#!/bin/sh

# Simple HTTP Server using Netcat (nc)
#
# Sends a greeting message and the date in the response.


# Info: Relies on the OpenBSD version of Netcat
#       GNU netcat may or may not work.

# Creating a FIFO so that the output of nc can be processed and used to determine the input.
# Allows for "passing values back round"
outfifo="/tmp/outfifo"
rm -f "$outfifo"
mkfifo "$outfifo"

# Run forever
while true; do
    x="$(date)"
    len="$(echo "$x" | wc -c)"
    cat "$outfifo" \
        | nc -l localhost 1500 \
        | while read -r line; do
            line=$(echo "$line" | tr -d '\r\n')
            echo "< $line"

            if echo "$line" | grep -qE '^GET /'; then
                # on reading the request line, extract a value from the request path and build the response
                name="$(echo $line | sed 's:GET /\([^ ]*\).*:\1:')"
                content="Hello $name, the date and time is $(date)."
                # Without Content-Length header, connection will not close properly
                len="$(echo "$content" | wc -c)"

                response="HTTP/1.1 200 OK\nContent-Length: $len\nContent-Type: plain/text\n\n$content"
            elif [ -z "$line" ]; then # end of request
                # send response once all of the request has been read
                echo -e "$response" > "$outfifo"
            fi
        done
    done