56 lines
8.2 KiB
HTML
56 lines
8.2 KiB
HTML
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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"/><meta content="width=device-width, initial-scale=1" name="viewport"/><link type="image/x-icon" href="resources/favicon.svg" rel="icon"/><!-- --><!-- --></head><body><div class="pure-g"><div class="home-menu pure-menu pure-menu-horizontal"><ul class="pure-menu-list"><li class="pure-menu-item"><a href="/home" class="pure-menu-link"> Home </a></li><li class="pure-menu-item"><a href="/projects" class="pure-menu-link"> Projects </a></li><li class="pure-menu-item"><a href="/blog" class="pure-menu-link"> Blog </a></li><li class="pure-menu-item"><a href="/about" class="pure-menu-link"> About </a></li></ul></div><div class="pure-u-1-1"><div class="header"><h1> Rust HTTP Server </h1><h2> Keywords: Back End - TCP - SSL </h2></div><div class="content"><h2 class="distinct"> Motivation </h2>
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As a systems programmer, I want to understand the technologies
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I use at a very low level. Modern web stacks abstract away the
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process of handling TCP connections, serving SSL certificates,
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and parsing HTTP requests. The best way to understand a technology
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is to implement it from the ground up, I studied the HTTP 1.1
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specification and wrote a server to host my website.
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<h2 class="distinct"> Architecture </h2>
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At the most basic level, the server will translate the request URL
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into a local file path, and respond with the file matching that path
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if it exists. Request URLs are sanitized to prevent accessing files
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outside of the server's directory. Two tables are used for rewriting
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and routing URLs. This makes handling URLs predictable and robust.
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Because I route all traffic through Cloudflare, I decided to use its
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caching feature rather than implement a cache locally.
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<div class="code-block">
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<pre><code>
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<span class="comment">// Snippet from the request handling code</span>
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<span class="keyword">pub</span> <span class="keyword">async</span> <span class="keyword function">fn</span> <span class="function">construct_response</span><span class="punctuation bracket">(</span><span class="keyword storage modifier">&</span><span class="variable builtin">self</span><span class="punctuation delimiter">,</span> <span class="variable parameter">request_url</span>: <span class="keyword storage modifier">&</span><span class="type builtin">str</span><span class="punctuation bracket">)</span> <span class="operator">-></span> <span class="type">Response</span> <span class="punctuation bracket">{</span>
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<span class="keyword storage">let</span> <span class="variable">sanitized_url</span> <span class="operator">=</span> <span class="function">rewrite_url</span><span class="punctuation bracket">(</span><span class="variable parameter">request_url</span><span class="punctuation bracket">)</span><span class="punctuation delimiter">;</span>
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<span class="keyword control conditional">if</span> <span class="variable">sanitized_url</span> <span class="operator">!=</span> <span class="variable parameter">request_url</span> <span class="punctuation bracket">{</span>
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<span class="keyword control return">return</span> <span class="type">Self</span><span class="punctuation delimiter">::</span><span class="function">redirect</span><span class="punctuation bracket">(</span><span class="operator">&</span><span class="variable">sanitized_url</span><span class="punctuation bracket">)</span><span class="punctuation delimiter">;</span>
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<span class="punctuation bracket">}</span>
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<span class="keyword storage">let</span> <span class="variable">routed_url</span> <span class="operator">=</span> <span class="variable builtin">self</span><span class="punctuation delimiter">.</span><span class="function">perform_routing</span><span class="punctuation bracket">(</span><span class="operator">&</span><span class="variable">sanitized_url</span><span class="punctuation bracket">)</span><span class="punctuation delimiter">.</span><span class="keyword control return">await</span><span class="punctuation delimiter">;</span>
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<span class="keyword control conditional">if</span> <span class="keyword storage">let</span> <span class="constructor">Some</span><span class="punctuation bracket">(</span><span class="variable">response</span><span class="punctuation bracket">)</span> <span class="operator">=</span>
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<span class="variable builtin">self</span><span class="punctuation delimiter">.</span><span class="function">perform_redirecting</span><span class="punctuation bracket">(</span><span class="operator">&</span><span class="variable">routed_url</span><span class="punctuation bracket">)</span><span class="punctuation delimiter">.</span><span class="keyword control return">await</span> <span class="punctuation bracket">{</span>
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<span class="keyword control return">return</span> <span class="variable">response</span><span class="punctuation delimiter">;</span>
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<span class="punctuation bracket">}</span>
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<span class="keyword control conditional">match</span> <span class="variable builtin">self</span><span class="punctuation delimiter">.</span><span class="function">get_resource</span><span class="punctuation bracket">(</span><span class="operator">&</span><span class="variable">routed_url</span><span class="punctuation bracket">)</span><span class="punctuation delimiter">.</span><span class="keyword control return">await</span> <span class="punctuation bracket">{</span>
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<span class="constructor">Some</span><span class="punctuation bracket">(</span><span class="variable">bytes</span><span class="punctuation bracket">)</span> <span class="operator">=></span> <span class="type">Response</span><span class="punctuation delimiter">::</span><span class="function">from_data</span><span class="punctuation bracket">(</span><span class="variable">bytes</span><span class="punctuation bracket">)</span><span class="punctuation delimiter">,</span>
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<span class="constructor">None</span> <span class="operator">=></span> <span class="type">Self</span><span class="punctuation delimiter">::</span><span class="function">not_found</span><span class="punctuation bracket">(</span><span class="punctuation bracket">)</span><span class="punctuation delimiter">,</span>
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<span class="punctuation bracket">}</span>
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<span class="punctuation bracket">}</span>
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</code></pre>
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</div><h2 class="distinct"> Dependencies </h2>
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My goal with this project was to provide a functional server using as few
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libraries as possible. The final project directly depends on four crates:
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<div class="code-block">
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<pre><code>
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// Snippet from Cargo<span class="punctuation delimiter">.</span>toml
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<span class="punctuation bracket">[</span><span class="type">dependencies</span><span class="punctuation bracket">]</span>
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<span class="variable other member">log</span> <span class="operator">=</span> <span class="string">"0.4"</span>
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<span class="variable other member">log4rs</span> <span class="operator">=</span> <span class="string">"1.3"</span>
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<span class="variable other member">tiny_http</span> <span class="operator">=</span> <span class="string">"0.12"</span>
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<span class="variable other member">tokio</span> <span class="operator">=</span> <span class="punctuation bracket">{</span><span class="variable other member">version</span> <span class="operator">=</span> <span class="string">"1"</span><span class="punctuation delimiter">,</span> <span class="variable other member">features</span> <span class="operator">=</span> <span class="punctuation bracket">[</span><span class="string">"full"</span><span class="punctuation bracket">]</span><span class="punctuation bracket">}</span>
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</code></pre>
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</div>
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The first two crates, log and log4rs, provide logging functions which aren't critical to the
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server's functionality. The tiny_http crate provides a simple wrapper for the standard
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library TCP stream, and performs SSL encryption. It is used as the backbone
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for many Rust web frameworks. While I could implement these features myself, I
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decided against it for security and browser compatibility reasons. Finally there is
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tokio, an async runtime. This is necessary because Rust does not provide a runtime
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by default, and building one is out of scope.
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</div></div></div></body></html>
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