fix: resolve text attachment MIME types

apps/api/plane/settings/common.py

@@ -533,6 +533,7 @@ def _retention_days(env_var, default):
     "text/css",
     "text/javascript",
     "application/json",
+    "application/yaml",
     "text/xml",
     "text/csv",
     "application/xml",

packages/services/package.json

@@ -14,6 +14,7 @@
   "scripts": {
     "build": "tsdown",
     "dev": "tsdown --watch --no-clean",
+    "test": "vitest run",
     "check:lint": "oxlint --max-warnings=6 .",
     "check:types": "tsc --noEmit",
     "check:format": "oxfmt --check .",
@@ -30,6 +31,7 @@
   "devDependencies": {
     "@plane/typescript-config": "workspace:*",
     "tsdown": "catalog:",
-    "typescript": "catalog:"
+    "typescript": "catalog:",
+    "vitest": "catalog:"
   }
 }

packages/services/src/file/helper.test.ts

@@ -0,0 +1,48 @@
+/**
+ * Copyright (c) 2023-present Plane Software, Inc. and contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * See the LICENSE file for details.
+ */
+
+import { describe, expect, it, vi } from "vitest";
+
+import { getFileMetaDataForUpload } from "./helper";
+
+const metadata = (name: string, type = "", contents: BlobPart[] = ["key: value"]) =>
+  getFileMetaDataForUpload(new File(contents, name, { type }));
+
+describe("getFileMetaDataForUpload", () => {
+  it.each([
+    ["program.txt", "text/plain"],
+    ["program.md", "text/markdown"],
+    ["program.markdown", "text/markdown"],
+    ["program.csv", "text/csv"],
+    ["program.yaml", "application/yaml"],
+    ["program.yml", "application/yaml"],
+  ])("detects %s without browser MIME", async (name, expected) => {
+    expect((await metadata(name)).type).toBe(expected);
+  });
+
+  it("falls back to browser MIME", async () => {
+    expect((await metadata("program.log", "text/plain")).type).toBe("text/plain");
+  });
+
+  it("prefers signature detection", async () => {
+    const pngHeader = new Uint8Array([
+      0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d, 0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00,
+      0x01, 0x00, 0x00, 0x00, 0x01, 0x08, 0x06, 0x00, 0x00, 0x00, 0x1f, 0x15, 0xc4, 0x89,
+    ]);
+
+    expect((await metadata("image.yaml", "application/yaml", [pngHeader])).type).toBe("image/png");
+  });
+
+  it("does not apply fallback to an unsafe filename", async () => {
+    const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => undefined);
+
+    try {
+      expect((await metadata("payload.exe.yaml")).type).toBe("");
+    } finally {
+      warnSpy.mockRestore();
+    }
+  });
+});

packages/services/src/file/helper.ts

@@ -10,6 +10,15 @@ import { fileTypeFromBuffer } from "file-type";
 import type { TFileMetaDataLite, TFileSignedURLResponse } from "@plane/types";
 import { DANGEROUS_EXTENSIONS } from "@plane/constants";
 
+const TEXT_MIME_TYPES_BY_EXTENSION: Record<string, string> = {
+  txt: "text/plain",
+  md: "text/markdown",
+  markdown: "text/markdown",
+  csv: "text/csv",
+  yaml: "application/yaml",
+  yml: "application/yaml",
+};
+
 /**
  * @description Filename validation - checks for double extensions and dangerous patterns
  * @param {string} filename
@@ -92,6 +101,7 @@ const validateAndDetectFileType = async (file: File): Promise<string> => {
   const filenameError = validateFilename(file.name);
   if (filenameError) {
     console.warn(`File validation warning: ${filenameError}`);
+    return "";
   }
 
   try {
@@ -103,8 +113,8 @@ const validateAndDetectFileType = async (file: File): Promise<string> => {
     console.warn("Error detecting file type from signature:", _error);
   }
 
-  // fallback for unknown files
-  return "";
+  const extension = file.name.split(".").pop()?.toLowerCase() ?? "";
+  return TEXT_MIME_TYPES_BY_EXTENSION[extension] || file.type || "";
 };
 
 /**