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use crate::{Error, ErrorKind, HttpError, ProtocolError};
use fnv::FnvHashSet;
use http::header::SEC_WEBSOCKET_PROTOCOL;
use http::{HeaderMap, HeaderValue};
use httparse::Header;
use std::borrow::Cow;
#[derive(Default, Debug, Clone)]
pub struct ProtocolRegistry {
registrants: FnvHashSet<Cow<'static, str>>,
header: Option<HeaderValue>,
}
impl ProtocolRegistry {
pub fn new<I>(i: I) -> Result<ProtocolRegistry, Error>
where
I: IntoIterator,
I::Item: Into<Cow<'static, str>>,
{
let registrants = i
.into_iter()
.map(Into::into)
.collect::<FnvHashSet<Cow<'static, str>>>();
let header_str = registrants
.clone()
.into_iter()
.collect::<Vec<_>>()
.join(", ");
let header = HeaderValue::from_str(&header_str).map_err(|_| {
crate::Error::with_cause(ErrorKind::Http, HttpError::MalformattedHeader(header_str))
})?;
Ok(ProtocolRegistry {
registrants,
header: Some(header),
})
}
}
enum Bias {
Client,
Server,
}
fn negotiate<'h, I>(
registry: &ProtocolRegistry,
headers: I,
bias: Bias,
) -> Result<Option<String>, ProtocolError>
where
I: Iterator<Item = &'h Header<'h>>,
{
for header in headers {
let value =
String::from_utf8(header.value.to_vec()).map_err(|_| ProtocolError::Encoding)?;
let protocols = value
.split(',')
.map(|s| s.trim().into())
.collect::<FnvHashSet<_>>();
let selected = match bias {
Bias::Client => {
if !registry.registrants.is_superset(&protocols) {
return Err(ProtocolError::UnknownProtocol);
}
protocols
.intersection(®istry.registrants)
.next()
.map(|s| s.to_string())
}
Bias::Server => registry
.registrants
.intersection(&protocols)
.next()
.map(|s| s.to_string()),
};
match selected {
Some(selected) => return Ok(Some(selected)),
None => continue,
}
}
Ok(None)
}
pub fn negotiate_response(
registry: &ProtocolRegistry,
response: &httparse::Response,
) -> Result<Option<String>, ProtocolError> {
let it = response
.headers
.iter()
.filter(|h| h.name.eq_ignore_ascii_case(SEC_WEBSOCKET_PROTOCOL.as_str()));
negotiate(registry, it, Bias::Client)
}
pub fn negotiate_request(
registry: &ProtocolRegistry,
request: &httparse::Request,
) -> Result<Option<String>, ProtocolError> {
let it = request
.headers
.iter()
.filter(|h| h.name.eq_ignore_ascii_case(SEC_WEBSOCKET_PROTOCOL.as_str()));
negotiate(registry, it, Bias::Server)
}
pub fn apply_to(registry: &ProtocolRegistry, target: &mut HeaderMap) {
if let Some(header) = ®istry.header {
target.insert(SEC_WEBSOCKET_PROTOCOL, header.clone());
}
}