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_flash_advanced_handler-default-implementations" data-v-e6f2a212><div><h1 id="⚡-handler-default-implementations-hdi" tabindex="-1">⚡ Handler Default Implementations (HDI) <a class="header-anchor" href="#⚡-handler-default-implementations-hdi" aria-label="Permalink to &quot;⚡ Handler Default Implementations (HDI)&quot;">​</a></h1><p>Handler Default Implementations (HDIs) provide an elegant way to standardize common behaviors across multiple request handlers. By defining base handlers that extend <code>RequestHandler</code> (or chaining multiple base handlers together), you can modularize logic for common tasks like authentication, user data retrieval, and rate limiting.</p><p>HDIs are designed using the <a href="https://en.wikipedia.org/wiki/Chain-of-responsibility_pattern" target="_blank" rel="noreferrer">Chain of Responsibility pattern</a>, making it easy to handle requests with layered logic.</p><h2 id="🔗-how-it-works" tabindex="-1">🔗 How It Works <a class="header-anchor" href="#🔗-how-it-works" aria-label="Permalink to &quot;🔗 How It Works&quot;">​</a></h2><p>Instead of repeating the same logic in each handler, create abstract handler classes that define common functionality. Your handler implementations then extend these base classes, inheriting the shared behavior while implementing the request-specific logic.</p><h3 id="semantics-of-an-hdi" tabindex="-1">Semantics of an HDI <a class="header-anchor" href="#semantics-of-an-hdi" aria-label="Permalink to &quot;Semantics of an HDI&quot;">​</a></h3><p>Creating an HDI is simple, but it&#39;s useful to follow some guidelines for clarity and maintainability:</p><ol><li><h3 id="base-hdi-class" tabindex="-1"><strong>Base HDI Class</strong>: <a class="header-anchor" href="#base-hdi-class" aria-label="Permalink to &quot;**Base HDI Class**:&quot;">​</a></h3><ul><li><strong>Extends</strong>: The base HDI class should extend <code>RequestHandler</code>.</li><li><strong>Constructor</strong>: The constructor must call the super constructor with <code>Request</code> and <code>Response</code> objects.</li><li><strong>Override</strong>: Override the <code>handle</code> method to include common behavior. The <code>handle</code> method should return the response to the client and should call the <em>Abstract Handler Method</em>, which is implemented by the handler or next HDI in the chain.<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:#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:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handle</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // Common logic here, then call the abstract method</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> handleCustom</span><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></li><li><strong>Abstract Handler Method</strong>: Define an abstract method that must be implemented by the handler to provide custom logic. It should look like this:<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;">protected</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> abstract</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleCustom</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">();</span></span></code></pre></div></li><li><strong>Protected Fields</strong>: If needed, declare protected fields in the base class to pass data between handlers in the chain.<div class="info custom-block"><p class="custom-block-title">INFO</p><p>Protected fields are accessible to the handler implementation inside the Abstract Handler Method. Example HDI :</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;"> abstract</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> class</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> MyHDI</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> extends</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> RequestHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> String data; </span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> public</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> BaseHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(Request </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">req</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, Response </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">res</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> super</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(req, res);</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 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:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handle</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> data </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;Some data&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">; </span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// Set the data</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> handleCustom</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:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> abstract</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleCustom</span><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>Example Handler Implementation :</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;"> MyHandler</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> extends</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> MyHDI</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:#6F42C1;--shiki-dark:#B392F0;"> MyHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(Request </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">req</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, Response </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">res</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> super</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(req, res);</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 style="--shiki-light:#D73A49;--shiki-dark:#F97583;">Override</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleCustom</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // The data is accessible here</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;">(data);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;Response&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 style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre></div></div></li></ul></li><li><h3 id="handler-implementation" tabindex="-1"><strong>Handler Implementation</strong>: <a class="header-anchor" href="#handler-implementation" aria-label="Permalink to &quot;**Handler Implementation**:&quot;">​</a></h3><ul><li><strong>Extends</strong>: The handler should extend the HDI class (or be the final handler in the chain).</li><li><strong>Constructor</strong>: The constructor should call the super constructor with <code>Request</code> and <code>Response</code> objects.</li><li><strong>Implement</strong>: Implement the <strong>Abstract Handler Method</strong> from the HDI.</li><li><strong>Response Logic</strong>: The response logic should be in the abstract method, and its return value is sent to the client.<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:#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;">protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleCustom</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // Custom logic here</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;Response&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></code></pre></div></li><li><strong>Protected Fields</strong>: The handler implementation can access data from the HDI using the protected fields, <strong>inside</strong> the Abstract Handler Method.</li></ul></li></ol><h3 id="🛠-example-api-key-authentication" tabindex="-1">🛠 Example: API Key Authentication <a class="header-anchor" href="#🛠-example-api-key-authentication" aria-label="Permalink to &quot;🛠 Example: API Key Authentication&quot;">​</a></h3><p>Now let&#39;s go over a simple example to demonstrate how HDIs work. Imagine you need to authenticate API requests by checking an API key. You can create an abstract <code>APIKeyProtectedHandler</code> that extends <code>RequestHandler</code> and handles the API key authentication:</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;"> abstract</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> class</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> APIKeyProtectedHandler</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> extends</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> RequestHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> String apiKey;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> public</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> APIKeyProtectedHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(Request </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">req</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, Response </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">res</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> super</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(req, res);</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:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handle</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> apiKey </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> req.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">header</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;X-API-Key&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (apiKey </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> null</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ||</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> !</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">isValidApiKey</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(apiKey)) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">status</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">403</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">type</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;application/json&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;{</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">error</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">:</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">Invalid API Key</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">}&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:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> handleAuthorized</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:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> abstract</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleAuthorized</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">();</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> private</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> boolean</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> isValidApiKey</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(String </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">key</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;"> // Implement key validation logic, e.g., checking against a database</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> true</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>Now, your API handler implementation only need to extend APIKeyProtectedHandler, ensuring every request has a valid API key before executing its logic:</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:#24292E;--shiki-dark:#E1E4E8;">@</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">RouteInfo</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">endpoint</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> =</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;/data&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">method</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> =</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> HttpMethod.GET)</span></span>
