Add utilities to handle text and binary payloads for mixnet messages

clients/webassembly/src/binary_message_helper.rs

@@ -0,0 +1,83 @@
+// Copyright 2022 - Nym Technologies SA <contact@nymtech.net>
+// SPDX-License-Identifier: Apache-2.0
+
+use wasm_bindgen::prelude::*;
+use wasm_bindgen::JsCast;
+use serde::{Serialize, Deserialize};
+
+#[wasm_bindgen(typescript_custom_section)]
+const TS_DEFS: &'static str = r#"
+export interface BinaryMessage {
+    kind: number,
+    payload: Uint8Array;
+}
+
+export interface StringMessage {
+    kind: number,
+    payload: string;
+}
+"#;
+
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(typescript_type = "BinaryMessage")]
+    pub type IBinaryMessage;
+    #[wasm_bindgen(typescript_type = "StringMessage")]
+    pub type IStringMessage;
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct BinaryMessage {
+    pub kind: u8,
+    pub payload: Vec<u8>,
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct StringMessage {
+    pub kind: u8,
+    pub payload: String,
+}
+
+/// Create a new binary message with a user-specified `kind`.
+#[wasm_bindgen]
+pub fn create_binary_message(kind: u8, payload: Vec<u8>) -> Vec<u8> {
+    vec![vec![kind], payload].concat()
+}
+
+/// Create a new message with a UTF-8 encoded string `payload` and a user-specified `kind`.
+#[wasm_bindgen]
+pub fn create_binary_message_from_string(kind: u8, payload: String) -> Vec<u8> {
+    vec!(vec![kind], payload.into_bytes()).concat()
+}
+
+/// Parse the `kind` and byte array `payload` from a byte array
+#[wasm_bindgen]
+pub async fn parse_binary_message(message: Vec<u8>) -> Result<IBinaryMessage, JsError> {
+    if message.len() < 2 {
+        return Err(JsError::new("Could not parse message, as less than 2 bytes long"));
+    }
+
+    let kind = message[0];
+    let payload = &message[1..];
+
+    Ok(serde_wasm_bindgen::to_value(&BinaryMessage {
+        kind,
+        payload: payload.to_vec(),
+    }).unwrap().unchecked_into::<IBinaryMessage>())
+}
+
+/// Parse the `kind` and UTF-8 string `payload` from a byte array
+#[wasm_bindgen]
+pub async fn parse_string_message(message: Vec<u8>) -> Result<IStringMessage, JsError> {
+    if message.len() < 2 {
+        return Err(JsError::new("Could not parse message, as less than 2 bytes long"));
+    }
+
+    let kind = message[0];
+    let payload = String::from_utf8_lossy(&message[1..]).into_owned();
+
+    Ok(serde_wasm_bindgen::to_value(&StringMessage {
+        kind,
+        payload,
+    }).unwrap().unchecked_into::<IStringMessage>())
+}

clients/webassembly/src/client/mod.rs

@@ -26,7 +26,7 @@ use nymsphinx::params::PacketSize;
 use rand::rngs::OsRng;
 use wasm_bindgen::prelude::*;
 use wasm_bindgen_futures::spawn_local;
-use wasm_utils::{console_log, console_warn};
+use wasm_utils::console_log;
 
 pub mod config;
 
@@ -45,6 +45,7 @@ pub struct NymClient {
 
     // callbacks
     on_message: Option<js_sys::Function>,
+    on_binary_message: Option<js_sys::Function>,
     on_gateway_connect: Option<js_sys::Function>,
 }
 
@@ -56,6 +57,7 @@ impl NymClient {
             config,
             key_manager: Self::setup_key_manager(),
             on_message: None,
+            on_binary_message: None,
             on_gateway_connect: None,
             input_tx: None,
         }
@@ -73,8 +75,11 @@ impl NymClient {
         self.on_message = Some(on_message);
     }
 
+    pub fn set_on_binary_message(&mut self, on_binary_message: js_sys::Function) {
+        self.on_binary_message = Some(on_binary_message);
+    }
+
     pub fn set_on_gateway_connect(&mut self, on_connect: js_sys::Function) {
-        console_log!("setting on connect...");
         self.on_gateway_connect = Some(on_connect)
     }
 
@@ -267,6 +272,7 @@ impl NymClient {
         received_buffer_request_sender: ReceivedBufferRequestSender,
     ) {
         let on_message = self.on_message.take();
+        let on_binary_message = self.on_binary_message.take();
 
         spawn_local(async move {
             let (reconstructed_sender, mut reconstructed_receiver) = mpsc::unbounded();
@@ -281,8 +287,14 @@ impl NymClient {
             let this = JsValue::null();
 
             while let Some(reconstructed) = reconstructed_receiver.next().await {
-                if let Some(ref callback) = on_message {
-                    for msg in reconstructed {
+                for msg in reconstructed {
+                    if let Some(ref callback_binary) = on_binary_message {
+                        let arg1 = serde_wasm_bindgen::to_value(&msg.message).unwrap();
+                        callback_binary
+                            .call1(&this, &arg1)
+                            .expect("on binary message failed!");
+                    }
+                    if let Some(ref callback) = on_message {
                         if msg.reply_surb.is_some() {
                             console_log!("the received message contained a reply-surb that we do not know how to handle (yet)")
                         }
@@ -290,9 +302,6 @@ impl NymClient {
                         let arg1 = serde_wasm_bindgen::to_value(&stringified).unwrap();
                         callback.call1(&this, &arg1).expect("on message failed!");
                     }
-                } else {
-                    console_warn!("no on_message callback was specified. the received message content is getting dropped");
-                    console_log!("the raw messages: {:?}", reconstructed)
                 }
             }
         });

clients/webassembly/src/lib.rs

@@ -3,6 +3,8 @@
 
 use wasm_bindgen::prelude::*;
 
+#[cfg(target_arch = "wasm32")]
+pub mod binary_message_helper;
 #[cfg(target_arch = "wasm32")]
 mod client;
 #[cfg(target_arch = "wasm32")]