+function createReqFiles (
+ fieldNames: string[],
+ mimeTypes: { [ id: string ]: string },
+ destinations: { [ fieldName: string ]: string }
+) {
+ const storage = multer.diskStorage({
+ destination: (req, file, cb) => {
+ cb(null, destinations[file.fieldname])
+ },
+
+ filename: async (req, file, cb) => {
+ const extension = mimeTypes[file.mimetype]
+ let randomString = ''
+
+ try {
+ randomString = await generateRandomString(16)
+ } catch (err) {
+ logger.error('Cannot generate random string for file name.', err)
+ randomString = 'fake-random-string'
+ }
+
+ cb(null, randomString + extension)
+ }
+ })
+
+ const fields = []
+ for (const fieldName of fieldNames) {
+ fields.push({
+ name: fieldName,
+ maxCount: 1
+ })
+ }
+
+ return multer({ storage }).fields(fields)
+}
+