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use std::convert::TryFrom;
use util::{QualityValue, TryFromValues};
use {ContentCoding, HeaderValue};
/// `Accept-Encoding` header, defined in
/// [RFC7231](https://tools.ietf.org/html/rfc7231#section-5.3.4)
///
/// The `Accept-Encoding` header field can be used by user agents to
/// indicate what response content-codings are acceptable in the response.
/// An "identity" token is used as a synonym for "no encoding" in
/// order to communicate when no encoding is preferred.
///
/// # ABNF
///
/// ```text
/// Accept-Encoding = #( codings [ weight ] )
/// codings = content-coding / "identity" / "*"
/// ```
///
/// # Example Values
///
/// * `gzip`
/// * `br;q=1.0, gzip;q=0.8`
///
#[derive(Clone, Debug)]
pub struct AcceptEncoding(pub QualityValue);
derive_header! {
AcceptEncoding(_),
name: ACCEPT_ENCODING
}
impl AcceptEncoding {
/// Convience method to create an `Accept-Encoding: gzip` header
#[inline]
pub fn gzip() -> AcceptEncoding {
AcceptEncoding(HeaderValue::from_static("gzip").into())
}
/// A convience method to create an Accept-Encoding header from pairs of values and qualities
///
/// # Example
///
/// ```
/// use headers::AcceptEncoding;
///
/// let pairs = vec![("gzip", 1.0), ("deflate", 0.8)];
/// let header = AcceptEncoding::from_quality_pairs(&mut pairs.into_iter());
/// ```
pub fn from_quality_pairs<'i, I>(pairs: &mut I) -> Result<AcceptEncoding, ::Error>
where
I: Iterator<Item = (&'i str, f32)>,
{
let values: Vec<HeaderValue> = pairs
.map(|pair| {
QualityValue::try_from(pair).map(|qual: QualityValue| HeaderValue::from(qual))
})
.collect::<Result<Vec<HeaderValue>, ::Error>>()?;
let value = QualityValue::try_from_values(&mut values.iter())?;
Ok(AcceptEncoding(value))
}
/// Returns the most prefered encoding that is specified by the header,
/// if one is specified.
///
/// Note: This peeks at the underlying iter, not modifying it.
///
/// # Example
///
/// ```
/// use headers::{AcceptEncoding, ContentCoding};
///
/// let pairs = vec![("gzip", 1.0), ("deflate", 0.8)];
/// let accept_enc = AcceptEncoding::from_quality_pairs(&mut pairs.into_iter()).unwrap();
/// let mut encodings = accept_enc.sorted_encodings();
///
/// assert_eq!(accept_enc.prefered_encoding(), Some(ContentCoding::GZIP));
/// ```
pub fn prefered_encoding(&self) -> Option<ContentCoding> {
self.0
.iter()
.peekable()
.peek()
.map(|s| ContentCoding::from_str(*s))
}
/// Returns a quality sorted iterator of the `ContentCoding`
///
/// # Example
///
/// ```
/// use headers::{AcceptEncoding, ContentCoding, HeaderValue};
///
/// let val = HeaderValue::from_static("deflate, gzip;q=1.0, br;q=0.8");
/// let accept_enc = AcceptEncoding(val.into());
/// let mut encodings = accept_enc.sorted_encodings();
///
/// assert_eq!(encodings.next(), Some(ContentCoding::DEFLATE));
/// assert_eq!(encodings.next(), Some(ContentCoding::GZIP));
/// assert_eq!(encodings.next(), Some(ContentCoding::BROTLI));
/// assert_eq!(encodings.next(), None);
/// ```
pub fn sorted_encodings<'a>(&'a self) -> impl Iterator<Item = ContentCoding> + 'a {
self.0.iter().map(|s| ContentCoding::from_str(s))
}
/// Returns a quality sorted iterator of values
///
/// # Example
///
/// ```
/// use headers::{AcceptEncoding, ContentCoding, HeaderValue};
///
/// let val = HeaderValue::from_static("deflate, gzip;q=1.0, br;q=0.8");
/// let accept_enc = AcceptEncoding(val.into());
/// let mut encodings = accept_enc.sorted_values();
///
/// assert_eq!(encodings.next(), Some("deflate"));
/// assert_eq!(encodings.next(), Some("gzip"));
/// assert_eq!(encodings.next(), Some("br"));
/// assert_eq!(encodings.next(), None);
/// ```
pub fn sorted_values(&self) -> impl Iterator<Item = &str> {
self.0.iter()
}
}
#[cfg(test)]
mod tests {
use super::*;
use {ContentCoding, HeaderValue};
#[test]
fn from_static() {
let val = HeaderValue::from_static("deflate, gzip;q=1.0, br;q=0.9");
let accept_enc = AcceptEncoding(val.into());
assert_eq!(accept_enc.prefered_encoding(), Some(ContentCoding::DEFLATE));
let mut encodings = accept_enc.sorted_encodings();
assert_eq!(encodings.next(), Some(ContentCoding::DEFLATE));
assert_eq!(encodings.next(), Some(ContentCoding::GZIP));
assert_eq!(encodings.next(), Some(ContentCoding::BROTLI));
assert_eq!(encodings.next(), None);
}
#[test]
fn from_pairs() {
let pairs = vec![("gzip", 1.0), ("br", 0.9)];
let accept_enc = AcceptEncoding::from_quality_pairs(&mut pairs.into_iter()).unwrap();
assert_eq!(accept_enc.prefered_encoding(), Some(ContentCoding::GZIP));
let mut encodings = accept_enc.sorted_encodings();
assert_eq!(encodings.next(), Some(ContentCoding::GZIP));
assert_eq!(encodings.next(), Some(ContentCoding::BROTLI));
assert_eq!(encodings.next(), None);
}
}