Use msgpack for API

Cargo.lock

@@ -200,9 +200,9 @@ checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
 
 [[package]]
 name = "cc"
-version = "1.2.53"
+version = "1.2.54"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "755d2fce177175ffca841e9a06afdb2c4ab0f593d53b4dee48147dfaade85932"
+checksum = "6354c81bbfd62d9cfa9cb3c773c2b7b2a3a482d569de977fd0e961f6e7c00583"
 dependencies = [
  "find-msvc-tools",
  "jobserver",
@@ -2214,10 +2214,12 @@ dependencies = [
  "rbx_xml",
  "reqwest",
  "ritz",
+ "rmp-serde",
  "roblox_install",
  "rojo-insta-ext",
  "semver",
  "serde",
+ "serde_bytes",
  "serde_json",
  "serde_yaml",
  "strum",
@@ -2358,6 +2360,16 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde_bytes"
+version = "0.11.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a5d440709e79d88e51ac01c4b72fc6cb7314017bb7da9eeff678aa94c10e3ea8"
+dependencies = [
+ "serde",
+ "serde_core",
+]
+
 [[package]]
 name = "serde_cbor"
 version = "0.11.2"
@@ -2501,9 +2513,9 @@ dependencies = [
 
 [[package]]
 name = "socket2"
-version = "0.6.1"
+version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "17129e116933cf371d018bb80ae557e889637989d8638274fb25622827b03881"
+checksum = "86f4aa3ad99f2088c990dfa82d367e19cb29268ed67c574d10d0a4bfe71f07e0"
 dependencies = [
  "libc",
  "windows-sys 0.60.2",
@@ -2698,7 +2710,7 @@ dependencies = [
  "libc",
  "mio 1.1.1",
  "pin-project-lite",
- "socket2 0.6.1",
+ "socket2 0.6.2",
  "tokio-macros",
  "windows-sys 0.61.2",
 ]
@@ -2940,9 +2952,9 @@ checksum = "b6c140620e7ffbb22c2dee59cafe6084a59b5ffc27a8859a5f0d494b5d52b6be"
 
 [[package]]
 name = "uuid"
-version = "1.19.0"
+version = "1.20.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2e054861b4bd027cd373e18e8d8d8e6548085000e41290d95ce0c373a654b4a"
+checksum = "ee48d38b119b0cd71fe4141b30f5ba9c7c5d9f4e7a3a8b4a674e4b6ef789976f"
 dependencies = [
  "getrandom 0.3.4",
  "js-sys",
@@ -3487,18 +3499,18 @@ dependencies = [
 
 [[package]]
 name = "zerocopy"
-version = "0.8.33"
+version = "0.8.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "668f5168d10b9ee831de31933dc111a459c97ec93225beb307aed970d1372dfd"
+checksum = "71ddd76bcebeed25db614f82bf31a9f4222d3fbba300e6fb6c00afa26cbd4d9d"
 dependencies = [
  "zerocopy-derive",
 ]
 
 [[package]]
 name = "zerocopy-derive"
-version = "0.8.33"
+version = "0.8.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2c7962b26b0a8685668b671ee4b54d007a67d4eaf05fda79ac0ecf41e32270f1"
+checksum = "d8187381b52e32220d50b255276aa16a084ec0a9017a0ca2152a1f55c539758d"
 dependencies = [
  "proc-macro2 1.0.106",
  "quote 1.0.44",
@@ -3561,9 +3573,9 @@ dependencies = [
 
 [[package]]
 name = "zmij"
-version = "1.0.16"
+version = "1.0.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dfcd145825aace48cff44a8844de64bf75feec3080e0aa5cdbde72961ae51a65"
+checksum = "02aae0f83f69aafc94776e879363e9771d7ecbffe2c7fbb6c14c5e00dfe88439"
 
 [[package]]
 name = "zstd"

Cargo.toml

@@ -87,7 +87,7 @@ toml = "0.5.11"
 termcolor = "1.4.1"
 thiserror = "1.0.69"
 tokio = { version = "1.49.0", features = ["rt", "rt-multi-thread", "macros"] }
-uuid = { version = "1.19.0", features = ["v4", "serde"] }
+uuid = { version = "1.20.0", features = ["v4", "serde"] }
 clap = { version = "3.2.25", features = ["derive"] }
 profiling = "1.0.17"
 yaml-rust2 = "0.10.4"
@@ -96,6 +96,8 @@ data-encoding = "2.10.0"
 blake3 = "1.8.3"
 float-cmp = "0.9.0"
 indexmap = { version = "2.13.0", features = ["serde"] }
+rmp-serde = "1.3.1"
+serde_bytes = "0.11.19"
 
