Struct JsonRpcService 

pub struct JsonRpcService<S> { /* private fields */ }

Service that handles JSON-RPC framing.

Wraps an MCP service and handles JSON-RPC request/response conversion. Supports single requests for every implemented revision. Request batches are accepted only after the exact runtime revision is known to be 2025-03-26; later MCP revisions removed top-level JSON-RPC batching.

Can be created directly via JsonRpcService::new or through the JsonRpcLayer for ServiceBuilder composition.

Example

use tower_mcp::{McpRouter, JsonRpcService};

let router = McpRouter::new().server_info("my-server", "1.0.0");
let service = JsonRpcService::new(router);

Implementations

impl<S> JsonRpcService<S>

pub fn new(inner: S) -> Self

Create a new JSON-RPC service wrapping the given inner service

pub fn with_extensions(self, ext: Extensions) -> Self

Set extensions to inject into every RouterRequest created by this service.

This is used by transports to bridge data (e.g., TokenClaims) from the HTTP/WebSocket layer into the MCP request pipeline.

pub fn protocol_support(self, support: ProtocolSupport) -> Self

Set the exact protocol versions this service accepts and advertises.

The default enables every protocol implementation compiled into tower-mcp. Transports expose the same policy so applications can narrow support per server instance.

pub fn protocol_versions<I, V>( self, versions: I, ) -> Result<Self, ProtocolSupportError>

where I: IntoIterator<Item = V>, V: Into<String>,

Construct and set an exact runtime protocol-version allow-list.

pub async fn call_single( &mut self, req: JsonRpcRequest, ) -> Result<JsonRpcResponse>

where S: Service<RouterRequest, Response = RouterResponse, Error = Infallible> + Clone + Send + 'static, S::Future: Send,

Process a single JSON-RPC request

pub async fn call_batch( &mut self, requests: Vec<JsonRpcRequest>, ) -> Result<Vec<JsonRpcResponse>>

where S: Service<RouterRequest, Response = RouterResponse, Error = Infallible> + Clone + Send + 'static, S::Future: Send,

Process a 2025-03-26 batch of JSON-RPC requests concurrently.

The exact revision must have been negotiated by initialize, supplied by a transport session, or be the sole entry in ProtocolSupport. Later revisions return an invalid-request error.

pub async fn call_message( &mut self, msg: JsonRpcMessage, ) -> Result<JsonRpcResponseMessage>

where S: Service<RouterRequest, Response = RouterResponse, Error = Infallible> + Clone + Send + 'static, S::Future: Send,

Process a JSON-RPC message (single or batch)

Trait Implementations

impl<S> Clone for JsonRpcService<S>

where S: Clone,

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<S> Service<JsonRpcMessage> for JsonRpcService<S>

where S: Service<RouterRequest, Response = RouterResponse, Error = Infallible> + Clone + Send + 'static, S::Future: Send,

Service implementation for JSON-RPC batch requests

type Response = JsonRpcResponseMessage

Responses given by the service.

type Error = Error

Errors produced by the service.

type Future = Pin<Box<dyn Future<Output = Result<<JsonRpcService<S> as Service<JsonRpcMessage>>::Response, <JsonRpcService<S> as Service<JsonRpcMessage>>::Error>> + Send>>

The future response value.

fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>

Returns Poll::Ready(Ok(())) when the service is able to process requests.

fn call(&mut self, msg: JsonRpcMessage) -> Self::Future

Process the request and return the response asynchronously.

impl<S> Service<JsonRpcRequest> for JsonRpcService<S>

where S: Service<RouterRequest, Response = RouterResponse, Error = Infallible> + Clone + Send + 'static, S::Future: Send,

type Response = JsonRpcResponse

Responses given by the service.

type Error = Error

Errors produced by the service.

type Future = Pin<Box<dyn Future<Output = Result<<JsonRpcService<S> as Service<JsonRpcRequest>>::Response, <JsonRpcService<S> as Service<JsonRpcRequest>>::Error>> + Send>>

The future response value.

fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>

Returns Poll::Ready(Ok(())) when the service is able to process requests.

fn call(&mut self, req: JsonRpcRequest) -> Self::Future

Process the request and return the response asynchronously.