FEAT - OPS ATTACHMENTS: multi-format upload, stable card drop zone and text previews

plane-src/packages/services/src/file/helper.ts

@@ -10,6 +10,30 @@ import { fileTypeFromBuffer } from "file-type";
 import type { TFileMetaDataLite, TFileSignedURLResponse } from "@plane/types";
 import { DANGEROUS_EXTENSIONS } from "@plane/constants";
 
+const TEXT_MIME_TYPES_BY_EXTENSION: Readonly<Record<string, string>> = {
+  cfg: "text/plain",
+  conf: "text/plain",
+  csv: "text/csv",
+  ini: "text/plain",
+  json: "application/json",
+  jsonl: "application/x-ndjson",
+  log: "text/plain",
+  markdown: "text/markdown",
+  md: "text/markdown",
+  mdown: "text/markdown",
+  mkd: "text/markdown",
+  mkdn: "text/markdown",
+  ndjson: "application/x-ndjson",
+  toml: "application/toml",
+  tsv: "text/tab-separated-values",
+  txt: "text/plain",
+  xml: "application/xml",
+  yaml: "application/yaml",
+  yml: "application/yaml",
+};
+
+const getFileExtension = (filename: string): string => filename.split(".").pop()?.trim().toLowerCase() ?? "";
+
 /**
  * @description Filename validation - checks for double extensions and dangerous patterns
  * @param {string} filename
@@ -82,8 +106,10 @@ const detectMimeTypeFromSignature = async (file: File): Promise<string> => {
 };
 
 /**
- * @description Validate and detect the MIME type of a file using signature detection
- * Also performs basic security checks on filename
+ * @description Validate and detect the MIME type of a file.
+ * Binary signatures take precedence. Text formats are resolved from a conservative
+ * extension map because they do not have a binary signature. Browser MIME metadata
+ * and application/octet-stream provide compatibility for other safe attachments.
  * @param {File} file
  * @returns {Promise<string>} validated and detected MIME type
  */
@@ -91,7 +117,7 @@ const validateAndDetectFileType = async (file: File): Promise<string> => {
   // Basic filename validation
   const filenameError = validateFilename(file.name);
   if (filenameError) {
-    console.warn(`File validation warning: ${filenameError}`);
+    throw new Error(filenameError);
   }
 
   try {
@@ -103,8 +129,15 @@ const validateAndDetectFileType = async (file: File): Promise<string> => {
     console.warn("Error detecting file type from signature:", _error);
   }
 
-  // fallback for unknown files
-  return "";
+  const extensionMimeType = TEXT_MIME_TYPES_BY_EXTENSION[getFileExtension(file.name)];
+  if (extensionMimeType) return extensionMimeType;
+
+  const browserMimeType = file.type.split(";", 1)[0]?.trim().toLowerCase();
+  if (browserMimeType) return browserMimeType;
+
+  // Preserve generic attachment support when neither the file signature nor the
+  // browser can identify a safe filename. The API still enforces its MIME allowlist.
+  return "application/octet-stream";
 };
 
 /**