 [target.'cfg(windows)'.dependencies]
 winreg = "0.10.1"

build.rs

@@ -30,6 +30,20 @@ fn snapshot_from_fs_path(path: &Path) -> io::Result<VfsSnapshot> {
                 continue;
             }
 
+            // Skip binary asset files that can't be read as text
+            if file_name.ends_with(".png")
+                || file_name.ends_with(".jpg")
+                || file_name.ends_with(".gif")
+                || file_name.ends_with(".webp")
+            {
+                continue;
+            }
+
+            // Skip directories that aren't needed for plugin functionality
+            if file_name == "assets" || file_name == "benchmark" {
+                continue;
+            }
+
             let child_snapshot = snapshot_from_fs_path(&entry.path())?;
             children.push((file_name, child_snapshot));
         }
@@ -66,6 +80,7 @@ fn main() -> Result<(), anyhow::Error> {
             "fmt" => snapshot_from_fs_path(&plugin_dir.join("fmt"))?,
             "http" => snapshot_from_fs_path(&plugin_dir.join("http"))?,
             "log" => snapshot_from_fs_path(&plugin_dir.join("log"))?,
+            "msgpack" => snapshot_from_fs_path(&plugin_dir.join("msgpack.lua"))?,
             "rbx_dom_lua" => snapshot_from_fs_path(&plugin_dir.join("rbx_dom_lua"))?,
             "src" => snapshot_from_fs_path(&plugin_dir.join("src"))?,
             "Packages" => snapshot_from_fs_path(&plugin_dir.join("Packages"))?,

plugin/http/Response.lua

@@ -1,5 +1,6 @@
 local HttpService = game:GetService("HttpService")
-local JSON5Decoder = require(script.Parent.Parent.json5.JSON5Decoder)
+
+local msgpack = require(script.Parent.Parent.msgpack)
 
 local stringTemplate = [[
 Http.Response {
@@ -29,13 +30,11 @@ function Response:isSuccess()
 end
 
 function Response:json()
-	-- Try fast native decode first, fallback to JSON5 for NaN/Infinity
+	return HttpService:JSONDecode(self.body)
-	local success, result = pcall(HttpService.JSONDecode, HttpService, self.body)
+end
-	if success then
+
-		return result
+function Response:msgpack()
-	end
+	return msgpack.decode(self.body)
-	print("[HTTP Response:json()] Native decode failed, using JSON5 for size:", #self.body)
-	return JSON5Decoder.Decode(self.body)
 end
 
 return Response

plugin/http/init.lua

@@ -1,9 +1,8 @@
 local HttpService = game:GetService("HttpService")
 
-local Promise = require(script.Parent.Promise)
 local Log = require(script.Parent.Log)
-local JSON5Decoder = require(script.Parent.json5.JSON5Decoder)
+local msgpack = require(script.Parent.msgpack)
-local JSONEncoder = require(script.Parent.json5.JSONEncoder)
+local Promise = require(script.Parent.Promise)
 
 local HttpError = require(script.Error)
 local HttpResponse = require(script.Response)
@@ -63,17 +62,19 @@ function Http.post(url, body)
 end
 
 function Http.jsonEncode(object)
-	return JSONEncoder.Compact5(object)
+	return HttpService:JSONEncode(object)
 end
 
 function Http.jsonDecode(source)
-	-- Try fast native decode first, fallback to JSON5 for NaN/Infinity
+	return HttpService:JSONDecode(source)
-	local success, result = pcall(HttpService.JSONDecode, HttpService, source)
+end
-	if success then
+
-		return result
+function Http.msgpackEncode(object)
-	end
+	return msgpack.encode(object)
-	print("[Http.jsonDecode] Native decode failed, using JSON5 for size:", #source)
+end
-	return JSON5Decoder.Decode(source)
+
+function Http.msgpackDecode(source)
+	return msgpack.decode(source)
 end
 
