From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 28 Mar 2022 00:56:06 +0000 (+0100)
Subject: resource leaf routing: Document why we're leaving it order-sensitive
X-Git-Tag: otter-1.0.0~90
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=bbd03bf415a9d2bcd8261583e37434ecbe4131ca;p=otter.git

resource leaf routing: Document why we're leaving it order-sensitive

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/TODO b/TODO
index 76fc57e8..91431989 100644
--- a/TODO
+++ b/TODO
@@ -2,4 +2,3 @@ TODOs in diff
 content-type for download bundles
 http2 HEAD requests
 fix listen
-fix that /_/updates vs /_/<leaf> involves ordering
diff --git a/daemon/main.rs b/daemon/main.rs
index d19f0a28..4cffdb28 100644
--- a/daemon/main.rs
+++ b/daemon/main.rs
@@ -296,6 +296,15 @@ async fn updates_route(query: Query<UpdatesParams>) -> impl Responder {
     .streaming(content)
 }
 
+// Actix dispatches to the first matching URL pattern in the list of
+// routes, and does not try another one even if this route says 404.
+// This pattern is quite general, so it has to come last.
+//
+// An alternative would be to use a Guard.  But the guard doesn't get
+// to give information directly to the route function.  We would have
+// to use the GuardContext to thread the CheckedResource through the
+// Extension type map.  It's easier just to make sure this URL pattern
+// is last in the list.
 #[route("/_/{leaf}", method="GET", method="HEAD")]
 #[throws(io::Error)]
 async fn resource(leaf: Path<Parse<CheckedResourceLeaf>>) -> impl Responder {
@@ -496,9 +505,9 @@ async fn main() -> Result<(),StartupError> {
         loading_p,
         bundle_route,
         updates_route,
-        resource,
         session::routes(),
         api::routes(),
+        resource, // Must come after more specific URL paths
       ])
       .app_data(json_config)
       .app_data(templates.clone())