feat: add grpc support

crates/mcpaas-adapter-grpc/src/codec.rs

@@ -0,0 +1,72 @@
+use prost::Message;
+use prost_reflect::{DynamicMessage, MessageDescriptor};
+use tonic::{
+    Status,
+    codec::{Codec, DecodeBuf, Decoder, EncodeBuf, Encoder},
+};
+
+pub struct JsonCodec {
+    request_descriptor: MessageDescriptor,
+    response_descriptor: MessageDescriptor,
+}
+
+impl JsonCodec {
+    pub fn new(
+        request_descriptor: MessageDescriptor,
+        response_descriptor: MessageDescriptor,
+    ) -> Self {
+        Self {
+            request_descriptor,
+            response_descriptor,
+        }
+    }
+}
+
+impl Codec for JsonCodec {
+    type Encode = serde_json::Value;
+    type Decode = serde_json::Value;
+
+    type Encoder = JsonEncoder;
+    type Decoder = JsonDecoder;
+
+    fn encoder(&mut self) -> Self::Encoder {
+        JsonEncoder(self.request_descriptor.clone())
+    }
+
+    fn decoder(&mut self) -> Self::Decoder {
+        JsonDecoder(self.response_descriptor.clone())
+    }
+}
+
+pub struct JsonEncoder(MessageDescriptor);
+
+impl Encoder for JsonEncoder {
+    type Item = serde_json::Value;
+    type Error = Status;
+
+    fn encode(&mut self, item: Self::Item, dst: &mut EncodeBuf<'_>) -> Result<(), Self::Error> {
+        let message = DynamicMessage::deserialize(self.0.clone(), item)
+            .map_err(|error| Status::invalid_argument(error.to_string()))?;
+
+        message.encode_raw(dst);
+        Ok(())
+    }
+}
+
+pub struct JsonDecoder(MessageDescriptor);
+
+impl Decoder for JsonDecoder {
+    type Item = serde_json::Value;
+    type Error = Status;
+
+    fn decode(&mut self, src: &mut DecodeBuf<'_>) -> Result<Option<Self::Item>, Self::Error> {
+        let mut message = DynamicMessage::new(self.0.clone());
+        message
+            .merge(src)
+            .map_err(|error| Status::internal(error.to_string()))?;
+
+        serde_json::to_value(&message)
+            .map(Some)
+            .map_err(|error| Status::internal(error.to_string()))
+    }
+}