Merge pull request #36 from Swechhya/example-koa-project

Add example project for koa

Author: kabirbaidhya

README.md

@@ -109,6 +109,7 @@ app.listen(port, () => console.log(`Example app listening on port ${port}!`));
 
 1. [Basic Node Web Server (TypeScript)](examples/node-http-server-ts)
 2. [Simple Express Web Server (TypeScript)](examples/express-http-server-ts)
+3. [Simple Koa Web Server (JavaScript)](examples/koa-http-server-js)
 
 ## API Docs
 

examples/koa-http-server-js/.babelrc

@@ -0,0 +1,12 @@
+{
+  "presets": [
+    [
+      "@babel/preset-env",
+      {
+        "targets": {
+          "node": true
+        }
+      }
+    ]
+  ]
+}

examples/koa-http-server-js/.eslintrc

@@ -0,0 +1,11 @@
+{
+  "extends": ["eslint-config-leapfrog"],
+  "parserOptions": {
+    "sourceType": "module"
+  },
+  "env": {
+    "es6": true,
+    "browser": true,
+    "node": true
+  }
+}

examples/koa-http-server-js/.gitignore

@@ -0,0 +1,2 @@
+node_modules
+dist/

examples/koa-http-server-js/README.md

@@ -0,0 +1,52 @@
+# Koa Example (JavaScript)
+
+Sample project for with [koa](https://koajs.com//).
+
+## Running
+
+Install dependencies.
+
+```bash
+$ yarn
+```
+
+Run the koa app server.
+
+```
+$ yarn start
+```
+
+Now you can test it through `curl`.
+
+```
+$ curl 'http://localhost:3000?a=20&b=30' && curl 'http://localhost:3000?a=10&b=50' && curl 'http://localhost:3000?a=50&b=100'
+```
+
+**Output**
+
+```
+2019-10-26T08:42:23.335Z [ INFO ] HTTP server listening on port 3000!
+
+2019-10-26T08:42:31.037Z [ DEBUG ] f45b64f0 - Persisted a: 20
+2019-10-26T08:42:31.037Z [ DEBUG ] f45b64f0 - Persisted b: 30
+2019-10-26T08:42:31.038Z [ DEBUG ] f45b64f0 - Simulating delayed access
+2019-10-26T08:42:31.039Z [ DEBUG ] f45b64f0 - Calculated sum: 50
+2019-10-26T08:42:31.039Z [ DEBUG ] f45b64f0 - Persisted sum: 50
+2019-10-26T08:42:31.042Z [ INFO ] f45b64f0 - Response sent
+2019-10-26T08:42:31.078Z [ DEBUG ] f5d8bbdb - Persisted a: 10
+2019-10-26T08:42:31.079Z [ DEBUG ] f5d8bbdb - Persisted b: 50
+2019-10-26T08:42:31.079Z [ DEBUG ] f5d8bbdb - Simulating delayed access
+2019-10-26T08:42:31.079Z [ DEBUG ] f5d8bbdb - Calculated sum: 60
+2019-10-26T08:42:31.079Z [ DEBUG ] f5d8bbdb - Persisted sum: 60
+2019-10-26T08:42:31.079Z [ INFO ] f5d8bbdb - Response sent
+2019-10-26T08:42:31.100Z [ DEBUG ] 9f06d9ba - Persisted a: 50
+2019-10-26T08:42:31.100Z [ DEBUG ] 9f06d9ba - Persisted b: 100
+2019-10-26T08:42:31.100Z [ DEBUG ] 9f06d9ba - Simulating delayed access
+2019-10-26T08:42:31.100Z [ DEBUG ] 9f06d9ba - Calculated sum: 150
+2019-10-26T08:42:31.100Z [ DEBUG ] 9f06d9ba - Persisted sum: 150
+2019-10-26T08:42:31.101Z [ INFO ] 9f06d9ba - Response sent
+2019-10-26T08:42:33.039Z [ INFO ] f45b64f0 - Store contents: {"a":"20","b":"30","sum":50}
+2019-10-26T08:42:33.080Z [ INFO ] f5d8bbdb - Store contents: {"a":"10","b":"50","sum":60}
+2019-10-26T08:42:33.106Z [ INFO ] 9f06d9ba - Store contents: {"a":"50","b":"100","sum":150}
+
+```