<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;"> GetDataHandler</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> extends</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> APIKeyProtectedHandler</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:#6F42C1;--shiki-dark:#B392F0;"> GetDataHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(Request </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">req</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, Response </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">res</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> super</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(req, res);</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;"> protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleAuthorized</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">type</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;application/json&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;{</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">data</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">:</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">Your API response here</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">}&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 style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre></div><h2 id="🏗️-chaining-hdis-for-modular-logic" tabindex="-1">🏗️ Chaining HDIs for Modular Logic <a class="header-anchor" href="#🏗️-chaining-hdis-for-modular-logic" aria-label="Permalink to &quot;🏗️ Chaining HDIs for Modular Logic&quot;">​</a></h2><p><img src="/assets/hdichain.FX-X2Mhu.png" alt="HDI Chain"></p><p>HDIs can be chained together to create multiple layers of logic. For example, if you need to authenticate a user and fetch their data from a database, you can create two HDIs:</p><ul><li><code>ProtectedHandler</code> ensures authentication.</li></ul><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;"> abstract</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> class</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> ProtectedHandler</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> extends</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> RequestHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> String authToken;</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> public</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> ProtectedHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(Request </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">req</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, Response </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">res</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> super</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(req, res);</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:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handle</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> authToken </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> req.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">header</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;Authorization&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (authToken </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> null</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> ||</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> !</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">isValidToken</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(authToken)) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">status</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">401</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">type</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;application/json&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;{</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">error</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">:</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">Unauthorized</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">}&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 style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> handleAuthenticated</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:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> abstract</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleAuthenticated</span><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><ul><li><code>AuthenticatedHandler</code> extends ProtectedHandler to fetch user data from the database, and overrides <code>handleAuthenticated</code> to ensure the user is authenticated before proceeding.</li></ul><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;"> abstract</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> class</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> AuthenticatedHandler</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> extends</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> ProtectedHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> {</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> User user;</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> private</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> String authToken; </span><span style="--shiki-light:#6A737D;--shiki-dark:#6A737D;">// inherited from ProtectedHandler</span></span>
<span class="line"></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> public</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> AuthenticatedHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(Request </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">req</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, Response </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">res</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> super</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(req, res);</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;"> protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleAuthenticated</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> user </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">=</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> getUserFromDatabase</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(authToken);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> if</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> (user </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">==</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> null</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">status</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">403</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">type</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;application/json&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;{</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">error</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">:</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">User not found</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">}&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 style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> handleWithUser</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:#D73A49;--shiki-dark:#F97583;"> protected</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> abstract</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleWithUser</span><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><ul><li>Your handler implementation <code>UserProfileHandler</code> extends <code>AuthenticatedHandler</code> and implements <code>handleWithUser</code> to ensure the user is authenticated and their profile data has been fetched before proceeding.</li></ul><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:#24292E;--shiki-dark:#E1E4E8;">@</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">RouteInfo</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">endpoint</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> =</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;/profile&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, </span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">method</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> =</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> HttpMethod.GET)</span></span>
<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;"> UserProfileHandler</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> extends</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;"> AuthenticatedHandler</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:#6F42C1;--shiki-dark:#B392F0;"> UserProfileHandler</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(Request </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">req</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">, Response </span><span style="--shiki-light:#E36209;--shiki-dark:#FFAB70;">res</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">) {</span></span>
<span class="line"><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;"> super</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(req, res);</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;"> protected</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> Object </span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">handleWithUser</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() {</span></span>
<span class="line"><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> res.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">type</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">(</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;application/json&quot;</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">);</span></span>
<span class="line"><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> return</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;{</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">username</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">:</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">&quot;</span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;"> +</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;"> user.</span><span style="--shiki-light:#6F42C1;--shiki-dark:#B392F0;">getUsername</span><span style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">() </span><span style="--shiki-light:#D73A49;--shiki-dark:#F97583;">+</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;"> &quot;</span><span style="--shiki-light:#005CC5;--shiki-dark:#79B8FF;">\&quot;</span><span style="--shiki-light:#032F62;--shiki-dark:#9ECBFF;">}&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 style="--shiki-light:#24292E;--shiki-dark:#E1E4E8;">}</span></span></code></pre></div></div></div></main><footer class="VPDocFooter" data-v-e6f2a212 data-v-1bcd8184><!--[--><!--]--><!----><nav class="prev-next" aria-labelledby="doc-footer-aria-label" data-v-1bcd8184><span class="visually-hidden" id="doc-footer-aria-label" data-v-1bcd8184>Pager</span><div class="pager" data-v-1bcd8184><a class="VPLink link pager-link prev" href="/flash/file-serving/dynamic-file-server.html" data-v-1bcd8184><!--[--><span class="desc" data-v-1bcd8184>Previous page</span><span class="title" data-v-1bcd8184>Dynamic Files Server</span><!--]--></a></div><div class="pager" data-v-1bcd8184><a class="VPLink link pager-link next" href="/flash/advanced/fullstack-development.html" data-v-1bcd8184><!--[--><span class="desc" data-v-1bcd8184>Next page</span><span class="title" data-v-1bcd8184>Fullstack Development</span><!--]--></a></div></nav></footer><!--[--><!--]--></div></div></div><!--[--><!--]--></div></div><!----><!--[--><!--]--></div></div>
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