done state

.gitignore

@@ -0,0 +1,9 @@
+node_modules
+
+/.settings
+/.classpath
+/.project
+
+/.idea
+*.iml
+*.log

examples/express1.js

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+'use strict';
+
+const express = require('express');
+const app = express();
+
+app.use(express.static('./'));
+
+app.listen(3000);

examples/express2.js

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+'use strict';
+
+const express = require('express');
+const app = express();
+
+app.use(express.static('./'));
+
+app.get('/api/tasks', getTasks);
+app.get('/api/tasks/:id', getTask);
+
+app.listen(3000, () => console.log('Server is running...'));
+
+function getTasks(request, response) {
+    response.set('Content-Type', 'application/json');
+    response.end(JSON.stringify([{ id: 1 }, { id: 2 }]));
+}
+
+function getTask(request, response) {
+    var id = request.params.id;
+    response.set('Content-Type', 'application/json');
+    response.end(JSON.stringify({ id: id }));
+}

examples/express3.js

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+'use strict';
+
+const express = require('express');
+const bodyParser = require('body-parser');
+const app = express();
+
+app.use(bodyParser.json());
+
+app.get('/api/tasks', getTasks);
+app.post('/api/tasks', saveTask);
+
+app.listen(3000, () => console.log('Server is running...'));
+
+function getTasks(request, response) {
+    response.json([{ id: 1 }, { id: 2 }]);
+}
+
+function saveTask(request, response) {
+    console.log(request.body); // request should have correct content-type
+    response.end();
+}

examples/express4.js

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+'use strict';
+
+const express = require('express');
+const app = express();
+
+app.get('/api/p1', p1);
+app.get('/api/p2', p2);
+app.get('/api/p3', p3);
+
+app.use(errorHandler); // after request handlers
+
+app.listen(3000, () => console.log('Server is running...'));
+
+function p1(request, response) {
+    try {
+        throw new Error('p1');
+    } catch (error) {
+        response.status(500).send(error.toString());
+    }
+
+}
+
+function p2(request, response) {
+    try {
+        throw new Error('p2');
+    } catch (error) {
+        response.status(500).send(error.toString());
+    }
+}
+
+function p3(request, response) {
+    throw new Error('p3');
+}
+
+function errorHandler(error, request, response, next) { // there must be 4 arguments
+    response.status(500).send(error.toString());
+}

examples/express5.js

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+'use strict';
+
+const express = require('express');
+const app = express();
+
+app.get('/api/p', p1);
+app.get('/api/p', p2);
+
+app.use(errorHandler); // after request handlers
+
+app.listen(3000, () => console.log('Server is running...'));
+
+function p1(request, response, next) {
+    console.log('p1');
+    next();
+}
+
+function p2(request, response, next) {
+    console.log('p2');
+    next('error from p2'); // argument makes it an error
+}
+
+function errorHandler(error, request, response, next) { // there must be 4 arguments
+    response.status(500).send(error.toString());
+}

examples/express6.js

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+'use strict';
+
+const express = require('express');
+const app = express();
+
+app.get('/api/p1', p1);
+app.get('/api/p2', p2);
+
+app.use(errorHandler); // after request handlers
+
+app.listen(3000, () => console.log('Server is running...'));
+
+function p1(request, response, next) {
+    getData()
+        .then(data => response.end('ok: ' + data))
+        .catch(error => next(error));
+}
+
+function p2(request, response, next) {
+    getDataFails()
+        .then(data => response.end(data))
+        .catch(next);
+}
+
+function errorHandler(error, request, response, next) { // there must be 4 arguments
+    response.status(500).send('error: ' + error.toString());
+}
+
+function getData() {
+    return Promise.resolve('some data');
+}
+
+function getDataFails() {
+    return Promise.reject('some error');
+}

package.json

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+{
+  "name": "exexpress",
+  "version": "1.0.0",
+  "scripts": {
+    "start": "nodemon server.js"
+  },
+  "devDependencies": {
+    "body-parser": "^1.17.1",
+    "express": "^4.15.2",
+    "nodemon": "^1.11.0"
+  }
+}

server.js

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+'use strict';
+
+const express = require('express');
+const bodyParser = require('body-parser');
+
+const Task = require('./task');
+const TaskService = require('./task-service');
+const dao = new TaskService();
+const app = express();
+
+app.use(bodyParser.json()); // before request handlers
+
+app.get('/api/tasks', getTasks);
+app.get('/api/tasks/:id', getTask);
+app.post('/api/tasks', saveTask);
+app.delete('/api/tasks/:id', deleteTask);
+
+app.use(errorHandler); // after request handlers
+
+app.listen(3000, () => console.log('Server is running...'));
+
+function getTasks(request, response, next) {
+    dao.getTasks()
+        .then(tasks => response.json(tasks))
+        .catch(next);
+}
+
+function getTask(request, response, next) {
+    var id = request.params.id;
+    dao.getTask(id)
+        .then(task => response.json(task))
+        .catch(next);
+}
+
+function saveTask(request, response, next) {
+    dao.saveTask(request.body)
+        .then(() => response.end())
+        .catch(next);
+}
+
+function deleteTask(request, response, next) {
+    var id = request.params.id;
+    dao.deleteTask(id)
+        .then(() => response.end())
+        .catch(next);
+}
+
+function errorHandler(error, request, response, next) { // there must be 4 arguments
+    response.status(500).json({ error: error.toString() });
+}

task-service.js

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+'use strict';
+
+const Task = require('./task');
+
+class MemTaskService {
+
+    constructor() {
+        this.tasks = [
+            Task.withId('1', 'Task 1'),
+            Task.withId('2', 'Task 2')
+        ];
+    }
+
+    clone(what) {
+        return JSON.parse(JSON.stringify(what));
+    }
+
+    getTasks() {
+        return Promise.resolve(this.clone(this.tasks));
+    }
+
+    getTask(id) {
+        let found = this.clone(this.tasks)
+            .filter(each => each._id === id)
+            .pop();
+
+        return found ? Promise.resolve(found) : Promise.reject('no task with id: ' + id);
+    }
+
+    saveTask(task) {
+        if (!task._id) {
+            task._id = this.getId();
+            this.tasks.push(task);
+            return Promise.resolve();
+        }
+
+        this.tasks = this.tasks
+            .map(each =>each._id === task._id ? task : each);
+
+        return Promise.resolve();
+    }
+
+    deleteTask(id) {
+        this.tasks = this.tasks
+            .filter(each => each._id !== id);
+
+        return Promise.resolve();
+    }
+
+    getId() {
+        return (Math.random() + 'A').substr(2);
+    }
+
+}
+
+module.exports = MemTaskService;

task.js

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+'use strict';
+
+class Task {
+    constructor(title) {
+        this.title = title;
+    }
+
+    static withId(id, title) {
+        let task = new Task(title);
+        task._id = id;
+        return task;
+    }
+}
+
+module.exports = Task;