Function read

Reads the entire contents of a file into a bytes vector.

This is an async version of std::fs::read.

This is a convenience function for using File::open and read_to_end with fewer imports and without an intermediate variable. It pre-allocates a buffer based on the file size when available, so it is generally faster than reading into a vector created with Vec::new().

This operation is implemented by running the equivalent blocking operation on a separate thread pool using spawn_blocking.

Errors

This function will return an error if path does not already exist. Other errors may also be returned according to OpenOptions::open.

It will also return an error if it encounters while reading an error of a kind other than ErrorKind::Interrupted.

io_uring support

On Linux, you can also use io_uring for executing system calls. To enable io_uring, you need to specify the --cfg tokio_unstable flag at compile time, enable the io-uring cargo feature, and set the Builder::enable_io_uring runtime option.

Support for io_uring is currently experimental, so its behavior may change or it may be removed in future versions.

Examples

use tokio::fs;
use std::net::SocketAddr;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error + 'static>> {
    let contents = fs::read("address.txt").await?;
    let foo: SocketAddr = String::from_utf8_lossy(&contents).parse()?;
    Ok(())
}