json-poller

Data-agnostic JSON polling. Works with any struct that implements Deserialize. Reuses HTTP connections instead of creating new ones each time, eliminating TCP and TLS handshake overhead on every request.

Installation

Add to your Cargo.toml:

[dependencies]
json-poller = "0.1"
tokio = { version = "1", features = ["full"] }
serde = { version = "1.0", features = ["derive"] }

Or install directly from GitHub:

[dependencies]
json-poller = { git = "https://github.com/erik404/json-poller" }
tokio = { version = "1", features = ["full"] }
serde = { version = "1.0", features = ["derive"] }

Usage

use json_poller::JsonPoller;
use serde::Deserialize;

#[derive(Deserialize)]
struct Weather {
    temperature: f64,
    condition: String,
    latitude: f64,
    longitude: f64
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let poller = JsonPoller::<Weather>::builder("https://api.weather.com/current")
        .poll_interval_ms(60000)
        .build()?;

    poller.start(|weather, duration| {
        println!("{:.1}°C - {} at ({:.2}, {:.2}) (fetched in {:?})",
         weather.temperature,
         weather.condition,
         weather.latitude,
         weather.longitude,
         duration
        );
    }).await;

    Ok(())
}

Configuration

let poller = JsonPoller::<MyType>::builder(url)
    .poll_interval_ms(500)        // How often to poll (default: 500ms)
    .request_timeout_ms(1000)     // Request timeout (default: 1000ms)
    .pool_max_idle_per_host(1)    // Connections to keep alive (default: 1)
    .pool_idle_timeout_secs(90)   // How long to keep connections (default: 90s)
    .tcp_keepalive_secs(60)       // TCP keepalive interval (default: 60s)
    .build()?;

Requirements

Works with any type that implements serde::Deserialize
Requires tokio async runtime
Only supports JSON responses

License