Temporary Files And Directories in Rust

Throughout program execution, we often want to create data that isn’t needed after the program exits. Temporary files and directories are useful for this purpose since they don’t pollute the file system over time.

use std::fs::File;
use std::io::Write;
use std::path::Path;
use tempfile::{tempdir, tempfile};

fn main() -> std::io::Result<()> {
    // The easiest way to create a temporary file is by using the
    // `tempfile` crate. It creates a file and opens it for reading
    // and writing.
    let mut f = tempfile()?;

    // Display the name of the temporary file. On Unix-based OSes
    // the directory will likely be `/tmp`. The file name is
    // chosen automatically to ensure that concurrent calls will
    // always create different file names.
    println!("Temp file name: {:?}", f.path());

    // We can write some data to the file.
    f.write_all(&[1, 2, 3, 4])?;

    // If we intend to create many temporary files, we may prefer
    // to create a temporary directory. The `tempdir` function
    // returns a directory that will be automatically removed when
    // it goes out of scope.
    let dir = tempdir()?;
    println!("Temp dir name: {:?}", dir.path());

    // Now we can synthesize temporary file names by joining them
    // with our temporary directory path.
    let file_path = dir.path().join("file1");
    let mut file = File::create(file_path)?;
    file.write_all(&[1, 2])?;

    Ok(())
}

To run the program:

$ cargo run
Temp file name: "/tmp/rustXXXXXX"
Temp dir name: "/tmp/rustXXXXXX"

Note that in Rust, we use the tempfile crate to handle temporary files and directories. This crate provides a safe and convenient way to create temporary files that are automatically deleted when they’re dropped.

The ? operator is used for error propagation. If an error occurs, it will be returned from the main function.

Unlike in some other languages, Rust’s temporary files and directories are automatically cleaned up when they go out of scope, so we don’t need to explicitly remove them.

The write_all method is used to write data to the file, which is similar to the Write method in the original example.

Instead of os.MkdirTemp, we use tempdir() to create a temporary directory. This returns a TempDir struct that is automatically removed when it goes out of scope.

File paths are manipulated using the Path and PathBuf types from the std::path module.

This Rust code provides equivalent functionality to the original example, with the added benefit of automatic cleanup and strong type safety.