From a03d3055074c70b9b815080d8fdf4bbb47b3adc4 Mon Sep 17 00:00:00 2001
From: Menci <huanghaorui301@gmail.com>
Date: Sat, 20 Apr 2019 21:55:03 +0800
Subject: [PATCH] Move syzoj-renderer to a child process

---
 app.js            |  5 ++--
 libs/highlight.js |  8 -------
 libs/markdown.js  | 33 -------------------------
 libs/renderer.js  | 32 +++++++++++++++++++++++++
 libs/rendererd.js | 61 +++++++++++++++++++++++++++++++++++++++++++++++
 utility.js        |  8 +++----
 6 files changed, 100 insertions(+), 47 deletions(-)
 delete mode 100644 libs/highlight.js
 delete mode 100644 libs/markdown.js
 create mode 100644 libs/renderer.js
 create mode 100644 libs/rendererd.js

diff --git a/app.js b/app.js
index fb82d22..0af7228 100644
--- a/app.js
+++ b/app.js
@@ -58,6 +58,8 @@ global.syzoj = {
     let winstonLib = require('./libs/winston');
     winstonLib.configureWinston(!syzoj.production);
 
+    this.utils = require('./utility');
+
     // Set assets dir
     app.use(Express.static(__dirname + '/static', { maxAge: syzoj.production ? '1y' : 0 }));
 
@@ -260,8 +262,7 @@ global.syzoj = {
       res.locals.res = res;
       next();
     });
-  },
-  utils: require('./utility')
+  }
 };
 
