Use msgpack for API (#1176)

.gitmodules

@@ -16,3 +16,6 @@
 [submodule "plugin/Packages/Highlighter"]
 	path = plugin/Packages/Highlighter
 	url = https://github.com/boatbomber/highlighter.git
+[submodule "plugin/Packages/msgpack-luau"]
+	path = plugin/Packages/msgpack-luau
+	url = https://github.com/cipharius/msgpack-luau/

CHANGELOG.md

@@ -31,6 +31,7 @@ Making a new release? Simply add the new header with the version and date undern
 
 ## Unreleased
 
+* `inf` and `nan` values in properties are now synced ([#1176])
 * Fixed a bug caused by having reference properties (such as `ObjectValue.Value`) that point to an Instance not included in syncback. ([#1179])
 * Fixed instance replacement fallback failing when too many instances needed to be replaced. ([#1192])
 * Added actors and bindable/remote event/function variants to be synced back as JSON files. ([#1199])
@@ -38,6 +39,7 @@ Making a new release? Simply add the new header with the version and date undern
 * Fixed a bug where the notification timeout thread would fail to cancel on unmount ([#1211])
 * Added a "Forget" option to the sync reminder notification to avoid being reminded for that place in the future ([#1215])
 
+[#1176]: https://github.com/rojo-rbx/rojo/pull/1176
 [#1179]: https://github.com/rojo-rbx/rojo/pull/1179
 [#1192]: https://github.com/rojo-rbx/rojo/pull/1192
 [#1199]: https://github.com/rojo-rbx/rojo/pull/1199

Cargo.lock

@@ -2078,10 +2078,12 @@ dependencies = [
  "rbx_xml",
  "reqwest",
  "ritz",
+ "rmp-serde",
  "roblox_install",
  "rojo-insta-ext",
  "semver",
  "serde",
+ "serde_bytes",
  "serde_json",
  "serde_yaml",
  "strum",
@@ -2222,6 +2224,16 @@ 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"

Cargo.toml

@@ -104,6 +104,8 @@ data-encoding = "2.8.0"
 blake3 = "1.5.0"
 float-cmp = "0.9.0"
 indexmap = { version = "2.10.0", features = ["serde"] }
+rmp-serde = "1.3.0"
+serde_bytes = "0.11.19"
 
 [target.'cfg(windows)'.dependencies]
 winreg = "0.10.1"

build.rs

@@ -30,6 +30,11 @@ fn snapshot_from_fs_path(path: &Path) -> io::Result<VfsSnapshot> {
                 continue;
             }
 
+            // Ignore images in msgpack-luau because they aren't UTF-8 encoded.
+            if file_name.ends_with(".png") {
+                continue;
+            }
+
             let child_snapshot = snapshot_from_fs_path(&entry.path())?;
             children.push((file_name, child_snapshot));
         }

plugin/http/Response.lua

@@ -1,5 +1,7 @@
 local HttpService = game:GetService("HttpService")
 
+local msgpack = require(script.Parent.Parent.msgpack)
+
 local stringTemplate = [[
 Http.Response {
 	code: %d
@@ -31,4 +33,8 @@ function Response:json()
 	return HttpService:JSONDecode(self.body)
 end
 
+function Response:msgpack()
+	return msgpack.decode(self.body)
+end
+
 return Response

plugin/http/init.lua

@@ -1,7 +1,8 @@
 local HttpService = game:GetService("HttpService")
 
-local Promise = require(script.Parent.Promise)
 local Log = require(script.Parent.Log)
+local msgpack = require(script.Parent.msgpack)
+local Promise = require(script.Parent.Promise)
 
 local HttpError = require(script.Error)
 local HttpResponse = require(script.Response)
@@ -68,4 +69,12 @@ function Http.jsonDecode(source)
 	return HttpService:JSONDecode(source)
 end
 
+function Http.msgpackEncode(object)
+	return msgpack.encode(object)
+end
+
+function Http.msgpackDecode(source)
+	return msgpack.decode(source)
+end
+
 return Http

