Struct Envelope

pub struct Envelope {
    pub id: MessageId,
    pub route: RouteKey,
    pub headers: BTreeMap<String, String>,
    pub content_type: ContentType,
    pub payload: Bytes,
}

Protocol-agnostic unit of data that crosses the engine.

The engine reads only Self::route. Headers, content type, and payload are opaque and are cloned to every matching subscriber. Header names are namespaced by owner (oag., stomp., agra.); that convention is not enforced here.

Fields

id: MessageId

Gateway-assigned id, not a protocol message id.

route: RouteKey

The only field crate::Engine::publish matches on.

headers: BTreeMap<String, String>

String pairs adapters stamp and read. The engine never looks here.

content_type: ContentType

How the payload is labelled, not how the engine parses it.

payload: Bytes

Uninterpreted bytes. JSON, XML, or anything else.

Implementations

impl Envelope

pub fn new(route: RouteKey, payload: impl Into<Bytes>) -> Self

Builds an envelope with a fresh MessageId, no headers, and ContentType::octet_stream.

Call Self::with_content_type when the bytes are known to be JSON or XML. The default is octet-stream because this constructor does not inspect payload.

pub fn with_content_type(self, content_type: ContentType) -> Self

Sets the content-type label. Does not parse or convert payload.

pub fn with_header( self, key: impl Into<String>, value: impl Into<String>, ) -> Self

Inserts or replaces one header. Last write for a key wins.

pub fn with_origin(self, id: &AdapterId) -> Self

Stamps HDR_ORIGIN so a bridging adapter can refuse its own echo. Last write wins.

pub fn origin(&self) -> Option<&str>

Value of HDR_ORIGIN, if stamped.

pub fn is_echo_of(&self, id: &AdapterId) -> bool

Whether this envelope was published by id’s inbound path.

Bridging adapters skip outbound-to-the-same-bus when this is true. The engine does not skip: one adapter id may cover many connections (OWP).

Trait Implementations

impl Clone for Envelope

fn clone(&self) -> Envelope

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Envelope

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

Formats the value using the given formatter.

impl PartialEq for Envelope

fn eq(&self, other: &Envelope) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Envelope

impl StructuralPartialEq for Envelope