hyper/ext/
mod.rs

1//! Extensions for HTTP messages in Hyper.
2//!
3//! This module provides types and utilities that extend the capabilities of HTTP requests and responses
4//! in Hyper. Extensions are additional pieces of information or features that can be attached to HTTP
5//! messages via the [`http::Extensions`] map, which is
6//! accessible through methods like [`http::Request::extensions`] and [`http::Response::extensions`].
7//!
8//! # What are extensions?
9//!
10//! Extensions allow Hyper to associate extra metadata or behaviors with HTTP messages, beyond the standard
11//! headers and body. These can be used by advanced users and library authors to access protocol-specific
12//! features, track original header casing, handle informational responses, and more.
13//!
14//! # How to access extensions
15//!
16//! Extensions are stored in the `Extensions` map of a request or response. You can access them using:
17//!
18//! ```rust
19//! # let response = http::Response::new(());
20//! if let Some(ext) = response.extensions().get::<hyper::ext::ReasonPhrase>() {
21//!     // use the extension
22//! }
23//! ```
24//!
25//! # Extension Groups
26//!
27//! The extensions in this module can be grouped as follows:
28//!
29//! - **HTTP/1 Reason Phrase**: [`ReasonPhrase`] — Access non-canonical reason phrases in HTTP/1 responses.
30//! - **Informational Responses**: [`on_informational`] — Register callbacks for 1xx HTTP/1 responses on the client.
31//! - **Header Case Tracking**: Internal types for tracking the original casing and order of headers as received.
32//! - **HTTP/2 Protocol Extensions**: [`Protocol`] — Access the `:protocol` pseudo-header for Extended CONNECT in HTTP/2.
33//!
34//! Some extensions are only available for specific protocols (HTTP/1 or HTTP/2) or use cases (client, server, FFI).
35//!
36//! See the documentation on each item for details about its usage and requirements.
37
38#[cfg(all(any(feature = "client", feature = "server"), feature = "http1"))]
39use bytes::Bytes;
40#[cfg(any(
41    all(any(feature = "client", feature = "server"), feature = "http1"),
42    feature = "ffi"
43))]
44use http::header::HeaderName;
45#[cfg(all(any(feature = "client", feature = "server"), feature = "http1"))]
46use http::header::{HeaderMap, IntoHeaderName, ValueIter};
47#[cfg(feature = "ffi")]
48use std::collections::HashMap;
49#[cfg(feature = "http2")]
50use std::fmt;
51
52#[cfg(any(feature = "http1", feature = "ffi"))]
53mod h1_reason_phrase;
54#[cfg(any(feature = "http1", feature = "ffi"))]
55pub use h1_reason_phrase::ReasonPhrase;
56
57#[cfg(all(feature = "http1", feature = "client"))]
58mod informational;
59#[cfg(all(feature = "http1", feature = "client"))]
60pub use informational::on_informational;
61#[cfg(all(feature = "http1", feature = "client"))]
62pub(crate) use informational::OnInformational;
63#[cfg(all(feature = "http1", feature = "client", feature = "ffi"))]
64pub(crate) use informational::{on_informational_raw, OnInformationalCallback};
65
66#[cfg(feature = "http2")]
67/// Extension type representing the `:protocol` pseudo-header in HTTP/2.
68///
69/// The `Protocol` extension allows access to the value of the `:protocol` pseudo-header
70/// used by the [Extended CONNECT Protocol](https://datatracker.ietf.org/doc/html/rfc8441#section-4).
71/// This extension is only sent on HTTP/2 CONNECT requests, most commonly with the value `websocket`.
