1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360

//! `async fn(HttpRequest) -> Result<HttpResponse, Error>`
//!
//! # Overview
//!
//! tower-http is a library that provides HTTP-specific middleware and utilities built on top of
//! [tower].
//!
//! All middleware uses the [http] and [http-body] crates as the HTTP abstractions. That means
//! they're compatible with any library or framework that also uses those crates, such as
//! [hyper], [tonic], and [warp].
//!
//! # Example server
//!
//! This example shows how to apply middleware from tower-http to a [`Service`] and then run
//! that service using [hyper].
//!
//! ```rust,no_run
//! use tower_http::{
//!     add_extension::AddExtensionLayer,
//!     compression::CompressionLayer,
//!     propagate_header::PropagateHeaderLayer,
//!     auth::RequireAuthorizationLayer,
//!     sensitive_headers::SetSensitiveRequestHeadersLayer,
//!     set_header::SetResponseHeaderLayer,
//!     trace::TraceLayer,
//! };
//! use tower::{ServiceBuilder, service_fn, make::Shared};
//! use http::{Request, Response, header::{HeaderName, CONTENT_TYPE, AUTHORIZATION}};
//! use hyper::{Body, Error, server::Server, service::make_service_fn};
//! use std::{sync::Arc, net::SocketAddr, convert::Infallible, iter::once};
//! # struct DatabaseConnectionPool;
//! # impl DatabaseConnectionPool {
//! #     fn new() -> DatabaseConnectionPool { DatabaseConnectionPool }
//! # }
//! # fn content_length_from_response<B>(_: &http::Response<B>) -> Option<http::HeaderValue> { None }
//! # async fn update_in_flight_requests_metric(count: usize) {}
//!
//! // Our request handler. This is where we would implement the application logic
//! // for responding to HTTP requests...
//! async fn handler(request: Request<Body>) -> Result<Response<Body>, Error> {
//!     // ...
//!     # todo!()
//! }
//!
//! // Shared state across all request handlers --- in this case, a pool of database connections.
//! struct State {
//!     pool: DatabaseConnectionPool,
//! }
//!
//! #[tokio::main]
//! async fn main() {
//!     // Construct the shared state.
//!     let state = State {
//!         pool: DatabaseConnectionPool::new(),
//!     };
//!
//!     // Use tower's `ServiceBuilder` API to build a stack of tower middleware
//!     // wrapping our request handler.
//!     let service = ServiceBuilder::new()
//!         // Mark the `Authorization` request header as sensitive so it doesn't show in logs
//!         .layer(SetSensitiveRequestHeadersLayer::new(once(AUTHORIZATION)))
//!         // High level logging of requests and responses
//!         .layer(TraceLayer::new_for_http())
//!         // Share an `Arc<State>` with all requests
//!         .layer(AddExtensionLayer::new(Arc::new(state)))
//!         // Compress responses
//!         .layer(CompressionLayer::new())
//!         // Propagate `X-Request-Id`s from requests to responses
//!         .layer(PropagateHeaderLayer::new(HeaderName::from_static("x-request-id")))
//!         // If the response has a known size set the `Content-Length` header
//!         .layer(SetResponseHeaderLayer::overriding(CONTENT_TYPE, content_length_from_response))
//!         // Authorize requests using a token
//!         .layer(RequireAuthorizationLayer::bearer("passwordlol"))
//!         // Wrap a `Service` in our middleware stack
//!         .service_fn(handler);
//!
//!     // And run our service using `hyper`
//!     let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
//!     Server::bind(&addr)
//!         .serve(Shared::new(service))
//!         .await
//!         .expect("server error");
//! }
//! ```
//!
//! Keep in mind that while this example uses [hyper], tower-http supports any HTTP
//! client/server implementation that uses the [http] and [http-body] crates.
//!
//! # Example client
//!
//! tower-http middleware can also be applied to HTTP clients:
//!
//! ```rust,no_run
//! use tower_http::{
//!     decompression::DecompressionLayer,
//!     set_header::SetRequestHeaderLayer,
//!     trace::TraceLayer,
//!     classify::StatusInRangeAsFailures,
//! };
//! use tower::{ServiceBuilder, Service, ServiceExt};
//! use hyper::Body;
//! use http::{Request, HeaderValue, header::USER_AGENT};
//!
//! #[tokio::main]
//! async fn main() {
//!     let mut client = ServiceBuilder::new()
//!         // Add tracing and consider server errors and client
//!         // errors as failures.
//!         .layer(TraceLayer::new(
//!             StatusInRangeAsFailures::new(400..=599).into_make_classifier()
//!         ))
//!         // Set a `User-Agent` header on all requests.
//!         .layer(SetRequestHeaderLayer::overriding(
//!             USER_AGENT,
//!             HeaderValue::from_static("tower-http demo")
//!         ))
//!         // Decompress response bodies
//!         .layer(DecompressionLayer::new())
//!         // Wrap a `hyper::Client` in our middleware stack.
//!         // This is possible because `hyper::Client` implements
//!         // `tower::Service`.
//!         .service(hyper::Client::new());
//!
//!     // Make a request
//!     let request = Request::builder()
//!         .uri("http://example.com")
//!         .body(Body::empty())
//!         .unwrap();
//!
//!     let response = client
//!         .ready()
//!         .await
//!         .unwrap()
//!         .call(request)
//!         .await
//!         .unwrap();
//! }
//! ```
//!
//! # Feature Flags
//!
//! All middleware are disabled by default and can be enabled using [cargo features].
//!
//! For example, to enable the [`Trace`] middleware, add the "trace" feature flag in
//! your `Cargo.toml`:
//!
//! ```toml
//! tower-http = { version = "0.1", features = ["trace"] }
//! ```
//!
//! You can use `"full"` to enable everything:
//!
//! ```toml
//! tower-http = { version = "0.1", features = ["full"] }
//! ```
//!
//! # Getting Help
//!
//! If you're new to tower its [guides] might help. In the tower-http repo we also have a [number
//! of examples][examples] showing how to put everything together. You're also welcome to ask in
//! the [`#tower` Discord channel][chat] or open an [issue] with your question.
//!
//! [tower]: https://crates.io/crates/tower
//! [http]: https://crates.io/crates/http
//! [http-body]: https://crates.io/crates/http-body
//! [hyper]: https://crates.io/crates/hyper
//! [guides]: https://github.com/tower-rs/tower/tree/master/guides
//! [tonic]: https://crates.io/crates/tonic
//! [warp]: https://crates.io/crates/warp
//! [cargo features]: https://doc.rust-lang.org/cargo/reference/features.html
//! [`AddExtension`]: crate::add_extension::AddExtension
//! [`Service`]: https://docs.rs/tower/latest/tower/trait.Service.html
//! [chat]: https://discord.gg/tokio
//! [issue]: https://github.com/tower-rs/tower-http/issues/new
//! [`Trace`]: crate::trace::Trace
//! [examples]: https://github.com/tower-rs/tower-http/tree/master/examples

