feat: add file validation utilities

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/utils/file.js

@@ -0,0 +1,43 @@
+const FILE_TYPES = {
+  document: 2 * 1024 * 1024 * 1024, // 2GB
+  photo: 10 * 1024 * 1024, // 10MB
+  video: 2 * 1024 * 1024 * 1024, // 2GB
+  audio: 200 * 1024 * 1024, // 200MB
+  voice: 200 * 1024 * 1024, // 200MB
+  animation: 2 * 1024 * 1024 * 1024 // 2GB
+};
+
+export const getFileType = (mime, caption) => {
+  const mimeUpper = mime?.split('/')[0]?.toLowerCase();
+  const captionLower = caption?.toLowerCase();
+
+  if (mimeUpper === 'video') return 'video';
+  if (mimeUpper === 'audio') return 'audio';
+  if (mimeUpper === 'document') return 'document';
+  if (mimeUpper === 'image') return captionLower?.includes('gif') ? 'animation' : 'photo';
+  if (captionLower?.includes('voice')) return 'voice';
+  if (captionLower?.includes('animation')) return 'animation';
+
+  return mimeUpper || 'document';
+};
+
+export const checkFileSize = (sizeBytes, fileType) => {
+  const limit = FILE_TYPES[fileType] || FILE_TYPES.document;
+  return sizeBytes <= limit;
+};
+
+export const extractFileName = (msg, request) => {
+  if (request?.headers?.['x-file-name']) {
+    return request.headers['x-file-name'];
+  }
+  return msg.document?.fileName || msg.photo?.slice(-1)[0]?.fileName || msg.audio?.fileName ||
+         msg.voice?.fileName || msg.animation?.fileName || 'file';
+};
+
+export const extractMimeType = (msg, request) => {
+  if (request?.headers?.['x-mime-type']) {
+    return request.headers['x-mime-type'];
+  }
+  return msg.document?.mimeType || msg.photo?.slice(-1)[0]?.mimeType || msg.audio?.mimeType ||
+         msg.voice?.mimeType || msg.animation?.mimeType || 'application/octet-stream';
+};

test/file.test.js

@@ -0,0 +1,88 @@
+import { describe, it, expect } from "bun:test";
+import { getFileType, checkFileSize, extractFileName, extractMimeType } from "../src/utils/file.js";
+
+describe("File Utilities", () => {
+  describe("getFileType", () => {
+    it("should classify video mime types as video", () => {
+      expect(getFileType("video/mp4", "")).toBe("video");
+      expect(getFileType("video/quicktime", "")).toBe("video");
+    });
+
+    it("should classify audio mime types as audio", () => {
+      expect(getFileType("audio/mpeg", "")).toBe("audio");
+      expect(getFileType("audio/ogg", "")).toBe("audio");
+    });
+
+    it("should classify image mime types based on caption", () => {
+      expect(getFileType("image/jpeg", "my photo")).toBe("photo");
+      expect(getFileType("image/png", "cool image.png")).toBe("photo");
+      expect(getFileType("image/gif", "funny.gif")).toBe("animation");
+      expect(getFileType("image/png", "funny gif")).toBe("animation");
+    });
+
+    it("should classify voice and animation based on caption", () => {
+      expect(getFileType("application/octet-stream", "this is a voice note")).toBe("voice");
+      expect(getFileType("application/octet-stream", "cool animation")).toBe("animation");
+    });
+
+    it("should default to mime first segment or document", () => {
+      expect(getFileType("application/pdf", "")).toBe("application");
+      expect(getFileType(null, "")).toBe("document");
+    });
+  });
+
+  describe("checkFileSize", () => {
+    it("should allow files under the size limit", () => {
+      expect(checkFileSize(5 * 1024 * 1024, "photo")).toBe(true); // Photo limit is 10MB
+      expect(checkFileSize(1 * 1024 * 1024 * 1024, "video")).toBe(true); // Video limit is 2GB
+    });
+
+    it("should block files exceeding the size limit", () => {
+      expect(checkFileSize(15 * 1024 * 1024, "photo")).toBe(false); // Photo limit is 10MB
+      expect(checkFileSize(3 * 1024 * 1024 * 1024, "video")).toBe(false); // Video limit is 2GB
+    });
+
+    it("should fall back to document limit if fileType is unknown", () => {
+      expect(checkFileSize(1 * 1024 * 1024 * 1024, "unknown")).toBe(true); // Document limit is 2GB
+      expect(checkFileSize(3 * 1024 * 1024 * 1024, "unknown")).toBe(false);
+    });
+  });
+
+  describe("extractFileName", () => {
+    it("should extract file name from headers if present", () => {
+      const req = { headers: { "x-file-name": "custom.txt" } };
+      expect(extractFileName({}, req)).toBe("custom.txt");
+    });
+
+    it("should extract file name from various message attachment types", () => {
+      expect(extractFileName({ document: { fileName: "doc.pdf" } }, null)).toBe("doc.pdf");
+      expect(extractFileName({ photo: [{ fileName: "low.jpg" }, { fileName: "high.jpg" }] }, null)).toBe("high.jpg");
+      expect(extractFileName({ audio: { fileName: "song.mp3" } }, null)).toBe("song.mp3");
+      expect(extractFileName({ voice: { fileName: "voice.ogg" } }, null)).toBe("voice.ogg");
+      expect(extractFileName({ animation: { fileName: "anim.gif" } }, null)).toBe("anim.gif");
+    });
+
+    it("should return default filename if not found", () => {
+      expect(extractFileName({}, null)).toBe("file");
+    });
+  });
+
+  describe("extractMimeType", () => {
+    it("should extract mime type from headers if present", () => {
+      const req = { headers: { "x-mime-type": "text/plain" } };
+      expect(extractMimeType({}, req)).toBe("text/plain");
+    });
+
+    it("should extract mime type from various message attachment types", () => {
+      expect(extractMimeType({ document: { mimeType: "application/pdf" } }, null)).toBe("application/pdf");
+      expect(extractMimeType({ photo: [{ mimeType: "image/jpeg" }, { mimeType: "image/png" }] }, null)).toBe("image/png");
+      expect(extractMimeType({ audio: { mimeType: "audio/mpeg" } }, null)).toBe("audio/mpeg");
+      expect(extractMimeType({ voice: { mimeType: "audio/ogg" } }, null)).toBe("audio/ogg");
+      expect(extractMimeType({ animation: { mimeType: "video/mp4" } }, null)).toBe("video/mp4");
+    });
+
+    it("should return default mime type if not found", () => {
+      expect(extractMimeType({}, null)).toBe("application/octet-stream");
+    });
+  });
+});