messaggero 0.1.1

High-performance agent-to-agent communication protocol for Rust. A2A-compatible over HTTP/JSON-RPC with a zero-overhead binary fast path over Unix sockets for local multi-agent systems.
Documentation 
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//! JSON-RPC 2.0 types for A2A protocol compatibility.

use serde::{Deserialize, Serialize};

pub const JSONRPC_VERSION: &str = "2.0";

// A2A method names
pub const METHOD_TASKS_SEND: &str = "tasks/send";
pub const METHOD_TASKS_GET: &str = "tasks/get";
pub const METHOD_TASKS_CANCEL: &str = "tasks/cancel";
pub const METHOD_AGENT_CARD: &str = "agent/authenticatedExtendedCard";

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct JsonRpcRequest {
    pub jsonrpc: String,
    pub method: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub params: Option<serde_json::Value>,
    pub id: serde_json::Value,
}

impl JsonRpcRequest {
    pub fn new(method: impl Into<String>, params: serde_json::Value) -> Self {
        Self {
            jsonrpc: JSONRPC_VERSION.into(),
            method: method.into(),
            params: Some(params),
            id: serde_json::Value::Number(1.into()),
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct JsonRpcResponse {
    pub jsonrpc: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub result: Option<serde_json::Value>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub error: Option<JsonRpcError>,
    pub id: serde_json::Value,
}

impl JsonRpcResponse {
    pub fn success(id: serde_json::Value, result: serde_json::Value) -> Self {
        Self {
            jsonrpc: JSONRPC_VERSION.into(),
            result: Some(result),
            error: None,
            id,
        }
    }

    pub fn error(id: serde_json::Value, code: i64, message: impl Into<String>) -> Self {
        Self {
            jsonrpc: JSONRPC_VERSION.into(),
            result: None,
            error: Some(JsonRpcError {
                code,
                message: message.into(),
                data: None,
            }),
            id,
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct JsonRpcError {
    pub code: i64,
    pub message: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub data: Option<serde_json::Value>,
}

// Standard JSON-RPC error codes
pub const PARSE_ERROR: i64 = -32700;
pub const INVALID_REQUEST: i64 = -32600;
pub const METHOD_NOT_FOUND: i64 = -32601;
pub const INVALID_PARAMS: i64 = -32602;
pub const INTERNAL_ERROR: i64 = -32603;

// A2A-specific error codes
pub const TASK_NOT_FOUND: i64 = -32001;
pub const TASK_NOT_CANCELABLE: i64 = -32002;

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn serialize_request() {
        let req = JsonRpcRequest::new("tasks/send", serde_json::json!({"id": "abc"}));
        let json = serde_json::to_string(&req).unwrap();
        assert!(json.contains("tasks/send"));
        assert!(json.contains("2.0"));
    }

    #[test]
    fn serialize_error_response() {
        let resp = JsonRpcResponse::error(serde_json::json!(1), METHOD_NOT_FOUND, "not found");
        let json = serde_json::to_string(&resp).unwrap();
        assert!(json.contains("-32601"));
    }
}