#![warn(
    clippy::all,
    clippy::dbg_macro,
    clippy::todo,
    clippy::empty_enum,
    clippy::enum_glob_use,
    clippy::pub_enum_variant_names,
    clippy::mem_forget,
    clippy::unused_self,
    clippy::filter_map_next,
    clippy::needless_continue,
    clippy::needless_borrow,
    clippy::match_wildcard_for_single_variants,
    clippy::if_let_mutex,
    clippy::mismatched_target_os,
    clippy::await_holding_lock,
    clippy::match_on_vec_items,
    clippy::imprecise_flops,
    clippy::suboptimal_flops,
    clippy::lossy_float_literal,
    clippy::rest_pat_in_fully_bound_structs,
    clippy::fn_params_excessive_bools,
    clippy::exit,
    clippy::inefficient_to_string,
    clippy::linkedlist,
    clippy::macro_use_imports,
    clippy::option_option,
    clippy::verbose_file_reads,
    clippy::unnested_or_patterns,
    rust_2018_idioms,
    future_incompatible,
    nonstandard_style,
    missing_docs
)]
#![deny(unreachable_pub, private_in_public)]
#![allow(
    elided_lifetimes_in_paths,
    // TODO: Remove this once the MSRV bumps to 1.42.0 or above.
    clippy::match_like_matches_macro,
    clippy::type_complexity
)]
#![forbid(unsafe_code)]
#![cfg_attr(docsrs, feature(doc_cfg))]
#![cfg_attr(test, allow(clippy::float_cmp))]

