Enum Protocol 

#[non_exhaustive]
pub enum Protocol {
    Connect,
    Grpc,
    GrpcWeb,
}

The wire protocol used for an RPC.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Connect

Connect protocol - HTTP-native with standard HTTP semantics.

Unary RPCs use bare message bodies and real HTTP status codes. Streaming RPCs use envelope framing with JSON end-of-stream messages.

Grpc

gRPC protocol - standard gRPC over HTTP/2.

All RPCs use envelope framing. Status is communicated via HTTP/2 trailing HEADERS (grpc-status, grpc-message). HTTP status is always 200.

GrpcWeb

gRPC-Web protocol - gRPC-Web for browser compatibility.

Like gRPC but works over HTTP/1.1. Trailers are encoded in the response body as a final frame with flag byte 0x80.

Implementations

impl Protocol

pub fn detect(headers: &HeaderMap) -> Option<RequestProtocol>

Detect the protocol, codec format, and streaming mode from request headers.

Returns None if the Content-Type doesn’t match any known protocol.

pub fn detect_from_content_type(content_type: &str) -> Option<RequestProtocol>

Detect the protocol from a Content-Type string.

Returns None if the content type doesn’t match any known protocol.

pub fn response_content_type( &self, format: CodecFormat, is_streaming: bool, ) -> &'static str

Get the Content-Type header value for a response with this protocol and codec.

pub fn timeout_header(&self) -> &'static str

Get the timeout header name for this protocol.

pub fn content_encoding_header(&self) -> &'static HeaderName

Get the content-encoding header name for this protocol (streaming).

Returns a pre-parsed HeaderName so callers can pass it directly to HeaderMap::insert without the from_bytes re-parse that Response::Builder::header(&str, _) does.

pub fn accept_encoding_header(&self) -> &'static HeaderName

Get the accept-encoding header name for this protocol (streaming).

pub fn uses_http_status_codes(&self) -> bool

Whether this protocol uses real HTTP status codes for errors.

Connect uses standard HTTP status codes for unary errors. gRPC and gRPC-Web always return HTTP 200, with errors in trailers.

pub fn requires_http2(&self) -> bool

Whether this protocol requires HTTP/2.

pub fn uses_http_trailers(&self) -> bool

Whether this protocol sends trailers via HTTP/2 HEADERS frames.

gRPC uses HTTP/2 trailers; Connect and gRPC-Web encode trailers in the body.

Trait Implementations

impl Clone for Protocol

fn clone(&self) -> Protocol

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Protocol

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

Formats the value using the given formatter.

impl Display for Protocol

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

Formats the value using the given formatter.

impl Hash for Protocol

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Protocol

fn eq(&self, other: &Protocol) -> 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 Copy for Protocol

impl Eq for Protocol

impl StructuralPartialEq for Protocol