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
@@ -206,13 +206,16 @@ 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)
-		Log.info("Write response: {:?}", responseBody)
+		:andThen(rejectFailedRequests)
+		:andThen(Http.Response.msgpack)
+		:andThen(function(responseBody)
+			Log.info("Write response: {:?}", responseBody)
 
-		return responseBody
+			return responseBody
-	end)
+		end)
 end
 
 function ApiContext:connectWebSocket(packetHandlers)
@@ -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
@@ -291,11 +294,11 @@ end
 
 function ApiContext:serialize(ids: { string })
 	local url = ("%s/api/serialize"):format(self.__baseUrl)
-	local request_body = Http.jsonEncode({ sessionId = self.__sessionId, ids = ids })
+	local request_body = Http.msgpackEncode({ sessionId = self.__sessionId, ids = ids })
 
 	return Http.post(url, request_body)
 		:andThen(rejectFailedRequests)
-		:andThen(Http.Response.json)
+		:andThen(Http.Response.msgpack)
 		:andThen(function(response_body)
 			if response_body.sessionId ~= self.__sessionId then
 				return Promise.reject("Server changed ID")
@@ -309,11 +312,11 @@ end
 
 function ApiContext:refPatch(ids: { string })
 	local url = ("%s/api/ref-patch"):format(self.__baseUrl)
-	local request_body = Http.jsonEncode({ sessionId = self.__sessionId, ids = ids })
+	local request_body = Http.msgpackEncode({ sessionId = self.__sessionId, ids = ids })
 
 	return Http.post(url, request_body)
 		:andThen(rejectFailedRequests)
-		:andThen(Http.Response.json)
+		:andThen(Http.Response.msgpack)
 		:andThen(function(response_body)
 			if response_body.sessionId ~= self.__sessionId then
 				return Promise.reject("Server changed ID")

plugin/src/Reconciler/diff.lua

@@ -54,6 +54,10 @@ local function trueEquals(a, b): boolean
 		end
 		return true
 
+	-- For NaN, check if both values are not equal to themselves
+	elseif a ~= a and b ~= b then
+		return true
+
 	-- For numbers, compare with epsilon of 0.0001 to avoid floating point inequality
 	elseif typeA == "number" and typeB == "number" then
 		return fuzzyEq(a, b, 0.0001)

src/snapshot/patch_compute.rs

@@ -8,7 +8,7 @@ use rbx_dom_weak::{
     ustr, HashMapExt as _, UstrMap, UstrSet,
 };
 
-use crate::{RojoRef, REF_POINTER_ATTRIBUTE_PREFIX};
+use crate::{variant_eq::variant_eq, RojoRef, REF_POINTER_ATTRIBUTE_PREFIX};
 
 use super::{
     patch::{PatchAdd, PatchSet, PatchUpdate},
@@ -127,7 +127,7 @@ fn compute_property_patches(
 
         match instance.properties().get(&name) {
             Some(instance_value) => {
-                if &snapshot_value != instance_value {
+                if !variant_eq(&snapshot_value, instance_value) {
                     changed_properties.insert(name, Some(snapshot_value));
                 }
             }

src/web/api.rs

@@ -13,7 +13,6 @@ use rbx_dom_weak::{
 };
 
 use crate::{
-    json,
     serve_session::ServeSession,
     snapshot::{InstanceWithMeta, PatchSet, PatchUpdate},
     web::{
@@ -22,11 +21,10 @@ use crate::{
             ServerInfoResponse, SocketPacket, SocketPacketBody, SocketPacketType, SubscribeMessage,
             WriteRequest, WriteResponse, PROTOCOL_VERSION, SERVER_VERSION,
         },
-        util::{json, json_ok},
+        util::{deserialize_msgpack, msgpack, msgpack_ok, serialize_msgpack},
     },
     web_api::{
-        BufferEncode, InstanceUpdate, RefPatchRequest, RefPatchResponse, SerializeRequest,
+        InstanceUpdate, RefPatchRequest, RefPatchResponse, SerializeRequest, SerializeResponse,
-        SerializeResponse,
     },
 };
 