 return Http

plugin/msgpack.lua

@@ -0,0 +1,2 @@
+-- Module alias for msgpack-luau
+return require(script.Parent.Packages["msgpack-luau"].src.msgpack)

plugin/src/ApiContext.lua

@@ -145,7 +145,7 @@ function ApiContext:connect()
 
 	return Http.get(url)
 		:andThen(rejectFailedRequests)
-		:andThen(Http.Response.json)
+		:andThen(Http.Response.msgpack)
 		:andThen(rejectWrongProtocolVersion)
 		:andThen(function(body)
 			assert(validateApiInfo(body))
@@ -163,7 +163,7 @@ end
 function ApiContext:read(ids)
 	local url = ("%s/api/read/%s"):format(self.__baseUrl, table.concat(ids, ","))
 
-	return Http.get(url):andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(body)
+	return Http.get(url):andThen(rejectFailedRequests):andThen(Http.Response.msgpack):andThen(function(body)
 		if body.sessionId ~= self.__sessionId then
 			return Promise.reject("Server changed ID")
 		end
@@ -191,9 +191,9 @@ function ApiContext:write(patch)
 		table.insert(updated, fixedUpdate)
 	end
 
-	-- Only add the 'added' field if the table is non-empty, or else Roblox's
+	-- Only add the 'added' field if the table is non-empty, or else the msgpack
-	-- JSON implementation will turn the table into an array instead of an
+	-- encode implementation will turn the table into an array instead of a map,
-	-- object, causing API validation to fail.
+	-- causing API validation to fail.
 	local added
 	if next(patch.added) ~= nil then
 		added = patch.added
@@ -206,9 +206,12 @@ function ApiContext:write(patch)
 		added = added,
 	}
 
-	body = Http.jsonEncode(body)
+	body = Http.msgpackEncode(body)
 
-	return Http.post(url, body):andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(responseBody)
+	return Http.post(url, body)
+		:andThen(rejectFailedRequests)
+		:andThen(Http.Response.msgpack)
+		:andThen(function(responseBody)
 			Log.info("Write response: {:?}", responseBody)
 
 			return responseBody
@@ -234,7 +237,7 @@ function ApiContext:connectWebSocket(packetHandlers)
 		local closed, errored, received
 
 		received = self.__wsClient.MessageReceived:Connect(function(msg)
-			local data = Http.jsonDecode(msg)
+			local data = Http.msgpackDecode(msg)
 			if data.sessionId ~= self.__sessionId then
 				Log.warn("Received message with wrong session ID; ignoring")
 				return
@@ -280,7 +283,7 @@ end
 function ApiContext:open(id)
 	local url = ("%s/api/open/%s"):format(self.__baseUrl, id)
 
-	return Http.post(url, ""):andThen(rejectFailedRequests):andThen(Http.Response.json):andThen(function(body)
+	return Http.post(url, ""):andThen(rejectFailedRequests):andThen(Http.Response.msgpack):andThen(function(body)
 		if body.sessionId ~= self.__sessionId then
 			return Promise.reject("Server changed ID")
 		end
@@ -290,38 +293,30 @@ function ApiContext:open(id)
 end
 
 function ApiContext:serialize(ids: { string })
-	local url = ("%s/api/serialize"):format(self.__baseUrl)
+	local url = ("%s/api/serialize/%s"):format(self.__baseUrl, table.concat(ids, ","))
-	local request_body = Http.jsonEncode({ sessionId = self.__sessionId, ids = ids })
 
-	return Http.post(url, request_body)
+	return Http.get(url):andThen(rejectFailedRequests):andThen(Http.Response.msgpack):andThen(function(body)
-		:andThen(rejectFailedRequests)
+		if body.sessionId ~= self.__sessionId then
-		:andThen(Http.Response.json)
-		:andThen(function(response_body)
-			if response_body.sessionId ~= self.__sessionId then
 			return Promise.reject("Server changed ID")
 		end
 
-			assert(validateApiSerialize(response_body))
+		assert(validateApiSerialize(body))
 
-			return response_body
+		return body
 	end)
 end
 
 function ApiContext:refPatch(ids: { string })
-	local url = ("%s/api/ref-patch"):format(self.__baseUrl)
+	local url = ("%s/api/ref-patch/%s"):format(self.__baseUrl, table.concat(ids, ","))
-	local request_body = Http.jsonEncode({ sessionId = self.__sessionId, ids = ids })
 
