pub struct HeaderName { /* private fields */ }
Expand description

Represents an HTTP header field name

Header field names identify the header. Header sets may include multiple headers with the same name. The HTTP specification defines a number of standard headers, but HTTP messages may include non-standard header names as well as long as they adhere to the specification.

HeaderName is used as the HeaderMap key. Constants are available for all standard header names in the header module.

Representation

HeaderName represents standard header names using an enum, as such they will not require an allocation for storage. All custom header names are lower cased upon conversion to a HeaderName value. This avoids the overhead of dynamically doing lower case conversion during the hash code computation and the comparison operation.

Implementations

Converts a slice of bytes to an HTTP header name.

This function normalizes the input.

Converts a slice of bytes to an HTTP header name.

This function expects the input to only contain lowercase characters. This is useful when decoding HTTP/2.0 or HTTP/3.0 headers. Both require that all headers be represented in lower case.

Examples

// Parsing a lower case header
let hdr = HeaderName::from_lowercase(b"content-length").unwrap();
assert_eq!(CONTENT_LENGTH, hdr);

// Parsing a header that contains uppercase characters
assert!(HeaderName::from_lowercase(b"Content-Length").is_err());

Converts a static string to a HTTP header name.

This function requires the static string to only contain lowercase characters, numerals and symbols, as per the HTTP/2.0 specification and header names internal representation within this library.

Panics

This function panics when the static string is a invalid header.

Until Allow panicking in constants 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:

error: any use of this value will cause an error
    --> http/src/header/name.rs:1241:13
     |
1241 |             ([] as [u8; 0])[0]; // Invalid header name
     |             ^^^^^^^^^^^^^^^^^^
     |             |
     |             index out of bounds: the length is 0 but the index is 0
     |             inside `http::HeaderName::from_static` at http/src/header/name.rs:1241:13
     |             inside `INVALID_NAME` at src/main.rs:3:34
     |
    ::: src/main.rs:3:1
     |
3    | const INVALID_NAME: HeaderName = HeaderName::from_static("Capitalized");
     | ------------------------------------------------------------------------
Examples
// Parsing a standard header
let hdr = HeaderName::from_static("content-length");
assert_eq!(CONTENT_LENGTH, hdr);

// Parsing a custom header
let CUSTOM_HEADER: &'static str = "custom-header";

let a = HeaderName::from_lowercase(b"custom-header").unwrap();
let b = HeaderName::from_static(CUSTOM_HEADER);
assert_eq!(a, b);
// Parsing a header that contains invalid symbols(s):
HeaderName::from_static("content{}{}length"); // This line panics!

// Parsing a header that contains invalid uppercase characters.
let a = HeaderName::from_static("foobar");
let b = HeaderName::from_static("FOOBAR"); // This line panics!

Returns a str representation of the header.

The returned string will always be lower case.

Trait Implementations

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

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

Immutably borrows from an owned value. Read more

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Formats the value using the given formatter. Read more

Converts to this type from the input type.

Converts to this type from the input type.

The associated error which can be returned from parsing.

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

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Performs a case-insensitive comparison of the string against the header name

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Performs a case-insensitive comparison of the string against the header name

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Performs a case-insensitive comparison of the string against the header name

Examples
use http::header::CONTENT_LENGTH;

assert_eq!(CONTENT_LENGTH, "content-length");
assert_eq!(CONTENT_LENGTH, "Content-Length");
assert_ne!(CONTENT_LENGTH, "content length");

This method tests for !=.

Performs a case-insensitive comparison of the string against the header name

Examples
use http::header::CONTENT_LENGTH;

assert_eq!(CONTENT_LENGTH, "content-length");
assert_eq!(CONTENT_LENGTH, "Content-Length");
assert_ne!(CONTENT_LENGTH, "content length");

This method tests for !=.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

Converts the given value to a String. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more