@@ -42,7 +40,7 @@ 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(
+                msgpack(
                     ErrorResponse::bad_request(
                         "/api/socket must be called as a websocket upgrade request",
                     ),
@@ -58,7 +56,7 @@ pub async fn call(serve_session: Arc<ServeSession>, mut request: Request<Body>)
         }
         (&Method::POST, "/api/write") => service.handle_api_write(request).await,
 
-        (_method, path) => json(
+        (_method, path) => msgpack(
             ErrorResponse::not_found(format!("Route not found: {}", path)),
             StatusCode::NOT_FOUND,
         ),
@@ -79,7 +77,7 @@ 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(),
@@ -98,7 +96,7 @@ impl ApiService {
         let input_cursor: u32 = match argument.parse() {
             Ok(v) => v,
             Err(err) => {
-                return json(
+                return msgpack(
                     ErrorResponse::bad_request(format!("Malformed message cursor: {}", err)),
                     StatusCode::BAD_REQUEST,
                 );
@@ -109,7 +107,7 @@ impl ApiService {
         let (response, websocket) = match upgrade(request, None) {
             Ok(result) => result,
             Err(err) => {
-                return json(
+                return msgpack(
                     ErrorResponse::internal_error(format!("WebSocket upgrade failed: {}", err)),
                     StatusCode::INTERNAL_SERVER_ERROR,
                 );
@@ -136,10 +134,10 @@ 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(
+                return msgpack(
                     ErrorResponse::bad_request(format!("Invalid body: {}", err)),
                     StatusCode::BAD_REQUEST,
                 );
@@ -147,7 +145,7 @@ impl ApiService {
         };
 
         if request.session_id != session_id {
-            return json(
+            return msgpack(
                 ErrorResponse::bad_request("Wrong session ID"),
                 StatusCode::BAD_REQUEST,
             );
@@ -173,7 +171,7 @@ impl ApiService {
             })
             .unwrap();
 
-        json_ok(WriteResponse { session_id })
+        msgpack_ok(WriteResponse { session_id })
     }
 
     async fn handle_api_read(&self, request: Request<Body>) -> Response<Body> {
@@ -183,7 +181,7 @@ impl ApiService {
         let requested_ids = match requested_ids {
             Ok(ids) => ids,
             Err(_) => {
-                return json(
+                return msgpack(
                     ErrorResponse::bad_request("Malformed ID list"),
                     StatusCode::BAD_REQUEST,
                 );
@@ -207,7 +205,7 @@ impl ApiService {
             }
         }
 
-        json_ok(ReadResponse {
+        msgpack_ok(ReadResponse {
             session_id: self.serve_session.session_id(),
             message_cursor,
             instances,
@@ -225,10 +223,10 @@ impl ApiService {
         let session_id = self.serve_session.session_id();
         let body = body::to_bytes(request.into_body()).await.unwrap();
 
-        let request: SerializeRequest = match json::from_slice(&body) {
+        let request: SerializeRequest = match deserialize_msgpack(&body) {
             Ok(request) => request,
             Err(err) => {
-                return json(
+                return msgpack(
                     ErrorResponse::bad_request(format!("Invalid body: {}", err)),
                     StatusCode::BAD_REQUEST,
                 );
@@ -236,7 +234,7 @@ impl ApiService {
         };
 
         if request.session_id != session_id {
-            return json(
+            return msgpack(
                 ErrorResponse::bad_request("Wrong session ID"),
                 StatusCode::BAD_REQUEST,
             );
@@ -269,7 +267,7 @@ impl ApiService {
 
                 response_dom.transfer_within(child_ref, object_value);
             } else {
-                json(
+                msgpack(
                     ErrorResponse::bad_request(format!("provided id {id} is not in the tree")),
                     StatusCode::BAD_REQUEST,
                 );
@@ -280,9 +278,9 @@ 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,
         })
     }
 
@@ -294,10 +292,10 @@ impl ApiService {
         let session_id = self.serve_session.session_id();
         let body = body::to_bytes(request.into_body()).await.unwrap();
 
