use bytes::{Bytes, BytesMut};
use std::convert::TryFrom;
use std::error::Error;
use std::fmt::Write;
use std::str::FromStr;
use std::{cmp, fmt, mem, str};
use crate::header::name::HeaderName;
/// Represents an HTTP header field value.
///
/// In practice, HTTP header field values are usually valid ASCII. However, the
/// HTTP spec allows for a header value to contain opaque bytes as well. In this
/// case, the header field value is not able to be represented as a string.
///
/// To handle this, the `HeaderValue` is useable as a type and can be compared
/// with strings and implements `Debug`. A `to_str` fn is provided that returns
/// an `Err` if the header value contains non visible ascii characters.
#[derive(Clone, Hash)]
pub struct HeaderValue {
inner: Bytes,
is_sensitive: bool,
}
/// A possible error when converting a `HeaderValue` from a string or byte
/// slice.
pub struct InvalidHeaderValue {
_priv: (),
}
/// A possible error when converting a `HeaderValue` to a string representation.
///
/// Header field values may contain opaque bytes, in which case it is not
/// possible to represent the value as a string.
#[derive(Debug)]
pub struct ToStrError {
_priv: (),
}
impl HeaderValue {
/// Convert a static string to a `HeaderValue`.
///
/// This function will not perform any copying, however the string is
/// checked to ensure that no invalid characters are present. Only visible
/// ASCII characters (32-127) are permitted.
///
/// # Panics
///
/// This function panics if the argument contains invalid header value
/// characters.
///
/// Until [Allow panicking in constants](https://github.com/rust-lang/rfcs/pull/2345)
/// makes its way into stable, the panic message at compile-time is
/// going to look cryptic, but should at least point at your header value:
///
/// ```text
/// error: any use of this value will cause an error
/// --> http/src/header/value.rs:67:17
/// |
/// 67 | ([] as [u8; 0])[0]; // Invalid header value
/// | ^^^^^^^^^^^^^^^^^^
/// | |
/// | index out of bounds: the length is 0 but the index is 0
/// | inside `HeaderValue::from_static` at http/src/header/value.rs:67:17
/// | inside `INVALID_HEADER` at src/main.rs:73:33
/// |
/// ::: src/main.rs:73:1
/// |
/// 73 | const INVALID_HEADER: HeaderValue = HeaderValue::from_static("жsome value");
/// | ----------------------------------------------------------------------------
/// ```
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_static("hello");
/// assert_eq!(val, "hello");
/// ```
#[inline]
#[allow(unconditional_panic)] // required for the panic circumvention
pub const fn from_static(src: &'static str) -> HeaderValue {
let bytes = src.as_bytes();
let mut i = 0;
while i < bytes.len() {
if !is_visible_ascii(bytes[i]) {
([] as [u8; 0])[0]; // Invalid header value
}
i += 1;
}
HeaderValue {
inner: Bytes::from_static(bytes),
is_sensitive: false,
}
}
/// Attempt to convert a string to a `HeaderValue`.
///
/// If the argument contains invalid header value characters, an error is
/// returned. Only visible ASCII characters (32-127) are permitted. Use
/// `from_bytes` to create a `HeaderValue` that includes opaque octets
/// (128-255).
///
/// This function is intended to be replaced in the future by a `TryFrom`
/// implementation once the trait is stabilized in std.
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_str("hello").unwrap();
/// assert_eq!(val, "hello");
/// ```
///
/// An invalid value
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_str("\n");
/// assert!(val.is_err());
/// ```
#[inline]
pub fn from_str(src: &str) -> Result<HeaderValue, InvalidHeaderValue> {
HeaderValue::try_from_generic(src, |s| Bytes::copy_from_slice(s.as_bytes()))
}
/// Converts a HeaderName into a HeaderValue
///
/// Since every valid HeaderName is a valid HeaderValue this is done infallibly.
///
/// # Examples
///
/// ```
/// # use http::header::{HeaderValue, HeaderName};
/// # use http::header::ACCEPT;
/// let val = HeaderValue::from_name(ACCEPT);
/// assert_eq!(val, HeaderValue::from_bytes(b"accept").unwrap());
/// ```
#[inline]
pub fn from_name(name: HeaderName) -> HeaderValue {
name.into()
}
/// Attempt to convert a byte slice to a `HeaderValue`.
