Function validateUrl

examples/pdf-server/server.ts:580–660

(url: string)

}

export function validateUrl(url: string): {
  valid: boolean;
  error?: string;
} {
  if (isFileUrl(url) || isLocalPath(url)) {
    // fileUrlToPath already decodes percent-encoding; for bare paths,
    // decode here in case the client sends %20 for spaces etc.
    const filePath = isFileUrl(url)
      ? fileUrlToPath(url)
      : decodeURIComponent(url);
    const resolved = path.resolve(filePath);

    // Check exact match (CLI args / roots)
    if (allowedLocalFiles.has(resolved)) {
      if (!fs.existsSync(resolved)) {
        return { valid: false, error: `File not found: ${resolved}` };
      }
      return { valid: true };
    }

    // Check directory match (MCP roots / CLI dirs).
    // Try both the raw path and its realpath (resolves symlinks).
    let realResolved: string | undefined;
    try {
      realResolved = fs.realpathSync(resolved);
    } catch {
      // File may not exist yet at this path
    }
    if (
      [...allowedLocalDirs].some((dir) => {
        let realDir: string | undefined;
        try {
          realDir = fs.realpathSync(dir);
        } catch {
          // Dir may not exist
        }
        return (
          isAncestorDir(dir, resolved) ||
          (realResolved != null && isAncestorDir(dir, realResolved)) ||
          (realDir != null && isAncestorDir(realDir, resolved)) ||
          (realDir != null &&
            realResolved != null &&
            isAncestorDir(realDir, realResolved))
        );
      })
    ) {
      if (!fs.existsSync(resolved)) {
        return { valid: false, error: `File not found: ${resolved}` };
      }
      return { valid: true };
    }

    console.error(
      `[pdf-server] Local file not in allowed list: ${resolved}\n  Allowed dirs: ${[...allowedLocalDirs].join(", ")}`,
    );
    return {
      valid: false,
      error: `Local file not in allowed list: ${resolved}\nAllowed directories: ${[...allowedLocalDirs].join(", ")}`,