114 lines
2.4 KiB
Markdown
114 lines
2.4 KiB
Markdown
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---
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tags:
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- node-js
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- REST
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- APIs
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---
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# Creating a RESTful API: Introduction
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We are going to use Express to create a
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[RESTful API](RESTful_APIs.md) in Node.js.
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## Request types
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Express provides us with methods corresponding to each of the
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[HTTP request types](HTTP_request_types.md):
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- `.get()`
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- `.post()`
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- `.put()`
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- `.delete()`
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## Our data set
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> Typically when you create a RESTful API you are going to be returning data
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> from a database. For simplicity we are just going simulate this with a simple
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> data array so that we can focus on the Express syntax rather than database
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> handling. Later we will integrate this with a
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> [MongoDB database](05_%20Integrating_the_database.md).
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We will mainly work with the following array of objects:
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```js
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const courses = [
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{
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id: 1,
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name: "First course",
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},
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{
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id: 2,
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name: "Second course",
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},
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{
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id: 3,
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name: "Third course",
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},
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];
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```
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## Creating an Express instance
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We first create an instance of Express within `index.js`. This will be the main
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coordinating file and we will aim to minimise the amount of business logic we
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have in this file. It should really just be for initialization and managing
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[middleware](Middleware_in_NodeJS.md).
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```js
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const express = require("express");
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const app = express();
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```
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## Routing
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We are going to receive all our HTTP requests at the path `/api/courses` and we
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will place all code related to this route in a dedicated Node module
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(`routes/courses.js`) rather than within `index.js` which should remain as
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uncluttered as possible.
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First we need to declare this in `index.js`:
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```js
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const courses = require("./routes/courses");
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app.use("/api/courses", courses);
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```
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Then within `courses.js` we instantiate an express router that `app.js` will
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route to:
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```js
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const router = express.Router();
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```
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Our REST requests will all follow the following pattern:
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```js
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router.get("/", (req, res) => {
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res.send(courses);
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});
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```
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We target the `Router` instance we created and all paths will be expressed as
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`/` since the app will route by default to `/courses/api` from `index.js`
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## Create listener
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With the routing established and the Express instance created we can now listen
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for requests:
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```js
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app.listen(3000, () => console.log("Listening on port 30000..."));
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```
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## REST endpoints
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We can now proceed to set up our RESTful endpoints:
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[GET requests](1_GET.md)
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[POST requests](2_POST.md)
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[PUT requests](3_PUT.md)
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[DELETE requests](4_DELETE.md)
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