Synchronous file downloading

download_with_progressbar.rs

use anyhow::{anyhow, Result};
use std::cmp::min;
use std::fs::File;
use std::io::{Read, Write};

use indicatif::{ProgressBar, ProgressStyle};
use reqwest::blocking::Client;

pub fn download_file(client: &Client, url: &str, path: &str) -> Result<()> {
    let mut res = client.get(url).send()?;
    let total_size = res
        .content_length()
        .ok_or(anyhow!("Failed to get content length from '{}'", &url))?;

    let pb = ProgressBar::new(total_size);
    pb.set_style(ProgressStyle::default_bar()
        .template("{msg}\n{spinner:.green} [{elapsed_precise}] [{bar:.cyan/blue}] {bytes}/{total_bytes} ({bytes_per_sec}, {eta})")
        .progress_chars("=> "));
    pb.set_message(&format!("Downloading {}", url));

    let mut file = File::create(path)?;
    let mut downloaded: u64 = 0;

    let mut buf = vec![0; 8_096];

    while downloaded < total_size {
        // TODO: Handle interrupted error
        let bytes = res.read(&mut buf)?;
        file.write_all(&buf[0..bytes])?;
        // Update progress bar
        downloaded = min(downloaded + (bytes as u64), total_size);
        pb.set_position(downloaded);
    }

    pb.finish_with_message(&format!("Downloaded {} to {}", url, path));

    Ok(())
}

fn main() -> Result<()> {
    download_file(
        &Client::new(),
        "https://releases.ubuntu.com/20.04/ubuntu-20.04.3-desktop-amd64.iso",
        "ubuntu.iso",
    )
}