refactor: consume async iterable

src/routes/files.ts

@@ -1,7 +1,7 @@
 import { FastifyPluginCallback } from "fastify";
 import multipart from "@fastify/multipart";
 import { getFileDownload, getFileLink, uploadFiles } from "../telegram";
-import { readFile } from "fs/promises";
+import { filesGeneratorToArray } from "../utils/array";
 
 export const FilesAPI: FastifyPluginCallback = async (fastify, _, done) => {
   await fastify.register(multipart, {
@@ -14,11 +14,8 @@ export const FilesAPI: FastifyPluginCallback = async (fastify, _, done) => {
   });
 
   fastify.post("/upload", async (req, res) => {
-    // saveRequestFiles saves files in tmp directory.
-    // This is to avoid working with req.files(), which is an async iterator... and a pain to work with.
-    // Files from saveRequestFiles() have a useless toBuffer method, so it needs to be replaced.
-    console.log("Saving file to disk...");
-    const files = (await req.saveRequestFiles()).map((file) => ({ ...file, toBuffer: () => readFile(file.filepath) }));
+    console.log("Loading files...");
+    const files = await filesGeneratorToArray(req.files());
     console.log(`Start upload of ${files.length} files...`);
     const ret = await uploadFiles(files);
 

src/telegram/telegram.ts

@@ -6,15 +6,14 @@ import {
   TRIPS_BOT_API_TOKEN,
 } from "../constants";
 import { throwError } from "../utils/throw";
-import { MultipartFile } from "@fastify/multipart";
-import { splitArrayIntoChunks } from "../utils/array";
+import { LoadedFile, splitArrayIntoChunks } from "../utils/array";
 
 // Disable warning
 process.env["NTBA_FIX_350"] = "1";
 
 const bot = new TelegramBot(TRIPS_BOT_API_TOKEN, { filepath: false });
 
-async function uploadFileGroup(files: MultipartFile[], media: InputMediaPhoto[]) {
+async function uploadFileGroup(files: LoadedFile[], media: InputMediaPhoto[]) {
   return (await bot.sendMediaGroup(CHAT_ID, media)).reduce(
     (prev, curr, i) => ({
       ...prev,
@@ -24,12 +23,11 @@ async function uploadFileGroup(files: MultipartFile[], media: InputMediaPhoto[])
   );
 }
 
-export async function uploadFiles(files: MultipartFile[]) {
+export async function uploadFiles(files: LoadedFile[]) {
   let ret: Record<string, string> = {};
-  console.log("Reading files from disk...");
   // This library has incorrect typescript typings... InputMediaDocument missing
   const media = (await Promise.all(
-    files.map(async (file) => ({ media: await file.toBuffer(), type: "document" })),
+    files.map(async (file) => ({ media: file.content, type: "document" })),
   )) as unknown as InputMediaPhoto[];
   const fileChunks = splitArrayIntoChunks(files, TELEGRAM_MAX_PHOTOS_PER_MESSAGE);
   const mediaChunks = splitArrayIntoChunks(media, TELEGRAM_MAX_PHOTOS_PER_MESSAGE);

src/utils/array.ts

@@ -1,3 +1,7 @@
+import { MultipartFile } from "@fastify/multipart";
+
+export type LoadedFile = MultipartFile & { content: Buffer };
+
 export function splitArrayIntoChunks<T>(arr: T[], chunkSize: number): T[][] {
   const result: T[][] = [];
 
@@ -7,3 +11,11 @@ export function splitArrayIntoChunks<T>(arr: T[], chunkSize: number): T[][] {
 
   return result;
 }
+
+export async function filesGeneratorToArray(files: AsyncIterableIterator<MultipartFile>) {
+  const out: LoadedFile[] = [];
+  for await (const file of files) {
+    out.push({ ...file, content: await file.toBuffer() });
+  }
+  return out;
+}