fix: do a serde encoding override to base64 encode bytes fields in Me…

…ssageApi

crates/xmtp-networking/Cargo.toml

@@ -16,6 +16,7 @@ tonic-reflection = "0.6.0"
 tokio-rustls = "0.24.0"
 serde = { version = "1.0.160", features = ["derive"] }
 serde_json = "1.0"
+base64 = "0.21.0"
 
 [build-dependencies]
 tonic-build = "^0.9"

crates/xmtp-networking/build.rs

@@ -15,6 +15,14 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         .build_client(true)
         .type_attribute(".", "#[derive(serde::Deserialize, serde::Serialize)]")
         .file_descriptor_set_path(out_dir.join("store_descriptor.bin"))
+        .field_attribute(
+            "xmtp.message_api.v1.Envelope.message",
+            "#[serde(serialize_with = \"crate::serialize_utils::as_base64\")]",
+        )
+        .field_attribute(
+            "xmtp.message_api.v1.IndexCursor.digest",
+            "#[serde(serialize_with = \"crate::serialize_utils::as_base64\")]",
+        )
         .out_dir("./src")
         .compile(
             &[

crates/xmtp-networking/src/grpc_api_helper.rs

@@ -104,6 +104,6 @@ pub fn test_envelope() -> String {
         message: vec![65],
         ..Default::default()
     };
-    let json = serde_json::to_string(&envelope).unwrap();
-    json
+
+    serde_json::to_string(&envelope).unwrap()
 }

crates/xmtp-networking/src/lib.rs

@@ -1,5 +1,8 @@
 pub mod grpc_api_helper;
 pub mod proto_helper;
+// Custom patching of protobuf serialization for bytes -> base64
+// https://github.com/tokio-rs/prost/issues/75#issuecomment-1383233271
+pub mod serialize_utils;
 
 #[cfg(test)]
 mod tests {
@@ -12,7 +15,7 @@ mod tests {
         let serialized = test_envelope();
         assert_eq!(
             serialized,
-            "{\"content_topic\":\"\",\"timestamp_ns\":0,\"message\":[QQ==]}"
+            "{\"content_topic\":\"\",\"timestamp_ns\":0,\"message\":\"QQ==\"}"
         );
     }
 

crates/xmtp-networking/src/serialize_utils.rs

@@ -0,0 +1,12 @@
+use base64::Engine;
+use serde::Serializer;
+
+pub fn as_base64<S>(
+    data: &[u8],
+    serializer: S,
+) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>
+where
+    S: Serializer,
+{
+    serializer.serialize_str(&base64::engine::general_purpose::STANDARD.encode(data))
+}

crates/xmtp-networking/src/xmtp.message_api.v1.rs

@@ -40,6 +40,7 @@ pub struct AuthData {
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct IndexCursor {
     #[prost(bytes = "vec", tag = "1")]
+    #[serde(serialize_with = "crate::serialize_utils::as_base64")]
     pub digest: ::prost::alloc::vec::Vec<u8>,
     #[prost(uint64, tag = "2")]
     pub sender_time_ns: u64,
@@ -98,6 +99,7 @@ pub struct Envelope {
     #[prost(uint64, tag = "2")]
     pub timestamp_ns: u64,
     #[prost(bytes = "vec", tag = "3")]
+    #[serde(serialize_with = "crate::serialize_utils::as_base64")]
     pub message: ::prost::alloc::vec::Vec<u8>,
 }
 /// Publish