Add canonical URL for source pages

Author: jsha

src/web/source.rs

@@ -165,6 +165,7 @@ struct SourcePage {
     show_parent_link: bool,
     file_content: Option<String>,
     is_rust_source: bool,
+    canonical_url: String,
 }
 
 impl_webpage! {
@@ -232,6 +233,11 @@ pub fn source_browser_handler(req: &mut Request) -> IronResult<Response> {
         (path, file_path)
     };
 
+    let canonical_url = format!(
+        "https://docs.rs/crate/{}/latest/source/{}",
+        crate_name, file_path
+    );
+
     let storage = extension!(req, Storage);
     let archive_storage: bool = {
         let rows = ctry!(
@@ -295,6 +301,7 @@ pub fn source_browser_handler(req: &mut Request) -> IronResult<Response> {
         show_parent_link: !req_path.is_empty(),
         file_content,
         is_rust_source,
+        canonical_url,
     }
     .into_response(req)
 }

templates/crate/source.html

@@ -5,6 +5,10 @@
     {{ macros::doc_title(name=file_list.metadata.name, version=file_list.metadata.version) }}
 {%- endblock title -%}
 
+{%- block meta -%}
+    <link rel="canonical" href="{{ canonical_url | safe }}" />
+{%- endblock -%}
+
 {%- block topbar -%}
   {%- set metadata = file_list.metadata -%}
   {%- set latest_version = "" -%}