client

Selium Client

This is the client library for the Selium platform. Clients of the Selium server should implement this library to send data to and/or receive data from the server.

Running the Examples

Before running the examples, you should generate a set of self-signed certificates to use for authenticating the client and server via mTLS.

You can do so via the selium-tools binary included in the workspace:

$ cargo run --bin selium-tools gen-certs

Getting Started

Once you've started a Selium server (see the server's README.md for details), use the client library to start sending and receiving messages.

Here's a minimal example:

use futures::SinkExt;
use selium::{prelude::*, std::codecs::StringCodec};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let connection = selium::client()
        .with_certificate_authority("certs/client/ca.der")?
        .with_cert_and_key(
            "certs/client/localhost.der",
            "certs/client/localhost.key.der",
        )?
        .connect("127.0.0.1:7001")
        .await?;

    let mut publisher = connection
        .publisher("/some/topic")
        .with_encoder(StringCodec)
        .open()
        .await?;

    publisher.send("Hello, world!".into()).await?;
    publisher.finish().await?;

    Ok(())
}

Familiar Features

Selium Client uses Rust's Futures and Tokio libraries under the hood for doing asynchronous I/O. If you are already familiar with these libs, then you already know how to drive Selium!

Take our example above:

let mut publisher = connection
    .publisher("/some/topic")
    ...;

Here, publisher is actually just a futures::Sink. This makes it instantly compatible with your existing streams/sinks:

let my_stream = ...; // whatever floats your boat!

my_stream.forward(publisher);

Now you're publishing messages!

There's lots more Selium can do, like sending things other than strings. Be sure to checkout the user guide for more details.