redis

Trait PubSubCommands

source 
pub trait PubSubCommands: Sized {
    // Required methods
    fn subscribe<C, F, U>(&mut self, _: C, _: F) -> RedisResult<U>
       where F: FnMut(Msg) -> ControlFlow<U>,
             C: ToRedisArgs;
    fn psubscribe<P, F, U>(&mut self, _: P, _: F) -> RedisResult<U>
       where F: FnMut(Msg) -> ControlFlow<U>,
             P: ToRedisArgs;
}
Expand description

The PubSub trait allows subscribing to one or more channels and receiving a callback whenever a message arrives.

Each method handles subscribing to the list of keys, waiting for messages, and unsubscribing from the same list of channels once a ControlFlow::Break is encountered.

Once (p)subscribe returns Ok(U), the connection is again safe to use for calling other methods.

§Examples

use redis::{PubSubCommands, ControlFlow};
let client = redis::Client::open("redis://127.0.0.1/")?;
let mut con = client.get_connection()?;
let mut count = 0;
con.subscribe(&["foo"], |msg| {
    // do something with message
    assert_eq!(msg.get_channel(), Ok(String::from("foo")));

    // increment messages seen counter
    count += 1;
    match count {
        // stop after receiving 10 messages
        10 => ControlFlow::Break(()),
        _ => ControlFlow::Continue,
    }
})?;

Required Methods§

source

fn subscribe<C, F, U>(&mut self, _: C, _: F) -> RedisResult<U>
where F: FnMut(Msg) -> ControlFlow<U>, C: ToRedisArgs,

Subscribe to a list of channels using SUBSCRIBE and run the provided closure for each message received.

For every Msg passed to the provided closure, either ControlFlow::Break or ControlFlow::Continue must be returned. This method will not return until ControlFlow::Break is observed.

source

fn psubscribe<P, F, U>(&mut self, _: P, _: F) -> RedisResult<U>
where F: FnMut(Msg) -> ControlFlow<U>, P: ToRedisArgs,

Subscribe to a list of channels using PSUBSCRIBE and run the provided closure for each message received.

For every Msg passed to the provided closure, either ControlFlow::Break or ControlFlow::Continue must be returned. This method will not return until ControlFlow::Break is observed.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§