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<!--replace-end-7--><!--replace-end-4--><!--replace-end-1--></head><body><div class="ui fluid container universe"><!--replace-start-2--><!--replace-start-3--><!--replace-start-6--><div class="ui text container" id="zettel-container" style="position: relative"><div class="zettel-view"><article class="ui raised attached segment zettel-content"><div class="pandoc"><h1 id="title-h1">Creating a RESTful API: <code>GET</code> requests</h1><p>With our GET request we will simply return the array of course objects.</p><p>We create an <a href="Events%20module.md#event-emitters">event emitter</a> and listener that listens for GET requests on a specified port and sends data in response to requests.</p><pre><code class="js language-js">// Return a value as response from specified URI
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router.get("/", (req, res) => {
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res.send(courses);
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});</code></pre><p>Our server is now set up:</p><p><img src="/static/server-listening.png" /></p><blockquote><p>When creating our API this structure of creating handlers for specific routes will be iterated. Every endpoint will be specified with <code>[app].[http_request_type]</code> and followed by a callback.</p></blockquote><p>We can now call the endpoint:</p><pre><code class="js language-js">const getAllCourses = async () => {
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try {
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const resp = await axios.get("http://localhost:3000/api/courses");
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console.log(resp.data);
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} catch (err) {
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console.error(err);
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}
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};
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getAllCourses();</code></pre><p>Returns:</p><pre><code class="js language-js">[
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{ id: 1, name: "First course" },
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{ id: 2, name: "Second course" },
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{ id: 3, name: "Third course" },
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];</code></pre><h2 id="parameters">Parameters</h2><p>The previous example serves the entire set of our data. But we will also need to retrieve specific values, we do this by adapting the GET callback to accept parameters. These parameters will correspond to the specific entry in our main data array.</p><pre><code class="js language-js">router.get("/:id", (req, res) => {
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res.send(req.params.id);
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});</code></pre><p>We use the <code>:</code> symbol in the URI to indicate that we looking to parse for a specific value in the data. Now if we call <code>/api/courses/2</code>, we will get the second item in the array.</p><p>The block above is the most basic format but we would want to add some kind of error handling, for example:</p><pre><code class="js language-js">router.get("/:id", (req, res) => {
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const course = courses.find((c) => c.id === parseInt(req.params.id));
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if (!course) res.status(404).send("A course with the given ID was not found");
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res.send(course);
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});</code></pre><h2 id="queries">Queries</h2><p>Whereas parameters return specific data points, queries don’t get data they aggregate or present the data that is returned in a certain way, such as for instance applying a search function. We indicate queries with a <code>?</code> in our URI. For example: <code>/api/posts/2018/1?sortBy=name</code>. To facilitate a request like this we have to create a GET path that allows for it:</p><pre><code class="js language-js">router.get("/:year/:month", (req, res) => {
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res.send(req.query);
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})[]();</code></pre><p>We would get the following back:</p><pre><code class="json language-json">{
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"sortBy": "name"
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}</code></pre><p>Again a JSON object with key-value pairs is returned.</p></div></article><nav class="ui attached segment deemphasized backlinksPane" id="neuron-backlinks-pane"><h3 class="ui header">Backlinks</h3><ul class="backlinks"><li><span class="zettel-link-container cf"><span class="zettel-link"><a href="0_Introduction.html">Creating a RESTful API: Introduction</a></span></span><ul class="context-list" style="zoom: 85%;"><li class="item"><div class="pandoc"><p><span class="zettel-link-container cf"><span class="zettel-link" title="Zettel: Creating a RESTful API: GET requests"><a href="1_GET.html">GET requests</a></span></span></p></div></li></ul></li></ul></nav><nav class="ui attached segment deemphasized bottomPane" id="neuron-tags-pane"><div><span class="ui basic label zettel-tag" title="Tag">APIs</span><span class="ui basic label zettel-tag" title="Tag">REST</span><span class="ui basic label zettel-tag" title="Tag">node-js</span></div></nav><nav class="ui bottom attached icon compact inverted menu blue" id="neuron-nav-bar"><!--replace-start-9--><!--replace-end-9--><a class="right item" href="impulse.html" title="Open Impulse"><i class="wave square icon"></i></a></nav></div></div><!--replace-end-6--><!--replace-end-3--><!--replace-end-2--><div class="ui center aligned container footer-version"><div class="ui tiny image"><a href="https://neuron.zettel.page"><img alt="logo" src="https://raw.githubusercontent.com/srid/neuron/master/assets/neuron.svg" title="Generated by Neuron 1.9.35.3" /></a></div></div></div></body></html>
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