-	return Http.post(url, request_body)
+	return Http.get(url):andThen(rejectFailedRequests):andThen(Http.Response.msgpack):andThen(function(body)
-		:andThen(rejectFailedRequests)
+		if body.sessionId ~= self.__sessionId then
-		:andThen(Http.Response.json)
-		:andThen(function(response_body)
-			if response_body.sessionId ~= self.__sessionId then
 			return Promise.reject("Server changed ID")
 		end
 
-			assert(validateApiRefPatch(response_body))
+		assert(validateApiRefPatch(body))
 
-			return response_body
+		return body
 	end)
 end
 

src/json.rs

@@ -163,6 +163,7 @@ impl serde::ser::Error for CompactJson5Error {
 /// # Errors
 ///
 /// Returns an error if the value cannot be serialized to JSON5.
+#[allow(dead_code)]
 pub fn to_string_compact<T: Serialize>(value: &T) -> anyhow::Result<String> {
     let mut output = String::new();
     let mut serializer = CompactJson5Serializer {

src/web/api.rs

@@ -19,7 +19,6 @@ use rbx_dom_weak::{
 };
 
 use crate::{
-    json,
     serve_session::ServeSession,
     snapshot::{InstanceWithMeta, PatchSet, PatchUpdate},
     web::{
@@ -28,12 +27,9 @@ use crate::{
             ServerInfoResponse, SocketPacket, SocketPacketBody, SocketPacketType, SubscribeMessage,
             WriteRequest, WriteResponse, PROTOCOL_VERSION, SERVER_VERSION,
         },
-        util::{json_ok, json_response},
+        util::{deserialize_msgpack, msgpack, msgpack_ok, serialize_msgpack},
-    },
-    web_api::{
-        BufferEncode, InstanceUpdate, RefPatchRequest, RefPatchResponse, SerializeRequest,
-        SerializeResponse,
     },
+    web_api::{InstanceUpdate, RefPatchResponse, SerializeResponse},
 };
 
 pub async fn call(serve_session: Arc<ServeSession>, mut request: Request<Body>) -> Response<Body> {
@@ -48,7 +44,7 @@ pub async fn call(serve_session: Arc<ServeSession>, mut request: Request<Body>)
             if is_upgrade_request(&request) {
                 service.handle_api_socket(&mut request).await
             } else {
-                json_response(
+                msgpack(
                     ErrorResponse::bad_request(
                         "/api/socket must be called as a websocket upgrade request",
                     ),
@@ -56,15 +52,19 @@ pub async fn call(serve_session: Arc<ServeSession>, mut request: Request<Body>)
                 )
             }
         }
-        (&Method::POST, "/api/serialize") => service.handle_api_serialize(request).await,
+        (&Method::GET, path) if path.starts_with("/api/serialize/") => {
-        (&Method::POST, "/api/ref-patch") => service.handle_api_ref_patch(request).await,
+            service.handle_api_serialize(request).await
+        }
+        (&Method::GET, path) if path.starts_with("/api/ref-patch/") => {
+            service.handle_api_ref_patch(request).await
+        }
 
         (&Method::POST, path) if path.starts_with("/api/open/") => {
             service.handle_api_open(request).await
         }
         (&Method::POST, "/api/write") => service.handle_api_write(request).await,
 
-        (_method, path) => json_response(
+        (_method, path) => msgpack(
             ErrorResponse::not_found(format!("Route not found: {}", path)),
             StatusCode::NOT_FOUND,
         ),
@@ -85,7 +85,7 @@ impl ApiService {
         let tree = self.serve_session.tree();
         let root_instance_id = tree.get_root_id();
 
