Temp File Round Trip - Dart Programming

Dart can reserve a fresh temporary directory for short-lived files. This program writes a small text file, reads it back, summarizes the result, and uses a finally block to delete the directory even if the body throws.

Program

Play the program to round-trip two lines of text through a temp file.

file_temp_roundtrip.dart

import 'dart:io';

void main() {
  var tempRoot = Directory.systemTemp;
  var dir = tempRoot.createTempSync('egtry_dart_');
  try {
    var path = '${dir.path}/note.txt';
    var file = File(path);
    var payload = 'Ada\nLin\n';
    file.writeAsStringSync(payload);
    var text = file.readAsStringSync();
    var lines = text.trim().split('\n');
    var count = lines.length;
    var first = lines[0];
    print('lines=$count first=$first');
  } finally {
    dir.deleteSync(recursive: true);
  }
}

Directory.systemTemp `createTempSync('prefix')` returns a fresh unique temp directory the program can write inside.

write/read round trip `writeAsStringSync` saves the text, `readAsStringSync` returns the same bytes back as a `String`.

finally cleanup `finally { dir.deleteSync(recursive: true); }` removes the directory even if the body throws.