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use crate::{error::*, Accept, MediaType};
use http::StatusCode;
use mime::Mime;
use std::{cmp::Ordering, str::FromStr};
impl Accept {
pub fn negotiate(&self, available: &[Mime]) -> Result<Mime, StatusCode> {
for media_type in &self.types {
if available.contains(&media_type.mime) {
return Ok(media_type.mime.clone());
}
}
if self.wildcard.is_some() {
if let Some(accept) = available.iter().next() {
return Ok(accept.clone());
}
}
Err(StatusCode::NOT_ACCEPTABLE)
}
}
impl FromStr for Accept {
type Err = Error;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let mut types = Vec::new();
let mut wildcard = None;
for part in s.split(',') {
let mtype: MediaType = part.trim().parse()?;
if mtype.mime.type_() == mime::STAR {
wildcard = Some(mtype);
} else {
types.push(mtype);
}
}
if let Some(w) = wildcard.as_ref() {
for mtype in &mut types {
if mtype.weight.is_none() {
mtype.weight = w.weight;
}
}
}
types.sort_by(|a, b| b.partial_cmp(a).unwrap_or(Ordering::Equal));
Ok(Accept { wildcard, types })
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn accept_should_be_parsed_and_sorted() {
let accept = "application/json, text/html;q=0.9, text/plain;q=0.8, */*;q=0.7, */*;q=0.6"
.parse::<Accept>()
.unwrap();
assert_eq!(
accept.wildcard,
Some(MediaType::from_str("*/*; q=0.6").unwrap())
);
assert_eq!(accept.types.len(), 3);
assert_eq!(accept.types[0].mime, Mime::from_str("text/html").unwrap());
assert_eq!(accept.types[0].weight, Some(0.9));
assert_eq!(accept.types[1].mime, Mime::from_str("text/plain").unwrap());
assert_eq!(accept.types[1].weight, Some(0.8));
assert_eq!(
accept.types[2].mime,
Mime::from_str("application/json").unwrap()
);
assert_eq!(accept.types[2].weight, Some(0.6));
}
#[test]
fn content_negotiation_should_work() {
let accept = "application/json, text/html;q=0.9, text/plain;q=0.8, */*;q=0.7"
.parse::<Accept>()
.unwrap();
let available = vec![
Mime::from_str("text/html").unwrap(),
Mime::from_str("application/json").unwrap(),
];
let negotiated = accept.negotiate(&available).unwrap();
assert_eq!(negotiated, Mime::from_str("text/html").unwrap());
let available = vec![Mime::from_str("application/xml").unwrap()];
let negotiated = accept.negotiate(&available).unwrap();
assert_eq!(negotiated, Mime::from_str("application/xml").unwrap());
}
#[test]
fn content_negotiation_should_fail_if_no_available() {
let accept = "application/json,text/html;q=0.9,text/plain;q=0.8"
.parse::<Accept>()
.unwrap();
let available = vec![Mime::from_str("application/xml").unwrap()];
let negotiated = accept.negotiate(&available);
assert_eq!(negotiated, Err(StatusCode::NOT_ACCEPTABLE));
}
}