//! Copied from https://github.com/felipenoris/hyper-reverse-proxy
//! See there for original Copyright notice
use anyhow::Result;
use log::*;
use std::convert::TryInto;
use http::header::HeaderName;
use hyper::header::{HeaderMap, HeaderValue};
use hyper::{Body, Client, Request, Response, Uri};
use lazy_static::lazy_static;
use std::net::IpAddr;
use std::str::FromStr;
fn is_hop_header(name: &str) -> bool {
use unicase::Ascii;
// A list of the headers, using `unicase` to help us compare without
// worrying about the case, and `lazy_static!` to prevent reallocation
// of the vector.
lazy_static! {
static ref HOP_HEADERS: Vec<Ascii<&'static str>> = vec![
Ascii::new("Connection"),
Ascii::new("Keep-Alive"),
Ascii::new("Proxy-Authenticate"),
Ascii::new("Proxy-Authorization"),
Ascii::new("Te"),
Ascii::new("Trailers"),
Ascii::new("Transfer-Encoding"),
Ascii::new("Upgrade"),
];
}
HOP_HEADERS.iter().any(|h| h == &name)
}
/// Returns a clone of the headers without the [hop-by-hop headers].
///
/// [hop-by-hop headers]: http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
fn remove_hop_headers(headers: &HeaderMap<HeaderValue>) -> HeaderMap<HeaderValue> {
let mut result = HeaderMap::new();
for (k, v) in headers.iter() {
if !is_hop_header(k.as_str()) {
result.insert(k.clone(), v.clone());
}
}
result
}
fn create_proxied_response<B>(mut response: Response<B>) -> Response<B> {
*response.headers_mut() = remove_hop_headers(response.headers());
response
}
fn forward_uri<B>(forward_url: &str, req: &Request<B>) -> Result<Uri> {
let forward_uri = match req.uri().query() {
Some(query) => format!("{}{}?{}", forward_url, req.uri().path(), query),
None => format!("{}{}", forward_url, req.uri().path()),
};
Ok(Uri::from_str(forward_uri.as_str())?)
}
fn create_proxied_request<B>(
client_ip: IpAddr,
forward_url: &str,
request: Request<B>,
) -> Result<Request<B>> {
let mut builder = Request::builder()
.method(request.method())
.uri(forward_uri(forward_url, &request)?);
*builder.headers_mut().unwrap() = remove_hop_headers(request.headers());
// If request does not have host header, add it from original URI authority
let host_header_name = "host";
if let Some(authority) = request.uri().authority() {
if let hyper::header::Entry::Vacant(entry) =
builder.headers_mut().unwrap().entry(host_header_name)
{
entry.insert(authority.as_str().parse()?);
}
}
// Add forwarding information in the headers
let x_forwarded_for_header_name = "x-forwarded-for";
match builder
.headers_mut()
.unwrap()
.entry(x_forwarded_for_header_name)
{
hyper::header::Entry::Vacant(entry) => {
entry.insert(client_ip.to_string().parse()?);
}
hyper::header::Entry::Occupied(mut entry) => {
let addr = format!("{}, {}", entry.get().to_str()?, client_ip);
entry.insert(addr.parse()?);
}
}
builder.headers_mut().unwrap().insert(HeaderName::from_bytes(b"x-forwarded-proto")?, "https".try_into()?);
if let Some(conn) = request.headers().get("connection") {
if conn.to_str()?.to_lowercase() == "upgrade" {
if let Some(upgrade) = request.headers().get("upgrade") {
builder.headers_mut().unwrap().insert(
HeaderName::from_bytes(b"connection")?,
"Upgrade".try_into()?,
);
builder
.headers_mut()
.unwrap()
.insert(HeaderName::from_bytes(b"upgrade")?, upgrade.clone());
}
}
}
Ok(builder.body(request.into_body())?)
}
pub async fn call(
client_ip: IpAddr,
forward_uri: &str,
request: Request<Body>,
) -> Result<Response<Body>> {
let proxied_request = create_proxied_request(client_ip, &forward_uri, request)?;
trace!("Proxied request: {:?}", proxied_request);
let client = Client::new();
let response = client.request(proxied_request).await?;
trace!("Inner response: {:?}", response);
let proxied_response = create_proxied_response(response);
Ok(proxied_response)
}
