Struct HeaderValue 

pub struct HeaderValue { /* private fields */ }

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. to_str returns an error if the value is not valid UTF-8.

Implementations

impl HeaderValue

pub const fn from_static(src: &'static str) -> 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 HTAB and visible ASCII characters (32-126) are permitted.

Panics

This function panics if the argument contains invalid header value characters.

Examples

let val = HeaderValue::from_static("hello");
assert_eq!(val, "hello");

pub fn from_str(src: &str) -> Result<HeaderValue, InvalidHeaderValue>

Attempt to convert a string to a HeaderValue.

If the argument contains invalid header value characters, an error is returned. The same bytes as in from_bytes are permitted, so non-ASCII characters are accepted.

Examples

let val = HeaderValue::from_str("hello").unwrap();
assert_eq!(val, "hello");

let val = HeaderValue::from_str("caf\u{e9}").unwrap();
assert_eq!(val.to_str().unwrap(), "caf\u{e9}");

An invalid value

let val = HeaderValue::from_str("\n");
assert!(val.is_err());

pub fn from_bytes(src: &[u8]) -> Result<HeaderValue, InvalidHeaderValue>

Attempt to convert a byte slice to a HeaderValue.

If the argument contains invalid header value bytes, an error is returned. Only HTAB and byte values between 32 and 255 (inclusive) are permitted, excluding byte 127 (DEL).

Examples

let val = HeaderValue::from_bytes(b"hello\xfa").unwrap();
assert_eq!(val, &b"hello\xfa"[..]);

An invalid value

let val = HeaderValue::from_bytes(b"\n");
assert!(val.is_err());

pub fn from_shared<T>(src: T) -> Result<HeaderValue, InvalidHeaderValue>

where Bytes: From<T>,

Attempt to convert a Bytes buffer to a HeaderValue.

The conversion avoids copying when src can be converted into the internal Bytes representation without allocation. The same bytes as in from_bytes are permitted.

pub unsafe fn from_shared_unchecked(src: Bytes) -> HeaderValue

Creates a header value from bytes without validation.

Safety

src must contain only bytes allowed in an HTTP header field value: HTAB and bytes 32 through 255, excluding 127.

pub fn to_str(&self) -> Result<&str, ToStrError>

Yields a &str slice if the HeaderValue is valid UTF-8.

This function validates the whole header value as UTF-8.

Examples

let val = HeaderValue::from_static("hello");
assert_eq!(val.to_str().unwrap(), "hello");

let val = HeaderValue::from_bytes(b"caf\xe9").unwrap();
assert!(val.to_str().is_err());

pub fn len(&self) -> usize

Returns the length of self.

This length is in bytes.

Examples

let val = HeaderValue::from_static("hello");
assert_eq!(val.len(), 5);

pub fn is_empty(&self) -> bool

Returns true if the header value is empty.

Examples

let val = HeaderValue::from_static("");
assert!(val.is_empty());

let val = HeaderValue::from_static("hello");
assert!(!val.is_empty());

pub fn as_bytes(&self) -> &[u8]

Returns the header value as a byte slice.

Examples

let val = HeaderValue::from_static("hello");
assert_eq!(val.as_bytes(), b"hello");

pub fn as_shared(&self) -> &Bytes

Returns the underlying shared byte buffer.

Examples

let val = HeaderValue::from_static("hello");
assert_eq!(val.as_shared(), &Bytes::from_static(b"hello"));

pub fn set_sensitive(&mut self, val: bool)

Marks whether the header value contains sensitive information.

Examples

let mut val = HeaderValue::from_static("my secret");

val.set_sensitive(true);
assert!(val.is_sensitive());

val.set_sensitive(false);
assert!(!val.is_sensitive());

pub fn is_sensitive(&self) -> bool

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

let mut val = HeaderValue::from_static("my secret");

val.set_sensitive(true);
assert!(val.is_sensitive());

val.set_sensitive(false);
assert!(!val.is_sensitive());

Trait Implementations

impl AsRef<[u8]> for HeaderValue

fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for HeaderValue

fn clone(&self) -> HeaderValue

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HeaderValue

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for HeaderValue

fn deserialize<D>( deserializer: D, ) -> Result<HeaderValue, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for HeaderValue

impl Extend<HeaderValue> for Value

fn extend<T>(&mut self, iter: T)

where T: IntoIterator<Item = HeaderValue>,

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<'a> From<&'a HeaderValue> for Value

fn from(hdr: &'a HeaderValue) -> Value

Converts to this type from the input type.

impl<'a> From<&'a HeaderValue> for HeaderValue

fn from(t: &'a HeaderValue) -> HeaderValue

Converts to this type from the input type.

