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| 1 | +use std::convert::TryFrom; |
| 2 | + |
| 3 | +use bytes::Bytes; |
| 4 | + |
| 5 | +/// A reason phrase in an HTTP/1 response. |
| 6 | +/// |
| 7 | +/// # Clients |
| 8 | +/// |
| 9 | +/// For clients, a `ReasonPhrase` will be present in the extensions of the `http::Response` returned |
| 10 | +/// for a request if the reason phrase is different from the canonical reason phrase for the |
| 11 | +/// response's status code. For example, if a server returns `HTTP/1.1 200 Awesome`, the |
| 12 | +/// `ReasonPhrase` will be present and contain `Awesome`, but if a server returns `HTTP/1.1 200 OK`, |
| 13 | +/// the response will not contain a `ReasonPhrase`. |
| 14 | +/// |
| 15 | +/// ```no_run |
| 16 | +/// # #[cfg(all(feature = "tcp", feature = "client", feature = "http1"))] |
| 17 | +/// # async fn fake_fetch() -> hyper::Result<()> { |
| 18 | +/// use hyper::{Client, Uri}; |
| 19 | +/// use hyper::ext::ReasonPhrase; |
| 20 | +/// |
| 21 | +/// let res = Client::new().get(Uri::from_static("http://example.com/non_canonical_reason")).await?; |
| 22 | +/// |
| 23 | +/// // Print out the non-canonical reason phrase, if it has one... |
| 24 | +/// if let Some(reason) = res.extensions().get::<ReasonPhrase>() { |
| 25 | +/// println!("non-canonical reason: {}", std::str::from_utf8(reason.as_bytes()).unwrap()); |
| 26 | +/// } |
| 27 | +/// # Ok(()) |
| 28 | +/// # } |
| 29 | +/// ``` |
| 30 | +/// |
| 31 | +/// # Servers |
| 32 | +/// |
| 33 | +/// When a `ReasonPhrase` is present in the extensions of the `http::Response` written by a server, |
| 34 | +/// its contents will be written in place of the canonical reason phrase when responding via HTTP/1. |
| 35 | +#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)] |
| 36 | +pub struct ReasonPhrase(Bytes); |
| 37 | + |
| 38 | +impl ReasonPhrase { |
| 39 | + /// Gets the reason phrase as bytes. |
| 40 | + pub fn as_bytes(&self) -> &[u8] { |
| 41 | + &self.0 |
| 42 | + } |
| 43 | + |
| 44 | + /// Converts a static byte slice to a reason phrase. |
| 45 | + pub fn from_static(reason: &'static [u8]) -> Self { |
| 46 | + // TODO: this can be made const once MSRV is >= 1.57.0 |
| 47 | + if find_invalid_byte(reason).is_some() { |
| 48 | + panic!("invalid byte in static reason phrase"); |
| 49 | + } |
| 50 | + Self(Bytes::from_static(reason)) |
| 51 | + } |
| 52 | + |
| 53 | + /// Converts a `Bytes` directly into a `ReasonPhrase` without validating. |
| 54 | + /// |
| 55 | + /// Use with care; invalid bytes in a reason phrase can cause serious security problems if |
| 56 | + /// emitted in a response. |
| 57 | + pub unsafe fn from_bytes_unchecked(reason: Bytes) -> Self { |
| 58 | + Self(reason) |
| 59 | + } |
| 60 | +} |
| 61 | + |
| 62 | +impl TryFrom<&[u8]> for ReasonPhrase { |
| 63 | + type Error = InvalidReasonPhrase; |
| 64 | + |
| 65 | + fn try_from(reason: &[u8]) -> Result<Self, Self::Error> { |
| 66 | + if let Some(bad_byte) = find_invalid_byte(reason) { |
| 67 | + Err(InvalidReasonPhrase { bad_byte }) |
| 68 | + } else { |
| 69 | + Ok(Self(Bytes::copy_from_slice(reason))) |
| 70 | + } |
| 71 | + } |
| 72 | +} |
| 73 | + |
| 74 | +impl TryFrom<Vec<u8>> for ReasonPhrase { |
| 75 | + type Error = InvalidReasonPhrase; |
| 76 | + |
| 77 | + fn try_from(reason: Vec<u8>) -> Result<Self, Self::Error> { |
| 78 | + if let Some(bad_byte) = find_invalid_byte(&reason) { |
| 79 | + Err(InvalidReasonPhrase { bad_byte }) |
| 80 | + } else { |
| 81 | + Ok(Self(Bytes::from(reason))) |
| 82 | + } |
| 83 | + } |
| 84 | +} |
| 85 | + |
| 86 | +impl TryFrom<String> for ReasonPhrase { |
| 87 | + type Error = InvalidReasonPhrase; |
| 88 | + |
| 89 | + fn try_from(reason: String) -> Result<Self, Self::Error> { |
| 90 | + if let Some(bad_byte) = find_invalid_byte(reason.as_bytes()) { |
| 91 | + Err(InvalidReasonPhrase { bad_byte }) |
| 92 | + } else { |
| 93 | + Ok(Self(Bytes::from(reason))) |
| 94 | + } |
| 95 | + } |
| 96 | +} |
| 97 | + |
| 98 | +impl TryFrom<Bytes> for ReasonPhrase { |
| 99 | + type Error = InvalidReasonPhrase; |
| 100 | + |
| 101 | + fn try_from(reason: Bytes) -> Result<Self, Self::Error> { |
