From 9a46647010989a0d8925f771240de9d49692b56b Mon Sep 17 00:00:00 2001
From: Slavi Pantaleev <slavi@devture.com>
Date: Wed, 28 Oct 2020 10:39:12 +0200
Subject: [PATCH] Make https://matrix.DOMAIN/ redirect to
 https://element.DOMAIN/

Fixes #696 (Github Issue)
---
 CHANGELOG.md                                       | 14 ++++++++++++++
 group_vars/matrix_servers                          |  2 ++
 roles/matrix-nginx-proxy/defaults/main.yml         |  6 ++++++
 .../templates/nginx/conf.d/matrix-synapse.conf.j2  |  6 +++++-
 4 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6b6dd8e54..089d06508 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,17 @@
+# 2020-10-28
+
+## (Compatibility Break) https://matrix.DOMAIN/ now redirects to https://element.DOMAIN/
+
+Until now, we used to serve a static page coming from Synapse at `https://matrix.DOMAIN/`. This page was not very useful to anyone.
+
+Since `matrix.DOMAIN` may be accessed by regular users in certain conditions, it's probably better to redirect them to a better place (e.g. to the [Element](docs/configuring-playbook-client-element.md) client).
+
+If Element is installed (`matrix_client_element_enabled: true`, which it is by default), we now redirect people to it, instead of showing them a Synapse static page.
+
+If you'd like to control where the redirect goes, use the `matrix_nginx_proxy_proxy_matrix_client_redirect_root_uri_to_domain` variable.
+To restore the old behavior of not redirecting anywhere and serving the Synapse static page, set it to an empty value (`matrix_nginx_proxy_proxy_matrix_client_redirect_root_uri_to_domain: ""`).
+
+
 # 2020-10-26
 
 ## (Compatibility Break) /_synapse/admin is no longer publicly exposed by default
diff --git a/group_vars/matrix_servers b/group_vars/matrix_servers
index 71a6bc85b..eabce668c 100755
--- a/group_vars/matrix_servers
+++ b/group_vars/matrix_servers
@@ -771,6 +771,8 @@ matrix_nginx_proxy_proxy_matrix_client_api_client_max_body_size_mb: "{{ matrix_s
 
 matrix_nginx_proxy_proxy_matrix_client_api_forwarded_location_synapse_admin_api_enabled: "{{ matrix_synapse_admin_enabled }}"
 
+matrix_nginx_proxy_proxy_matrix_client_redirect_root_uri_to_domain: "{{ matrix_server_fqn_element if matrix_client_element_enabled else '' }}"
+
 matrix_nginx_proxy_proxy_matrix_enabled: true
 matrix_nginx_proxy_proxy_element_enabled: "{{ matrix_client_element_enabled }}"
 matrix_nginx_proxy_proxy_dimension_enabled: "{{ matrix_dimension_enabled }}"
diff --git a/roles/matrix-nginx-proxy/defaults/main.yml b/roles/matrix-nginx-proxy/defaults/main.yml
index 2ce8eb30c..6d9ff33bd 100644
--- a/roles/matrix-nginx-proxy/defaults/main.yml
+++ b/roles/matrix-nginx-proxy/defaults/main.yml
@@ -169,6 +169,12 @@ matrix_nginx_proxy_proxy_matrix_client_api_forwarded_location_prefix_regexes: |
     (['/_synapse/admin'] if matrix_nginx_proxy_proxy_matrix_client_api_forwarded_location_synapse_admin_api_enabled else [])
   }}
 
+# Specifies where requests for the root URI (`/`) on the `matrix.` domain should be redirected.
+# If this has an empty value, they're just passed to the homeserver, which serves a static page.
+# If you'd like to make `https://matrix.DOMAIN` redirect to `https://element.DOMAIN` (or something of that sort), specify the domain name here.
+# Example value: `element.DOMAIN` (or `{{ matrix_server_fqn_element }}`).
+matrix_nginx_proxy_proxy_matrix_client_redirect_root_uri_to_domain: ""
+
 # Controls whether proxying for the Matrix Federation API should be done.
 matrix_nginx_proxy_proxy_matrix_federation_api_enabled: false
 matrix_nginx_proxy_proxy_matrix_federation_api_addr_with_container: "matrix-synapse:8048"
diff --git a/roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-synapse.conf.j2 b/roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-synapse.conf.j2
index 463aec075..adbee18e6 100644
--- a/roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-synapse.conf.j2
+++ b/roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-synapse.conf.j2
@@ -151,7 +151,11 @@
 	}
 
 	location / {
-		rewrite ^/$ /_matrix/static/ last;
+		{% if matrix_nginx_proxy_proxy_matrix_client_redirect_root_uri_to_domain %}
+			return 302 $scheme://{{ matrix_nginx_proxy_proxy_matrix_client_redirect_root_uri_to_domain }}$request_uri;
+		{% else %}
+			rewrite ^/$ /_matrix/static/ last;
+		{% endif %}
 	}
 {% endmacro %}