-        json_ok(&ServerInfoResponse {
+        msgpack_ok(&ServerInfoResponse {
             server_version: SERVER_VERSION.to_owned(),
             protocol_version: PROTOCOL_VERSION,
             session_id: self.serve_session.session_id(),
@@ -105,7 +105,7 @@ impl ApiService {
         let input_cursor: u32 = match argument.parse() {
             Ok(v) => v,
             Err(err) => {
-                return json_response(
+                return msgpack(
                     ErrorResponse::bad_request(format!("Malformed message cursor: {}", err)),
                     StatusCode::BAD_REQUEST,
                 );
@@ -116,7 +116,7 @@ impl ApiService {
         let (response, websocket) = match upgrade(request, None) {
             Ok(result) => result,
             Err(err) => {
-                return json_response(
+                return msgpack(
                     ErrorResponse::internal_error(format!("WebSocket upgrade failed: {}", err)),
                     StatusCode::INTERNAL_SERVER_ERROR,
                 );
@@ -143,10 +143,10 @@ impl ApiService {
 
         let body = body::to_bytes(request.into_body()).await.unwrap();
 
-        let request: WriteRequest = match json::from_slice(&body) {
+        let request: WriteRequest = match deserialize_msgpack(&body) {
             Ok(request) => request,
             Err(err) => {
-                return json_response(
+                return msgpack(
                     ErrorResponse::bad_request(format!("Invalid body: {}", err)),
                     StatusCode::BAD_REQUEST,
                 );
@@ -154,7 +154,7 @@ impl ApiService {
         };
 
         if request.session_id != session_id {
-            return json_response(
+            return msgpack(
                 ErrorResponse::bad_request("Wrong session ID"),
                 StatusCode::BAD_REQUEST,
             );
@@ -180,7 +180,7 @@ impl ApiService {
             })
             .unwrap();
 
-        json_ok(WriteResponse { session_id })
+        msgpack_ok(WriteResponse { session_id })
     }
 
     async fn handle_api_read(&self, request: Request<Body>) -> Response<Body> {
@@ -190,7 +190,7 @@ impl ApiService {
         let requested_ids = match requested_ids {
             Ok(ids) => ids,
             Err(_) => {
-                return json_response(
+                return msgpack(
                     ErrorResponse::bad_request("Malformed ID list"),
                     StatusCode::BAD_REQUEST,
                 );
@@ -254,7 +254,7 @@ impl ApiService {
             }
         }
 
-        json_ok(ReadResponse {
+        msgpack_ok(ReadResponse {
             session_id: self.serve_session.session_id(),
             message_cursor,
             instances,
@@ -269,30 +269,23 @@ impl ApiService {
     /// that correspond to the requested Instances. These values have their
     /// `Value` property set to point to the requested Instance.
     async fn handle_api_serialize(&self, request: Request<Body>) -> Response<Body> {
-        let session_id = self.serve_session.session_id();
+        let argument = &request.uri().path()["/api/serialize/".len()..];
-        let body = body::to_bytes(request.into_body()).await.unwrap();
+        let requested_ids: Result<Vec<Ref>, _> = argument.split(',').map(Ref::from_str).collect();
 
-        let request: SerializeRequest = match json::from_slice(&body) {
+        let requested_ids = match requested_ids {
-            Ok(request) => request,
+            Ok(ids) => ids,
-            Err(err) => {
+            Err(_) => {
-                return json_response(
+                return msgpack(
-                    ErrorResponse::bad_request(format!("Invalid body: {}", err)),
+                    ErrorResponse::bad_request("Malformed ID list"),
                     StatusCode::BAD_REQUEST,
                 );
             }
         };
 
-        if request.session_id != session_id {
-            return json_response(
-                ErrorResponse::bad_request("Wrong session ID"),
-                StatusCode::BAD_REQUEST,
-            );
-        }
-
         let mut response_dom = WeakDom::new(InstanceBuilder::new("Folder"));
 
         let tree = self.serve_session.tree();
-        for id in &request.ids {
+        for id in &requested_ids {
             if let Some(instance) = tree.get_instance(*id) {
                 let clone = response_dom.insert(
                     Ref::none(),
@@ -316,7 +309,7 @@ impl ApiService {
 
                 response_dom.transfer_within(child_ref, object_value);
             } else {
-                json_response(
+                msgpack(
                     ErrorResponse::bad_request(format!("provided id {id} is not in the tree")),
                     StatusCode::BAD_REQUEST,
                 );
@@ -327,9 +320,9 @@ impl ApiService {
         let mut source = Vec::new();
         rbx_binary::to_writer(&mut source, &response_dom, &[response_dom.root_ref()]).unwrap();
 
