<$line);;
            "") break;;
        esac
    done

    if [[ -n $content_length ]]; then
        read -n $content_length -r data
        echo -n "$data"
    fi
}

function reply-http {
    # Send a 200 OK reply to the client
    local data

    read -r -d '' data

    # Reply with correct headers and body
    if [[ -n $data ]]; then
        cat <<EOF
HTTP/1.1 $*
Content-Type: text/plain
Content-Length: ${#data}

$data
EOF
    else
        cat <<EOF
HTTP/1.1 $*

EOF
    fi
}

function reply-http-success {
    reply-http "200 OK"
}

function reply-http-error {
    reply-http "500 Internal Server Error"
}

# Capture the request to a file
mkdir -p $(dirname $capture_file)
read-http > $capture_file
log "Saved request to $capture_file"

# Respond to HTTP request
if [[ -n $handler ]]; then
    log "Sending request to $handler"
    $handler <$capture_file | reply-http-success
else
    log "Sending generic 200 OK response"
    echo "" | reply-http-success
fi