From eb767a2b325a304e196fca87dd8e644f1e8086d6 Mon Sep 17 00:00:00 2001
From: Pierre Krieger <pierre.krieger1708@gmail.com>
Date: Sat, 10 Sep 2022 13:25:55 +0200
Subject: [PATCH] Add support for system_nodeRoles (#2725)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
---
 bin/light-base/src/json_rpc_service.rs         |  5 ++++-
 bin/light-base/src/json_rpc_service/getters.rs | 17 ++++++++++++++++-
 bin/wasm-node/CHANGELOG.md                     |  4 ++++
 src/json_rpc/methods.rs                        | 13 ++++++++++++-
 4 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/bin/light-base/src/json_rpc_service.rs b/bin/light-base/src/json_rpc_service.rs
index 8b5785471c..be0e7483fb 100644
--- a/bin/light-base/src/json_rpc_service.rs
+++ b/bin/light-base/src/json_rpc_service.rs
@@ -918,6 +918,10 @@ impl<TPlat: Platform> Background<TPlat> {
                 self.system_name(request_id, &state_machine_request_id)
                     .await;
             }
+            methods::MethodCall::system_nodeRoles {} => {
+                self.system_node_roles(request_id, &state_machine_request_id)
+                    .await;
+            }
             methods::MethodCall::system_peers {} => {
                 self.system_peers(request_id, &state_machine_request_id)
                     .await;
@@ -1109,7 +1113,6 @@ impl<TPlat: Platform> Background<TPlat> {
             | methods::MethodCall::system_addReservedPeer { .. }
             | methods::MethodCall::system_dryRun { .. }
             | methods::MethodCall::system_networkState { .. }
-            | methods::MethodCall::system_nodeRoles { .. }
             | methods::MethodCall::system_removeReservedPeer { .. }
             | methods::MethodCall::network_unstable_subscribeEvents { .. }
             | methods::MethodCall::network_unstable_unsubscribeEvents { .. }) => {
diff --git a/bin/light-base/src/json_rpc_service/getters.rs b/bin/light-base/src/json_rpc_service/getters.rs
index 53ad29393d..eac46e18ed 100644
--- a/bin/light-base/src/json_rpc_service/getters.rs
+++ b/bin/light-base/src/json_rpc_service/getters.rs
@@ -19,7 +19,7 @@
 
 use super::{Background, Platform};
 
-use alloc::{format, string::ToString as _, sync::Arc, vec::Vec};
+use alloc::{borrow::Cow, format, string::ToString as _, sync::Arc, vec::Vec};
 use core::num::NonZeroUsize;
 use smoldot::{
     header,
@@ -251,6 +251,21 @@ impl<TPlat: Platform> Background<TPlat> {
             .await;
     }
 
+    /// Handles a call to [`methods::MethodCall::system_nodeRoles`].
+    pub(super) async fn system_node_roles(
+        self: &Arc<Self>,
+        request_id: &str,
+        state_machine_request_id: &requests_subscriptions::RequestId,
+    ) {
+        self.requests_subscriptions
+            .respond(
+                state_machine_request_id,
+                methods::Response::system_nodeRoles(Cow::Borrowed(&[methods::NodeRole::Light]))
+                    .to_json_response(request_id),
+            )
+            .await;
+    }
+
     /// Handles a call to [`methods::MethodCall::system_peers`].
     pub(super) async fn system_peers(
         self: &Arc<Self>,
diff --git a/bin/wasm-node/CHANGELOG.md b/bin/wasm-node/CHANGELOG.md
index bcfd97a94f..6cff939c36 100644
--- a/bin/wasm-node/CHANGELOG.md
+++ b/bin/wasm-node/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Added
+
+- Add support for the `system_nodeRoles` JSON-RPC method. ([#2725](https://github.com/paritytech/smoldot/pull/2725))
+
 ## 0.6.32 - 2022-09-07
 
 ### Fixed
diff --git a/src/json_rpc/methods.rs b/src/json_rpc/methods.rs
index 83b836f094..3af43dfb33 100644
--- a/src/json_rpc/methods.rs
+++ b/src/json_rpc/methods.rs
@@ -393,7 +393,7 @@ define_methods! {
     /// Returns, as an opaque string, the name of the client serving these JSON-RPC requests.
     system_name() -> Cow<'a, str>,
     system_networkState() -> (), // TODO:
-    system_nodeRoles() -> (), // TODO:
+    system_nodeRoles() -> Cow<'a, [NodeRole]>,
     system_peers() -> Vec<SystemPeer>,
     system_properties() -> Box<serde_json::value::RawValue>,
     system_removeReservedPeer() -> (), // TODO:
@@ -900,6 +900,17 @@ pub enum MaybeRuntimeSpec<'a> {
     Invalid { error: String }, // TODO: String because it's more convenient; improve
 }
 
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
+pub enum NodeRole {
+    // Note that "Light" isn't in the Substrate source code and is a custom addition.
+    #[serde(rename = "Light")]
+    Light,
+    #[serde(rename = "Full")]
+    Full,
+    #[serde(rename = "Authority")]
+    Authority,
+}
+
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub struct RuntimeSpec<'a> {
     #[serde(rename = "specName")]