check file type with validation

ui/desktop/src/main.ts

@@ -12,8 +12,10 @@ import {
   powerSaveBlocker,
   Tray,
 } from 'electron';
+import { isTextFile } from './utils/fileUtils';
 import started from 'electron-squirrel-startup';
 import path from 'node:path';
+import fs from 'node:fs';
 import { startGoosed } from './goosed';
 import { getBinaryPath } from './utils/binaryPath';
 import { loadShellEnv } from './utils/loadEnv';
@@ -315,14 +317,35 @@ process.on('unhandledRejection', (error) => {
   handleFatalError(error instanceof Error ? error : new Error(String(error)));
 });
 
-// Add file/directory selection handler
 ipcMain.handle('select-file-or-directory', async () => {
   const result = await dialog.showOpenDialog({
     properties: ['openFile', 'openDirectory'],
+    title: 'Select a text file or directory',
   });
 
   if (!result.canceled && result.filePaths.length > 0) {
-    return result.filePaths[0];
+    const path = result.filePaths[0];
+    const stats = await fs.promises.stat(path);
+
+    // If it's a directory, allow it
+    if (stats.isDirectory()) {
+      return path;
+    }
+
+    // If it's a file, check if it's text
+    if (stats.isFile()) {
+      if (isTextFile(path)) {
+        return path;
+      } else {
+        dialog.showMessageBox({
+          type: 'error',
+          title: 'Unsupported File Type',
+          message: 'Only text files can be attached.',
+          detail: 'The selected file appears to be binary or non-text content.',
+        });
+        return null;
+      }
+    }
   }
   return null;
 });

ui/desktop/src/utils/fileUtils.ts

@@ -0,0 +1,34 @@
+import fs from 'node:fs';
+import { Buffer } from 'node:buffer';
+
+/**
+ * Checks if a file is likely to be a text file by reading its first chunk
+ * and checking for null bytes and valid UTF-8 encoding
+ */
+export function isTextFile(filePath: string): boolean {
+  try {
+    // Read the first 8KB of the file
+    const buffer = Buffer.alloc(8192);
+    const fd = fs.openSync(filePath, 'r');
+    const bytesRead = fs.readSync(fd, buffer, 0, 8192, 0);
+    fs.closeSync(fd);
+
+    // If file is empty, consider it text
+    if (bytesRead === 0) return true;
+
+    // Check for null bytes which usually indicate binary content
+    for (let i = 0; i < bytesRead; i++) {
+      if (buffer[i] === 0) return false;
+    }
+
+    // Try to decode as UTF-8
+    const content = buffer.slice(0, bytesRead).toString('utf8');
+
+    // If we can decode it as UTF-8 and it contains printable characters
+    // we'll consider it a text file
+    return content.length > 0 && /^[\x20-\x7E\t\n\r\x80-\xFF]*$/.test(content);
+  } catch (error) {
+    console.error('Error checking file type:', error);
+    return false;
+  }
+}