penpals.sh

#!/bin/bash

main () {
    # Create a temporary file for the handle_request script
    HANDLE_REQUESTS=$(mktemp /tmp/handle_request.XXXXXX)

    # Write the handle_request function to the temporary file
    cat << 'EOF' > "$HANDLE_REQUESTS"
#!/bin/bash

PARENT_PID=$PPID

shutdown() {
    kill -TERM $PARENT_PID
    exit 0
}

# Trap signals
trap shutdown SIGTERM

# Read the request from stdin
read -r REQUEST

# Parse the request (we only care about GET requests)
if [[ $REQUEST =~ ^GET ]]; then
    # Generate a simple HTTP response with a 200 OK status and some HTML content
    RESPONSE="HTTP/1.1 200 OK\r\n"
    RESPONSE+="Content-Type: text/plain\r\n"
    RESPONSE+="Connection: close\r\n"
    RESPONSE+="\r\n"
    RESPONSE+="$(cat /tmp/hexSum)"

    # Send the response
    echo -en "$RESPONSE"
    shutdown
else
    # Respond with a 400 Bad Request for any non-GET requests
    RESPONSE="HTTP/1.1 400 Bad Request\r\n"
    RESPONSE+="Content-Type: text/plain\r\n"
    RESPONSE+="Connection: close\r\n"
    RESPONSE+="\r\n"
    RESPONSE+="-1"

    # Send the response
    echo -en "$RESPONSE"
fi
EOF

    # Make the temporary script executable
    chmod +x "$HANDLE_REQUESTS"

    # Generate proofs
    RANDOM_DATA=$(openssl rand -hex 16)
    PROOF=$(echo -n "$RANDOM_DATA" | sha256sum | awk '{print $1}')
    #PUBLIC_PROOF=$(echo -n "$PROOF" | sha256sum | awk '{print $1}')
    HEX_DIGITS=$(echo "$PROOF" | tr -cd '[:xdigit:]')
    HEX_SUM=1
    # Loop through each hexadecimal digit and sum them up
    for ((i = 0; i < ${#HEX_DIGITS}; i += 2)); do
        # Extract two characters at a time
        HEX_PAIR=${HEX_DIGITS:$i:2}
        # Convert the hexadecimal pair to decimal and add it to the sum
        DECIMAL=$((16#$HEX_PAIR))
        HEX_SUM=$((HEX_SUM * (DECIMAL + 1)))
    done

    echo "$HEX_SUM" > /tmp/hexSum

    echo "https://airtable.com/apppJsMZ2MAT6iLkN/shr8pabyEDG9vBryN?prefill_Proof=$PROOF" > /tmp/proof

    # Generate form
    EXTERNAL_IP=$(curl -s ifconfig.me/ip)
    echo "https://airtable.com/apppJsMZ2MAT6iLkN/shrMGGBajfUIdGjJe?prefill_URL=$EXTERNAL_IP:$PORT&prefill_HexSum=$HEX_SUM&prefill_Proof=$PROOF"

    # Define the port to listen on
    PORT=8080

    # Use socat to listen on the specified port and handle requests
    socat TCP-LISTEN:"$PORT",reuseaddr,fork EXEC:"$HANDLE_REQUESTS"
    # @TODO shut this down after verification

    # Clean up the temporary script on exit
    trap "rm -f $HANDLE_REQUESTS" EXIT
}

main