@beignet/core/src/server/trusted-proxy-internal.ts

Core framework primitives for Beignet

import type { TrustedProxyConfig } from "./trusted-proxy.js";

export class InvalidRequestUrlError extends Error {
  constructor() {
    super("req.url must be an absolute HTTP or HTTPS URL.");
    this.name = "InvalidRequestUrlError";
  }
}

export function parseHttpRequestUrl(value: string): URL {
  try {
    const url = new URL(value);
    if (url.protocol !== "http:" && url.protocol !== "https:") {
      throw new InvalidRequestUrlError();
    }
    return url;
  } catch (error) {
    if (error instanceof InvalidRequestUrlError) throw error;
    throw new InvalidRequestUrlError();
  }
}

export function requireTrustedProxyHeaderName(
  name: string,
  optionName: string,
): string {
  const header = name.trim();
  if (!header) {
    throw new Error(`${optionName} must be a non-empty header name.`);
  }

  try {
    new Headers().get(header);
  } catch {
    throw new Error(`${optionName} must be a valid HTTP header name.`);
  }

  return header;
}

export function assertValidTrustedProxyConfig(
  config: TrustedProxyConfig,
): void {
  if (!config) return;

  if (config.hostHeader !== undefined && config.hostHeader !== false) {
    requireTrustedProxyHeaderName(config.hostHeader, "trustedProxy.hostHeader");
  }
  if (config.protocolHeader !== undefined && config.protocolHeader !== false) {
    requireTrustedProxyHeaderName(
      config.protocolHeader,
      "trustedProxy.protocolHeader",
    );
  }
  if (typeof config.clientIp === "object") {
    requireTrustedProxyHeaderName(
      config.clientIp.header,
      "trustedProxy.clientIp.header",
    );
  }
}