feat(storage): complete phase 3 branding foundation

server/files/paths.ts

@@ -0,0 +1,36 @@
+import path from "node:path";
+import { DomainError } from "../domain/errors";
+
+export function resolveStoragePath(uploadsDir: string, storagePath: string): string {
+  if (
+    !storagePath ||
+    path.isAbsolute(storagePath) ||
+    storagePath.includes("\\") ||
+    storagePath.includes("\0")
+  ) {
+    throw invalidPath();
+  }
+
+  const segments = storagePath.split("/");
+  if (segments.some((segment) => !segment || segment === "." || segment === "..")) {
+    throw invalidPath();
+  }
+
+  const root = path.resolve(uploadsDir);
+  const resolved = path.resolve(root, ...segments);
+  if (!resolved.startsWith(`${root}${path.sep}`)) {
+    throw invalidPath();
+  }
+  return resolved;
+}
+
+export function buildStoragePath(directory: string, id: string, extension: string): string {
+  if (!/^[a-z-]+$/.test(directory) || !/^[a-zA-Z0-9-]+$/.test(id) || !/^[a-z0-9]+$/.test(extension)) {
+    throw invalidPath();
+  }
+  return `${directory}/${id}.${extension}`;
+}
+
+function invalidPath() {
+  return new DomainError("VALIDATION_ERROR", "Geçersiz dosya yolu.");
+}