From c7e5b4b2f987d6ad869d8e0414fbeec2f6a96ce7 Mon Sep 17 00:00:00 2001
From: Travis Ralston <travis@t2bot.io>
Date: Thu, 11 Apr 2024 10:42:39 -0600
Subject: [PATCH] Support receiving `/versions` and enabling MSC3916 support

---
 api/r0/versions.go        | 26 ++++++++++++++++++++++++++
 api/routes.go             |  5 +++++
 dev/homeserver.nginx.conf | 10 ++++++++++
 matrix/breakers.go        |  4 ----
 matrix/requests_info.go   | 17 +++++++++++++++++
 5 files changed, 58 insertions(+), 4 deletions(-)
 create mode 100644 api/r0/versions.go
 create mode 100644 matrix/requests_info.go

diff --git a/api/r0/versions.go b/api/r0/versions.go
new file mode 100644
index 00000000..023f9a66
--- /dev/null
+++ b/api/r0/versions.go
@@ -0,0 +1,26 @@
+package r0
+
+import (
+	"github.com/getsentry/sentry-go"
+	"github.com/t2bot/matrix-media-repo/api/_apimeta"
+	"github.com/t2bot/matrix-media-repo/api/_responses"
+	"github.com/t2bot/matrix-media-repo/matrix"
+
+	"net/http"
+
+	"github.com/t2bot/matrix-media-repo/common/rcontext"
+)
+
+func ClientVersions(r *http.Request, rctx rcontext.RequestContext, user _apimeta.UserInfo) interface{} {
+	versions, err := matrix.ClientVersions(rctx, r.Host, user.UserId, user.AccessToken, r.RemoteAddr)
+	if err != nil {
+		rctx.Log.Error(err)
+		sentry.CaptureException(err)
+		return _responses.InternalServerError("unable to get versions")
+	}
+	if versions.UnstableFeatures == nil {
+		versions.UnstableFeatures = make(map[string]bool)
+	}
+	versions.UnstableFeatures["org.matrix.msc3916"] = true
+	return versions
+}
diff --git a/api/routes.go b/api/routes.go
index d30feea9..d7393a52 100644
--- a/api/routes.go
+++ b/api/routes.go
@@ -45,6 +45,7 @@ func buildRoutes() http.Handler {
 	register([]string{"POST"}, PrefixClient, "logout", mxSpecV3TransitionCS, router, makeRoute(_routers.RequireAccessToken(r0.Logout), "logout", counter))
 	register([]string{"POST"}, PrefixClient, "logout/all", mxSpecV3TransitionCS, router, makeRoute(_routers.RequireAccessToken(r0.LogoutAll), "logout_all", counter))
 	register([]string{"POST"}, PrefixMedia, "create", mxV1, router, makeRoute(_routers.RequireAccessToken(v1.CreateMedia), "create", counter))
+	register([]string{"GET"}, PrefixClient, "versions", mxNoVersion, router, makeRoute(_routers.OptionalAccessToken(r0.ClientVersions), "client_versions", counter))
 
 	// MSC3916 - Authentication & endpoint API separation
 	register([]string{"GET"}, PrefixClient, "media/preview_url", msc3916, router, previewUrlRoute)
@@ -148,12 +149,16 @@ var (
 	mxR0                 matrixVersions = []string{"r0"}
 	mxV1                 matrixVersions = []string{"v1"}
 	mxV3                 matrixVersions = []string{"v3"}
+	mxNoVersion          matrixVersions = []string{""}
 )
 
 func register(methods []string, prefix string, postfix string, versions matrixVersions, router *httprouter.Router, handler http.Handler) {
 	for _, method := range methods {
 		for _, version := range versions {
 			path := fmt.Sprintf("%s/%s/%s", prefix, version, postfix)
+			if version == "" {
+				path = fmt.Sprintf("%s/%s", prefix, postfix)
+			}
 			router.Handler(method, path, http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
 				defer func() {
 					// hopefully the body was already closed, but maybe it wasn't
diff --git a/dev/homeserver.nginx.conf b/dev/homeserver.nginx.conf
index 10f39142..8a975aa1 100644
--- a/dev/homeserver.nginx.conf
+++ b/dev/homeserver.nginx.conf
@@ -9,6 +9,16 @@ server {
       proxy_pass http://host.docker.internal:8001;
     }
 
+    location /_matrix/client/versions {
+      proxy_set_header Host localhost;
+      proxy_pass http://host.docker.internal:8001;
+    }
+
+    location /_matrix/client/unstable/org.matrix.msc3916 {
+      proxy_set_header Host localhost;
+      proxy_pass http://host.docker.internal:8001;
+    }
+
     location /_matrix {
       proxy_pass http://media_repo_synapse:8008;
     }
diff --git a/matrix/breakers.go b/matrix/breakers.go
index 5f6ee6a9..911f92f2 100644
--- a/matrix/breakers.go
+++ b/matrix/breakers.go
@@ -50,10 +50,6 @@ func getFederationBreaker(hostname string) *circuit.Breaker {
 }
 
 func doBreakerRequest(ctx rcontext.RequestContext, serverName string, accessToken string, appserviceUserId string, ipAddr string, method string, path string, resp interface{}) error {
-	if accessToken == "" {
-		return ErrInvalidToken
-	}
-
 	hs, cb := getBreakerAndConfig(serverName)
 
 	var replyError error
diff --git a/matrix/requests_info.go b/matrix/requests_info.go
new file mode 100644
index 00000000..c2cc1de0
--- /dev/null
+++ b/matrix/requests_info.go
@@ -0,0 +1,17 @@
+package matrix
+
+import "github.com/t2bot/matrix-media-repo/common/rcontext"
+
+type ClientVersionsResponse struct {
+	Versions         []string        `json:"versions"`
+	UnstableFeatures map[string]bool `json:"unstable_features"`
+}
+
+func ClientVersions(ctx rcontext.RequestContext, serverName string, accessToken string, appserviceUserId string, ipAddr string) (*ClientVersionsResponse, error) {
+	response := &ClientVersionsResponse{}
+	err := doBreakerRequest(ctx, serverName, accessToken, appserviceUserId, ipAddr, "GET", "/_matrix/client/versions", response)
+	if err != nil {
+		return nil, err
+	}
+	return response, nil
+}