Crate squalo

🦈 Minimal, elegant, fast, async Kraken exchange WebSockets API client | Written in Rust

Description

squalo library aims to interface your software with the Kraken exchange WebSockets API in no time.

Prerequisites

The Kraken exchange allows WebSockets API interaction with both public and private data.

Only for the private one, you need to issue an API-Key and an API-Secret to the squalo library, in order to generate authentication token for signed subscriptions on WebSockets endpoints.

If you are not familiar with, please have a look at WebSockets API - FAQ for a general overview, or at WebSockets API document.

Implementation

Add this to your Cargo.toml:

[dependencies]
squalo = {version = 0.1.0}

and then add this to your code:

use squalo;

Methods

squalo::print_crate_info();

Description: prints crate information (name, description, version, author and repository).

squalo::set_kraken_api_credentials(api_key: String, api_secret: String);

Description: sets Kraken API credentials for private data access.

Required:

• api_key: String
• api_secret: String

squalo::get_websockets_token();

Description: retrieves a WebSockets API token with a signed request from a Kraken REST API endpoint.

Output: returns a WebSockets API token in the String format.

polipo::attach_websockets_stream(callback: fn(&str), stringified_json_message).await;

Description: spawns a thread which initializes a WebSocket client and writes the stringified_json_message.

Required:

• callback: fn (eg: fn callback(data: &str) { println(“data: {}”, data); })
• stringified_json_message: String (eg: {“event”:“subscribe”, “subscription”:{“name”:“trade”}, “pair”:[“XBT/USD”]})

Output: any incoming message forwared from the WebSockets stream to the issued callback comes in stringified JSON format (parse accordingly with the outcome shape).

Example

The example below shows how easy is to implement squalo from zero knowledge.

use squalo;
 
fn callback(data: &str) {
    println!("data: {}", data);
}
 
#[tokio::main]
async fn main() {
     
    // printing crate information
    squalo::print_crate_info();
 
    // enveloping a message pointing on public endpoint
    let payload =
        r#"{"event":"subscribe", "subscription":{"name":"trade"}, "pair":["XRP/EUR", "ETH/USD"]}"#.to_string();
 
    // attaching websockets to public data stream
    squalo::attach_websockets_stream(callback, payload).await;
 
    // issuing credentials enables private data interaction
    squalo::set_kraken_api_credentials(
        "YOUR_KRAKEN_API_KEY_HERE".to_string(),
        "YOUR_KRAKEN_API_SECRET".to_string(),
    );
 
    // requesting a websockets token
    let token = squalo::get_websockets_token().await;
 
    // enveloping a message pointing on private endpoint
    let payload = format!(
        r#"{{"event":"subscribe", "subscription":{{"name":"ownTrades", "token":"{}"}}}}"#,
        token
    );
 
    // attaching websockets to private data stream
    squalo::attach_websockets_stream(callback, payload).await;
}

Disclaimer

This software comes without any kind of warranties.

I will not be liable for any damages related to the use or the misuse of this software.

You are the sole responsible.

Functions

attach_websockets_stream
get_websockets_token
print_crate_info
set_kraken_api_credentials