-        let request: RefPatchRequest = match json::from_slice(&body) {
+        let request: RefPatchRequest = match deserialize_msgpack(&body) {
             Ok(request) => request,
             Err(err) => {
-                return json(
+                return msgpack(
                     ErrorResponse::bad_request(format!("Invalid body: {}", err)),
                     StatusCode::BAD_REQUEST,
                 );
@@ -305,7 +303,7 @@ impl ApiService {
         };
 
         if request.session_id != session_id {
-            return json(
+            return msgpack(
                 ErrorResponse::bad_request("Wrong session ID"),
                 StatusCode::BAD_REQUEST,
             );
@@ -338,7 +336,7 @@ impl ApiService {
             }
         }
 
-        json_ok(RefPatchResponse {
+        msgpack_ok(RefPatchResponse {
             session_id: self.serve_session.session_id(),
             patch: SubscribeMessage {
                 added: HashMap::new(),
@@ -354,7 +352,7 @@ impl ApiService {
         let requested_id = match Ref::from_str(argument) {
             Ok(id) => id,
             Err(_) => {
-                return json(
+                return msgpack(
                     ErrorResponse::bad_request("Invalid instance ID"),
                     StatusCode::BAD_REQUEST,
                 );
@@ -366,7 +364,7 @@ impl ApiService {
         let instance = match tree.get_instance(requested_id) {
             Some(instance) => instance,
             None => {
-                return json(
+                return msgpack(
                     ErrorResponse::bad_request("Instance not found"),
                     StatusCode::NOT_FOUND,
                 );
@@ -376,7 +374,7 @@ impl ApiService {
         let script_path = match pick_script_path(instance) {
             Some(path) => path,
             None => {
-                return json(
+                return msgpack(
                     ErrorResponse::bad_request(
                         "No appropriate file could be found to open this script",
                     ),
@@ -389,7 +387,7 @@ impl ApiService {
             Ok(()) => {}
             Err(error) => match error {
                 OpenError::Io(io_error) => {
-                    return json(
+                    return msgpack(
                         ErrorResponse::internal_error(format!(
                             "Attempting to open {} failed because of the following io error: {}",
                             script_path.display(),
@@ -403,7 +401,7 @@ impl ApiService {
                     status,
                     stderr,
                 } => {
-                    return json(
+                    return msgpack(
                         ErrorResponse::internal_error(format!(
                             r#"The command '{}' to open '{}' failed with the error code '{}'.
                             Error logs:
@@ -419,7 +417,7 @@ impl ApiService {
             },
         };
 
-        json_ok(OpenResponse {
+        msgpack_ok(OpenResponse {
             session_id: self.serve_session.session_id(),
         })
     }
@@ -483,7 +481,7 @@ 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 = messages
                                     .into_iter()
@@ -499,12 +497,12 @@ async fn handle_websocket_subscription(
                                     }),
                                 };
 
-                                serde_json::to_string(&response)?
+                                serialize_msgpack(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;

src/web/interface.rs

@@ -249,31 +249,8 @@ 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

@@ -1,8 +1,48 @@
 use hyper::{header::CONTENT_TYPE, Body, Response, StatusCode};
-use serde::Serialize;
+use serde::{Deserialize, Serialize};
 
-pub fn json_ok<T: Serialize>(value: T) -> Response<Body> {
+pub fn msgpack_ok<T: Serialize>(value: T) -> Response<Body> {
-    json(value, StatusCode::OK)
+    msgpack(value, StatusCode::OK)
+}
+
+pub fn msgpack<T: Serialize>(value: T, code: StatusCode) -> Response<Body> {
+    let mut serialized = Vec::new();
+    let mut serializer = rmp_serde::Serializer::new(&mut serialized)
+        .with_human_readable()
+        .with_struct_map();
+
+    if let Err(err) = value.serialize(&mut serializer) {
+        return Response::builder()
+            .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> {

tests/rojo_test/serve_util.rs

@@ -10,6 +10,7 @@ use std::{
 use hyper_tungstenite::tungstenite::{connect, Message};
 use rbx_dom_weak::types::Ref;
 
