fix: multi-part file upload + validations + specs

api/src/middlewares/multer.ts

@@ -0,0 +1,77 @@
+import path from 'path'
+import { Request } from 'express'
+import multer, { FileFilterCallback, Options } from 'multer'
+import { getTmpUploadsPath } from '../utils'
+
+const acceptableExtensions = ['.sas']
+const fieldNameSize = 300
+const fileSize = 10485760 // 10 MB
+
+const storage = multer.diskStorage({
+  destination: getTmpUploadsPath(),
+  filename: function (
+    _req: Request,
+    file: Express.Multer.File,
+    callback: (error: Error | null, filename: string) => void
+  ) {
+    callback(
+      null,
+      file.fieldname + path.extname(file.originalname) + '-' + Date.now()
+    )
+  }
+})
+
+const limits: Options['limits'] = {
+  fieldNameSize,
+  fileSize
+}
+
+const fileFilter: Options['fileFilter'] = (
+  req: Request,
+  file: Express.Multer.File,
+  callback: FileFilterCallback
+) => {
+  const fileExtension = path.extname(file.originalname).toLocaleLowerCase()
+
+  if (!acceptableExtensions.includes(fileExtension)) {
+    return callback(
+      new Error(
+        `File extension '${fileExtension}' not acceptable. Valid extension(s): ${acceptableExtensions.join(
+          ', '
+        )}`
+      )
+    )
+  }
+
+  const uploadFileSize = parseInt(req.headers['content-length'] ?? '')
+  if (uploadFileSize > fileSize) {
+    return callback(
+      new Error(
+        `File size is over limit. File limit is: ${fileSize / 1024 / 1024} MB`
+      )
+    )
+  }
+
+  callback(null, true)
+}
+
+const options: Options = { storage, limits, fileFilter }
+
+const multerInstance = multer(options)
+
+export const multerSingle = (fileName: string, arg: any) => {
+  const [req, res, next] = arg
+  const upload = multerInstance.single(fileName)
+
+  upload(req, res, function (err) {
+    if (err instanceof multer.MulterError) {
+      return res.status(500).send(err.message)
+    } else if (err) {
+      return res.status(400).send(err.message)
+    }
+    // Everything went fine.
+    next()
+  })
+}
+
+export default multerInstance