add CDN caching to rustdoc redirects only

Author: syphar

src/web/mod.rs

@@ -99,7 +99,7 @@ use extensions::InjectExtensions;
 use failure::Error;
 use iron::{
     self,
-    headers::{Expires, HttpDate},
+    headers::{CacheControl, CacheDirective, Expires, HttpDate},
     modifiers::Redirect,
     status,
     status::Status,
@@ -496,6 +496,28 @@ fn redirect(url: Url) -> Response {
     resp
 }
 
+/// creates a redirect-response which is cached on the CDN level for
+/// the given amount of seconds. Browser-Local caching is deactivated.
+/// The used s-maxage is respected by CloudFront (which we can invalidate
+/// if we need to), and perhaps by other proxies in between.
+/// When the cache-seconds are reasonably small, this should be fine.
+///
+/// CloudFront doesn't have `surrogate-control` headers which would be only
+/// used by CloudFront and dropped (Fastly has them).
+///
+/// The `Expires` header from `redirect` is still kept to be safe,
+/// CloudFront ignores it when it gets `Cache-Control: max-age` or
+/// `s-maxage`.
+fn cached_redirect(url: Url, cache_seconds: u32) -> Response {
+    let mut resp = redirect(url);
+    resp.headers.set(CacheControl(vec![
+        CacheDirective::MaxAge(0),
+        CacheDirective::SMaxAge(cache_seconds),
+    ]));
+
+    resp
+}
+
 fn redirect_base(req: &Request) -> String {
     // Try to get the scheme from CloudFront first, and then from iron
     let scheme = req

src/web/rustdoc.rs

@@ -70,14 +70,8 @@ pub fn rustdoc_redirector_handler(req: &mut Request) -> IronResult<Response> {
         }
         let url = ctry!(req, Url::parse(&url_str));
         let config = extension!(req, Config);
-        let mut resp = Response::with((status::Found, Redirect(url)));
-        resp.headers.set(CacheControl(vec![
-            CacheDirective::MaxAge(0),
-            // s-maxage is only for the CDN.
-            CacheDirective::SMaxAge(config.cache_rustdoc_redirects),
-        ]));
-
-        Ok(resp)
+
+        Ok(super::cached_redirect(url, config.cache_rustdoc_redirects))
     }
 
     fn redirect_to_crate(req: &Request, name: &str, vers: &str) -> IronResult<Response> {
@@ -87,14 +81,7 @@ pub fn rustdoc_redirector_handler(req: &mut Request) -> IronResult<Response> {
         );
 
         let config = extension!(req, Config);
-        let mut resp = Response::with((status::Found, Redirect(url)));
-        resp.headers.set(CacheControl(vec![
-            CacheDirective::MaxAge(0),
-            // s-maxage is only for the CDN.
-            CacheDirective::SMaxAge(config.cache_rustdoc_redirects),
-        ]));
-
-        Ok(resp)
+        Ok(super::cached_redirect(url, config.cache_rustdoc_redirects))
     }
 
     let metrics = extension!(req, Metrics).clone();
@@ -292,7 +279,7 @@ pub fn rustdoc_html_server_handler(req: &mut Request) -> IronResult<Response> {
         );
         let url = ctry!(req, Url::parse(&redirect_path));
 
-        Ok(super::redirect(url))
+        Ok(super::cached_redirect(url, config.cache_rustdoc_redirects))
     };
 
     rendering_time.step("match version");
@@ -561,10 +548,7 @@ pub fn target_redirect_handler(req: &mut Request) -> IronResult<Response> {
     );
 
     let url = ctry!(req, Url::parse(&url));
-    let mut resp = Response::with((status::Found, Redirect(url)));
-    resp.headers.set(Expires(HttpDate(time::now())));
-
-    Ok(resp)
+    Ok(super::cached_redirect(url, config.cache_rustdoc_redirects))
 }
 
 pub fn badge_handler(req: &mut Request) -> IronResult<Response> {