| 102 | + if let Some(bad_byte) = find_invalid_byte(&reason) { |
| 103 | + Err(InvalidReasonPhrase { bad_byte }) |
| 104 | + } else { |
| 105 | + Ok(Self(reason)) |
| 106 | + } |
| 107 | + } |
| 108 | +} |
| 109 | + |
| 110 | +impl Into<Bytes> for ReasonPhrase { |
| 111 | + fn into(self) -> Bytes { |
| 112 | + self.0 |
| 113 | + } |
| 114 | +} |
| 115 | + |
| 116 | +impl AsRef<[u8]> for ReasonPhrase { |
| 117 | + fn as_ref(&self) -> &[u8] { |
| 118 | + &self.0 |
| 119 | + } |
| 120 | +} |
| 121 | + |
| 122 | +/// Error indicating an invalid byte when constructing a `ReasonPhrase`. |
| 123 | +/// |
| 124 | +/// See [the spec][spec] for details on allowed bytes. |
| 125 | +/// |
| 126 | +/// [spec]: https://httpwg.org/http-core/draft-ietf-httpbis-messaging-latest.html#rfc.section.4.p.7 |
| 127 | +#[derive(Debug)] |
| 128 | +pub struct InvalidReasonPhrase { |
| 129 | + bad_byte: u8, |
| 130 | +} |
| 131 | + |
| 132 | +impl std::fmt::Display for InvalidReasonPhrase { |
| 133 | + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { |
| 134 | + write!(f, "Invalid byte in reason phrase: {}", self.bad_byte) |
| 135 | + } |
| 136 | +} |
| 137 | + |
| 138 | +impl std::error::Error for InvalidReasonPhrase {} |
| 139 | + |
| 140 | +const fn is_valid_byte(b: u8) -> bool { |
| 141 | + // See https://www.rfc-editor.org/rfc/rfc5234.html#appendix-B.1 |
| 142 | + const fn is_vchar(b: u8) -> bool { |
| 143 | + 0x21 <= b && b <= 0x7E |
| 144 | + } |
| 145 | + |
| 146 | + // See https://httpwg.org/http-core/draft-ietf-httpbis-semantics-latest.html#fields.values |
| 147 | + // |
| 148 | + // The 0xFF comparison is technically redundant, but it matches the text of the spec more |
| 149 | + // clearly and will be optimized away. |
| 150 | + #[allow(unused_comparisons)] |
| 151 | + const fn is_obs_text(b: u8) -> bool { |
| 152 | + 0x80 <= b && b <= 0xFF |
| 153 | + } |
| 154 | + |
| 155 | + // See https://httpwg.org/http-core/draft-ietf-httpbis-messaging-latest.html#rfc.section.4.p.7 |
| 156 | + b == b'\t' || b == b' ' || is_vchar(b) || is_obs_text(b) |
| 157 | +} |
| 158 | + |
| 159 | +const fn find_invalid_byte(bytes: &[u8]) -> Option<u8> { |
| 160 | + let mut i = 0; |
| 161 | + while i < bytes.len() { |
| 162 | + let b = bytes[i]; |
| 163 | + if !is_valid_byte(b) { |
| 164 | + return Some(b); |
| 165 | + } |
| 166 | + i += 1; |
| 167 | + } |
| 168 | + None |
| 169 | +} |
| 170 | + |
| 171 | +#[cfg(test)] |
| 172 | +mod tests { |
| 173 | + use super::*; |
| 174 | + |
| 175 | + #[test] |
| 176 | + fn basic_valid() { |
| 177 | + const PHRASE: &'static [u8] = b"OK"; |
| 178 | + assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE); |
| 179 | + assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE); |
| 180 | + } |
| 181 | + |
| 182 | + #[test] |
| 183 | + fn empty_valid() { |
| 184 | + const PHRASE: &'static [u8] = b""; |
| 185 | + assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE); |
| 186 | + assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE); |
| 187 | + } |
| 188 | + |
| 189 | + #[test] |
| 190 | + fn obs_text_valid() { |
| 191 | + const PHRASE: &'static [u8] = b"hyp\xe9r"; |
| 192 | + assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE); |
| 193 | + assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE); |
| 194 | + } |
| 195 | + |
| 196 | + const NEWLINE_PHRASE: &'static [u8] = b"hyp\ner"; |
| 197 | + |
| 198 | + #[test] |
| 199 | + #[should_panic] |
| 200 | + fn newline_invalid_panic() { |
| 201 | + ReasonPhrase::from_static(NEWLINE_PHRASE); |
| 202 | + } |
| 203 | + |
| 204 | + #[test] |
| 205 | + fn newline_invalid_err() { |
| 206 | + assert!(ReasonPhrase::try_from(NEWLINE_PHRASE).is_err()); |
| 207 | + } |
| 208 | + |
| 209 | + const CR_PHRASE: &'static [u8] = b"hyp\rer"; |
| 210 | + |
| 211 | + #[test] |
| 212 | + #[should_panic] |
| 213 | + fn cr_invalid_panic() { |
| 214 | + ReasonPhrase::from_static(CR_PHRASE); |
| 215 | + } |
| 216 | + |
| 217 | + #[test] |
| 218 | + fn cr_invalid_err() { |
| 219 | + assert!(ReasonPhrase::try_from(CR_PHRASE).is_err()); |
| 220 | + } |
| 221 | +} |
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