+use serde::{Deserialize, Serialize};
 use tempfile::{tempdir, TempDir};
 
 use librojo::{
@@ -161,22 +162,16 @@ impl TestServeSession {
 
     pub fn get_api_rojo(&self) -> Result<ServerInfoResponse, reqwest::Error> {
         let url = format!("http://localhost:{}/api/rojo", self.port);
-        let body = reqwest::blocking::get(url)?.text()?;
+        let body = reqwest::blocking::get(url)?.bytes()?;
 
-        let value = jsonc_parser::parse_to_serde_value(&body, &Default::default())
+        Ok(deserialize_msgpack(&body).expect("Server returned malformed response"))
-            .expect("Failed to parse JSON")
-            .expect("No JSON value");
-        Ok(serde_json::from_value(value).expect("Server returned malformed response"))
     }
 
     pub fn get_api_read(&self, id: Ref) -> Result<ReadResponse<'_>, reqwest::Error> {
         let url = format!("http://localhost:{}/api/read/{}", self.port, id);
-        let body = reqwest::blocking::get(url)?.text()?;
+        let body = reqwest::blocking::get(url)?.bytes()?;
 
-        let value = jsonc_parser::parse_to_serde_value(&body, &Default::default())
+        Ok(deserialize_msgpack(&body).expect("Server returned malformed response"))
-            .expect("Failed to parse JSON")
-            .expect("No JSON value");
-        Ok(serde_json::from_value(value).expect("Server returned malformed response"))
     }
 
     pub fn get_api_socket_packet(
@@ -198,8 +193,8 @@ impl TestServeSession {
             }
 
             match socket.read() {
-                Ok(Message::Text(text)) => {
+                Ok(Message::Binary(binary)) => {
-                    let packet: SocketPacket = serde_json::from_str(&text)?;
+                    let packet: SocketPacket = deserialize_msgpack(&binary)?;
                     if packet.packet_type != packet_type {
                         continue;
                     }
@@ -212,7 +207,7 @@ impl TestServeSession {
                     return Err("WebSocket closed before receiving messages".into());
                 }
                 Ok(_) => {
-                    // Ignore other message types (ping, pong, binary)
+                    // Ignore other message types (ping, pong, text)
                     continue;
                 }
                 Err(hyper_tungstenite::tungstenite::Error::Io(e))
@@ -236,15 +231,37 @@ impl TestServeSession {
     ) -> Result<SerializeResponse, reqwest::Error> {
         let client = reqwest::blocking::Client::new();
         let url = format!("http://localhost:{}/api/serialize", self.port);
-        let body = serde_json::to_string(&SerializeRequest {
+        let body = serialize_msgpack(&SerializeRequest {
             session_id,
             ids: ids.to_vec(),
-        });
+        })
+        .unwrap();
 
-        client.post(url).body((body).unwrap()).send()?.json()
+        let body = client.post(url).body(body).send()?.bytes()?;
+
+        Ok(deserialize_msgpack(&body).expect("Server returned malformed response"))
     }
 }
 
+fn serialize_msgpack<T: Serialize>(value: T) -> Result<Vec<u8>, rmp_serde::encode::Error> {
+    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)
+}
+
+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)
+}
+
 /// Probably-okay way to generate random enough port numbers for running the
 /// Rojo live server.
 ///
@@ -262,11 +279,7 @@ fn get_port_number() -> usize {
 /// Since the provided structure intentionally includes unredacted referents,
 /// some post-processing is done to ensure they don't show up in the model.
 pub fn serialize_to_xml_model(response: &SerializeResponse, redactions: &RedactionMap) -> String {
-    let model_content = data_encoding::BASE64
+    let mut dom = rbx_binary::from_reader(response.model_contents.as_slice()).unwrap();
-        .decode(response.model_contents.model().as_bytes())
-        .unwrap();
-
-    let mut dom = rbx_binary::from_reader(model_content.as_slice()).unwrap();
     // This makes me realize that maybe we need a `descendants_mut` iter.
     let ref_list: Vec<Ref> = dom.descendants().map(|inst| inst.referent()).collect();
     for referent in ref_list {