///
/// If the argument contains invalid header value bytes, an error is
/// returned. Only byte values between 32 and 255 (inclusive) are permitted,
/// excluding byte 127 (DEL).
///
/// This function is intended to be replaced in the future by a `TryFrom`
/// implementation once the trait is stabilized in std.
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_bytes(b"hello\xfa").unwrap();
/// assert_eq!(val, &b"hello\xfa"[..]);
/// ```
///
/// An invalid value
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_bytes(b"\n");
/// assert!(val.is_err());
/// ```
#[inline]
pub fn from_bytes(src: &[u8]) -> Result<HeaderValue, InvalidHeaderValue> {
HeaderValue::try_from_generic(src, Bytes::copy_from_slice)
}
/// Attempt to convert a `Bytes` buffer to a `HeaderValue`.
///
/// This will try to prevent a copy if the type passed is the type used
/// internally, and will copy the data if it is not.
pub fn from_maybe_shared<T>(src: T) -> Result<HeaderValue, InvalidHeaderValue>
where
T: AsRef<[u8]> + 'static,
{
if_downcast_into!(T, Bytes, src, {
return HeaderValue::from_shared(src);
});
HeaderValue::from_bytes(src.as_ref())
}
/// Convert a `Bytes` directly into a `HeaderValue` without validating.
///
/// This function does NOT validate that illegal bytes are not contained
/// within the buffer.
pub unsafe fn from_maybe_shared_unchecked<T>(src: T) -> HeaderValue
where
T: AsRef<[u8]> + 'static,
{
if cfg!(debug_assertions) {
match HeaderValue::from_maybe_shared(src) {
Ok(val) => val,
Err(_err) => {
panic!("HeaderValue::from_maybe_shared_unchecked() with invalid bytes");
}
}
} else {
if_downcast_into!(T, Bytes, src, {
return HeaderValue {
inner: src,
is_sensitive: false,
};
});
let src = Bytes::copy_from_slice(src.as_ref());
HeaderValue {
inner: src,
is_sensitive: false,
}
}
}
fn from_shared(src: Bytes) -> Result<HeaderValue, InvalidHeaderValue> {
HeaderValue::try_from_generic(src, std::convert::identity)
}
fn try_from_generic<T: AsRef<[u8]>, F: FnOnce(T) -> Bytes>(src: T, into: F) -> Result<HeaderValue, InvalidHeaderValue> {
for &b in src.as_ref() {
if !is_valid(b) {
return Err(InvalidHeaderValue { _priv: () });
}
}
Ok(HeaderValue {
inner: into(src),
is_sensitive: false,
})
}
/// Yields a `&str` slice if the `HeaderValue` only contains visible ASCII
/// chars.
///
/// This function will perform a scan of the header value, checking all the
/// characters.
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_static("hello");
/// assert_eq!(val.to_str().unwrap(), "hello");
/// ```
pub fn to_str(&self) -> Result<&str, ToStrError> {
let bytes = self.as_ref();
for &b in bytes {
if !is_visible_ascii(b) {
return Err(ToStrError { _priv: () });
}
}
unsafe { Ok(str::from_utf8_unchecked(bytes)) }
}
/// Returns the length of `self`.
///
/// This length is in bytes.
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_static("hello");
/// assert_eq!(val.len(), 5);
/// ```
#[inline]
pub fn len(&self) -> usize {
self.as_ref().len()
}
/// Returns true if the `HeaderValue` has a length of zero bytes.
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_static("");
/// assert!(val.is_empty());
///
/// let val = HeaderValue::from_static("hello");
/// assert!(!val.is_empty());
/// ```
#[inline]
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Converts a `HeaderValue` to a byte slice.
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let val = HeaderValue::from_static("hello");
/// assert_eq!(val.as_bytes(), b"hello");
/// ```
#[inline]
pub fn as_bytes(&self) -> &[u8] {
self.as_ref()
}
/// Mark that the header value represents sensitive information.
