Struct w5500_hl::Hostname

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pub struct Hostname<'a> { /* private fields */ }

Expand description

A validated hostname.

This is not used within this crate, it is provided here for crates implementing protocols such as DNS and DHCP to use.

Implementations§

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impl<'a> Hostname<'a>

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pub const fn new(hostname: &'a str) -> Option<Self>

Create a new hostname.

This validates the hostname for RFC-1035 compliance:

A hostname is valid if the following condition are true:

It does not start or end with '-' or '.'.
It does not contain any characters outside of the alphanumeric range, except for '-' and '.'.
It is not empty.
It is 253 or fewer characters.
Its labels (characters separated by .) are not empty.
Its labels are 63 or fewer characters.
Its labels do not start or end with '-' or '.'.

Example

use w5500_hl::Hostname;

assert!(Hostname::new("is-valid-example").is_some());
assert!(Hostname::new("this-is-not-?-valid").is_none());

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pub const fn new_unwrapped(hostname: &'a str) -> Self

Create a new hostname, panicking if the hostname is invalid.

Panics

This is the same as new, but it will panic on invalid hostnames.

This should only be used in const contexts where the evaluation will fail at compile time.

Example

use w5500_hl::Hostname;

const MY_HOSTNAME: Hostname = Hostname::new_unwrapped("valid.hostname");

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pub fn labels(&self) -> Split<'a, char>

Returns an iterator over the labels of the hostname.

Example

use core::str::Split;
use w5500_hl::Hostname;

const DOCS_RS: Hostname = Hostname::new_unwrapped("docs.rs");
let mut lables: Split<char> = DOCS_RS.labels();

assert_eq!(lables.next(), Some("docs"));
assert_eq!(lables.next(), Some("rs"));
assert_eq!(lables.next(), None);

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pub fn len(&self) -> u8

Length of the hostname in bytes.

Example

use w5500_hl::Hostname;

const DOCS_RS: Hostname = Hostname::new_unwrapped("docs.rs");

assert_eq!(DOCS_RS.len(), 7);

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pub const unsafe fn new_unchecked(hostname: &'a str) -> Self

Create a new hostname without checking for validity.

Safety

The hostname argument must meet all the conditions for validity described in new.

Example

use w5500_hl::Hostname;

// safety: doc.rs is a valid hostname
const DOCS_RS: Hostname = unsafe { Hostname::new_unchecked("docs.rs") };

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

Converts the hostname to a byte slice.

Example

use w5500_hl::Hostname;

const DOCS_RS: Hostname = Hostname::new_unwrapped("docs.rs");
assert_eq!(DOCS_RS.as_bytes(), [100, 111, 99, 115, 46, 114, 115]);