Comment by goombacloud

When socat is around a simple server can also be constructed with it:

        tee /tmp/server > /dev/null <<'EOF'
        #!/bin/bash
        set -euo pipefail
        SERVE="$1"
        TYPE="$2"
        read -a WORDS
        if [ "${#WORDS[@]}" != 3 ] || [ "${WORDS[0]}" != "GET" ]; then
          echo -ne "HTTP/1.1 400 Bad request\r\n\r\n"; exit 0
        fi
        # Subfolders are not supported for security reasons as this avoids having to deal with ../../ attacks
        FILE="${SERVE}/$(basename -- "${WORDS[1]}")"
        if [ -d "${FILE}" ] || [ ! -e "${FILE}" ]; then
          echo -ne "HTTP/1.1 404 Not found\r\n\r\n" ; exit 0
        fi
        echo -ne "HTTP/1.1 200 OK\r\n"
        echo -ne "Content-Type: ${TYPE};\r\n"
        LEN=$(stat -L --printf='%s\n' "${FILE}")
        echo -ne "Content-Length: ${LEN}\r\n"
        echo -ne "\r\n"
        cat "${FILE}"
        EOF
        chmod +x /tmp/server
        # switch from "text/plain" to "application/octet-stream" for file downloads
        socat TCP-LISTEN:8000,reuseaddr,fork SYSTEM:'/tmp/server /tmp/ text-plain'

# test: curl -v http://localhost:8000/server