Include next_page and prev_page metadata on search

Cargo.toml

@@ -82,6 +82,7 @@ futures = "0.1"
 tokio = "0.1"
 hyper = "0.12"
 ctrlc = { version = "3.0", features = ["termination"] }
+indexmap = "1.0.2"
 
 [dev-dependencies]
 conduit-test = "0.8"

src/controllers.rs

@@ -14,14 +14,15 @@ mod prelude {
     use std::collections::HashMap;
     use std::io;
 
+    use indexmap::IndexMap;
     use serde::Serialize;
     use url;
 
     pub trait RequestUtils {
         fn redirect(&self, url: String) -> Response;
 
         fn json<T: Serialize>(&self, t: &T) -> Response;
-        fn query(&self) -> HashMap<String, String>;
+        fn query(&self) -> IndexMap<String, String>;
         fn wants_json(&self) -> bool;
         fn pagination(&self, default: usize, max: usize) -> CargoResult<(i64, i64)>;
     }
@@ -31,7 +32,7 @@ mod prelude {
             crate::util::json_response(t)
         }
 
-        fn query(&self) -> HashMap<String, String> {
+        fn query(&self) -> IndexMap<String, String> {
             url::form_urlencoded::parse(self.query_string().unwrap_or("").as_bytes())
                 .map(|(a, b)| (a.into_owned(), b.into_owned()))
                 .collect()

src/controllers/krate/search.rs

@@ -222,6 +222,27 @@ pub fn search(req: &mut dyn Request) -> CargoResult<Response> {
         )
         .collect();
 
+    let mut next_page = None;
+    let mut prev_page = None;
+    let page_num = params.get("page").map(|s| s.parse()).unwrap_or(Ok(1))?;
+
+    let url_for_page = |num: i64| {
+        let mut params = req.query();
+        params.insert("page".into(), num.to_string());
+        let query_string = url::form_urlencoded::Serializer::new(String::new())
+            .clear()
+            .extend_pairs(params)
+            .finish();
+        Some(format!("?{}", query_string))
+    };
+
+    if offset + limit < total {
+        next_page = url_for_page(page_num + 1);
+    }
+    if page_num != 1 {
+        prev_page = url_for_page(page_num - 1);
+    };
+
     #[derive(Serialize)]
     struct R {
         crates: Vec<EncodableCrate>,
@@ -230,10 +251,16 @@ pub fn search(req: &mut dyn Request) -> CargoResult<Response> {
     #[derive(Serialize)]
     struct Meta {
         total: i64,
+        next_page: Option<String>,
+        prev_page: Option<String>,
     }
 
     Ok(req.json(&R {
         crates,
-        meta: Meta { total },
+        meta: Meta {
+            total,
+            next_page,
+            prev_page,
+        },
     }))
 }

src/tests/all.rs

@@ -93,6 +93,8 @@ pub struct CrateList {
 #[derive(Deserialize)]
 struct CrateMeta {
     total: i32,
+    next_page: Option<String>,
+    prev_page: Option<String>,
 }
 #[derive(Deserialize)]
 pub struct CrateResponse {

src/tests/krate.rs

@@ -2172,3 +2172,26 @@ fn publish_rate_limit_doesnt_affect_existing_crates() {
     token.enqueue_publish(new_version).good();
     app.run_pending_background_jobs();
 }
+
+#[test]
+fn pagination_links_included_if_applicable() {
+    let (app, anon, user) = TestApp::init().with_user();
+    let user = user.as_model();
+
+    app.db(|conn| {
+        CrateBuilder::new("pagination_links_1", user.id).expect_build(conn);
+        CrateBuilder::new("pagination_links_2", user.id).expect_build(conn);
+        CrateBuilder::new("pagination_links_3", user.id).expect_build(conn);
+    });
+
+    let page1 = anon.search("per_page=1");
+    let page2 = anon.search("page=2&per_page=1");
+    let page3 = anon.search("page=3&per_page=1");
+
+    assert_eq!(Some("?per_page=1&page=2".to_string()), page1.meta.next_page);
+    assert_eq!(None, page1.meta.prev_page);
+    assert_eq!(Some("?page=3&per_page=1".to_string()), page2.meta.next_page);
+    assert_eq!(Some("?page=1&per_page=1".to_string()), page2.meta.prev_page);
+    assert_eq!(None, page3.meta.next_page);
+    assert_eq!(Some("?page=2&per_page=1".to_string()), page3.meta.prev_page);
+}