impl<'a> From<&'a HeaderValue> for HeaderValue

fn from(t: &'a HeaderValue) -> HeaderValue

Converts to this type from the input type.

impl From<HeaderValue> for Value

fn from(hdr: HeaderValue) -> Value

Converts to this type from the input type.

impl From<HeaderValue> for HeaderValue

fn from(t: HeaderValue) -> HeaderValue

Converts to this type from the input type.

impl From<i16> for HeaderValue

fn from(num: i16) -> HeaderValue

Converts to this type from the input type.

impl From<i32> for HeaderValue

fn from(num: i32) -> HeaderValue

Converts to this type from the input type.

impl From<i64> for HeaderValue

fn from(num: i64) -> HeaderValue

Converts to this type from the input type.

impl From<isize> for HeaderValue

fn from(num: isize) -> HeaderValue

Converts to this type from the input type.

impl From<u16> for HeaderValue

fn from(num: u16) -> HeaderValue

Converts to this type from the input type.

impl From<u32> for HeaderValue

fn from(num: u32) -> HeaderValue

Converts to this type from the input type.

impl From<u64> for HeaderValue

fn from(num: u64) -> HeaderValue

Converts to this type from the input type.

impl From<usize> for HeaderValue

fn from(num: usize) -> HeaderValue

Converts to this type from the input type.

impl FromStr for HeaderValue

type Err = InvalidHeaderValue

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<HeaderValue, <HeaderValue as FromStr>::Err>

Parses a string s to return a value of this type.

impl Hash for HeaderValue

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for HeaderValue

fn cmp(&self, other: &HeaderValue) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for HeaderValue

fn eq(&self, other: &HeaderValue) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<'a, T> PartialEq<&'a T> for HeaderValue

where HeaderValue: PartialEq<T>, T: ?Sized,

fn eq(&self, other: &&'a T) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialEq<HeaderValue> for &HeaderValue

fn eq(&self, other: &HeaderValue) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialEq<String> for HeaderValue

fn eq(&self, other: &String) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialEq<[u8]> for HeaderValue

fn eq(&self, other: &[u8]) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialEq<str> for HeaderValue

fn eq(&self, other: &str) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for HeaderValue

fn partial_cmp(&self, other: &HeaderValue) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a, T> PartialOrd<&'a T> for HeaderValue

where HeaderValue: PartialOrd<T>, T: ?Sized,

fn partial_cmp(&self, other: &&'a T) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<HeaderValue> for &HeaderValue

fn partial_cmp(&self, other: &HeaderValue) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<String> for HeaderValue

fn partial_cmp(&self, other: &String) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<[u8]> for HeaderValue

fn partial_cmp(&self, other: &[u8]) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl PartialOrd<str> for HeaderValue

fn partial_cmp(&self, other: &str) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for HeaderValue

fn serialize<S>( &self, serializer: S, ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<'a> TryFrom<&'a ByteString> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( s: &'a ByteString, ) -> Result<HeaderValue, <HeaderValue as TryFrom<&'a ByteString>>::Error>

Performs the conversion.

impl<'a> TryFrom<&'a String> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( s: &'a String, ) -> Result<HeaderValue, <HeaderValue as TryFrom<&'a String>>::Error>

Performs the conversion.

impl<'a> TryFrom<&'a [u8]> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( t: &'a [u8], ) -> Result<HeaderValue, <HeaderValue as TryFrom<&'a [u8]>>::Error>

Performs the conversion.

impl<'a> TryFrom<&'a str> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( t: &'a str, ) -> Result<HeaderValue, <HeaderValue as TryFrom<&'a str>>::Error>

Performs the conversion.

impl TryFrom<ByteString> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( s: ByteString, ) -> Result<HeaderValue, <HeaderValue as TryFrom<ByteString>>::Error>

Performs the conversion.

impl TryFrom<Bytes> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( bytes: Bytes, ) -> Result<HeaderValue, <HeaderValue as TryFrom<Bytes>>::Error>

Performs the conversion.

impl TryFrom<BytesMut> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( bytes: BytesMut, ) -> Result<HeaderValue, <HeaderValue as TryFrom<BytesMut>>::Error>

Performs the conversion.

impl TryFrom<String> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( s: String, ) -> Result<HeaderValue, <HeaderValue as TryFrom<String>>::Error>

Performs the conversion.

impl TryFrom<Vec<u8>> for HeaderValue

type Error = InvalidHeaderValue

The type returned in the event of a conversion error.

fn try_from( vec: Vec<u8>, ) -> Result<HeaderValue, <HeaderValue as TryFrom<Vec<u8>>>::Error>

Performs the conversion.