Serve file over HTTP with Socat

serve_file_over_http.sh

#!/bin/bash

FILE="$1"
PORT=${PORT:-9999}

MIME_TYPE=$(mimetype "$FILE")
SIZE_BYTES=$(du -b "$FILE" | cut -f1)
FILE_NAME=$(basename "$FILE")
HEADER="\
HTTP/1.1 200 OK
Content-Type: $MIME_TYPE
Content-Disposition: attachment; filename=$FILE_NAME
Content-Length: $SIZE_BYTES

"
socat -d -d - tcp-l:"$PORT",reuseaddr,fork < <(printf "$HEADER"; cat "$FILE")