Download image with rust fails (image corrupted) - image

Question

I am trying to download image/file with rust, works like a wget.
I followed this https://rust-lang-nursery.github.io/rust-cookbook/web/clients/download.html#download-a-file-to-a-temporary-directory
But a temp file isn't created, not sure why. If you remove the temp folder part, a png file is created but cannot be read. Seems corrupted.
How do I download a binary file with Rust? I could not find a good solution online.

Answer 1

Found the solution.
Use .bytes instead of .text(), and has to wrap the bytes inside std::io::Cursor.
Since temp file is removed on exit, I commented one line out to see the resulting image in cwd.
let mut content = Cursor::new(response.bytes().await?);
copy(&mut content, &mut dest)?;
Complete Solution
use error_chain::error_chain;
use std::io::copy;
use std::fs::File;
use tempfile::Builder;
use std::io::Cursor;
error_chain! {
foreign_links {
Io(std::io::Error);
HttpRequest(reqwest::Error);
}
}
#[tokio::main]
async fn main() -> Result<()> {
let tmp_dir = Builder::new().prefix("example").tempdir()?;
let target = "https://www.rust-lang.org/logos/rust-logo-512x512.png";
let response = reqwest::get(target).await?;
let mut dest = {
let fname = response
.url()
.path_segments()
.and_then(|segments| segments.last())
.and_then(|name| if name.is_empty() { None } else { Some(name) })
.unwrap_or("tmp.bin");
println!("file to download: '{}'", fname);
// let fname = tmp_dir.path().join(fname);
println!("will be located under: '{:?}'", fname);
File::create(fname)?
};
// let content = response.text().await?;
// copy(&mut content.as_bytes(), &mut dest)?;
let mut content = Cursor::new(response.bytes().await?);
copy(&mut content, &mut dest)?;
Ok(())
}