download: redirect to docs/introduction/installation

This change unifies our handling of install-related URLs/docs, suitable
for go-live, but allowing each affected URL to have unique content
written for it as & when we choose.

It does this by:

- re-enabling Hugo's "aliases" (client-side redirects)
- teaching /docs/introduction/installation that it has these aliases:
  - /docs/install
  - /download
  - /install
  - /dl
- removing the Netlify-level redirection of /download to /docs/install
  (which was a 404 until this change)

These aliases' redirections will get overwritten by any page content
that's created for the above 4 URLs in the future, as per
https://gohugo.io/content-management/urls/#how-aliases-work. So,
*unlike* the Netlify redirect, future content authors won't have to
figure out why content added at /download doesn't get served.

There should be no SEO impact, as the client-side redirect provides a
"canonical" link element alongside a meta robots element that should
stop the alias getting indexed.

The only consumer who will be affected by this change will be those
using user-agents that don't follow or expose meta-based redirections
(`http-equiv="refresh"`), such as Curl. Given the human-centric nature
of this page's content, this doesn't seem onerous.

For: cue-lang/docs-and-content#52
For: cue-lang/docs-and-content#63
Preview-Path: /docs/install
Preview-Path: /download
Preview-Path: /install
Preview-Path: /dl
Change-Id: I99a04f6a1520dd309f1cc00751ac00abc31e7b28
Signed-off-by: Jonathan Matthews <github@hello.jonathanmatthews.com>
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cuelang.org/+/1168925
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Paul Jolly <paul@myitcv.io>

content/docs/introduction/installation/en.md

@@ -1,6 +1,11 @@
 ---
 title: Installation
 weight: 20
+aliases:
+- /docs/install
+- /download
+- /install
+- /dl
 ---
 
 The Go APIs for CUE are defined in the

hugo/config/_default/config.toml

@@ -9,7 +9,11 @@ enableMissingTranslationPlaceholders = true  # Useful when translating
 enableRobotsTXT = true # Render robots.txt
 enableGitInfo = true # Will give git-info values to .Lastmod etc.
 disableKinds = ["RSS", "taxonomy", "term"]
-disableAliases = true # We use Netlify server-side redirects instead of generated aliases
+
+# We use Netlify server-side redirects instead of generated aliases,
+# but the 2 aren't mutually exclusive. Allow Hugo to generate aliases
+# if requested.
+disableAliases = false
 
 # Hugo allows theme composition (and inheritance). Precedence is from left to right.
 # theme = ["docsy"]

hugo/content/en/docs/introduction/installation/index.md

@@ -1,6 +1,11 @@
 ---
 title: Installation
 weight: 20
+aliases:
+- /docs/install
+- /download
+- /install
+- /dl
 ---
 
 The Go APIs for CUE are defined in the

internal/ci/netlify/netlify.cue

@@ -80,9 +80,6 @@ config: #config & {
 	}, {
 		from: "/issue/*"
 		to:   "https://github.com/cue-lang/cue/issues/:splat"
-	}, {
-		from: "/download"
-		to:   "/docs/install"
 	}, {
 		from: "/issues/*"
 		to:   "https://github.com/cue-lang/cue/issues/:splat"

netlify.toml

@@ -50,12 +50,6 @@
   status = 302
   force = true
 
-[[redirects]]
-  from = "/download"
-  to = "/docs/install"
-  status = 302
-  force = true
-
 [[redirects]]
   from = "/issues/*"
   to = "https://github.com/cue-lang/cue/issues/:splat"