Struct SessionState 

pub struct SessionState { /* private fields */ }

Shared session state that can be cloned across requests.

Uses atomic operations for thread-safe state transitions. Includes a type-safe extensions map for storing session-scoped data like authentication claims.

Example

use tower_mcp::SessionState;

#[derive(Debug, Clone)]
struct UserClaims {
    user_id: String,
    role: String,
}

let session = SessionState::new();

// Store auth claims in the session
session.insert(UserClaims {
    user_id: "user123".to_string(),
    role: "admin".to_string(),
});

// Retrieve claims later
if let Some(claims) = session.get::<UserClaims>() {
    assert_eq!(claims.role, "admin");
}

Implementations

impl SessionState

pub fn new() -> Self

Create a new session in the Uninitialized phase

pub fn insert<T: Send + Sync + Clone + 'static>(&self, val: T)

Insert a value into the session extensions.

This is typically used by auth middleware to store claims that can be checked by capability filters.

Example

use tower_mcp::SessionState;

let session = SessionState::new();
session.insert(42u32);
assert_eq!(session.get::<u32>(), Some(42));

pub fn get<T: Send + Sync + Clone + 'static>(&self) -> Option<T>

Get a cloned value from the session extensions.

Returns None if no value of the given type has been inserted or if the lock cannot be acquired.

Example

use tower_mcp::SessionState;

let session = SessionState::new();
session.insert("hello".to_string());
assert_eq!(session.get::<String>(), Some("hello".to_string()));
assert_eq!(session.get::<u32>(), None);

pub fn phase(&self) -> SessionPhase

Get the current session phase

pub fn is_initialized(&self) -> bool

Check if the session is initialized (operation phase)

pub fn mark_initializing(&self) -> bool

Transition from Uninitialized to Initializing. Called after responding to an initialize request. Returns true if the transition was successful.

pub fn mark_initialized(&self) -> bool

Transition from Initializing to Initialized. Called when receiving an initialized notification. Returns true if the transition was successful.

pub fn is_request_allowed(&self, method: &str) -> bool

Check if a request method is allowed in the current phase. Per spec:

• Before initialization: only initialize and ping are valid
• During all phases: ping is always valid

Trait Implementations

impl Clone for SessionState

fn clone(&self) -> SessionState

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for SessionState

fn default() -> Self

Returns the “default value” for a type.