-        json_ok(SerializeResponse {
+        msgpack_ok(SerializeResponse {
             session_id: self.serve_session.session_id(),
-            model_contents: BufferEncode::new(source),
+            model_contents: source,
         })
     }
 
@@ -337,26 +330,22 @@ impl ApiService {
     /// provided IDs. Used because the plugin does not store a RojoTree,
     /// and referent properties need to be updated after the serialize
     /// endpoint is used.
-    async fn handle_api_ref_patch(self, request: Request<Body>) -> Response<Body> {
+    async fn handle_api_ref_patch(&self, request: Request<Body>) -> Response<Body> {
-        let session_id = self.serve_session.session_id();
+        let argument = &request.uri().path()["/api/ref-patch/".len()..];
-        let body = body::to_bytes(request.into_body()).await.unwrap();
+        let requested_ids: Result<Vec<Ref>, _> = argument.split(',').map(Ref::from_str).collect();
 
-        let request: RefPatchRequest = match json::from_slice(&body) {
+        let requested_ids = match requested_ids {
-            Ok(request) => request,
+            Ok(ids) => ids,
-            Err(err) => {
+            Err(_) => {
-                return json_response(
+                return msgpack(
-                    ErrorResponse::bad_request(format!("Invalid body: {}", err)),
+                    ErrorResponse::bad_request("Malformed ID list"),
                     StatusCode::BAD_REQUEST,
                 );
             }
         };
 
-        if request.session_id != session_id {
+        // Convert to HashSet for efficient lookup
-            return json_response(
+        let ids: HashSet<Ref> = requested_ids.into_iter().collect();
-                ErrorResponse::bad_request("Wrong session ID"),
-                StatusCode::BAD_REQUEST,
-            );
-        }
 
         let mut instance_updates: HashMap<Ref, InstanceUpdate> = HashMap::new();
 
@@ -366,7 +355,7 @@ impl ApiService {
                 let Variant::Ref(prop_value) = prop_value else {
                     continue;
                 };
-                if let Some(target_id) = request.ids.get(prop_value) {
+                if let Some(target_id) = ids.get(prop_value) {
                     let instance_id = instance.id();
                     let update =
                         instance_updates
@@ -385,7 +374,7 @@ impl ApiService {
             }
         }
 
-        json_ok(RefPatchResponse {
+        msgpack_ok(RefPatchResponse {
             session_id: self.serve_session.session_id(),
             patch: SubscribeMessage {
                 added: HashMap::new(),
@@ -401,7 +390,7 @@ impl ApiService {
         let requested_id = match Ref::from_str(argument) {
             Ok(id) => id,
             Err(_) => {
-                return json_response(
+                return msgpack(
                     ErrorResponse::bad_request("Invalid instance ID"),
                     StatusCode::BAD_REQUEST,
                 );
@@ -413,7 +402,7 @@ impl ApiService {
         let instance = match tree.get_instance(requested_id) {
             Some(instance) => instance,
             None => {
-                return json_response(
+                return msgpack(
                     ErrorResponse::bad_request("Instance not found"),
                     StatusCode::NOT_FOUND,
                 );
@@ -423,7 +412,7 @@ impl ApiService {
         let script_path = match pick_script_path(instance) {
             Some(path) => path,
             None => {
-                return json_response(
+                return msgpack(
                     ErrorResponse::bad_request(
                         "No appropriate file could be found to open this script",
                     ),
@@ -436,7 +425,7 @@ impl ApiService {
             Ok(()) => {}
             Err(error) => match error {
                 OpenError::Io(io_error) => {
-                    return json_response(
+                    return msgpack(
                         ErrorResponse::internal_error(format!(
                             "Attempting to open {} failed because of the following io error: {}",
                             script_path.display(),
@@ -450,7 +439,7 @@ impl ApiService {
                     status,
                     stderr,
                 } => {
-                    return json_response(
+                    return msgpack(
                         ErrorResponse::internal_error(format!(
                             r#"The command '{}' to open '{}' failed with the error code '{}'.
                             Error logs:
@@ -466,7 +455,7 @@ impl ApiService {
             },
         };
 