72///
73/// # Example
74///
75/// ```rust
76/// use hyper::ext::Protocol;
77/// use http::{Request, Method, Version};
78///
79/// let mut req = Request::new(());
80/// *req.method_mut() = Method::CONNECT;
81/// *req.version_mut() = Version::HTTP_2;
82/// req.extensions_mut().insert(Protocol::from_static("websocket"));
83/// // Now the request will include the `:protocol` pseudo-header with value "websocket"
84/// ```
85#[derive(Clone, Eq, PartialEq)]
86pub struct Protocol {
87    inner: h2::ext::Protocol,
88}
89
90#[cfg(feature = "http2")]
91impl Protocol {
92    /// Converts a static string to a protocol name.
93    pub const fn from_static(value: &'static str) -> Self {
94        Self {
95            inner: h2::ext::Protocol::from_static(value),
96        }
97    }
98
99    /// Returns a str representation of the header.
100    pub fn as_str(&self) -> &str {
101        self.inner.as_str()
102    }
103
104    #[cfg(feature = "server")]
105    pub(crate) fn from_inner(inner: h2::ext::Protocol) -> Self {
106        Self { inner }
107    }
108
109    #[cfg(all(feature = "client", feature = "http2"))]
110    pub(crate) fn into_inner(self) -> h2::ext::Protocol {
111        self.inner
112    }
113}
114
115#[cfg(feature = "http2")]
116impl<'a> From<&'a str> for Protocol {
117    fn from(value: &'a str) -> Self {
118        Self {
119            inner: h2::ext::Protocol::from(value),
120        }
121    }
122}
123
124#[cfg(feature = "http2")]
125impl AsRef<[u8]> for Protocol {
126    fn as_ref(&self) -> &[u8] {
127        self.inner.as_ref()
128    }
129}
130
131#[cfg(feature = "http2")]
132impl fmt::Debug for Protocol {
133    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
134        self.inner.fmt(f)
135    }
136}
137
138/// A map from header names to their original casing as received in an HTTP message.
139///
140/// If an HTTP/1 response `res` is parsed on a connection whose option
141/// [`preserve_header_case`] was set to true and the response included
142/// the following headers:
143///
144/// ```ignore
145/// x-Bread: Baguette
146/// X-BREAD: Pain
147/// x-bread: Ficelle
148/// ```
149///
150/// Then `res.extensions().get::<HeaderCaseMap>()` will return a map with:
151///
152/// ```ignore
153/// HeaderCaseMap({
154///     "x-bread": ["x-Bread", "X-BREAD", "x-bread"],
155/// })
156/// ```
157///
158/// [`preserve_header_case`]: /client/struct.Client.html#method.preserve_header_case
159#[cfg(all(any(feature = "client", feature = "server"), feature = "http1"))]
160#[derive(Clone, Debug)]
161pub(crate) struct HeaderCaseMap(HeaderMap<Bytes>);
162
163#[cfg(all(any(feature = "client", feature = "server"), feature = "http1"))]
164impl HeaderCaseMap {
165    /// Returns a view of all spellings associated with that header name,
166    /// in the order they were found.
167    #[cfg(feature = "client")]
168    pub(crate) fn get_all<'a>(
169        &'a self,
170        name: &HeaderName,
171    ) -> impl Iterator<Item = impl AsRef<[u8]> + 'a> + 'a {
172        self.get_all_internal(name)
173    }
174
175    /// Returns a view of all spellings associated with that header name,
176    /// in the order they were found.
177    #[cfg(any(feature = "client", feature = "server"))]
178    pub(crate) fn get_all_internal(&self, name: &HeaderName) -> ValueIter<'_, Bytes> {
179        self.0.get_all(name).into_iter()
180    }
181
182    #[cfg(any(feature = "client", feature = "server"))]
183    pub(crate) fn default() -> Self {
184        Self(Default::default())
185    }
186
187    #[cfg(any(test, feature = "ffi"))]
188    pub(crate) fn insert(&mut self, name: HeaderName, orig: Bytes) {
189        self.0.insert(name, orig);
190    }
191
192    #[cfg(any(feature = "client", feature = "server"))]
193    pub(crate) fn append<N>(&mut self, name: N, orig: Bytes)
194    where
195        N: IntoHeaderName,
196    {
197        self.0.append(name, orig);
198    }
199}
200
201#[cfg(feature = "ffi")]
202#[derive(Clone, Debug)]
203/// Hashmap<Headername, numheaders with that name>
204pub(crate) struct OriginalHeaderOrder {
205    /// Stores how many entries a Headername maps to. This is used
206    /// for accounting.
