From ac9248bf7f81c24faef1503bddc5aea3d48fec4d Mon Sep 17 00:00:00 2001
From: Sergey Yarkov <serzh.yarkov@gmail.com>
Date: Wed, 16 Mar 2022 19:59:17 +0300
Subject: [PATCH] feat: added middlewares

---
 helpers/string.js  |  12 +++++
 middlewares.js     |  13 ++++++
 preloads/routes.js |  11 +++--
 router.js          | 107 +++++++++++++++++++++++++++++++++++----------
 4 files changed, 116 insertions(+), 27 deletions(-)
 create mode 100644 helpers/string.js
 create mode 100644 middlewares.js

diff --git a/helpers/string.js b/helpers/string.js
new file mode 100644
index 0000000..2fce2d3
--- /dev/null
+++ b/helpers/string.js
@@ -0,0 +1,12 @@
+class StringHelper {
+  /**
+   * Delete the trailing slash from url
+   *
+   * @param {string} url
+   */
+  static delTrailingSlash(url) {
+    return url.slice(-1) === '/' ? url.slice(0, -1) : url;
+  }
+}
+
+export default StringHelper;
diff --git a/middlewares.js b/middlewares.js
new file mode 100644
index 0000000..fa26371
--- /dev/null
+++ b/middlewares.js
@@ -0,0 +1,13 @@
+import http from 'node:http';
+import Response from './response.js';
+
+/**
+ * This middleware just prints text to console
+ *
+ * @param {http.ClientRequest} req
+ * @param {Response} res
+ * @param {function} next
+ */
+export const helloMiddleware = (req, res) => {
+  console.log('[LOG]: Hello from `helloMiddleware` function');
+};
diff --git a/preloads/routes.js b/preloads/routes.js
index 7c8abdf..4a2b03c 100644
--- a/preloads/routes.js
+++ b/preloads/routes.js
@@ -9,6 +9,11 @@ import {
   getArticlesHandler,
 } from '../handlers.js';
 
-router.define('GET', '/api/articles', getArticlesHandler);
-router.define('GET', '/api/article/:id', getArticleHandler);
-router.define('POST', '/api/article', createArticleHandler);
+/**
+ * Middlewares
+ */
+import { helloMiddleware } from '../middlewares.js';
+
+router.get('/api/articles', getArticlesHandler).middleware([helloMiddleware]);
+router.get('/api/article/:id', getArticleHandler).middleware([helloMiddleware]);
+router.post('/api/article', createArticleHandler);
diff --git a/router.js b/router.js
index 2815172..7baea98 100644
--- a/router.js
+++ b/router.js
@@ -1,5 +1,6 @@
 import http from 'node:http';
 import { pathToRegexp } from 'path-to-regexp';
+import StringHelper from './helpers/string.js';
 
 class Router {
   constructor() {
@@ -17,24 +18,28 @@ class Router {
    * @returns {boolean} Is route has been handled
    */
   call(req, res) {
-    const mask = `${req.method}:${req.url}`;
-
-    /**
-     * Find the exact route
-     */
-    if (this.routes.hasOwnProperty(mask)) {
-      this.routes[mask].handler(req, res);
-      return true;
-    }
-
-    /**
-     * Find route by regular expression
-     */
+    const mask = `${req.method}:${StringHelper.delTrailingSlash(req.url)}`;
     const keys = Object.keys(this.routes);
     let i = keys.length;
 
     while (i--) {
-      const route = this.routes[keys[i]];
+      let route = this.routes[mask];
+
+      /**
+       * Find exact route
+       */
+      if (this.routes.hasOwnProperty(mask)) {
+        this.#middlewares(route, req, res);
+        route.handler(req, res);
+        return true;
+      }
+
+      /* Route url is not exact */
+      route = this.routes[keys[i]];
+
+      /**
+       * Find route by regular expression
+       */
       if (!route.options.exact && route.options.regexp !== undefined) {
         const match = req.url.match(route.options.regexp);
         if (match && keys[i].includes(req.method)) {
@@ -44,6 +49,7 @@ class Router {
               req.params[param.name] = match[1];
             });
           }
+          this.#middlewares(route, req, res);
           route.handler(req, res);
           return true;
         }
@@ -53,29 +59,82 @@ class Router {
     return false;
   }
 
+  /**
+   * This function will execute every middleware of a route
+   *
+   * @param {*} route
+   * @param {http.ClientRequest} req
+   * @param {Response} res
+   * @returns
+   */
+  #middlewares(route, req, res) {
+    if (!route || !route.middlewares || !Array.isArray(route.middleware)) {
+      return;
+    }
+
+    const middlewares = route.middlewares.flat();
+    if (middlewares.length !== 0) {
+      for (const middleware of middlewares) {
+        middleware(req, res);
+      }
+    }
+  }
+
   /**
    * Add more routes to router store
    *
-   * @param {string} url
-   * @param {function} handler
-   * @param {boolean} exact
+   * @param {string} method HTTP Method
+   * @param {string} url Route url
+   * @param {function} handler Route handler function
    */
-  define(
-    method = 'GET',
-    url,
-    handler,
-    options = { exact: true, regexp: undefined, params: undefined }
-  ) {
+  define(method = 'GET', url, handler) {
+    const mask = `${method}:${StringHelper.delTrailingSlash(url)}`;
+    const options = { exact: true, regexp: undefined, params: undefined };
+
     if (url.includes(':')) {
       options.params = [];
       options.exact = false;
       options.regexp = pathToRegexp(url, options.params);
     }
-    this.routes[`${method}:${url}`] = {
+
+    this.routes[mask] = {
       method,
       handler,
       options,
+      middlewares: [],
     };
+
+    return {
+      /**
+       * Store the list of middlewares for each router
+       *
+       * @param {function | [function]} middleware
+       */
+      middleware: (middleware) => {
+        middleware = Array.isArray(middleware) ? middleware : [middleware];
+        this.routes[mask].middlewares.push(middleware);
+      },
+    };
+  }
+
+  /**
+   * GET Method route
+   *
+   * @param {string} url
+   * @param {function} handler
+   */
+  get(url, handler) {
+    return this.define('GET', url, handler);
+  }
+
+  /**
+   * POST Method route
+   *
+   * @param {string} url
+   * @param {function} handler
+   */
+  post(url, handler) {
+    return this.define('POST', url, handler);
   }
 }