From b3ffcb916ba06f8a355fbd1e91e867e3b7c605cc Mon Sep 17 00:00:00 2001
From: Magnus Hoff <maghoff@gmail.com>
Date: Sun, 22 Oct 2017 13:38:13 +0200
Subject: [PATCH] Redirect after-pagination queries to the corresponding
 before-queries

This normalizes the URLs, avoiding duplicate URLs for a sublist
---
 src/resources/changes_resource.rs            | 15 ++++---
 src/resources/mod.rs                         |  2 +
 src/resources/temporary_redirect_resource.rs | 46 ++++++++++++++++++++
 src/wiki_lookup.rs                           |  2 +-
 4 files changed, 58 insertions(+), 7 deletions(-)
 create mode 100644 src/resources/temporary_redirect_resource.rs

diff --git a/src/resources/changes_resource.rs b/src/resources/changes_resource.rs
index 7b30609..2e3dbfc 100644
--- a/src/resources/changes_resource.rs
+++ b/src/resources/changes_resource.rs
@@ -11,16 +11,19 @@ use state::State;
 use web::{Resource, ResponseFuture};
 
 use super::pagination::Pagination;
+use super::TemporaryRedirectResource;
 
 const PAGE_SIZE: i32 = 30;
 
+type BoxResource = Box<Resource + Sync + Send>;
+
 pub struct ChangesResource {
     state: State,
     before: Option<i32>,
 }
 
 impl ChangesResource {
-    pub fn new(state: State, pagination: Pagination<i32>) -> Box<Future<Item=ChangesResource, Error=::web::Error>> {
+    pub fn new(state: State, pagination: Pagination<i32>) -> Box<Future<Item=BoxResource, Error=::web::Error>> {
         match pagination {
             Pagination::After(x) => Box::new(
                 state.query_article_revision_stubs(move |query| {
@@ -38,14 +41,14 @@ impl ChangesResource {
                         None
                     };
 
-                    Ok(Self {
-                        state,
-                        before: extra_element.map(|x| x.sequence_number),
+                    Ok(match extra_element {
+                        Some(x) => Box::new(TemporaryRedirectResource::new(format!("?before={}", x.sequence_number))) as BoxResource,
+                        None => Box::new(TemporaryRedirectResource::new(format!("_changes"))) as BoxResource,
                     })
                 })
             ),
-            Pagination::Before(x) => Box::new(finished(Self { state, before: Some(x) })),
-            Pagination::None => Box::new(finished(Self { state, before: None })),
+            Pagination::Before(x) => Box::new(finished(Box::new(Self { state, before: Some(x) }) as BoxResource)),
+            Pagination::None => Box::new(finished(Box::new(Self { state, before: None }) as BoxResource)),
         }
     }
 }
diff --git a/src/resources/mod.rs b/src/resources/mod.rs
index 097b909..6a66aa1 100644
--- a/src/resources/mod.rs
+++ b/src/resources/mod.rs
@@ -5,9 +5,11 @@ mod article_resource;
 mod changes_resource;
 mod new_article_resource;
 mod sitemap_resource;
+mod temporary_redirect_resource;
 
 pub use self::article_redirect_resource::ArticleRedirectResource;
 pub use self::article_resource::ArticleResource;
 pub use self::changes_resource::ChangesResource;
 pub use self::new_article_resource::NewArticleResource;
 pub use self::sitemap_resource::SitemapResource;
+pub use self::temporary_redirect_resource::TemporaryRedirectResource;
diff --git a/src/resources/temporary_redirect_resource.rs b/src/resources/temporary_redirect_resource.rs
new file mode 100644
index 0000000..085072e
--- /dev/null
+++ b/src/resources/temporary_redirect_resource.rs
@@ -0,0 +1,46 @@
+use futures::{self, Future};
+use hyper;
+use hyper::header::Location;
+use hyper::server::*;
+
+use web::{Resource, ResponseFuture};
+
+pub struct TemporaryRedirectResource {
+    location: String,
+}
+
+impl TemporaryRedirectResource {
+    pub fn new(location: String) -> Self {
+        Self { location }
+    }
+}
+
+impl Resource for TemporaryRedirectResource {
+    fn allow(&self) -> Vec<hyper::Method> {
+        use hyper::Method::*;
+        vec![Options, Head, Get, Put, Post]
+    }
+
+    fn head(&self) -> ResponseFuture {
+        Box::new(futures::finished(Response::new()
+            .with_status(hyper::StatusCode::TemporaryRedirect)
+            .with_header(Location::new(self.location.clone()))
+        ))
+    }
+
+    fn get(self: Box<Self>) -> ResponseFuture {
+        Box::new(self.head()
+            .and_then(move |head| {
+                Ok(head
+                    .with_body(format!("Moved to {}", self.location)))
+            }))
+    }
+
+    fn put(self: Box<Self>, _body: hyper::Body, _identity: Option<String>) -> ResponseFuture {
+        Box::new(self.head()
+            .and_then(move |head| {
+                Ok(head
+                    .with_body(format!("Moved to {}", self.location)))
+            }))
+    }
+}
diff --git a/src/wiki_lookup.rs b/src/wiki_lookup.rs
index 44ffc65..9574918 100644
--- a/src/wiki_lookup.rs
+++ b/src/wiki_lookup.rs
@@ -87,7 +87,7 @@ impl WikiLookup {
                 Box::new(
                     done(pagination::from_str(query.unwrap_or("")).map_err(Into::into))
                     .and_then(move |pagination| ChangesResource::new(state, pagination))
-                    .and_then(|changes_resource| Ok(Some(Box::new(changes_resource) as BoxResource)))
+                    .and_then(|resource| Ok(Some(resource)))
                 )
             },
             ("_new", None) =>