Struct ServerStdioTransport

pub struct ServerStdioTransport { /* private fields */ }

Server transport that communicates with MCP clients over standard I/O.

The ServerStdioTransport uses standard input and output streams (stdin/stdout) to send and receive MCP messages. This transport is ideal for command-line applications, where the server needs to communicate with a client that launched it as a child process.

Use cases include:

• CLI tools that implement MCP
• Embedding MCP in existing command-line applications
• Testing and development scenarios

Example

use mcp_core::{protocol::Protocol, transport::{ServerStdioTransport, Transport}};

async fn example() {
    let protocol = Protocol::builder().build();
    let transport = ServerStdioTransport::new(protocol);
    // Start handling messages
    transport.open().await.expect("Failed to start stdio server");
}

Implementations

impl ServerStdioTransport

pub fn new(protocol: Protocol) -> Self

Creates a new ServerStdioTransport instance.

Arguments

• protocol - The MCP protocol instance to use for handling messages

Returns

A new ServerStdioTransport instance

Trait Implementations

impl Clone for ServerStdioTransport

fn clone(&self) -> ServerStdioTransport

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Transport for ServerStdioTransport

fn open<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Opens the transport and starts processing messages.

This method enters a loop that:

1. Polls for incoming messages from stdin
2. Processes each message according to its type (request, notification, response)
3. Sends responses as needed
4. Continues until EOF is received on stdin

Returns

A Result indicating success or failure

fn close<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Closes the transport.

This is a no-op for the stdio transport as standard I/O streams are managed by the OS.

Returns

A Result indicating success

fn poll_message<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<Option<Message>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Polls for incoming messages from stdin.

This method reads a line from stdin and parses it as a JSON-RPC message.

Returns

A Result containing an Option<Message>. None indicates EOF.

fn request( &self, method: &str, params: Option<Value>, options: RequestOptions, ) -> Pin<Box<dyn Future<Output = Result<JsonRpcResponse>> + Send + Sync>>

Sends a request to the client and waits for a response.

This method:

1. Creates a new request ID
2. Constructs a JSON-RPC request
3. Sends it to stdout
4. Waits for a response with the same ID, with a timeout

Arguments

• method - The method name for the request
• params - Optional parameters for the request
• options - Request options (like timeout)

Returns

A Future that resolves to a Result containing the response

fn send_notification<'life0, 'life1, 'async_trait>( &'life0 self, method: &'life1 str, params: Option<Value>, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Sends a notification to the client.

This method constructs a JSON-RPC notification and writes it to stdout. Unlike requests, notifications do not expect a response.

Arguments

• method - The method name for the notification
• params - Optional parameters for the notification

Returns

A Result indicating success or failure

fn send_response<'life0, 'async_trait>( &'life0 self, id: RequestId, result: Option<Value>, error: Option<JsonRpcError>, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Sends a response to the client.

This method constructs a JSON-RPC response and writes it to stdout.

Arguments

• id - The ID of the request being responded to
• result - Optional successful result
• error - Optional error information

Returns

A Result indicating success or failure