Use native MD5 to prevent out of memory

models/problem.js

@@ -117,8 +117,7 @@ class Problem extends Model {
     let fs = Promise.promisifyAll(require('fs'));
 
     let buf = await fs.readFileAsync(path);
-    let md5 = require('md5');
-    let key = md5(buf);
+    let key = syzoj.utils.md5(buf);
     await fs.rename(path, TestData.resolvePath(key));
 
     let file = await TestData.create({

package.json

@@ -32,7 +32,6 @@
     "express-session": "^1.14.1",
     "file-size": "^1.0.0",
     "gravatar": "^1.5.2",
-    "md5": "^2.2.1",
     "moemark-renderer": "^1.2.0",
     "moment": "^2.15.0",
     "multer": "^1.2.0",

utility.js

@@ -220,6 +220,12 @@ module.exports = {
   removeTitleTag(s) {
     return s.replace(/「[\S\s]+?」/, '');
   },
+  md5(data) {
+    let crypto = require('crypto');
+    let md5 = crypto.createHash('md5');
+    md5.update(data);
+    return md5.digest('hex');
+  },
   async hitokoto() {
     let request = require('request-promise');
     return await request({