camelcase structs returned over RPC (#1507)

substrate/core/sr-version/src/lib.rs

@@ -71,7 +71,8 @@ macro_rules! create_apis_vec {
 /// In particular: bug fixes should result in an increment of `spec_version` and possibly `authoring_version`,
 /// absolutely not `impl_version` since they change the semantics of the runtime.
 #[derive(Clone, PartialEq, Eq, Encode)]
-#[cfg_attr(feature = "std", derive(Debug, Serialize, Deserialize, Decode))]
+#[cfg_attr(feature = "std", derive(Debug, Serialize, Decode))]
+#[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
 pub struct RuntimeVersion {
 	/// Identifies the different Substrate runtimes. There'll be at least polkadot and node.
 	/// A different on-chain spec_name to that of the native runtime would normally result
@@ -103,6 +104,7 @@ pub struct RuntimeVersion {
 	pub impl_version: u32,
 
 	/// List of supported API "features" along with their versions.
+	#[cfg_attr(feature = "std", serde(serialize_with = "apis_serialize::serialize"))]
 	pub apis: ApisVec,
 }
 
@@ -154,3 +156,36 @@ impl NativeVersion {
 			self.can_author_with.contains(&other.authoring_version))
 	}
 }
+
+#[cfg(feature = "std")]
+mod apis_serialize {
+	extern crate impl_serde;
+	extern crate serde;
+
+	use super::*;
+	use self::impl_serde::serialize as bytes;
+	use self::serde::{Serializer, ser::SerializeTuple};
+
+	#[derive(Serialize)]
+	struct ApiId<'a>(
+		#[serde(serialize_with="serialize_bytesref")] &'a super::ApiId,
+		&'a u32,
+	);
+
+	pub fn serialize<S>(apis: &ApisVec, ser: S) -> Result<S::Ok, S::Error> where
+		S: Serializer,
+	{
+		let len = apis.len();
+		let mut seq = ser.serialize_tuple(len)?;
+		for (api, ver) in &**apis {
+			seq.serialize_element(&ApiId(api, ver))?;
+		}
+		seq.end()
+	}
+
+	pub fn serialize_bytesref<S>(apis: &&super::ApiId, ser: S) -> Result<S::Ok, S::Error> where
+		S: Serializer,
+	{
+		bytes::serialize(*apis, ser)
+	}
+}