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use conduit::{header, Body, HeaderMap, Method, RequestExt, Response, StatusCode};
use conduit_middleware::{AfterResult, Middleware};
use std::borrow::Cow;
use time::{OffsetDateTime, ParseError, PrimitiveDateTime};
#[allow(missing_copy_implementations)]
pub struct ConditionalGet;
impl Middleware for ConditionalGet {
fn after(&self, req: &mut dyn RequestExt, res: AfterResult) -> AfterResult {
let res = res?;
match *req.method() {
Method::GET | Method::HEAD => {
if is_ok(&res) && is_fresh(req, &res) {
let (mut parts, _) = res.into_parts();
parts.status = StatusCode::NOT_MODIFIED;
parts.headers.remove(header::CONTENT_TYPE);
parts.headers.remove(header::CONTENT_LENGTH);
return Ok(Response::from_parts(parts, Body::empty()));
}
}
_ => (),
}
Ok(res)
}
}
fn is_ok(response: &Response<Body>) -> bool {
response.status() == 200
}
fn is_fresh(req: &dyn RequestExt, res: &Response<Body>) -> bool {
let modified_since = get_and_concat_header(req.headers(), header::IF_MODIFIED_SINCE);
let none_match = get_and_concat_header(req.headers(), header::IF_NONE_MATCH);
if modified_since.is_empty() && none_match.is_empty() {
return false;
}
let is_modified_since = match std::str::from_utf8(&modified_since) {
Err(_) => true,
Ok(string) if string.is_empty() => true,
Ok(modified_since) => {
let modified_since = parse_http_date(modified_since);
match modified_since {
Err(_) => return false,
Ok(parsed) => is_modified_since(parsed, res),
}
}
};
is_modified_since && etag_matches(&none_match, res)
}
fn etag_matches(none_match: &[u8], res: &Response<Body>) -> bool {
let value = get_and_concat_header(res.headers(), header::ETAG);
value == none_match
}
fn is_modified_since(modified_since: OffsetDateTime, res: &Response<Body>) -> bool {
let last_modified = get_and_concat_header(res.headers(), header::LAST_MODIFIED);
match std::str::from_utf8(&last_modified) {
Err(_) => false,
Ok(last_modified) => match parse_http_date(last_modified) {
Err(_) => false,
Ok(last_modified) => modified_since.unix_timestamp() >= last_modified.unix_timestamp(),
},
}
}
fn get_and_concat_header(headers: &HeaderMap, name: header::HeaderName) -> Cow<'_, [u8]> {
let mut values = headers.get_all(name).iter();
if values.size_hint() == (1, Some(1)) {
Cow::Borrowed(values.next().unwrap().as_bytes())
} else {
let values: Vec<_> = values.map(|val| val.as_bytes()).collect();
Cow::Owned(values.concat())
}
}
fn parse_http_date(string: &str) -> Result<OffsetDateTime, ()> {
parse_rfc1123(string)
.or_else(|_| parse_rfc850(string))
.or_else(|_| parse_asctime(string))
.map_err(|_| ())
}
fn parse_rfc1123(string: &str) -> Result<OffsetDateTime, ParseError> {
Ok(PrimitiveDateTime::parse(string, "%a, %d %b %Y %T GMT")?.assume_utc())
}
fn parse_rfc850(string: &str) -> Result<OffsetDateTime, ParseError> {
Ok(PrimitiveDateTime::parse(string, "%a, %d-%m-%y %T GMT")?.assume_utc())
}
fn parse_asctime(string: &str) -> Result<OffsetDateTime, ParseError> {
Ok(PrimitiveDateTime::parse(string, "%a %m\t%d %T %Y")?.assume_utc())
}
#[cfg(test)]
mod tests {
use conduit::{
box_error, header, Body, Handler, HandlerResult, HeaderMap, Method, RequestExt, Response,
StatusCode,
};
use conduit_middleware::MiddlewareBuilder;
use conduit_test::{MockRequest, ResponseExt};
use time::{Duration, OffsetDateTime};
use super::ConditionalGet;
macro_rules! returning {
($status:expr, $($header:expr => $value:expr),+) => ({
use std::convert::TryInto;
let mut headers = HeaderMap::new();
$(headers.append($header, $value.try_into().unwrap());)+
let handler = SimpleHandler::new(headers, $status, "hello");
let mut stack = MiddlewareBuilder::new(handler);
stack.add(ConditionalGet);
stack
});
($($header:expr => $value:expr),+) => ({
returning!(StatusCode::OK, $($header => $value),+)
