feat: implement MCP streamable HTTP server

apps/mcp-server/src/jsonrpc.rs

@@ -0,0 +1,63 @@
+use serde_json::{Value, json};
+
+pub const CURRENT_PROTOCOL_VERSION: &str = "2025-11-25";
+pub const DEFAULT_PROTOCOL_VERSION: &str = "2025-03-26";
+pub const SUPPORTED_PROTOCOL_VERSIONS: &[&str] = &[
+    DEFAULT_PROTOCOL_VERSION,
+    "2025-06-18",
+    CURRENT_PROTOCOL_VERSION,
+];
+
+pub fn request_id(message: &Value) -> Value {
+    message.get("id").cloned().unwrap_or(Value::Null)
+}
+
+pub fn method_name(message: &Value) -> Option<&str> {
+    message.get("method").and_then(Value::as_str)
+}
+
+pub fn params(message: &Value) -> Value {
+    message
+        .get("params")
+        .cloned()
+        .unwrap_or_else(|| Value::Object(Default::default()))
+}
+
+pub fn is_notification(message: &Value) -> bool {
+    method_name(message).is_some() && message.get("id").is_none()
+}
+
+pub fn is_request(message: &Value) -> bool {
+    method_name(message).is_some() && message.get("id").is_some()
+}
+
+pub fn is_response(message: &Value) -> bool {
+    method_name(message).is_none()
+        && (message.get("result").is_some() || message.get("error").is_some())
+}
+
+pub fn jsonrpc_result(id: Value, result: Value) -> Value {
+    json!({
+        "jsonrpc": "2.0",
+        "id": id,
+        "result": result
+    })
+}
+
+pub fn jsonrpc_error(id: Value, code: i64, message: impl Into<String>) -> Value {
+    json!({
+        "jsonrpc": "2.0",
+        "id": id,
+        "error": {
+            "code": code,
+            "message": message.into()
+        }
+    })
+}
+
+pub fn negotiated_protocol_version(requested: &str) -> Option<&'static str> {
+    SUPPORTED_PROTOCOL_VERSIONS
+        .iter()
+        .copied()
+        .find(|version| *version == requested)
+}