207    num_entries: HashMap<HeaderName, usize>,
208    /// Stores the ordering of the headers. ex: `vec[i] = (headerName, idx)`,
209    /// The vector is ordered such that the ith element
210    /// represents the ith header that came in off the line.
211    /// The `HeaderName` and `idx` are then used elsewhere to index into
212    /// the multi map that stores the header values.
213    entry_order: Vec<(HeaderName, usize)>,
214}
215
216#[cfg(all(feature = "http1", feature = "ffi"))]
217impl OriginalHeaderOrder {
218    pub(crate) fn default() -> Self {
219        OriginalHeaderOrder {
220            num_entries: HashMap::new(),
221            entry_order: Vec::new(),
222        }
223    }
224
225    pub(crate) fn insert(&mut self, name: HeaderName) {
226        if !self.num_entries.contains_key(&name) {
227            let idx = 0;
228            self.num_entries.insert(name.clone(), 1);
229            self.entry_order.push((name, idx));
230        }
231        // Replacing an already existing element does not
232        // change ordering, so we only care if its the first
233        // header name encountered
234    }
235
236    pub(crate) fn append<N>(&mut self, name: N)
237    where
238        N: IntoHeaderName + Into<HeaderName> + Clone,
239    {
240        let name: HeaderName = name.into();
241        let idx;
242        if self.num_entries.contains_key(&name) {
243            idx = self.num_entries[&name];
244            *self.num_entries.get_mut(&name).unwrap() += 1;
245        } else {
246            idx = 0;
247            self.num_entries.insert(name.clone(), 1);
248        }
249        self.entry_order.push((name, idx));
250    }
251
252    // No doc test is run here because `RUSTFLAGS='--cfg hyper_unstable_ffi'`
253    // is needed to compile. Once ffi is stabilized `no_run` should be removed
254    // here.
255    /// This returns an iterator that provides header names and indexes
256    /// in the original order received.
257    ///
258    /// # Examples
259    /// ```no_run
260    /// use hyper::ext::OriginalHeaderOrder;
261    /// use hyper::header::{HeaderName, HeaderValue, HeaderMap};
262    ///
263    /// let mut h_order = OriginalHeaderOrder::default();
264    /// let mut h_map = Headermap::new();
265    ///
266    /// let name1 = b"Set-CookiE";
267    /// let value1 = b"a=b";
268    /// h_map.append(name1);
269    /// h_order.append(name1);
270    ///
271    /// let name2 = b"Content-Encoding";
272    /// let value2 = b"gzip";
273    /// h_map.append(name2, value2);
274    /// h_order.append(name2);
275    ///
276    /// let name3 = b"SET-COOKIE";
277    /// let value3 = b"c=d";
278    /// h_map.append(name3, value3);
279    /// h_order.append(name3)
280    ///
281    /// let mut iter = h_order.get_in_order()
282    ///
283    /// let (name, idx) = iter.next();
284    /// assert_eq!(b"a=b", h_map.get_all(name).nth(idx).unwrap());
285    ///
286    /// let (name, idx) = iter.next();
287    /// assert_eq!(b"gzip", h_map.get_all(name).nth(idx).unwrap());
288    ///
289    /// let (name, idx) = iter.next();
290    /// assert_eq!(b"c=d", h_map.get_all(name).nth(idx).unwrap());
291    /// ```
292    pub(crate) fn get_in_order(&self) -> impl Iterator<Item = &(HeaderName, usize)> {
293        self.entry_order.iter()
294    }
295}
hyper/ext/mod.rs

hyper/ext/
mod.rs
