CORS HTTPS Proxy

cors-proxy.sh

  backend="$1"
  if [ -z "$backend" ]; then
    echo "Please provide a backend URL"
    return
  fi

  port="$2"
  if [ -z "$port" ]; then
    port=5555
  fi

  ssl_dir="$HOME/.config/https-server"
  ssl_cert_file="${ssl_dir}/localhost.crt"
  ssl_key_file="${ssl_dir}/localhost.key"

  if [ ! -f "${ssl_cert_file}" ] || [ ! -f "${ssl_key_file}" ]; then
    echo "Generating certificates and saving it in ${ssl_cert_file}..."

    mkdir -p "${ssl_dir}"
    openssl req -x509 -out "${ssl_cert_file}" -keyout "${ssl_key_file}" \
    -newkey rsa:2048 -nodes -sha256 \
    -subj '/CN=localhost' -extensions EXT -config <( \
    printf "[dn]\nCN=localhost\n[req]\ndistinguished_name = dn\n[EXT]\nsubjectAltName=DNS:localhost\nkeyUsage=digitalSignature\nextendedKeyUsage=serverAuth")

    echo "Adding certificate to trusted certs, please type your password:"
    sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain "${ssl_cert_file}"
  fi

  if [ ! -f "${ssl_cert_file}" ] || [ ! -f "${ssl_key_file}" ]; then
    echo "Can't find certificate at ${ssl_cert_file} or key at ${ssl_key_file}"
    return;
  fi

cat <<EOF > /tmp/cors_proxy.conf
events {}

http {
  server {
    listen ${port} ssl;
    ssl_certificate ${ssl_cert_file};
    ssl_certificate_key ${ssl_key_file};
    access_log /dev/stdout;
    error_log /dev/stderr;

    location / {
      # Handle CORS preflight requests
      if (\$request_method = OPTIONS) {
        add_header 'Access-Control-Allow-Origin' '*';
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
        add_header 'Access-Control-Allow-Headers' '*';
        add_header 'Access-Control-Max-Age' 86400;
        add_header 'Content-Length' 0;
        add_header 'Content-Type' 'text/plain charset=UTF-8';
        return 204;
      }

      # Proxy all other requests
      proxy_pass $backend;
      add_header 'Access-Control-Allow-Origin' '*';
      add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
      add_header 'Access-Control-Allow-Headers' '*';
    }
  }
}
EOF

  echo "Starting CORS proxy for '${backend}' at 'https://127.0.0.1:${port}'"
  nginx -c /tmp/cors_proxy.conf -g 'daemon off;'