-        json_ok(OpenResponse {
+        msgpack_ok(OpenResponse {
             session_id: self.serve_session.session_id(),
         })
     }
@@ -531,7 +520,7 @@ async fn handle_websocket_subscription(
                 match result {
                     Ok((new_cursor, messages)) => {
                         if !messages.is_empty() {
-                            let json_message = {
+                            let msgpack_message = {
                                 let tree = tree_handle.lock().unwrap();
                                 let api_messages: Vec<_> = messages
                                     .into_iter()
@@ -555,13 +544,12 @@ async fn handle_websocket_subscription(
                                     }),
                                 };
 
-                                // Use compact JSON5 encoder for transport efficiency, preserves NaN/Infinity
+                                serialize_msgpack(response)?
-                                json::to_string_compact(&response)?
                             };
 
                             log::debug!("Sending batch of messages over WebSocket subscription");
 
-                            if websocket.send(Message::Text(json_message)).await.is_err() {
+                            if websocket.send(Message::Binary(msgpack_message)).await.is_err() {
                                 // Client disconnected
                                 log::debug!("WebSocket subscription closed by client");
                                 break;
@@ -677,7 +665,7 @@ fn filter_subscribe_message_for_scripts(
     // ALL instances get ignoreUnknownInstances: true in scripts-only mode
     // This ensures we only sync script content, never delete/modify other instances
     // Non-scripts also have their properties cleared - they're just tree structure
-    for (_id, inst) in &mut msg.added {
+    for inst in msg.added.values_mut() {
         inst.metadata = Some(InstanceMetadata {
             ignore_unknown_instances: true,
         });

src/web/interface.rs

@@ -160,9 +160,33 @@ pub struct ServerInfoResponse {
     pub server_version: String,
     pub protocol_version: u64,
     pub project_name: String,
+    #[serde(
+        serialize_with = "serialize_place_ids",
+        deserialize_with = "deserialize_place_ids",
+        skip_serializing_if = "Option::is_none",
+        default
+    )]
     pub expected_place_ids: Option<HashSet<u64>>,
+    #[serde(
+        serialize_with = "serialize_place_ids",
+        deserialize_with = "deserialize_place_ids",
+        skip_serializing_if = "Option::is_none",
+        default
+    )]
     pub unexpected_place_ids: Option<HashSet<u64>>,
+    #[serde(
+        serialize_with = "serialize_optional_u64_as_f64",
+        deserialize_with = "deserialize_optional_f64_as_u64",
+        skip_serializing_if = "Option::is_none",
+        default
+    )]
     pub game_id: Option<u64>,
+    #[serde(
+        serialize_with = "serialize_optional_u64_as_f64",
+        deserialize_with = "deserialize_optional_f64_as_u64",
+        skip_serializing_if = "Option::is_none",
+        default
+    )]
     pub place_id: Option<u64>,
     pub root_instance_id: Ref,
     /// When true, the server only supports syncing script Source property changes.
@@ -171,6 +195,50 @@ pub struct ServerInfoResponse {
     pub sync_source_only: bool,
 }
 
+// Serialize place IDs as f64 to avoid msgpack uint64 encoding issues with Lua
+fn serialize_place_ids<S>(ids: &Option<HashSet<u64>>, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    match ids {
+        Some(set) => {
+            use serde::ser::SerializeSeq;
+            let mut seq = serializer.serialize_seq(Some(set.len()))?;
+            for id in set {
+                seq.serialize_element(&(*id as f64))?;
+            }
+            seq.end()
+        }
+        None => serializer.serialize_none(),
+    }
+}
+
+fn deserialize_place_ids<'de, D>(deserializer: D) -> Result<Option<HashSet<u64>>, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let opt: Option<Vec<f64>> = Option::deserialize(deserializer)?;
+    Ok(opt.map(|v| v.into_iter().map(|f| f as u64).collect()))
+}
+
+fn serialize_optional_u64_as_f64<S>(value: &Option<u64>, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    match value {
+        Some(v) => serializer.serialize_f64(*v as f64),
+        None => serializer.serialize_none(),
+    }
+}
+
+fn deserialize_optional_f64_as_u64<'de, D>(deserializer: D) -> Result<Option<u64>, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let opt: Option<f64> = Option::deserialize(deserializer)?;
+    Ok(opt.map(|f| f as u64))
+}
+
 /// Response body from /api/read/{id}
 #[derive(Debug, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -253,31 +321,8 @@ pub struct SerializeRequest {
 #[serde(rename_all = "camelCase")]
 pub struct SerializeResponse {
     pub session_id: SessionId,
-    pub model_contents: BufferEncode,
+    #[serde(with = "serde_bytes")]
-}
+    pub model_contents: Vec<u8>,
-
-/// Using this struct we can force Roblox to JSONDecode this as a buffer.
-/// This is what Roblox's serde APIs use, so it saves a step in the plugin.
-#[derive(Debug, Serialize, Deserialize)]
-pub struct BufferEncode {
-    m: (),
-    t: Cow<'static, str>,
-    base64: String,
-}
-
-impl BufferEncode {
-    pub fn new(content: Vec<u8>) -> Self {
-        let base64 = data_encoding::BASE64.encode(&content);
-        Self {
-            m: (),
-            t: Cow::Borrowed("buffer"),
-            base64,
-        }
-    }
-
-    pub fn model(&self) -> &str {
-        &self.base64
-    }
 }
 