#[macro_use]
pub(crate) mod macros;

#[cfg(feature = "auth")]
#[cfg_attr(docsrs, doc(cfg(feature = "auth")))]
pub mod auth;

#[cfg(feature = "set-header")]
#[cfg_attr(docsrs, doc(cfg(feature = "set-header")))]
pub mod set_header;

#[cfg(feature = "propagate-header")]
#[cfg_attr(docsrs, doc(cfg(feature = "propagate-header")))]
pub mod propagate_header;

#[cfg(any(
    feature = "compression-br",
    feature = "compression-deflate",
    feature = "compression-gzip"
))]
#[cfg_attr(
    docsrs,
    doc(cfg(any(
        feature = "compression-br",
        feature = "compression-deflate",
        feature = "compression-gzip"
    )))
)]
pub mod compression;

#[cfg(feature = "add-extension")]
#[cfg_attr(docsrs, doc(cfg(feature = "add-extension")))]
pub mod add_extension;

#[cfg(feature = "sensitive-headers")]
#[cfg_attr(docsrs, doc(cfg(feature = "sensitive-headers")))]
pub mod sensitive_headers;

#[cfg(any(
    feature = "decompression-br",
    feature = "decompression-deflate",
    feature = "decompression-gzip"
))]
#[cfg_attr(
    docsrs,
    doc(cfg(any(
        feature = "decompression-br",
        feature = "decompression-deflate",
        feature = "decompression-gzip"
    )))
)]
pub mod decompression;

#[cfg(any(
    feature = "compression-br",
    feature = "compression-deflate",
    feature = "compression-gzip",
    feature = "decompression-br",
    feature = "decompression-deflate",
    feature = "decompression-gzip",
    feature = "fs" // Used for serving precompressed static files as well
))]
mod content_encoding;

#[cfg(any(
    feature = "compression-br",
    feature = "compression-deflate",
    feature = "compression-gzip",
    feature = "decompression-br",
    feature = "decompression-deflate",
    feature = "decompression-gzip",
))]
mod compression_utils;

#[cfg(feature = "map-response-body")]
#[cfg_attr(docsrs, doc(cfg(feature = "map-response-body")))]
pub mod map_response_body;

#[cfg(feature = "map-request-body")]
#[cfg_attr(docsrs, doc(cfg(feature = "map-request-body")))]
pub mod map_request_body;

#[cfg(feature = "trace")]
#[cfg_attr(docsrs, doc(cfg(feature = "trace")))]
pub mod trace;

#[cfg(feature = "follow-redirect")]
#[cfg_attr(docsrs, doc(cfg(feature = "follow-redirect")))]
pub mod follow_redirect;

#[cfg(feature = "metrics")]
#[cfg_attr(docsrs, doc(cfg(feature = "metrics")))]
pub mod metrics;

#[cfg(feature = "cors")]
#[cfg_attr(docsrs, doc(cfg(feature = "cors")))]
pub mod cors;

#[cfg(feature = "request-id")]
#[cfg_attr(docsrs, doc(cfg(feature = "request-id")))]
pub mod request_id;

#[cfg(feature = "catch-panic")]
#[cfg_attr(docsrs, doc(cfg(feature = "catch-panic")))]
pub mod catch_panic;

pub mod classify;
pub mod services;

#[cfg(feature = "util")]
mod builder;

#[cfg(feature = "util")]
#[cfg_attr(docsrs, doc(cfg(feature = "util")))]
#[doc(inline)]
pub use self::builder::ServiceBuilderExt;

/// The latency unit used to report latencies by middleware.
#[non_exhaustive]
#[derive(Copy, Clone, Debug)]
pub enum LatencyUnit {
    /// Use seconds.
    Seconds,
    /// Use milliseconds.
    Millis,
    /// Use microseconds.
    Micros,
    /// Use nanoseconds.
    Nanos,
}

/// Alias for a type-erased error type.
pub type BoxError = Box<dyn std::error::Error + Send + Sync>;

mod sealed {
    #[allow(unreachable_pub)]
    pub trait Sealed<T> {}
}