Struct PubSubContext 

pub struct PubSubContext { /* private fields */ }

Per-delivery context for a Redis Pub/Sub delivery (RedisPubSubMessage).

Pub/Sub keeps no history, so there is nothing to reposition and no position to report: the fields are the delivery’s own channel and how it matched.

Implementations

impl PubSubContext

pub fn new(channel: impl Into<String>, from_pattern: bool, pool: Pool) -> Self

Constructs a context directly from its native fields (mainly for tests).

Examples

use std::error::Error;

use fred::clients::Pool;
use fred::types::config::Config;
use ruststream_fred::context::PubSubContext;

/// The region a fan-out delivery belongs to, read off the channel it arrived on.
fn region(cx: &PubSubContext) -> &str {
    cx.channel().rsplit_once('.').map_or("", |(_, region)| region)
}

// An unconnected pool: `Pool::new` opens no socket.
let pool = Pool::new(Config::default(), None, None, None, 1)?;
let cx = PubSubContext::new("events.eu", true, pool);
assert_eq!(region(&cx), "eu");

pub const fn pool(&self) -> &Pool

The broker’s connection pool, for a command whose answer the handler needs now.

pub fn channel(&self) -> &str

The concrete channel this message arrived on (the matched channel, not the subscription glob, for a pattern subscription).

pub const fn from_pattern(&self) -> bool

Whether the delivery matched through a PSUBSCRIBE pattern rather than an exact subscribe.

Trait Implementations

impl BuildContext<RedisPubSubMessage> for PubSubContext

fn build(msg: &RedisPubSubMessage) -> Self

Builds the context value by reading fields out of msg.

impl Clone for PubSubContext

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PubSubContext

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

Formats the value using the given formatter.

impl Field<PubSubContext> for FredPool

type Value<'a> = &'a Pool

The value read through this key, borrowed from the source for 'a.

fn get(self, src: &PubSubContext) -> &Pool

Reads this key’s field out of src.

impl Field<PubSubContext> for Channel

type Value<'a> = &'a str

The value read through this key, borrowed from the source for 'a.

fn get(self, src: &PubSubContext) -> &str

Reads this key’s field out of src.

impl Field<PubSubContext> for FromPattern

type Value<'a> = bool

The value read through this key, borrowed from the source for 'a.

fn get(self, src: &PubSubContext) -> bool

Reads this key’s field out of src.

impl<State: Sync> FromContext<PubSubContext, State> for Ctx<FredPool>

Ctx<keys::FredPool> beside a Pub/Sub key: the handler’s context is PubSubContext there.

type Rejection = !

The error returned when extraction fails. It is converted into a HandlerOutcome (the reflexive conversion makes HandlerOutcome itself a valid rejection, and Infallible works for an extractor that never fails) and the delivery is settled by that outcome, skipping the handler body.

fn from_context( ctx: &mut Context<'_, PubSubContext, State>, ) -> impl Future<Output = Result<Self, Infallible>> + Send

Resolves the value from the delivery context. The context is borrowed mutably so an extractor may also read broker fields or take scratch a middleware left for it.