From 00e21b27a56d682bcdac938fe488ff2e1c8ea2be Mon Sep 17 00:00:00 2001
From: Alice Gaudon <alice@gaudon.pro>
Date: Fri, 20 Nov 2020 13:38:32 +0100
Subject: [PATCH] Make file download unavailable while caching is in progress

---
 src/controllers/GiteaRepoLatestReleaseController.ts | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/controllers/GiteaRepoLatestReleaseController.ts b/src/controllers/GiteaRepoLatestReleaseController.ts
index 7312285..2837eab 100644
--- a/src/controllers/GiteaRepoLatestReleaseController.ts
+++ b/src/controllers/GiteaRepoLatestReleaseController.ts
@@ -3,7 +3,7 @@ import {NextFunction, Request, Response} from "express";
 import * as https from "https";
 import config from "config";
 import {log} from "swaf/Logger";
-import {NotFoundHttpError} from "swaf/HttpError";
+import {NotFoundHttpError, ServiceUnavailableHttpError} from "swaf/HttpError";
 import * as fs from "fs";
 import {promisify} from "util";
 import path from "path";
@@ -85,10 +85,15 @@ export default class GiteaRepoLatestReleaseController extends Controller {
         }
 
         const assetPath = path.resolve(ASSETS_BASE_DIR, '' + downloadProperties.asset.id);
+        const tmpAssetPath = assetPath + '.tmp';
 
         // Download asset if it doesn't exist
         if (!await promisify(fs.exists)(assetPath)) {
-            const file = fs.createWriteStream(assetPath);
+            if (await promisify(fs.exists)(tmpAssetPath)) {
+                throw new ServiceUnavailableHttpError('This file is currently being cached. Please try again later.');
+            }
+
+            const file = fs.createWriteStream(tmpAssetPath);
             await new Promise((resolve, reject) => {
                 const httpRequest = https.get(downloadProperties.asset.url, res => {
                     res.on('end', () => {
@@ -102,6 +107,7 @@ export default class GiteaRepoLatestReleaseController extends Controller {
                 httpRequest.end();
             });
             file.close();
+            await promisify(fs.rename)(tmpAssetPath, assetPath);
         }
 
         // Respond