Struct Cx 

pub struct Cx { /* private fields */ }

The request context.

Add cx: &Cx to a handler or component to access context. Topcoat supplies it automatically. Read shared application values with app_context and values scoped to the request with request_context.

Clones share the request’s state. Use with or with_many to add context values in a child scope without changing the parent. Move an owned clone into work that outlives the handler, such as a streaming response.

Implementations

impl Cx

pub fn new(app_context: Arc<AppContext>) -> Cx

Creates the context for one request over the shared app context, with an empty request context.

pub fn id(&self) -> CxId

Returns this request’s unique CxId.

pub fn keyed(&self, key: impl IdentityKey) -> Cx

Returns a child context with a key derived from the parent’s key, this call’s source location, and key.

Use () to distinguish separate call locations, or an item key to distinguish repeated calls at one location:

let first = cx.keyed(());
let second = cx.keyed(());

for id in [1, 2, 3] {
    let child = cx.keyed(id);
}

The same inputs produce the same key. Moving the call in source changes it. The child shares the parent’s request state and context values.

pub fn with<T>(&self, value: T) -> Cx

where T: Any + Send + Sync,

Returns a child handle whose request context also holds value.

The child inherits other context values and shares the request’s state. If this type is already registered, the child sees value while the parent still sees the original.

pub fn with_many<V>(&self, values: V) -> Cx

where V: ContextValues,

Returns a child handle whose request context also holds every value in values, a tuple of context values or a RequestContext.

Behaves like chained with calls, but builds the child’s request context in one step.

Trait Implementations

impl Clone for Cx

fn clone(&self) -> Cx

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Cx

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Cx

fn default() -> Cx

Returns the “default value” for a type.