Factor out pagination resolver from ChangesResource and call it ChangesLookup

src/resources/changes_resource.rs

@@ -1,5 +1,5 @@
 use futures::{self, Future};
-use futures::future::finished;
+use futures::future::{done, finished};
 use hyper;
 use hyper::header::ContentType;
 use hyper::server::*;
@@ -17,14 +17,24 @@ const PAGE_SIZE: i32 = 30;
 
 type BoxResource = Box<Resource + Sync + Send>;
 
-pub struct ChangesResource {
+#[derive(Clone)]
+pub struct ChangesLookup {
     state: State,
-    before: Option<i32>,
 }
 
-impl ChangesResource {
-    pub fn new(state: State, pagination: Pagination<i32>) -> Box<Future<Item=BoxResource, Error=::web::Error>> {
-        match pagination {
+impl ChangesLookup {
+    pub fn new(state: State) -> ChangesLookup {
+        Self { state }
+    }
+
+    pub fn lookup(&self, query: Option<&str>) -> Box<Future<Item=Option<BoxResource>, Error=::web::Error>> {
+        use super::pagination;
+
+        let state = self.state.clone();
+
+        Box::new(
+            done(pagination::from_str(query.unwrap_or("")).map_err(Into::into))
+            .and_then(move |pagination| match pagination {
                 Pagination::After(x) => Box::new(
                     state.query_article_revision_stubs(move |query| {
                         use diesel::prelude::*;
@@ -41,16 +51,28 @@ impl ChangesResource {
                             None
                         };
 
-                    Ok(match extra_element {
+                        Ok(Some(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,
+                        }))
                     })
+                ) as Box<Future<Item=Option<BoxResource>, Error=::web::Error>>,
+                Pagination::Before(x) => Box::new(finished(Some(Box::new(ChangesResource::new(state, Some(x))) as BoxResource))),
+                Pagination::None => Box::new(finished(Some(Box::new(ChangesResource::new(state, None)) as BoxResource))),
             })
-            ),
-            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)),
+        )
     }
 }
+
+pub struct ChangesResource {
+    state: State,
+    before: Option<i32>,
+}
+
+impl ChangesResource {
+    pub fn new(state: State, before: Option<i32>) -> Self {
+        Self { state, before }
+    }
 }
 
 impl Resource for ChangesResource {

src/resources/mod.rs

@@ -9,7 +9,7 @@ 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::changes_resource::{ChangesLookup, ChangesResource};
 pub use self::new_article_resource::NewArticleResource;
 pub use self::sitemap_resource::SitemapResource;
 pub use self::temporary_redirect_resource::TemporaryRedirectResource;

src/wiki_lookup.rs

@@ -2,7 +2,7 @@ use std::borrow::Cow;
 use std::collections::HashMap;
 use std::str::Utf8Error;
 
-use futures::{Future, finished, failed, done};
+use futures::{Future, finished, failed};
 use futures::future::FutureResult;
 use percent_encoding::percent_decode;
 use slug::slugify;
@@ -40,7 +40,8 @@ lazy_static! {
 
 #[derive(Clone)]
 pub struct WikiLookup {
-    state: State
+    state: State,
+    changes_lookup: ChangesLookup,
 }
 
 fn split_one(path: &str) -> Result<(Cow<str>, Option<&str>), Utf8Error> {
@@ -70,7 +71,9 @@ fn asset_lookup(path: &str) -> FutureResult<Option<BoxResource>, Box<::std::erro
 
 impl WikiLookup {
     pub fn new(state: State) -> WikiLookup {
-        WikiLookup { state }
+        let changes_lookup = ChangesLookup::new(state.clone());
+
+        WikiLookup { state, changes_lookup }
     }
 
     fn reserved_lookup(&self, path: &str, query: Option<&str>) -> <Self as Lookup>::Future {
@@ -82,14 +85,8 @@ impl WikiLookup {
         match (head.as_ref(), tail) {
             ("_assets", Some(asset)) =>
                 Box::new(asset_lookup(asset)),
-            ("_changes", None) => {
-                let state = self.state.clone();
-                Box::new(
-                    done(pagination::from_str(query.unwrap_or("")).map_err(Into::into))
-                    .and_then(move |pagination| ChangesResource::new(state, pagination))
-                    .and_then(|resource| Ok(Some(resource)))
-                )
-            },
+            ("_changes", None) =>
+                Box::new(ChangesLookup::new(self.state.clone()).lookup(query)),
             ("_new", None) =>
                 Box::new(finished(Some(Box::new(NewArticleResource::new(self.state.clone(), None)) as BoxResource))),
             ("_sitemap", None) =>