From bf689887abf6b1f020890974797544bd37b27e30 Mon Sep 17 00:00:00 2001
From: Jang Ryeol <ryeolj5911@gmail.com>
Date: Mon, 22 Oct 2018 16:39:19 +0900
Subject: [PATCH] Render html as png #43

---
 package-lock.json                             | 12 +++++++-
 package.json                                  |  2 ++
 src/api/routes/TimetableRouter.ts             | 14 +++++++++
 src/core/nightmare/NightmareService.ts        | 30 +++++++++++++++++++
 .../timetable/TimetableImageRenderService.ts  | 11 +++++++
 5 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 src/core/nightmare/NightmareService.ts
 create mode 100644 src/core/timetable/TimetableImageRenderService.ts

diff --git a/package-lock.json b/package-lock.json
index 390a0885..ff930b06 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "snutt",
-  "version": "2.1.6",
+  "version": "2.1.9",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -22,6 +22,11 @@
       "resolved": "https://registry.npmjs.org/@types/async/-/async-2.0.49.tgz",
       "integrity": "sha1-kuM9E/dMiVy5p/OLqX24Qx7RS8A="
     },
+    "@types/async-lock": {
+      "version": "1.1.0",
+      "resolved": "http://registry.npmjs.org/@types/async-lock/-/async-lock-1.1.0.tgz",
+      "integrity": "sha512-Eo8EXiqmChtkt0ETf6AQ8aiDHT3Tht6OuMSa3/9nfuyqFimp7ZwPMiufsA56A7ZUGBuwFzH860jO0d8n0lETtg=="
+    },
     "@types/bcrypt": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/@types/bcrypt/-/bcrypt-2.0.0.tgz",
@@ -342,6 +347,11 @@
         "lodash": "^4.8.0"
       }
     },
+    "async-lock": {
+      "version": "1.1.3",
+      "resolved": "https://registry.npmjs.org/async-lock/-/async-lock-1.1.3.tgz",
+      "integrity": "sha512-nxlfFLGfCJ1r7p9zhR5OuL6jYkDd9P7FqSitfLji+C1NdyhCz4+rWW3kiPiyPASHhN7VlsKEvRWWbnME9lYngw=="
+    },
     "asynckit": {
       "version": "0.4.0",
       "resolved": "https://registry.npmjs.org/asynckit/-/asynckit-0.4.0.tgz",
diff --git a/package.json b/package.json
index 5a930b16..61cec4fb 100644
--- a/package.json
+++ b/package.json
@@ -13,6 +13,7 @@
   },
   "dependencies": {
     "@types/async": "~2.0.49",
+    "@types/async-lock": "^1.1.0",
     "@types/bcrypt": "~2.0.0",
     "@types/express": "^4.0.34",
     "@types/express-promise-router": "^2.0.0",
@@ -29,6 +30,7 @@
     "@types/sinon": "^5.0.1",
     "assert-rejects": "^0.1.1",
     "async": "~2.0.1",
+    "async-lock": "^1.1.3",
     "bcrypt": "~2.0.1",
     "body-parser": "~1.18.3",
     "cookie-parser": "~1.4.3",
diff --git a/src/api/routes/TimetableRouter.ts b/src/api/routes/TimetableRouter.ts
index 13f36ad8..fc593f5b 100644
--- a/src/api/routes/TimetableRouter.ts
+++ b/src/api/routes/TimetableRouter.ts
@@ -3,6 +3,7 @@ var router = ExpressPromiseRouter();
 
 import TimetableService = require('@app/core/timetable/TimetableService');
 import TimetableLectureService = require('@app/core/timetable/TimetableLectureService');
+import TimetableImageRenderService = require('@app/core/timetable/TimetableImageRenderService');
 import User from '@app/core/user/model/User';
 import * as log4js from 'log4js';
 import DuplicateTimetableTitleError from '@app/core/timetable/error/DuplicateTimetableTitleError';
@@ -51,6 +52,19 @@ restGet(router, '/:id')(async function(context, req) {
   return result;
 });
 
+router.get('/:id/image', async function(req, res, next) {
+  let context: RequestContext = req['context'];
+  let user:User = context.user;
+  
+  let table = await TimetableService.getByMongooseId(user._id, req.params.id);
+  if (!table) {
+    throw new ApiError(404, ErrorCode.TIMETABLE_NOT_FOUND, "timetable not found");
+  }
+  let imageBuffer = await TimetableImageRenderService.renderTimetableAsPng(table, 1920, 1080);
+  res.contentType('image/png');
+  res.send(imageBuffer);
+});
+
 restGet(router, '/:year/:semester')(async function(context, req) {
   let user:User = context.user;
   let result = await TimetableService.getBySemester(user._id, req.params.year, req.params.semester);
diff --git a/src/core/nightmare/NightmareService.ts b/src/core/nightmare/NightmareService.ts
new file mode 100644
index 00000000..d4f02fe2
--- /dev/null
+++ b/src/core/nightmare/NightmareService.ts
@@ -0,0 +1,30 @@
+import Nightmare = require('nightmare');
+import AsyncLock = require('async-lock');
+
+let nm = Nightmare({
+    show: false,
+    executionTimeout: 1000,
+    waitTimeout: 1000
+});
+
+let nmLock = new AsyncLock({maxPending : 100, timeout: 5000});
+const NM_LOCK_KEY = "NightmareServiceLock";
+
+function execute<T>(f: (Nightmare) => Promise<T>): Promise<T> {
+    return nmLock.acquire(NM_LOCK_KEY, function() {
+        return f(nm);
+    });
+}
+
+export function renderHtmlAsPng(html: string, width: number, height: number): Promise<Buffer> {
+    return execute(async function(nm) {
+        nm.viewport(width, height);
+        nm.goto("about:blank");
+        await nm.wait(function (html: string){
+            document.body.innerHTML = html;
+            return true;
+        }, html);
+        let buffer: Buffer = await nm.screenshot();
+        return buffer;
+    });
+}
diff --git a/src/core/timetable/TimetableImageRenderService.ts b/src/core/timetable/TimetableImageRenderService.ts
new file mode 100644
index 00000000..80f6b5e9
--- /dev/null
+++ b/src/core/timetable/TimetableImageRenderService.ts
@@ -0,0 +1,11 @@
+import log4js = require('log4js');
+
+import NightmareService = require('@app/core/nightmare/NightmareService');
+import Timetable from './model/Timetable';
+
+let logger = log4js.getLogger();
+
+export function renderTimetableAsPng(timetable: Timetable, width: number, height: number): Promise<Buffer> {
+    let html = "<p>Timetable title: " + timetable.title + "</p>";
+    return NightmareService.renderHtmlAsPng(html, width, height);
+}