Expand description
redis-asio is a Redis client library written in pure Rust based on
asynchronous tokio
library.
The library provides a base
module for low-level request sending and
response handling, and a stream
module that contains specific interfaces
for work with Redis-Stream “https://redis.io/topics/streams-intro”.
The library works with binary-safe strings that allows users to serialize their message structures and send via RESP protocol “https://redis.io/topics/protocol”.
§Use in project
Depend on the redis-asio in project via Cargo:
[dependencies]
redis-async = "0.1"
Resolve the crate interfaces:
extern crate redis_asio;
§Motivating examples
§SET, GET value from cache
use std::net::SocketAddr;
use futures::Future;
use redis_asio::{RedisCoreConnection, RedisValue, command, from_redis_value};
let address = &"127.0.0.1:6379".parse::<SocketAddr>().unwrap();
let set_req = command("SET").arg("foo").arg(123);
let get_req = command("GET").arg("foo");
let future = RedisCoreConnection::connect(address)
.and_then(move |con| {
// send "SET foo 123" request
con.send(set_req)
})
.and_then(|(con, response)| {
// check if the value has been set
assert_eq!(RedisValue::Ok, response);
// send "GET foo" request
con.send(get_req)
})
.map(move |(_, response)|
// check if the received value is the same
assert_eq!(123, from_redis_value(&response).unwrap()))
.map_err(|_| unreachable!());
// start the Tokio runtime using the `future`
tokio::run(future);
§Subscribe to a Redis Stream
Subscribe to a Redis stream and process all incoming entries. Redis Streams requires to send XREAD/XREADGROUP requests every time the client receives a response on the previous, in other words Redis Streams does not provide an interface to subscribe to a Redis stream.
In the Crate the subscription is possible by hidden requests sending within the Crate engine.
Request that will be sent to get new entries in the following example: “XREADGROUP GROUP mygroup Bob BLOCK 0 STREAMS mystream <”
use std::net::SocketAddr;
use futures::{Future, Stream};
use redis_asio::stream::{RedisStream, SubscribeOptions, StreamEntry,
RedisGroup};
let address = &"127.0.0.1:6379".parse::<SocketAddr>().unwrap();
// create options to pass it into RedisStream::subscribe()
let group_info = RedisGroup::new("mygroup".to_string(), "Bob".to_string());
let subscribe_options =
SubscribeOptions::with_group(vec!["mystream".to_string()], group_info);
let future = RedisStream::connect(address)
.and_then(move |stream: RedisStream| {
stream.subscribe(subscribe_options)
})
.and_then(|subscribe| /*:Subscribe*/ {
// pass the closure that will be called on each incoming entries
subscribe.for_each(|entries: Vec<StreamEntry>| {
for entry in entries.into_iter() {
println!("Received: {:?}", entry);
}
Ok(())
})
})
.map_err(|err| eprintln!("something went wrong: {}", err));
// start the Tokio runtime using the `future`
tokio::run(future);
§Send an entry into a Redis Stream
Send an entry into a Redis stream. Request that will be sent to push a specified entry in the following example: “XADD mystream * type 3 data "Hello, world"”
use std::net::SocketAddr;
use std::collections::HashMap;
use futures::Future;
use redis_asio::{RedisArgument, IntoRedisArgument};
use redis_asio::stream::{RedisStream, SendEntryOptions, EntryId};
let address = &"127.0.0.1:6379".parse::<SocketAddr>().unwrap();
// create options to pass it into RedisStream::send_entry()
let send_options = SendEntryOptions::new("mystream".to_string());
// create key-value pairs
let mut request: HashMap<String, RedisArgument> = HashMap::new();
request.insert("type".to_string(), 3i32.into_redis_argument());
request.insert("data".to_string(), "Hello, world!".into_redis_argument());
let future = RedisStream::connect(address)
.and_then(move |stream: RedisStream| {
// HashMap<String, RedisArgument> satisfies the
// HashMap<String, ToRedisArgument>
stream.send_entry(send_options, request)
})
.map(|(_, inserted_entry_id): (RedisStream, EntryId)| {
println!("{:?} has sent", inserted_entry_id.to_string());
})
.map_err(|err| eprintln!("something went wrong: {}", err));
tokio::run(future);
Modules§
- Stream module that contains specific interfaces for work with Redis-Stream “https://redis.io/topics/streams-intro”.
Structs§
- Redis command wrapper represents array of
BulkString
s - Actual Redis connection converts packets from
RESP
packets intoRedisValue
and fromRedisCommand
intoRESP
packets.
Enums§
- Enumeration of base types that can be put into
RedisCommand
chain as argument. - Set of types that are parsed to and from RESP binary packets. Represents RESP protocol: “https://redis.io/topics/protocol”.
Traits§
- Trait interface requires to implement method to convert
RedisValue
into base type. - Trait interface requires to implement method to convert base type into
RedisArgument
.
Functions§
- Make a Redis command represents array of
BulkString
s wrapped intoRedisCommand
. - Convert
RedisValue
intoT
value.