Implements client-side http transport

* Adds support of node 20 to package.json

Author: rgbabaev

JavaScript/9-logger/http.js

@@ -2,6 +2,11 @@
 
 const http = require('node:http');
 
+const answerNotFound = (res, headers) => {
+  res.writeHead(404, headers);
+  res.end('Not found');
+};
+
 const receiveArgs = async (req) => {
   const buffers = [];
   for await (const chunk of req) buffers.push(chunk);
@@ -10,22 +15,34 @@ const receiveArgs = async (req) => {
 };
 
 module.exports = (routing, port, console) => {
-  http.createServer(async (req, res) => {
-    const { url, socket } = req;
-    const [name, method, id] = url.substring(1).split('/');
-    const entity = routing[name];
-    if (!entity) return void res.end('Not found');
-    const handler = entity[method];
-    if (!handler) return void res.end('Not found');
-    const src = handler.toString();
-    const signature = src.substring(0, src.indexOf(')'));
-    const args = [];
-    if (signature.includes('(id')) args.push(id);
-    if (signature.includes('{')) args.push(await receiveArgs(req));
-    console.log(`${socket.remoteAddress} ${method} ${url}`);
-    const result = await handler(...args);
-    res.end(JSON.stringify(result.rows));
-  }).listen(port);
+  http
+    .createServer(async (req, res) => {
+      const headers = {
+        'Access-Control-Allow-Origin':
+          '*' /* @dev First, read about security */,
+        'Access-Control-Allow-Methods': 'POST',
+        'Access-Control-Max-Age': 2592000, // 30 days
+        /** add other headers as per requirement */
+      };
+
+      const { url, socket } = req;
+      const [name, method, id] = url.substring(1).split('/');
+      const entity = routing[name];
+      if (!entity) return void answerNotFound(res, headers);
+      const handler = entity[method];
+      if (!handler) return void answerNotFound(res, headers);
+
+      res.writeHead(200, headers);
+      const src = handler.toString();
+      const signature = src.substring(0, src.indexOf(')'));
+      const args = [];
+      if (signature.includes('(id')) args.push(id);
+      args.push(...(await receiveArgs(req)));
+      console.log(`${socket.remoteAddress} ${req.method} ${url}`);
+      const result = await handler(...args);
+      res.end(JSON.stringify(result.rows));
+    })
+    .listen(port);
 
   console.log(`API on port ${port}`);
 };

JavaScript/9-logger/package.json

@@ -6,7 +6,7 @@
   "private": true,
   "main": "main.js",
   "engines": {
-    "node": "14 || 16 || 18"
+    "node": "14 || 16 || 18 || 20"
   },
   "scripts": {
     "start": "node --experimental-vm-modules main.js"

JavaScript/9-logger/static/client.js

@@ -1,44 +1,82 @@
 'use strict';
 
-const socket = new WebSocket('ws://127.0.0.1:8001/');
+const HTTP_API_URL = 'http://localhost:8001';
+let socket;
 
-const scaffold = (structure) => {
+const transports = {
+  ws: (name, method) => {
+    if (!socket) socket = new WebSocket('ws://127.0.0.1:8001/');
+    return (...args) => {
+      return new Promise((resolve) => {
+        const packet = { name, method, args };
+        socket.send(JSON.stringify(packet));
+        socket.onmessage = (event) => {
+          const data = JSON.parse(event.data);
+          resolve(data);
+        };
+      });
+    };
+  },
+
+  http:
+    (name, method, methodArgs) =>
+    (...args) => {
+      const urlParts = [HTTP_API_URL, name, method];
+      if (methodArgs[0] === 'id') urlParts.push(args.shift());
+
+      return fetch(urlParts.join('/'), {
+        method: 'POST',
+        body: JSON.stringify(args),
+      }).then((response) => response.json());
+    },
+};
+
+const scaffold = (structure, transport) => {
   const api = {};
   const services = Object.keys(structure);
   for (const serviceName of services) {
     api[serviceName] = {};
     const service = structure[serviceName];
     const methods = Object.keys(service);
     for (const methodName of methods) {
-      api[serviceName][methodName] = (...args) => new Promise((resolve) => {
-        const packet = { name: serviceName, method: methodName, args };
-        socket.send(JSON.stringify(packet));
-        socket.onmessage = (event) => {
-          const data = JSON.parse(event.data);
-          resolve(data);
-        };
-      });
+      api[serviceName][methodName] = transport(
+        serviceName,
+        methodName,
+        service[methodName],
+      );
     }
   }
   return api;
 };
 
-const api = scaffold({
-  user: {
-    create: ['record'],
-    read: ['id'],
-    update: ['id', 'record'],
-    delete: ['id'],
-    find: ['mask'],
+const api = scaffold(
+  {
+    user: {
+      create: ['record'],
+      read: ['id'],
+      update: ['id', 'record'],
+      delete: ['id'],
+      find: ['mask'],
+    },
+    city: {
+      read: ['id'],
+      create: ['record'],
+      update: ['id', 'record'],
+      delete: ['id'],
+    },
+    country: {
+      read: ['id'],
+      create: ['record'],
+      update: ['id', 'record'],
+      delete: ['id'],
+    },
   },
-  country: {
-    read: ['id'],
-    delete: ['id'],
-    find: ['mask'],
-  },
-});
+  transports.http,
+);
+
+// socket.addEventListener('open', async () => {
+//   const data = await api.user.read(3);
+//   console.dir({ data });
+// });
 
-socket.addEventListener('open', async () => {
-  const data = await api.user.read(3);
-  console.dir({ data });
-});
+(async () => console.log(await api.user.read(3)))();