import{_ as i,c as e,a0 as a,o as t}from"./chunks/framework.p2VkXzrt.js";const c=JSON.parse('{"title":"🌐 Websockets","description":"","frontmatter":{"banner_title":"Flash - Websockets","banner_description":"Learn how to create and manage server-side Websockets in Flash.","head":[["meta",{"name":"twitter:image","content":"/assets/banner-cards/flash-core-concepts-websockets.png"}],["meta",{"name":"twitter:image:src","content":"https://docs.pixel-services.com/assets/banner-cards/flash-core-concepts-websockets.png"}],["meta",{"name":"twitter:card","content":"summary_large_image"}],["meta",{"name":"twitter:image:height","content":"1280"}],["meta",{"name":"twitter:image:width","content":"669"}],["meta",{"name":"twitter:description","content":""}]]},"headers":[],"relativePath":"flash/core-concepts/websockets.md","filePath":"flash/core-concepts/websockets.md"}'),n={name:"flash/core-concepts/websockets.md"};function h(l,s,k,p,o,d){return t(),e("div",null,s[0]||(s[0]=[a(`<h1 id="🌐-websockets" tabindex="-1">🌐 Websockets <a class="header-anchor" href="#🌐-websockets" aria-label="Permalink to &quot;🌐 Websockets&quot;">​</a></h1><p>In this section, we illustrate how to create and manage Websockets in Flash, which are used to establish a bidirectional communication channel between the client and the server.</p><h2 id="understanding-websockets" tabindex="-1">Understanding Websockets <a class="header-anchor" href="#understanding-websockets" aria-label="Permalink to &quot;Understanding Websockets&quot;">​</a></h2><p>Websockets are a communication protocol that provides full-duplex communication channels over a single TCP connection. Unlike HTTP, which is a request-response protocol, Websockets allow for real-time, low-latency communication between the client and the server.</p><p>Imagine a scenario where you need to send real-time updates to the client, such as a chat application or a live feed: if you were to use HTTP, you would need to poll the server at regular intervals to check for updates, which is inefficient and resource-intensive.</p><h2 id="creating-a-websocket" tabindex="-1">Creating a Websocket <a class="header-anchor" href="#creating-a-websocket" aria-label="Permalink to &quot;Creating a Websocket&quot;">​</a></h2><p>To create a Websocket in Flash, you need to extend the <code>WebsocketHandler</code> class and override the <code>onOpen</code>, <code>onMessage</code>, <code>onClose</code>, and <code>onError</code> methods. These methods are called when the Websocket connection is opened, a message is received, the connection is closed, and an error occurs, respectively, and they provide you with an instance of the <code>WebSocketSession</code> object to be able to interact with it.</p><div class="language-java vp-adaptive-theme"><button title="Copy Code" class="copy"></button><span class="lang">java</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">public</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> class</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> MyWebsocketHandler</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> extends</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> WebsocketHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    @</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">Override</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">    public</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> void</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> onOpen</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(WebSocketSession </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">session</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">        System.out.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">println</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;WebSocket connection opened&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    @</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">Override</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">    public</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> void</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> onClose</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(WebSocketSession </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">session</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">int</span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;"> statusCode</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, String </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">reason</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">        System.out.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">println</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;WebSocket connection closed&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    @</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">Override</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">    public</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> void</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> onMessage</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(WebSocketSession </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">session</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, String </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">message</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">        System.out.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">println</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;Received message: &quot;</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> message);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">        //optionally send a reponse back to the client</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">        session.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">sendMessage</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;I received your message!&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    }</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    @</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">Override</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">    public</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> void</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> onError</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(WebSocketSession </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">session</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, Throwable </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">error</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">        System.out.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">println</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;WebSocket error: &quot;</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> error.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">getMessage</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">());</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    }</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre></div><p>To register your Websocket handler with the server, you can use the <code>server.ws()</code> method:</p><div class="language-java vp-adaptive-theme"><button title="Copy Code" class="copy"></button><span class="lang">java</span><pre class="shiki shiki-themes github-light github-dark vp-code" tabindex="0"><code><span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">public</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> class</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> Example</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">    public</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> static</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> void</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> main</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">String</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">[] </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">args</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">        FlashServer server </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> new</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> FlashServer</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">8080</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">        server.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">ws</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;/ws&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">)</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">            .</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">register</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">new</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> MyWebsocketHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">());</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">        server.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">start</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">();</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">    }</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre></div><h2 id="interacting-with-websockets-sessions" tabindex="-1">Interacting with Websockets sessions <a class="header-anchor" href="#interacting-with-websockets-sessions" aria-label="Permalink to &quot;Interacting with Websockets sessions&quot;">​</a></h2><p>The <code>WebSocketSession</code> object provides methods to interact with the Websocket session, such as sending messages, closing the connection, and getting the remote address and session ID.</p><table tabindex="0"><thead><tr><th>Method</th><th>Params</th><th>Description</th></tr></thead><tbody><tr><td><code>getChannel()</code></td><td><code>none</code></td><td>Returns an instance of <code>AsynchronousSocketChannel</code> useful for retrieving info about the client .</td></tr><tr><td><code>getRequestInfo()</code></td><td><code>none</code></td><td>Returns an instance of <code>RequestInfo</code> containing all sorts of information about the request (headers, method, path etc.) .</td></tr><tr><td><code>getPath()</code></td><td><code>none</code></td><td>Returns the path to the websocket endpoint as a <code>String</code>.</td></tr><tr><td><code>getId()</code></td><td><code>none</code></td><td>Returns the id of the websocket session as a <code>String</code>, useful if you want to keep track of the connected clients in a custom manager.</td></tr><tr><td><code>getBuffer()</code></td><td><code>none</code></td><td>Returns the ByteBuffer for that session.</td></tr><tr><td><code>sendMessage()</code></td><td><code>String message</code></td><td>Sends the <code>message</code> to the client as a <code>String</code>. it&#39;s up to the developer to stringify and de-stringify any data you want to send back and forth</td></tr><tr><td><code>close()</code></td><td><code>none</code></td><td>Closes the websocket session.</td></tr></tbody></table><div class="warning custom-block"><p class="custom-block-title">NOTE</p><p><code>WebsocketHandler</code> includes a <code>setId(String id)</code> method for overriding the default session ID. Unless you have a specific reason to change it, it&#39;s best to leave it as is.</p><p>Similarly, the <code>setBuffer(ByteBuffer buffer)</code> method allows you to override the default buffer. If you&#39;re unsure about this, it&#39;s recommended to keep the default setting.</p></div>`,14)]))}const E=i(n,[["render",h]]);export{c as __pageData,E as default};