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let mut val = HeaderValue::from_static("my secret");
///
/// val.set_sensitive(true);
/// assert!(val.is_sensitive());
///
/// val.set_sensitive(false);
/// assert!(!val.is_sensitive());
/// ```
#[inline]
pub fn set_sensitive(&mut self, val: bool) {
self.is_sensitive = val;
}
/// Returns `true` if the value represents sensitive data.
///
/// Sensitive data could represent passwords or other data that should not
/// be stored on disk or in memory. By marking header values as sensitive,
/// components using this crate can be instructed to treat them with special
/// care for security reasons. For example, caches can avoid storing
/// sensitive values, and HPACK encoders used by HTTP/2.0 implementations
/// can choose not to compress them.
///
/// Additionally, sensitive values will be masked by the `Debug`
/// implementation of `HeaderValue`.
///
/// Note that sensitivity is not factored into equality or ordering.
///
/// # Examples
///
/// ```
/// # use http::header::HeaderValue;
/// let mut val = HeaderValue::from_static("my secret");
///
/// val.set_sensitive(true);
/// assert!(val.is_sensitive());
///
/// val.set_sensitive(false);
/// assert!(!val.is_sensitive());
/// ```
#[inline]
pub fn is_sensitive(&self) -> bool {
self.is_sensitive
}
}
impl AsRef<[u8]> for HeaderValue {
#[inline]
fn as_ref(&self) -> &[u8] {
self.inner.as_ref()
}
}
impl fmt::Debug for HeaderValue {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if self.is_sensitive {
f.write_str("Sensitive")
} else {
f.write_str("\"")?;
let mut from = 0;
let bytes = self.as_bytes();
for (i, &b) in bytes.iter().enumerate() {
if !is_visible_ascii(b) || b == b'"' {
if from != i {
f.write_str(unsafe { str::from_utf8_unchecked(&bytes[from..i]) })?;
}
if b == b'"' {
f.write_str("\\\"")?;
} else {
write!(f, "\\x{:x}", b)?;
}
from = i + 1;
}
}
f.write_str(unsafe { str::from_utf8_unchecked(&bytes[from..]) })?;
f.write_str("\"")
}
}
}
impl From<HeaderName> for HeaderValue {
#[inline]
fn from(h: HeaderName) -> HeaderValue {
HeaderValue {
inner: h.into_bytes(),
is_sensitive: false,
}
}
}
macro_rules! from_integers {
($($name:ident: $t:ident => $max_len:expr),*) => {$(
impl From<$t> for HeaderValue {
fn from(num: $t) -> HeaderValue {
let mut buf = if mem::size_of::<BytesMut>() - 1 < $max_len {
// On 32bit platforms, BytesMut max inline size
// is 15 bytes, but the $max_len could be bigger.
//
// The likelihood of the number *actually* being
// that big is very small, so only allocate
// if the number needs that space.
//
// The largest decimal number in 15 digits:
// It wold be 10.pow(15) - 1, but this is a constant
// version.
if num as u64 > 999_999_999_999_999_999 {
BytesMut::with_capacity($max_len)
} else {
// fits inline...
BytesMut::new()
}
} else {
// full value fits inline, so don't allocate!