 syzoj.run();
diff --git a/libs/highlight.js b/libs/highlight.js
deleted file mode 100644
index d3d4240..0000000
--- a/libs/highlight.js
+++ /dev/null
@@ -1,8 +0,0 @@
-const { highlight } = require('syzoj-renderer');
-const objectHash = require('object-hash');
-
-module.exports = async (code, lang, cb) => {
-  highlight(code, lang, syzoj.redisCache, {
-    wrapper: null
-  }).then(cb);
-}
diff --git a/libs/markdown.js b/libs/markdown.js
deleted file mode 100644
index 0666363..0000000
--- a/libs/markdown.js
+++ /dev/null
@@ -1,33 +0,0 @@
-const { markdown } = require('syzoj-renderer');
-const XSS = require('xss');
-const CSSFilter = require('cssfilter');
-const xssWhiteList = Object.assign({}, require('xss/lib/default').whiteList);
-
-delete xssWhiteList.audio;
-delete xssWhiteList.video;
-
-for (const tag in xssWhiteList) {
-  xssWhiteList[tag] = xssWhiteList[tag].concat(['style', 'class']);
-}
-
-const xss = new XSS.FilterXSS({
-  whiteList: xssWhiteList,
-  stripIgnoreTag: true,
-  onTagAttr: (tag, name, value, isWhiteAttr) => {
-    if (tag.toLowerCase() === 'img' && name.toLowerCase() === 'src' && value.startsWith('data:image/')) {
-      return name + '="' + XSS.escapeAttrValue(value) + '"';
-    }
-  }
-});
-
-function filter(html) {
-  html = xss.process(html);
-  if (html) {
-    html = `<div style="position: relative; overflow: hidden; ">${html}</div>`;
-  }
-  return html;
-};
-
-module.exports = (markdownCode, callback) => {
-  markdown(markdownCode, syzoj.redisCache, filter).then(callback);
-};
diff --git a/libs/renderer.js b/libs/renderer.js
new file mode 100644
index 0000000..eacbec6
--- /dev/null
+++ b/libs/renderer.js
@@ -0,0 +1,32 @@
+const child_process = require('child_process');
+
+const rendererd = child_process.fork(__dirname + '/rendererd', [syzoj.config.redis]);
+
+const resolver = {};
+let currentId = 0;
+
+rendererd.on('message', msg => {
+  resolver[msg.id](msg.result);
+  delete resolver[msg.id];
+});
+
+exports.markdown = (markdownCode, callback) => {
+  resolver[++currentId] = callback;
+  rendererd.send({
+    id: currentId,
+    type: 'markdown',
+    source: markdownCode
+  });
+}
+
+exports.highlight = (code, lang, callback) => {
+  resolver[++currentId] = callback;
+  rendererd.send({
+    id: currentId,
+    type: 'highlight',
+    source: {
+      code,
+      lang
+    }
+  });
+}
diff --git a/libs/rendererd.js b/libs/rendererd.js
new file mode 100644
index 0000000..49d5aa4
--- /dev/null
+++ b/libs/rendererd.js
@@ -0,0 +1,61 @@
+const renderer = require('syzoj-renderer');
+const XSS = require('xss');
+const xssWhiteList = Object.assign({}, require('xss/lib/default').whiteList);
+delete xssWhiteList.audio;
+delete xssWhiteList.video;
+
+for (const tag in xssWhiteList) {
+  xssWhiteList[tag] = xssWhiteList[tag].concat(['style', 'class']);
+}
+
+const xss = new XSS.FilterXSS({
+  whiteList: xssWhiteList,
+  stripIgnoreTag: true,
+  onTagAttr: (tag, name, value, isWhiteAttr) => {
+    if (tag.toLowerCase() === 'img' && name.toLowerCase() === 'src' && value.startsWith('data:image/')) {
+      return name + '="' + XSS.escapeAttrValue(value) + '"';
+    }
+  }
+});
+
+const Redis = require('redis');
+const util = require('util');
+const redis = Redis.createClient(process.argv[2]);
+const redisCache = {
+  get: util.promisify(redis.get).bind(redis),
+  set: util.promisify(redis.set).bind(redis)
+};
+
+async function highlight(code, lang) {
+  return await renderer.highlight(code, lang, redisCache, {
+    wrapper: null
+  });
+}
+
+async function markdown(markdownCode) {
+  function filter(html) {
+    html = xss.process(html);
+    if (html) {
+      html = `<div style="position: relative; overflow: hidden; ">${html}</div>`;
+    }
+    return html;
+  };
+
+  return await renderer.markdown(markdownCode, redisCache, filter);
+}
+
+process.on('message', async msg => {
+  if (msg.type === 'markdown') {
+    process.send({
+      id: msg.id,
+      result: await markdown(msg.source)
+    });
+  } else if (msg.type === 'highlight') {
+    process.send({
+      id: msg.id,
+      result: await highlight(msg.source.code, msg.source.lang)
+    });
+  }
+});
+
+process.on('disconnect', () => process.exit());
diff --git a/utility.js b/utility.js
index f2524fa..d300cb9 100644
--- a/utility.js
+++ b/utility.js
@@ -19,7 +19,6 @@ let Promise = require('bluebird');
 let path = require('path');
 let fs = Promise.promisifyAll(require('fs-extra'));
 let util = require('util');
-let markdownRenderer = require('./libs/markdown');
 let moment = require('moment');
 let url = require('url');
 let querystring = require('querystring');
@@ -27,6 +26,7 @@ let gravatar = require('gravatar');
 let filesize = require('file-size');
 let AsyncLock = require('async-lock');
 let JSDOM = require('jsdom').JSDOM;
+let renderer = require('./libs/renderer');
 
 module.exports = {
   resolvePath(s) {
@@ -56,13 +56,13 @@ module.exports = {
     return new Promise((resolve, reject) => {
       if (!keys) {
         if (!obj || !obj.trim()) resolve("");
-        else markdownRenderer(obj, s => {
+        else renderer.markdown(obj, s => {
             resolve(replaceUI(s));
         });
       } else {
         let res = obj, cnt = keys.length;
         for (let key of keys) {
-          markdownRenderer(res[key], (s) => {
+          renderer.markdown(res[key], (s) => {
             res[key] = replaceUI(s);
             if (!--cnt) resolve(res);
           });
@@ -133,7 +133,7 @@ module.exports = {
   },
   highlight(code, lang) {
     return new Promise((resolve, reject) => {
-      require('./libs/highlight')(code, lang, res => {
+      renderer.highlight(code, lang, res => {
         resolve(res);
       });
     });