| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/tower-layer-0.3.2/src/lib.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lib.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../tower_layer/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../tower_layer/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="attribute">#![warn( |
| missing_debug_implementations, |
| missing_docs, |
| rust_2018_idioms, |
| unreachable_pub |
| )] |
| #![forbid(unsafe_code)] |
| </span><span class="comment">// `rustdoc::broken_intra_doc_links` is checked on CI |
| |
| </span><span class="doccomment">//! Layer traits and extensions. |
| //! |
| //! A layer decorates an service and provides additional functionality. It |
| //! allows other services to be composed with the service that implements layer. |
| //! |
| //! A middleware implements the [`Layer`] and [`Service`] trait. |
| //! |
| //! [`Service`]: https://docs.rs/tower/latest/tower/trait.Service.html |
| |
| </span><span class="kw">mod </span>identity; |
| <span class="kw">mod </span>layer_fn; |
| <span class="kw">mod </span>stack; |
| <span class="kw">mod </span>tuple; |
| |
| <span class="kw">pub use </span><span class="self">self</span>::{ |
| identity::Identity, |
| layer_fn::{layer_fn, LayerFn}, |
| stack::Stack, |
| }; |
| |
| <span class="doccomment">/// Decorates a [`Service`], transforming either the request or the response. |
| /// |
| /// Often, many of the pieces needed for writing network applications can be |
| /// reused across multiple services. The `Layer` trait can be used to write |
| /// reusable components that can be applied to very different kinds of services; |
| /// for example, it can be applied to services operating on different protocols, |
| /// and to both the client and server side of a network transaction. |
| /// |
| /// # Log |
| /// |
| /// Take request logging as an example: |
| /// |
| /// ```rust |
| /// # use tower_service::Service; |
| /// # use std::task::{Poll, Context}; |
| /// # use tower_layer::Layer; |
| /// # use std::fmt; |
| /// |
| /// pub struct LogLayer { |
| /// target: &'static str, |
| /// } |
| /// |
| /// impl<S> Layer<S> for LogLayer { |
| /// type Service = LogService<S>; |
| /// |
| /// fn layer(&self, service: S) -> Self::Service { |
| /// LogService { |
| /// target: self.target, |
| /// service |
| /// } |
| /// } |
| /// } |
| /// |
| /// // This service implements the Log behavior |
| /// pub struct LogService<S> { |
| /// target: &'static str, |
| /// service: S, |
| /// } |
| /// |
| /// impl<S, Request> Service<Request> for LogService<S> |
| /// where |
| /// S: Service<Request>, |
| /// Request: fmt::Debug, |
| /// { |
| /// type Response = S::Response; |
| /// type Error = S::Error; |
| /// type Future = S::Future; |
| /// |
| /// fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { |
| /// self.service.poll_ready(cx) |
| /// } |
| /// |
| /// fn call(&mut self, request: Request) -> Self::Future { |
| /// // Insert log statement here or other functionality |
| /// println!("request = {:?}, target = {:?}", request, self.target); |
| /// self.service.call(request) |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// The above log implementation is decoupled from the underlying protocol and |
| /// is also decoupled from client or server concerns. In other words, the same |
| /// log middleware could be used in either a client or a server. |
| /// |
| /// [`Service`]: https://docs.rs/tower/latest/tower/trait.Service.html |
| </span><span class="kw">pub trait </span>Layer<S> { |
| <span class="doccomment">/// The wrapped service |
| </span><span class="kw">type </span>Service; |
| <span class="doccomment">/// Wrap the given service with the middleware, returning a new service |
| /// that has been decorated with the middleware. |
| </span><span class="kw">fn </span>layer(<span class="kw-2">&</span><span class="self">self</span>, inner: S) -> <span class="self">Self</span>::Service; |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, T, S> Layer<S> <span class="kw">for </span><span class="kw-2">&</span><span class="lifetime">'a </span>T |
| <span class="kw">where |
| </span>T: <span class="question-mark">?</span>Sized + Layer<S>, |
| { |
| <span class="kw">type </span>Service = T::Service; |
| |
| <span class="kw">fn </span>layer(<span class="kw-2">&</span><span class="self">self</span>, inner: S) -> <span class="self">Self</span>::Service { |
| (<span class="kw-2">**</span><span class="self">self</span>).layer(inner) |
| } |
| } |
| </code></pre></div> |
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