BytesMut::new()
};
let _ = buf.write_str(::itoa::Buffer::new().format(num));
HeaderValue {
inner: buf.freeze(),
is_sensitive: false,
}
}
}
#[test]
fn $name() {
let n: $t = 55;
let val = HeaderValue::from(n);
assert_eq!(val, &n.to_string());
let n = ::std::$t::MAX;
let val = HeaderValue::from(n);
assert_eq!(val, &n.to_string());
}
)*};
}
from_integers! {
// integer type => maximum decimal length
// u8 purposely left off... HeaderValue::from(b'3') could be confusing
from_u16: u16 => 5,
from_i16: i16 => 6,
from_u32: u32 => 10,
from_i32: i32 => 11,
from_u64: u64 => 20,
from_i64: i64 => 20
}
#[cfg(target_pointer_width = "16")]
from_integers! {
from_usize: usize => 5,
from_isize: isize => 6
}
#[cfg(target_pointer_width = "32")]
from_integers! {
from_usize: usize => 10,
from_isize: isize => 11
}
#[cfg(target_pointer_width = "64")]
from_integers! {
from_usize: usize => 20,
from_isize: isize => 20
}
#[cfg(test)]
mod from_header_name_tests {
use super::*;
use crate::header::map::HeaderMap;
use crate::header::name;
#[test]
fn it_can_insert_header_name_as_header_value() {
let mut map = HeaderMap::new();
map.insert(name::UPGRADE, name::SEC_WEBSOCKET_PROTOCOL.into());
map.insert(
name::ACCEPT,
name::HeaderName::from_bytes(b"hello-world").unwrap().into(),
);
assert_eq!(
map.get(name::UPGRADE).unwrap(),
HeaderValue::from_bytes(b"sec-websocket-protocol").unwrap()
);
assert_eq!(
map.get(name::ACCEPT).unwrap(),
HeaderValue::from_bytes(b"hello-world").unwrap()
);
}
}
impl FromStr for HeaderValue {
type Err = InvalidHeaderValue;
#[inline]
fn from_str(s: &str) -> Result<HeaderValue, Self::Err> {
HeaderValue::from_str(s)
}
}
impl<'a> From<&'a HeaderValue> for HeaderValue {
#[inline]
fn from(t: &'a HeaderValue) -> Self {
t.clone()
}
}
impl<'a> TryFrom<&'a str> for HeaderValue {
type Error = InvalidHeaderValue;
#[inline]
fn try_from(t: &'a str) -> Result<Self, Self::Error> {
t.parse()
}
}
impl<'a> TryFrom<&'a String> for HeaderValue {
type Error = InvalidHeaderValue;
#[inline]
fn try_from(s: &'a String) -> Result<Self, Self::Error> {
Self::from_bytes(s.as_bytes())
}
}
impl<'a> TryFrom<&'a [u8]> for HeaderValue {
type Error = InvalidHeaderValue;
#[inline]
fn try_from(t: &'a [u8]) -> Result<Self, Self::Error> {
HeaderValue::from_bytes(t)
}
}
impl TryFrom<String> for HeaderValue {
type Error = InvalidHeaderValue;
#[inline]
fn try_from(t: String) -> Result<Self, Self::Error> {
HeaderValue::from_shared(t.into())
}
}
impl TryFrom<Vec<u8>> for HeaderValue {
type Error = InvalidHeaderValue;
#[inline]
fn try_from(vec: Vec<u8>) -> Result<Self, Self::Error> {
HeaderValue::from_shared(vec.into())
}
}
#[cfg(test)]
mod try_from_header_name_tests {
use super::*;
use crate::header::name;
#[test]
fn it_converts_using_try_from() {
assert_eq!(
HeaderValue::try_from(name::UPGRADE).unwrap(),
HeaderValue::from_bytes(b"upgrade").unwrap()
);
}
}
const fn is_visible_ascii(b: u8) -> bool {
b >= 32 && b < 127 || b == b'\t'
}
#[inline]
fn is_valid(b: u8) -> bool {
b >= 32 && b != 127 || b == b'\t'
}
impl fmt::Debug for InvalidHeaderValue {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("InvalidHeaderValue")
// skip _priv noise
.finish()
}
}
impl fmt::Display for InvalidHeaderValue {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("failed to parse header value")
}
}
impl Error for InvalidHeaderValue {}
impl fmt::Display for ToStrError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("failed to convert header to a str")
}
}
impl Error for ToStrError {}
// ===== PartialEq / PartialOrd =====
impl PartialEq for HeaderValue {