 #[derive(Debug, Serialize, Deserialize)]

src/web/util.rs

@@ -1,18 +1,52 @@
 use hyper::{header::CONTENT_TYPE, Body, Response, StatusCode};
-use serde::Serialize;
+use serde::{Deserialize, Serialize};
 
-use crate::json as json_module;
+pub fn msgpack_ok<T: Serialize>(value: T) -> Response<Body> {
-
+    msgpack(value, StatusCode::OK)
-pub fn json_ok<T: Serialize>(value: T) -> Response<Body> {
-    json_response(value, StatusCode::OK)
 }
 
-/// Alias for backwards compatibility
+pub fn msgpack<T: Serialize>(value: T, code: StatusCode) -> Response<Body> {
-pub use json_response as json;
+    let mut serialized = Vec::new();
+    let mut serializer = rmp_serde::Serializer::new(&mut serialized)
+        .with_human_readable()
+        .with_struct_map();
 
-pub fn json_response<T: Serialize>(value: T, code: StatusCode) -> Response<Body> {
+    if let Err(err) = value.serialize(&mut serializer) {
-    // Use compact JSON5 for transport efficiency, preserves NaN/Infinity
+        return Response::builder()
-    let serialized = match json_module::to_string_compact(&value) {
+            .status(StatusCode::INTERNAL_SERVER_ERROR)
+            .header(CONTENT_TYPE, "text/plain")
+            .body(Body::from(err.to_string()))
+            .unwrap();
+    };
+
+    Response::builder()
+        .status(code)
+        .header(CONTENT_TYPE, "application/msgpack")
+        .body(Body::from(serialized))
+        .unwrap()
+}
+
+pub fn serialize_msgpack<T: Serialize>(value: T) -> anyhow::Result<Vec<u8>> {
+    let mut serialized = Vec::new();
+    let mut serializer = rmp_serde::Serializer::new(&mut serialized)
+        .with_human_readable()
+        .with_struct_map();
+
+    value.serialize(&mut serializer)?;
+
+    Ok(serialized)
+}
+
+pub fn deserialize_msgpack<'a, T: Deserialize<'a>>(
+    input: &'a [u8],
+) -> Result<T, rmp_serde::decode::Error> {
+    let mut deserializer = rmp_serde::Deserializer::new(input).with_human_readable();
+
+    T::deserialize(&mut deserializer)
+}
+
+pub fn json<T: Serialize>(value: T, code: StatusCode) -> Response<Body> {
+    let serialized = match serde_json::to_string(&value) {
         Ok(v) => v,
         Err(err) => {
             return Response::builder()

tests/tests/serve.rs

@@ -646,7 +646,7 @@ fn meshpart_with_id() {
             .unwrap();
 
         let serialize_response = session
-            .get_api_serialize(&[*meshpart, *objectvalue], info.session_id)
+            .get_api_serialize(&[*meshpart, *objectvalue])
             .unwrap();
 
         // We don't assert a snapshot on the SerializeResponse because the model includes the
@@ -673,9 +673,7 @@ fn forced_parent() {
             read_response.intern_and_redact(&mut redactions, root_id)
         );
 
-        let serialize_response = session
+        let serialize_response = session.get_api_serialize(&[root_id]).unwrap();
-            .get_api_serialize(&[root_id], info.session_id)
-            .unwrap();
 
         assert_eq!(serialize_response.session_id, info.session_id);