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use std::convert::TryFrom;
use bytes::Bytes;
/// A reason phrase in an HTTP/1 response.
///
/// # Clients
///
/// For clients, a `ReasonPhrase` will be present in the extensions of the `http::Response` returned
/// for a request if the reason phrase is different from the canonical reason phrase for the
/// response's status code. For example, if a server returns `HTTP/1.1 200 Awesome`, the
/// `ReasonPhrase` will be present and contain `Awesome`, but if a server returns `HTTP/1.1 200 OK`,
/// the response will not contain a `ReasonPhrase`.
///
/// ```no_run
/// # #[cfg(all(feature = "tcp", feature = "client", feature = "http1"))]
/// # async fn fake_fetch() -> hyper::Result<()> {
/// use hyper::{Client, Uri};
/// use hyper::ext::ReasonPhrase;
///
/// let res = Client::new().get(Uri::from_static("http://example.com/non_canonical_reason")).await?;
///
/// // Print out the non-canonical reason phrase, if it has one...
/// if let Some(reason) = res.extensions().get::<ReasonPhrase>() {
/// println!("non-canonical reason: {}", std::str::from_utf8(reason.as_bytes()).unwrap());
/// }
/// # Ok(())
/// # }
/// ```
///
/// # Servers
///
/// When a `ReasonPhrase` is present in the extensions of the `http::Response` written by a server,
/// its contents will be written in place of the canonical reason phrase when responding via HTTP/1.
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ReasonPhrase(Bytes);
impl ReasonPhrase {
/// Gets the reason phrase as bytes.
pub fn as_bytes(&self) -> &[u8] {
&self.0
}
/// Converts a static byte slice to a reason phrase.
pub fn from_static(reason: &'static [u8]) -> Self {
// TODO: this can be made const once MSRV is >= 1.57.0
if find_invalid_byte(reason).is_some() {
panic!("invalid byte in static reason phrase");
}
Self(Bytes::from_static(reason))
}
/// Converts a `Bytes` directly into a `ReasonPhrase` without validating.
///
/// Use with care; invalid bytes in a reason phrase can cause serious security problems if
/// emitted in a response.
pub unsafe fn from_bytes_unchecked(reason: Bytes) -> Self {
Self(reason)
}
}
impl TryFrom<&[u8]> for ReasonPhrase {
type Error = InvalidReasonPhrase;
fn try_from(reason: &[u8]) -> Result<Self, Self::Error> {
if let Some(bad_byte) = find_invalid_byte(reason) {
Err(InvalidReasonPhrase { bad_byte })
} else {
Ok(Self(Bytes::copy_from_slice(reason)))
}
}
}
impl TryFrom<Vec<u8>> for ReasonPhrase {
type Error = InvalidReasonPhrase;
fn try_from(reason: Vec<u8>) -> Result<Self, Self::Error> {
if let Some(bad_byte) = find_invalid_byte(&reason) {
Err(InvalidReasonPhrase { bad_byte })
} else {
Ok(Self(Bytes::from(reason)))
}
}
}
impl TryFrom<String> for ReasonPhrase {
type Error = InvalidReasonPhrase;
fn try_from(reason: String) -> Result<Self, Self::Error> {
if let Some(bad_byte) = find_invalid_byte(reason.as_bytes()) {
Err(InvalidReasonPhrase { bad_byte })
} else {
Ok(Self(Bytes::from(reason)))
}
}
}
impl TryFrom<Bytes> for ReasonPhrase {
type Error = InvalidReasonPhrase;
fn try_from(reason: Bytes) -> Result<Self, Self::Error> {
if let Some(bad_byte) = find_invalid_byte(&reason) {
Err(InvalidReasonPhrase { bad_byte })
} else {
Ok(Self(reason))
}
}
}
impl Into<Bytes> for ReasonPhrase {
fn into(self) -> Bytes {
self.0
}
}
impl AsRef<[u8]> for ReasonPhrase {
fn as_ref(&self) -> &[u8] {
&self.0
}
}
/// Error indicating an invalid byte when constructing a `ReasonPhrase`.
///
/// See [the spec][spec] for details on allowed bytes.
///
#[derive(Debug)]
pub struct InvalidReasonPhrase {
bad_byte: u8,
}
impl std::fmt::Display for InvalidReasonPhrase {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "Invalid byte in reason phrase: {}", self.bad_byte)
}
}
impl std::error::Error for InvalidReasonPhrase {}
const fn is_valid_byte(b: u8) -> bool {
const fn is_vchar(b: u8) -> bool {
0x21 <= b && b <= 0x7E
}
//
// The 0xFF comparison is technically redundant, but it matches the text of the spec more
// clearly and will be optimized away.
#[allow(unused_comparisons)]
const fn is_obs_text(b: u8) -> bool {
0x80 <= b && b <= 0xFF
}
b == b'\t' || b == b' ' || is_vchar(b) || is_obs_text(b)
}
const fn find_invalid_byte(bytes: &[u8]) -> Option<u8> {
let mut i = 0;
while i < bytes.len() {
let b = bytes[i];
if !is_valid_byte(b) {
return Some(b);
}
i += 1;
}
None
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn basic_valid() {
const PHRASE: &'static [u8] = b"OK";
assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE);
assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE);
}
#[test]
fn empty_valid() {
const PHRASE: &'static [u8] = b"";
assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE);
assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE);
}
#[test]
fn obs_text_valid() {
const PHRASE: &'static [u8] = b"hyp\xe9r";
assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE);
assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE);
}
const NEWLINE_PHRASE: &'static [u8] = b"hyp\ner";
#[test]
#[should_panic]
fn newline_invalid_panic() {
ReasonPhrase::from_static(NEWLINE_PHRASE);
}
#[test]
fn newline_invalid_err() {
assert!(ReasonPhrase::try_from(NEWLINE_PHRASE).is_err());
}
const CR_PHRASE: &'static [u8] = b"hyp\rer";
#[test]
#[should_panic]
fn cr_invalid_panic() {
ReasonPhrase::from_static(CR_PHRASE);
}
#[test]
fn cr_invalid_err() {
assert!(ReasonPhrase::try_from(CR_PHRASE).is_err());
}
}