Use lang specific redirects + catch all

content/docs/languages/android/_index.md

@@ -6,4 +6,4 @@ These language-specific pages are available:
 
 - [Quick start](quickstart)
 - [Basics tutorial](basics)
-- [API reference](https://grpc.github.io/grpc-java/javadoc)
+- [API reference](api)

content/docs/languages/android/api.md

@@ -0,0 +1,5 @@
+---
+title: API reference
+weight: 90
+# Note: this is a placeholder page. The URL to this page redirects elsewhere.
+---

content/docs/languages/csharp/_index.md

@@ -7,7 +7,7 @@ core-library][core-library] implementation is covered here:
 
 - [Quick start](quickstart)
 - [Basics tutorial](basics)
-- [API reference](https://grpc.github.io/grpc/csharp/api/Grpc.Core)
+- [API reference](api)
 
 For details concerning the newer gRPC for .NET implementation, see [gRPC for
 .NET](dotnet).

content/docs/languages/csharp/api.md

@@ -0,0 +1,5 @@
+---
+title: API reference
+weight: 90
+# Note: this is a placeholder page. The URL to this page redirects elsewhere.
+---

content/docs/languages/csharp/dotnet.md

@@ -1,5 +1,6 @@
 ---
 title: gRPC for .NET
+weight: 60
 ---
 
 The following pages cover the C# implementation of gRPC for .NET
@@ -7,7 +8,7 @@ The following pages cover the C# implementation of gRPC for .NET
 
 - [Introduction to gRPC on .NET Core](https://docs.microsoft.com/aspnet/core/grpc)
 - [Tutorial: Create a gRPC client and server in ASP.NET Core][tutorial]
-- [API reference](https://grpc.github.io/grpc/csharp-dotnet/api/Grpc.Core)
+- [API reference](api)
 
 Several sample applications are available from the [examples][] folder in the
 [grpc-dotnet][] repository.

layouts/_default/_markup/render-link.html

@@ -1,4 +1,4 @@
-{{ $isExternal := hasPrefix .Destination "http" -}}
+{{ $isExternal := or (hasPrefix .Destination "http") (findRE "^(|/docs/languages/.+?/)api/?$" .Destination) -}}
 <a href="{{ .Destination | safeURL }}"
   {{- with .Title }} title="{{ . }}"{{ end -}}
   {{- if $isExternal }} target="_blank" rel="noopener"{{ end -}}

layouts/index.redirects

@@ -12,8 +12,14 @@
 /docs/reference/:lang/generated-code  /docs/languages/:lang/generated-code
 /docs/tutorials/basic/:lang           /docs/languages/:lang/basics
 
-# These redirect rules are for API reference docs. For a list of
+# API reference docs (prior to 2020/06)
-# source URLs, see the apis.yaml file.
 
 /grpc/*     https://grpc.github.io/grpc/:splat
 /grpc-*     https://grpc.github.io/grpc-:splat
+
+# API reference docs
+
+/docs/languages/android/api       https://grpc.github.io/grpc-java/javadoc 301!
+/docs/languages/csharp/dotnet/api https://grpc.github.io/grpc/csharp-dotnet/api/Grpc.Core 301!
+/docs/languages/csharp/api        https://grpc.github.io/grpc/csharp/api/Grpc.Core 301!
+#/docs/languages/:lang/api         https://grpc.github.io/grpc/:lang 301!