Add session persistent storage

Author: tshemsedinov

JavaScript/client.js

@@ -53,7 +53,7 @@ class Client {
 
   sendCookie() {
     const { res, preparedCookie } = this;
-    console.dir({ preparedCookie, headersSent: res.headersSent });
+    //console.dir({ preparedCookie, headersSent: res.headersSent });
     if (preparedCookie.length && !res.headersSent) {
       console.dir({ preparedCookie });
       res.setHeader('Set-Cookie', preparedCookie);

JavaScript/server.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const http = require('http');
+
 const Client = require('./client.js');
 const Session = require('./session.js');
 
@@ -12,6 +13,7 @@ const routing = {
   },
   '/api/method1': async client => {
     if (client.session) {
+      client.session.set('method1', 'called');
       return { data: 'example result' };
     } else {
       return { data: 'access is denied' };
@@ -32,12 +34,12 @@ const types = {
 
 http.createServer((req, res) => {
   const client = new Client(req, res);
-  console.dir({
-    url: req.url,
-    status: res.statusCode,
-    cookie: client.cookie,
-  });
+  const { method, url, headers } = req;
+  console.log(`${method} ${url} ${headers.cookie}`);
   const handler = routing[req.url];
+  res.on('finish', () => {
+    if (client.session) client.session.save();
+  });
   if (handler) {
     handler(client)
       .then(data => {
@@ -47,7 +49,6 @@ http.createServer((req, res) => {
         client.sendCookie();
         res.end(result);
       }, err => {
-        console.error(err.stack);
         res.statusCode = 500;
         res.end('Internal Server Error 500');
       });

JavaScript/session.js

@@ -1,8 +1,8 @@
 'use strict';
 
-const sessions = new Map();
+const storage = require('./storage.js');
 
-const TOKEN_LENGTH = 100;
+const TOKEN_LENGTH = 32;
 const ALPHA_UPPER = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
 const ALPHA_LOWER = 'abcdefghijklmnopqrstuvwxyz';
 const ALPHA = ALPHA_UPPER + ALPHA_LOWER;
@@ -32,33 +32,37 @@ class Session extends Map {
     const session = new Session(token);
     client.session = session;
     client.setCookie('token', token);
-    sessions.set(token, session);
+    storage.set(token, session);
     return session;
   }
 
   static restore(client) {
     const { cookie } = client;
     const sessionToken = cookie.token;
-    console.log({ sessionToken });
     if (sessionToken) {
-      const session = sessions.get(sessionToken);
-      if (session) {
-        client.token = sessionToken;
-        client.session = session;
-        return session;
-      }
+      storage.get(sessionToken, (err, session) => {
+        if (session) {
+          Object.setPrototypeOf(session, Session.prototype);
+          client.token = sessionToken;
+          client.session = session;
+        }
+      });
     }
   }
 
   static drop(client) {
     const { token } = client;
     if (token) {
-      sessions.delete(token);
+      storage.delete(token);
       client.deleteCookie('token');
       client.token = undefined;
       client.session = null;
     }
   }
+
+  save() {
+    storage.save(this.token);
+  }
 }
 
 module.exports = Session;

JavaScript/sessions/README.md

@@ -0,0 +1 @@
+# Stored sessions

JavaScript/storage.js

@@ -0,0 +1,57 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const v8 = require('v8');
+
+const PATH = `${__dirname}/sessions`;
+
+const safePath = fn => (token, ...args) => {
+  const callback = args[args.length - 1];
+  const fileName = path.join(PATH, token);
+  if (!fileName.startsWith(PATH)) {
+    callback(new Error('Invalid session token'));
+    return;
+  }
+  fn(fileName, ...args, callback);
+};
+
+const readSession = safePath(fs.readFile);
+const writeSession = safePath(fs.writeFile);
+const deleteSession = safePath(fs.unlink);
+
+class Storage extends Map {
+  get(key, callback) {
+    const value = super.get(key);
+    if (value) {
+      callback(null, value);
+      return;
+    }
+    readSession(key, (err, data) => {
+      if (err) {
+        callback(err);
+        return;
+      }
+      console.log(`Session loaded: ${key}`);
+      const session = v8.deserialize(data);
+      super.set(key, session);
+      callback(null, session);
+    });
+  }
+
+  save(key) {
+    const value = super.get(key);
+    const data = v8.serialize(value);
+    if (value) writeSession(key, data, () => {
+      console.log(`Session saved: ${key}`);
+    });
+  }
+
+  delete(key) {
+    deleteSession(key, () => {
+      console.log(`Session deleted: ${key}`);
+    });
+  }
+}
+
+module.exports = new Storage();