#[inline]
fn eq(&self, other: &HeaderValue) -> bool {
self.inner == other.inner
}
}
impl Eq for HeaderValue {}
impl PartialOrd for HeaderValue {
#[inline]
fn partial_cmp(&self, other: &HeaderValue) -> Option<cmp::Ordering> {
self.inner.partial_cmp(&other.inner)
}
}
impl Ord for HeaderValue {
#[inline]
fn cmp(&self, other: &Self) -> cmp::Ordering {
self.inner.cmp(&other.inner)
}
}
impl PartialEq<str> for HeaderValue {
#[inline]
fn eq(&self, other: &str) -> bool {
self.inner == other.as_bytes()
}
}
impl PartialEq<[u8]> for HeaderValue {
#[inline]
fn eq(&self, other: &[u8]) -> bool {
self.inner == other
}
}
impl PartialOrd<str> for HeaderValue {
#[inline]
fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
(*self.inner).partial_cmp(other.as_bytes())
}
}
impl PartialOrd<[u8]> for HeaderValue {
#[inline]
fn partial_cmp(&self, other: &[u8]) -> Option<cmp::Ordering> {
(*self.inner).partial_cmp(other)
}
}
impl PartialEq<HeaderValue> for str {
#[inline]
fn eq(&self, other: &HeaderValue) -> bool {
*other == *self
}
}
impl PartialEq<HeaderValue> for [u8] {
#[inline]
fn eq(&self, other: &HeaderValue) -> bool {
*other == *self
}
}
impl PartialOrd<HeaderValue> for str {
#[inline]
fn partial_cmp(&self, other: &HeaderValue) -> Option<cmp::Ordering> {
self.as_bytes().partial_cmp(other.as_bytes())
}
}
impl PartialOrd<HeaderValue> for [u8] {
#[inline]
fn partial_cmp(&self, other: &HeaderValue) -> Option<cmp::Ordering> {
self.partial_cmp(other.as_bytes())
}
}
impl PartialEq<String> for HeaderValue {
#[inline]
fn eq(&self, other: &String) -> bool {
*self == &other[..]
}
}
impl PartialOrd<String> for HeaderValue {
#[inline]
fn partial_cmp(&self, other: &String) -> Option<cmp::Ordering> {
self.inner.partial_cmp(other.as_bytes())
}
}
impl PartialEq<HeaderValue> for String {
#[inline]
fn eq(&self, other: &HeaderValue) -> bool {
*other == *self
}
}
impl PartialOrd<HeaderValue> for String {
#[inline]
fn partial_cmp(&self, other: &HeaderValue) -> Option<cmp::Ordering> {
self.as_bytes().partial_cmp(other.as_bytes())
}
}
impl<'a> PartialEq<HeaderValue> for &'a HeaderValue {
#[inline]
fn eq(&self, other: &HeaderValue) -> bool {
**self == *other
}
}
impl<'a> PartialOrd<HeaderValue> for &'a HeaderValue {
#[inline]
fn partial_cmp(&self, other: &HeaderValue) -> Option<cmp::Ordering> {
(**self).partial_cmp(other)
}
}
impl<'a, T: ?Sized> PartialEq<&'a T> for HeaderValue
where
HeaderValue: PartialEq<T>,
{
#[inline]
fn eq(&self, other: &&'a T) -> bool {
*self == **other
}
}
impl<'a, T: ?Sized> PartialOrd<&'a T> for HeaderValue
where
HeaderValue: PartialOrd<T>,
{
#[inline]
fn partial_cmp(&self, other: &&'a T) -> Option<cmp::Ordering> {
self.partial_cmp(*other)
}
}
impl<'a> PartialEq<HeaderValue> for &'a str {
#[inline]
fn eq(&self, other: &HeaderValue) -> bool {
*other == *self
}
}
impl<'a> PartialOrd<HeaderValue> for &'a str {
#[inline]
fn partial_cmp(&self, other: &HeaderValue) -> Option<cmp::Ordering> {
self.as_bytes().partial_cmp(other.as_bytes())
}
}
#[test]
fn test_try_from() {
HeaderValue::try_from(vec![127]).unwrap_err();
}
#[test]
fn test_debug() {
let cases = &[
("hello", "\"hello\""),
("hello \"world\"", "\"hello \\\"world\\\"\""),
("\u{7FFF}hello", "\"\\xe7\\xbf\\xbfhello\""),
];
for &(value, expected) in cases {
let val = HeaderValue::from_bytes(value.as_bytes()).unwrap();
let actual = format!("{:?}", val);
assert_eq!(expected, actual);
}
let mut sensitive = HeaderValue::from_static("password");
sensitive.set_sensitive(true);
assert_eq!("Sensitive", format!("{:?}", sensitive));
}