})
}
macro_rules! request {
($($header:expr => $value:expr),+) => ({
let mut req = MockRequest::new(Method::GET, "/");
$(req.header($header, &$value.to_string());)+
req
})
}
#[test]
fn test_sends_304() {
let handler = returning!(header::LAST_MODIFIED => httpdate(OffsetDateTime::now_utc()));
expect_304(handler.call(&mut request!(
header::IF_MODIFIED_SINCE => httpdate(OffsetDateTime::now_utc())
)));
}
#[test]
fn test_sends_304_if_older_than_now() {
let handler = returning!(header::LAST_MODIFIED => before_now());
expect_304(handler.call(&mut request!(
header::IF_MODIFIED_SINCE => httpdate(OffsetDateTime::now_utc())
)));
}
#[test]
fn test_sends_304_with_etag() {
let handler = returning!(header::ETAG => "1234");
expect_304(handler.call(&mut request!(
header::IF_NONE_MATCH => "1234"
)));
}
#[test]
fn test_sends_200_with_fresh_time_but_not_etag() {
let handler = returning!(header::LAST_MODIFIED => before_now(), header::ETAG => "1234");
expect_200(handler.call(&mut request!(
header::IF_MODIFIED_SINCE => now(),
header::IF_NONE_MATCH => "4321"
)));
}
#[test]
fn test_sends_200_with_fresh_etag_but_not_time() {
let handler = returning!(header::LAST_MODIFIED => now(), header::ETAG => "1234");
expect_200(handler.call(&mut request!(
header::IF_MODIFIED_SINCE => before_now(),
header::IF_NONE_MATCH => "1234"
)));
}
#[test]
fn test_sends_200_with_fresh_etag() {
let handler = returning!(header::ETAG => "1234");
expect_200(handler.call(&mut request!(
header::IF_NONE_MATCH => "4321"
)));
}
#[test]
fn test_sends_200_with_fresh_time() {
let handler = returning!(header::LAST_MODIFIED => now());
expect_200(handler.call(&mut request!(
header::IF_MODIFIED_SINCE => before_now()
)));
}
#[test]
fn test_sends_304_with_fresh_time_and_etag() {
let handler = returning!(header::LAST_MODIFIED => before_now(), header::ETAG => "1234");
expect_304(handler.call(&mut request!(
header::IF_MODIFIED_SINCE => now(),
header::IF_NONE_MATCH => "1234"
)));
}
#[test]
fn test_does_not_affect_non_200() {
let handler = returning!(StatusCode::FOUND, header::LAST_MODIFIED => before_now(), header::ETAG => "1234");
expect(
StatusCode::FOUND,
handler.call(&mut request!(
header::IF_MODIFIED_SINCE => now(),
header::IF_NONE_MATCH => "1234"
)),
);
}
#[test]
fn test_does_not_affect_malformed_timestamp() {
let bad_stamp = OffsetDateTime::now_utc().format("%Y-%m-%d %H:%M:%S %z");
let handler = returning!(header::LAST_MODIFIED => before_now());
expect_200(handler.call(&mut request!(
header::IF_MODIFIED_SINCE => bad_stamp
)));
}
fn expect_304(response: HandlerResult) {
let response = response.expect("No response");
assert_eq!(response.status(), StatusCode::NOT_MODIFIED);
assert_eq!(*response.into_cow(), b""[..]);
}
fn expect_200(response: HandlerResult) {
expect(StatusCode::OK, response);
}
fn expect(status: StatusCode, response: HandlerResult) {
let response = response.expect("No response");
assert_eq!(response.status(), status);
assert_eq!(*response.into_cow(), b"hello"[..]);
}
struct SimpleHandler {
headers: HeaderMap,
status: StatusCode,
body: &'static str,
}
impl SimpleHandler {
fn new(headers: HeaderMap, status: StatusCode, body: &'static str) -> SimpleHandler {
SimpleHandler {
headers,
status,
body,
}
}
}
impl Handler for SimpleHandler {
fn call(&self, _: &mut dyn RequestExt) -> HandlerResult {
let mut builder = Response::builder().status(self.status);
builder.headers_mut().unwrap().extend(self.headers.clone());
builder
.body(Body::from_static(self.body.as_bytes()))
.map_err(box_error)
}
}
fn before_now() -> String {
let now = OffsetDateTime::now_utc();
httpdate(now - Duration::weeks(52))
}
fn now() -> String {
httpdate(OffsetDateTime::now_utc())
}
fn httpdate(time: OffsetDateTime) -> String {
time.format("%a, %d-%m-%y %T GMT")
}
}