http://www.liaoxuefeng.com/wiki/001434446689867b27157e896e74d51a89c25cc8b43bdb3000/0014735944539193ab2edd2740f44a79efb438a05e83727000
package.json
{
"name": "rest-koa",
"version": "1.0.0",
"description": "koa 2 example with rest api",
"main": "app.js",
"scripts": {
"start": "node --use_strict app.js"
},
"keywords": [
"koa",
"rest",
"api"
],
"author": "Michael Liao",
"license": "Apache-2.0",
"repository": {
"type": "git",
"url": "https://github.com/michaelliao/learn-javascript.git"
},
"dependencies": {
"koa": "2.0.0",
"koa-bodyparser": "3.2.0",
"koa-router": "7.0.0",
"nunjucks": "2.4.2",
"mime": "1.3.4",
"mz": "2.4.0"
}
}
views
base.html
{{ title }}
Getting started with REST API!
Learn JavaScript, Node.js, REST, WebSocket, npm, koa2, nunjucks, babel, etc. at liaoxuefeng.com.
{% block main %} {% endblock %}
index.html
{% extends "base.html" %} {% block main %}
{% endblock %}
static-files.js
const path = require('path');
const mime = require('mime');
const fs = require('mz/fs');
function staticFiles(url, dir) {
return async (ctx, next) => {
let rpath = ctx.request.path;
if (rpath.startsWith(url)) {
let fp = path.join(dir, rpath.substring(url.length));
if (await fs.exists(fp)) {
ctx.response.type = mime.lookup(rpath);
ctx.response.body = await fs.readFile(fp);
} else {
ctx.response.status = 404;
}
} else {
await next();
}
};
}
module.exports = staticFiles;
templating.js
const nunjucks = require('nunjucks');
function createEnv(path, opts) {
var
autoescape = opts.autoescape === undefined ? true : opts.autoescape,
noCache = opts.noCache || false,
watch = opts.watch || false,
throwOnUndefined = opts.throwOnUndefined || false,
env = new nunjucks.Environment(
new nunjucks.FileSystemLoader(path, {
noCache: noCache,
watch: watch,
}), {
autoescape: autoescape,
throwOnUndefined: throwOnUndefined
});
if (opts.filters) {
for (var f in opts.filters) {
env.addFilter(f, opts.filters[f]);
}
}
return env;
}
function templating(path, opts) {
var env = createEnv(path, opts);
return async (ctx, next) => {
ctx.render = function (view, model) {
ctx.response.body = env.render(view, Object.assign({}, ctx.state || {}, model || {}));
ctx.response.type = 'text/html';
};
await next();
};
}
module.exports = templating;
product.js
// store products as database:
var id = 0;
function nextId() {
id++;
return 'p' + id;
}
function Product(name, manufacturer, price) {
this.id = nextId();
this.name = name;
this.manufacturer = manufacturer;
this.price = price;
}
var products = [
new Product('iPhone 7', 'Apple', 6800),
new Product('ThinkPad T440', 'Lenovo', 5999),
new Product('LBP2900', 'Canon', 1099)
];
module.exports = {
getProducts: () => {
return products;
},
getProduct: (id) => {
var i;
for (i = 0; i < products.length; i++) {
if (products[i].id === id) {
return products[i];
}
}
return null;
},
createProduct: (name, manufacturer, price) => {
var p = new Product(name, manufacturer, price);
products.push(p);
return p;
},
deleteProduct: (id) => {
var
index = -1,
i;
for (i = 0; i < products.length; i++) {
if (products[i].id === id) {
index = i;
break;
}
}
if (index >= 0) {
// remove products[index]:
return products.splice(index, 1)[0];
}
return null;
}
};
controller.js
const fs = require('fs');
// add url-route in /controllers:
function addMapping(router, mapping) {
for (var url in mapping) {
if (url.startsWith('GET ')) {
var path = url.substring(4);
router.get(path, mapping[url]);
console.log(`register URL mapping: GET ${path}`);
} else if (url.startsWith('POST ')) {
var path = url.substring(5);
router.post(path, mapping[url]);
console.log(`register URL mapping: POST ${path}`);
} else if (url.startsWith('PUT ')) {
var path = url.substring(4);
router.put(path, mapping[url]);
console.log(`register URL mapping: PUT ${path}`);
} else if (url.startsWith('DELETE ')) {
var path = url.substring(7);
router.del(path, mapping[url]);
console.log(`register URL mapping: DELETE ${path}`);
} else {
console.log(`invalid URL: ${url}`);
}
}
}
function addControllers(router, dir) {
fs.readdirSync(__dirname + '/' + dir).filter((f) => {
return f.endsWith('.js');
}).forEach((f) => {
console.log(`process controller: ${f}...`);
let mapping = require(__dirname + '/' + dir + '/' + f);
addMapping(router, mapping);
});
}
module.exports = function (dir) {
let
controllers_dir = dir || 'controllers',
router = require('koa-router')();
addControllers(router, controllers_dir);
return router.routes();
};
api.js
const products = require('../products');
const APIError = require('../rest').APIError;
module.exports = {
'GET /api/products': async (ctx, next) => {
ctx.rest({
products: products.getProducts()
});
},
'POST /api/products': async (ctx, next) => {
var p = products.createProduct(ctx.request.body.name, ctx.request.body.manufacturer, parseFloat(ctx.request.body.price));
ctx.rest(p);
},
'DELETE /api/products/:id': async (ctx, next) => {
console.log(`delete product ${ctx.params.id}...`);
var p = products.deleteProduct(ctx.params.id);
if (p) {
ctx.rest(p);
} else {
throw new APIError('product:not_found', 'product not found by id.');
}
}
};
index.js
module.exports = {
'GET /': async (ctx, next) => {
ctx.render('index.html');
}
};
rest.js
module.exports = {
APIError: function (code, message) {
this.code = code || 'internal:unknown_error';
this.message = message || '';
},
restify: (pathPrefix) => {
pathPrefix = pathPrefix || '/api/';
return async (ctx, next) => {
if (ctx.request.path.startsWith(pathPrefix)) {
console.log(`Process API ${ctx.request.method} ${ctx.request.url}...`);
ctx.rest = (data) => {
ctx.response.type = 'application/json';
ctx.response.body = data;
}
try {
await next();
} catch (e) {
console.log('Process API error...');
ctx.response.status = 400;
ctx.response.type = 'application/json';
ctx.response.body = {
code: e.code || 'internal:unknown_error',
message: e.message || ''
};
}
} else {
await next();
}
};
}
};
app.js
const Koa = require('koa');
const bodyParser = require('koa-bodyparser');
const controller = require('./controller');
const templating = require('./templating');
const rest = require('./rest');
const app = new Koa();
// log request URL:
app.use(async (ctx, next) => {
console.log(`Process ${ctx.request.method} ${ctx.request.url}...`);
await next();
});
// static file support:
let staticFiles = require('./static-files');
app.use(staticFiles('/static/', __dirname + '/static'));
// parse request body:
app.use(bodyParser());
// add nunjucks as view:
app.use(templating('views', {
noCache: true,
watch: true
}));
// bind .rest() for ctx:
app.use(rest.restify());
// add controllers:
app.use(controller());
app.listen(3000);
console.log('app started at port 3000...');