fix: stream FilePond uploads to S3 and proxy private file previews

Disk-based multer plus an authenticated content endpoint match the working Node.js uploader and avoid browser signed-URL failures on SeaweedFS.

components/files/fileService.js

@@ -1,17 +1,32 @@
 // /components/files/fileService.js
 
+const fs = require('fs/promises');
 const path = require('path');
 const config = require('../../config/config');
 const {
   uploadToTempBucket,
   commitTempFile,
   generatePresignedUrl,
+  getObjectBuffer,
   deleteFromBucket
 } = require('../../utils/s3Client');
 const AppError = require('../../utils/AppError');
 
-const uploadTempFile = async (fileBuffer, originalName, mimeType) => {
-  if (!fileBuffer || !originalName) {
+const unlinkQuietly = async (filePath) => {
+  if (!filePath) return;
+  try {
+    await fs.unlink(filePath);
+  } catch {
+    // temp disk file may already be gone
+  }
+};
+
+const uploadTempFile = async (file) => {
+  const originalName = file?.originalname || file?.originalName;
+  const mimeType = file?.mimetype || file?.mimeType || 'application/octet-stream';
+  const source = file?.path || file?.buffer;
+
+  if (!source || !originalName) {
     throw new AppError('FILE_REQUIRED');
   }
 
@@ -19,13 +34,17 @@ const uploadTempFile = async (fileBuffer, originalName, mimeType) => {
   const uniquePrefix = `${Date.now()}-${Math.round(Math.random() * 1E9)}`;
   const tempFileName = `temp-${uniquePrefix}${ext}`;
 
-  const result = await uploadToTempBucket(fileBuffer, tempFileName, mimeType);
-  return {
-    tempFileName: result.tempFileName,
-    originalName,
-    mimeType,
-    bucket: result.bucket
-  };
+  try {
+    const result = await uploadToTempBucket(source, tempFileName, mimeType);
+    return {
+      tempFileName: result.tempFileName,
+      originalName,
+      mimeType,
+      bucket: result.bucket
+    };
+  } finally {
+    await unlinkQuietly(file.path);
+  }
 };
 
 const getPresignedUrl = async (filename, bucket = null) => {
@@ -44,6 +63,13 @@ const getPresignedUrl = async (filename, bucket = null) => {
   };
 };
 
+const getFileContent = async (filename, bucket = null) => {
+  if (!filename) {
+    throw new AppError('VALIDATION_FAILED', null, 'Filename is required');
+  }
+  return getObjectBuffer(filename, bucket || config.S3_TEMP_BUCKET);
+};
+
 const commitFile = async (tempFileName, targetFileName = null, targetBucket = 'certificates') => {
   return commitTempFile(tempFileName, targetFileName, targetBucket);
 };
@@ -55,6 +81,7 @@ const deleteFile = async (filename, bucket = null) => {
 module.exports = {
   uploadTempFile,
   getPresignedUrl,
+  getFileContent,
   commitFile,
   deleteFile
 };