Module rama::http::headers

Expand description

typed http headers

rama has the opinion that headers should be strongly-typed, because that’s why we’re using Rust in the first place. To set or get any header, an object must implement the Header trait from this module. Several common headers are already provided, such as Host, ContentType, UserAgent, and others.

§Why typed?

Or, why not stringly-typed? Types give the following advantages:

  • More difficult to typo, since typos in types should be caught by the compiler
  • Parsing to a proper type by default

§Defining Custom Headers

§Implementing the Header trait

Consider a Do Not Track header. It can be true or false, but it represents that via the numerals 1 and 0.

use rama_http::{headers::Header, HeaderName, HeaderValue};

struct Dnt(bool);

impl Header for Dnt {
    fn name() -> &'static HeaderName {
         &http::header::DNT
    }

    fn decode<'i, I>(values: &mut I) -> Result<Self, headers::Error>
    where
        I: Iterator<Item = &'i HeaderValue>,
    {
        let value = values
            .next()
            .ok_or_else(headers::Error::invalid)?;

        if value == "0" {
            Ok(Dnt(false))
        } else if value == "1" {
            Ok(Dnt(true))
        } else {
            Err(headers::Error::invalid())
        }
    }

    fn encode<E>(&self, values: &mut E)
    where
        E: Extend<HeaderValue>,
    {
        let s = if self.0 {
            "1"
        } else {
            "0"
        };

        let value = HeaderValue::from_static(s);

        values.extend(std::iter::once(value));
    }
}

Modules§

Structs§

Traits§

  • ForwardHeader
    A trait for types headers that is used by middleware which supports headers that can be converted into and from Forward data.
  • Header
    A trait for any object that will represent a header field and value.
  • HeaderExt
    An external trait adding helper methods to types which implement Header trait.
  • HeaderMapExt
    An extension trait adding “typed” methods to http::HeaderMap.