Module extensions

Expand description

Extensions passed to and between services

§State

rama supports two kinds of states:

static state: this state can be a part of the service struct or captured by a closure
dynamic state: these can be injected as Extensionss in Requests/Responses/Connections if it ExtensionsRef

Any state that is optional, and especially optional state injected by middleware, can be inserted using extensions. It is however important to try as much as possible to then also consume this state in an approach that deals gracefully with its absence. Good examples of this are header-related inputs. Headers might be set or not, and so absence of Extensionss that might be created as a result of these might reasonably not exist. It might of course still mean the app returns an error response when it is absent, but it should not unwrap/panic.

§Examples

§Example: Extensions

use rama_core::extensions::{Extensions, Extension};

#[derive(Debug, Clone, PartialEq)]
struct MyExt(i32);
impl Extension for MyExt {}

let mut ext = Extensions::default();
ext.insert(MyExt(5));
assert_eq!(ext.get_ref::<MyExt>(), Some(&MyExt(5)));

Structs§

Egress: Egress connection wrapper use by client
Extensions: A type map of protocol extensions.
Ingress: Ingress connection wrapper use by servers
TypeErasedExtension: A TypeErasedExtension is a type erased item which can be stored in an Extensions

Traits§

DnsExtension: DNS resolution related extensions.
Extension: Extension is type which can be stored inside an Extensions store
ExtensionsRef
GetManyArc: Helper trait powering Extensions::get_many_arc; the owned-Arc counterpart of GetManyRef.
GetManyRef: Helper trait powering Extensions::get_many_ref: implemented for tuples of Extension types (up to arity 12).
GrpcExtension: gRPC related extensions.
HttpExtension: HTTP protocol related extensions.
NetExtension: Network and connection level extensions.
ProxyExtension: Proxy related extensions.
TlsExtension: TLS and secure transport related extensions.
UaExtension: User-agent emulation related extensions.
WsExtension: WebSocket related extensions.

Derive Macros§

Extension: Derive an implementation of rama_core::extensions::Extension for a type.
FromExtensions: Derive a from_extensions constructor that gathers extension pieces from a rama_core::extensions::Extensions store in a single pass.