Rustで一時ファイルを作成・管理する方法｜tempfileクレートの徹底解説

[dependencies]
tempfile = "3.10"  # 最新バージョンを指定

cargo build

use tempfile::NamedTempFile;

fn main() -> std::io::Result<()> {
    let temp_file = NamedTempFile::new()?;
    println!("Temporary file created: {:?}", temp_file.path());
    Ok(())
}

use tempfile::NamedTempFile;
use std::io::{Write, Read};

fn main() -> std::io::Result<()> {
    // 一時ファイルを作成
    let mut temp_file = NamedTempFile::new()?;
    println!("Temporary file created: {:?}", temp_file.path());

    // ファイルにデータを書き込む
    writeln!(temp_file, "Hello, Tempfile!")?;

    // ファイルを読み込むために、再度読み込み位置を先頭に戻す
    let mut contents = String::new();
    temp_file.as_file_mut().seek(std::io::SeekFrom::Start(0))?;
    temp_file.as_file_mut().read_to_string(&mut contents)?;

    println!("File contents: {}", contents);

    Ok(())
}

   let mut temp_file = NamedTempFile::new()?;

   writeln!(temp_file, "Hello, Tempfile!")?;

   temp_file.as_file_mut().seek(std::io::SeekFrom::Start(0))?;
   temp_file.as_file_mut().read_to_string(&mut contents)?;

Temporary file created: "/tmp/.tmp3aB2Cd"
File contents: Hello, Tempfile!

use tempfile::TempDir;
use std::fs::File;
use std::io::Write;

fn main() -> std::io::Result<()> {
    // 一時ディレクトリを作成
    let temp_dir = TempDir::new()?;
    println!("Temporary directory created: {:?}", temp_dir.path());

    // 一時ディレクトリ内にファイルを作成
    let file_path = temp_dir.path().join("example.txt");
    let mut file = File::create(&file_path)?;
    writeln!(file, "This is a temporary file.")?;

    println!("Temporary file created: {:?}", file_path);

    // TempDirはスコープを抜けると自動で削除される
    Ok(())
}

   let temp_dir = TempDir::new()?;

   let file_path = temp_dir.path().join("example.txt");
   let mut file = File::create(&file_path)?;
   writeln!(file, "This is a temporary file.")?;

Temporary directory created: "/tmp/.tmpA1B2C3"
Temporary file created: "/tmp/.tmpA1B2C3/example.txt"

use tempfile::NamedTempFile;

fn main() -> std::io::Result<()> {
    {
        let temp_file = NamedTempFile::new()?;
        println!("Temporary file created: {:?}", temp_file.path());
        // temp_fileがこのブロックのスコープを抜けると削除される
    } // ここで自動的に削除される

    println!("Temporary file deleted automatically.");
    Ok(())
}

Temporary file created: "/tmp/.tmp1234abcd"
Temporary file deleted automatically.

use tempfile::TempDir;

fn main() -> std::io::Result<()> {
    {
        let temp_dir = TempDir::new()?;
        println!("Temporary directory created: {:?}", temp_dir.path());
        // temp_dirがスコープを抜けると削除される
    } // ここで自動的に削除される

    println!("Temporary directory deleted automatically.");
    Ok(())
}

Temporary directory created: "/tmp/.tmp5678efgh"
Temporary directory deleted automatically.

use tempfile::NamedTempFile;

fn main() -> std::io::Result<()> {
    let temp_file = NamedTempFile::new()?;
    println!("Temporary file created: {:?}", temp_file.path());

    // 手動で削除する
    temp_file.close()?;
    println!("Temporary file deleted manually.");

    Ok(())
}

use tempfile::NamedTempFile;
use std::io;

fn main() {
    match NamedTempFile::new() {
        Ok(temp_file) => {
            println!("Temporary file created: {:?}", temp_file.path());
        },
        Err(e) => {
            eprintln!("Failed to create temporary file: {}", e);
        }
    }
}

Failed to create temporary file: No space left on device (os error 28)

use tempfile::TempDir;
use std::io;

fn main() {
    match TempDir::new() {
        Ok(temp_dir) => {
            println!("Temporary directory created: {:?}", temp_dir.path());
        },
        Err(e) => {
            eprintln!("Failed to create temporary directory: {}", e);
        }
    }
}

use tempfile::NamedTempFile;
use std::io::{Write, Read};

fn write_message_to_file(mut file: &std::fs::File, message: &str) -> std::io::Result<()> {
    writeln!(file, "{}", message)
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::io::Seek;

    #[test]
    fn test_write_message_to_file() -> std::io::Result<()> {
        // 一時ファイルを作成
        let mut temp_file = NamedTempFile::new()?;

        // テスト対象の関数を実行
        write_message_to_file(temp_file.as_file_mut(), "Hello, Test!")?;

        // ファイルの内容を読み込むため、先頭に戻す
        temp_file.as_file_mut().seek(std::io::SeekFrom::Start(0))?;
        let mut contents = String::new();
        temp_file.as_file_mut().read_to_string(&mut contents)?;

        // 内容が期待通りか検証
        assert_eq!(contents.trim(), "Hello, Test!");

        Ok(())
    }
}

   fn write_message_to_file(mut file: &std::fs::File, message: &str) -> std::io::Result<()> {
       writeln!(file, "{}", message)
   }

   let mut temp_file = NamedTempFile::new()?;

   write_message_to_file(temp_file.as_file_mut(), "Hello, Test!")?;

   assert_eq!(contents.trim(), "Hello, Test!");

use tempfile::TempDir;
use std::fs::{self, File};
use std::io::Write;

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_multiple_files_in_temp_dir() -> std::io::Result<()> {
        let temp_dir = TempDir::new()?;

        // 一時ディレクトリ内に複数のファイルを作成
        let file_path1 = temp_dir.path().join("file1.txt");
        let file_path2 = temp_dir.path().join("file2.txt");

        let mut file1 = File::create(&file_path1)?;
        let mut file2 = File::create(&file_path2)?;

        writeln!(file1, "File 1 Content")?;
        writeln!(file2, "File 2 Content")?;

        // 内容を確認
        assert!(file_path1.exists());
        assert!(file_path2.exists());

        Ok(())
    }
}