examples/koa-http-server-js/backpack.config.js

@@ -0,0 +1,21 @@
+const path = require('path');
+
+module.exports = {
+  webpack: config => {
+    config.context = path.resolve(__dirname, 'src');
+    config.entry = {
+      main: './index.js'
+    };
+    config.output.path = path.resolve(__dirname, 'dist');
+    config.resolve.extensions = ['.js', '.json'];
+
+    // When we build with webpack it messes up the global '__dirname'
+    // given by node. To undo this we have to set this configuration
+    // https://github.com/webpack/webpack/issues/1599
+    config.node = {
+      __dirname: false
+    };
+
+    return config;
+  }
+};

examples/koa-http-server-js/eslint.json

@@ -0,0 +1,3 @@
+{
+  "extends": ["eslint-config-leapfrog", "eslint-config-prettier"]
+}

examples/koa-http-server-js/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "koa-http-server-js",
+  "version": "1.0.0",
+  "description": "A basic example for async-store and koa",
+  "main": "index.js",
+  "author": "Swechhya Bista",
+  "license": "MIT",
+  "scripts": {
+    "lint": "eslint -c eslint.json 'src/*.js'",
+    "lint:fix": "eslint --fix -c eslint.json 'src/*.js'",
+    "start": "backpack",
+    "build": "backpack build"
+  },
+  "dependencies": {
+    "@leapfrogtechnology/async-store": "^1.0.2",
+    "koa": "^2.10.0",
+    "koa-request": "^1.0.0",
+    "qs": "^6.9.0"
+  },
+  "devDependencies": {
+    "babel-preset-es2015": "^6.24.1",
+    "babel-preset-es2017": "^6.24.1",
+    "backpack-core": "^0.8.4",
+    "eslint": "^6.6.0",
+    "eslint-config-leapfrog": "^2.0.1",
+    "eslint-config-prettier": "^6.4.0"
+  }
+}

examples/koa-http-server-js/src/index.js

@@ -0,0 +1,36 @@
+import Koa from 'koa';
+
+import * as store from '@leapfrogtechnology/async-store';
+
+import * as logger from './logger';
+import { storeParams, calculateSum } from './middlewares';
+
+const app = new Koa();
+
+const port = process.env.PORT || 3000;
+
+app.use(ctx => {
+  store.initialize()(() => {
+    storeParams(ctx);
+    calculateSum();
+    handleRequest(ctx);
+  });
+});
+
+app.listen(port, () => {
+  logger.info(`HTTP server listening on port ${port}!\n`);
+});
+
+/**
+ * Handle incoming request.
+ *
+ * @param {Object} ctx
+ */
+function handleRequest(ctx) {
+  const a = store.get('a');
+  const b = store.get('b');
+  const sum = store.get('sum');
+
+  ctx.body = `Sum of ${a}, ${b} = ${sum}\n`;
+  logger.info('Response sent');
+}

examples/koa-http-server-js/src/logger.js

@@ -0,0 +1,57 @@
+import * as store from '@leapfrogtechnology/async-store';
+
+/**
+ * Get unique request id from store or return empty string.
+ *
+ * @returns {string}
+ */
+function getRequestId() {
+  return (store.getId() || '').substring(0, 8);
+}
+
+/**
+ * Print log message to the stdout / stderr.
+ *
+ * @param {string} level
+ * @param {string} message
+ */
+function log(level, message) {
+  const timestamp = new Date().toISOString();
+  const requestId = getRequestId();
+  const line = `${timestamp} [ ${level} ] ${requestId ? `${requestId} - ` : ''}${message}\n`;
+
+  if (level === 'ERROR') {
+    process.stderr.write(line);
+
+    return;
+  }
+
+  process.stdout.write(line);
+}
+
+/**
+ * Write info logs and associated request id to stdout.
+ *
+ * @param {string} message
+ */
+export function info(message) {
+  log('INFO', message);
+}
+
+/**
+ * Write debug logs and associated request id to stdout.
+ *
+ * @param {string} message
+ */
+export function debug(message) {
+  log('DEBUG', message);
+}
+
+/**
+ * Write error logs and associated request id to stdout.
+ *
+ * @param {any} err
+ */
+export function error(err) {
+  log('ERROR', err);
+}