io 0.3.3

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Contains utilities for the Dart VM's dart:io.

Build Status

Contributing #

NOTE: Due to the changing nature of the Dart SDK (towards 2.0.0), running dartfmt requires the local executable:

$ pub run dart_style:format

Usage - io.dart #

Files #


Returns whether a provided file path is considered executable on the host operating system.

Processes #


An enum-like class that contains known exit codes.


A higher-level service for spawning and communicating with processes.

Use spawn to create a process with std[in|out|err] forwarded by default
/// Runs `dartfmt` commands and `pub publish`.
Future<Null> main() async {
  final manager = new ProcessManager();
  // Runs dartfmt --version and outputs the result via stdout.
  print('Running dartfmt --version');
  var spawn = await manager.spawn('dartfmt', ['--version']);
  await spawn.exitCode;
  // Runs dartfmt -n . and outputs the result via stdout.
  print('Running dartfmt -n .');
  spawn = await manager.spawn('dartfmt', ['-n', '.']);
  await spawn.exitCode;
  // Runs pub publish. Upon hitting a blocking stdin state, you may directly
  // output to the processes's stdin via your own, similar to how a bash or
  // shell script would spawn a process.
  print('Running pub publish');
  spawn = await manager.spawn('pub', ['publish']);
  await spawn.exitCode;
  // Closes stdin for the entire program.
  await sharedStdIn.terminate();


A safer version of the default stdin stream from dart:io that allows a subscriber to cancel their subscription, and then allows a new subscriber to start listening. This differs from the default behavior where only a single listener is ever allowed in the application lifecycle:

test('should allow multiple subscribers', () async {
  final logs = <String>[];
  final asUtf8 = sharedStdIn.transform(UTF8.decoder);
  // Wait for input for the user.
  logs.add(await asUtf8.first);
  // Wait for more input for the user.
  logs.add(await asUtf8.first);
  expect(logs, ['Hello World', 'Goodbye World']);

For testing, an instance of SharedStdIn may be created directly.

Usage - ansi.dart #

import 'dart:io' as io;
import 'package:io/ansi.dart';

void main() {
  // To use one style, call the `wrap` method on one of the provided top-level
  // values.
  io.stderr.writeln(red.wrap("Bad error!"));

  // To use multiple styles, call `wrapWith`.
  print(wrapWith('** Important **', [red, styleBold, styleUnderlined]));

  // The wrap functions will simply return the provided value unchanged if
  // `ansiOutputEnabled` is false.
  // You can override the value `ansiOutputEnabled` by wrapping code in
  // `overrideAnsiOutput`.
  overrideAnsiOutput(false, () {
    assert('Normal text' == green.wrap('Normal text'));

0.3.3 #

  • Updates for Dart 2 constants. Require at least Dart 2.0.0-dev.54.

  • Fix the type of StartProcess typedef to match Process.start from dart:io.

0.3.2+1 #

  • ansi.dart

    • The "forScript" code paths now ignore the ansiOutputEnabled value. Affects the escapeForScript property on AnsiCode and the wrap and wrapWith functions when forScript is true.

0.3.2 #

  • ansi.dart

    • Added forScript named argument to top-level wrapWith function.

    • AnsiCode

      • Added String get escapeForScript property.

      • Added forScript named argument to wrap function.

0.3.1 #

  • Added SharedStdIn.nextLine (similar to readLineSync) and lines:
main() async {
  // Prints the first line entered on stdin.
  print(await sharedStdIn.nextLine());
  // Prints all remaining lines.
  await for (final line in sharedStdIn.lines) {
  • Added a copyPath and copyPathSync function, similar to cp -R.

  • Added a dependency on package:path.

  • Added the remaining missing arguments to ProcessManager.spawnX which forward to Process.start. It is now an interchangeable function for running a process.

0.3.0 #

  • BREAKING CHANGE: The arguments argument to ProcessManager.spawn is now positional (not named) and required. This makes it more similar to the built-in Process.start, and easier to use as a drop in replacement:
main() {
  processManager.spawn('dart', ['--version']);
  • Fixed a bug where processes created from ProcessManager.spawn could not have their stdout/stderr read through their respective getters (a runtime error was always thrown).

  • Added ProcessMangaer#spawnBackground, which does not forward stdin.

  • Added ProcessManager#spawnDetached, which does not forward any I/O.

  • Added the shellSplit() function, which parses a list of arguments in the same manner as the POSIX shell.

0.2.0 #

  • Initial commit of...
    • FutureOr<bool> String isExecutable(path).
    • ExitCode
    • ProcessManager and Spawn
    • sharedStdIn and SharedStdIn
    • ansi.dart library with support for formatting terminal output

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  io: ^0.3.3

2. Install it

You can install packages from the command line:

with pub:

$ pub get

with Flutter:

$ flutter pub get

Alternatively, your editor might support pub get or flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:io/io.dart';
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Code health derived from static analysis. [more]
Reflects how tidy and up-to-date the package is. [more]
Weighted score of the above. [more]
Learn more about scoring.

We analyzed this package on Mar 31, 2020, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.7.1
  • pana: 0.13.6

Health suggestions

Fix lib/src/ansi_code.dart. (-25 points)

Analysis of lib/src/ansi_code.dart reported 64 hints, including:

line 41 col 42: Avoid const keyword.

line 44 col 37: Avoid const keyword.

line 47 col 42: Avoid const keyword.

line 50 col 37: Avoid const keyword.

line 84 col 38: Use = to separate a named parameter from its default value.

Fix lib/src/process_manager.dart. (-7.71 points)

Analysis of lib/src/process_manager.dart reported 16 hints, including:

line 49 col 14: Unnecessary new keyword.

line 51 col 12: Unnecessary new keyword.

line 72 col 34: Use = to separate a named parameter from its default value.

line 73 col 20: Use = to separate a named parameter from its default value.

line 74 col 29: Use = to separate a named parameter from its default value.

Fix lib/src/exit_code.dart. (-7.24 points)

Analysis of lib/src/exit_code.dart reported 15 hints, including:

line 10 col 26: Avoid const keyword.

line 16 col 24: Avoid const keyword.

line 21 col 23: Avoid const keyword.

line 24 col 26: Avoid const keyword.

line 27 col 25: Avoid const keyword.

Fix additional 4 files with analysis or formatting issues. (-10.81 points)

Additional issues in the following files:

  • lib/src/copy_path.dart (11 hints)
  • lib/src/shared_stdin.dart (7 hints)
  • lib/src/permissions.dart (2 hints)
  • lib/src/shell_words.dart (2 hints)

Maintenance suggestions

Package is getting outdated. (-71.78 points)

The package was last published 89 weeks ago.

The package description is too short. (-20 points)

Add more detail to the description field of pubspec.yaml. Use 60 to 180 characters to describe the package, what it does, and its target use case.

Maintain an example.

None of the files in the package's example/ directory matches known example patterns.

Common filename patterns include main.dart, example.dart, and io.dart. Packages with multiple examples should provide example/

For more information see the pub package layout conventions.


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.0.0-dev.54 <3.0.0
charcode ^1.0.0 1.1.3
meta ^1.0.2 1.1.8
path ^1.5.1 1.6.4
string_scanner >=0.1.5 <2.0.0 1.0.5
Transitive dependencies
collection 1.14.12
source_span 1.7.0
term_glyph 1.1.0
Dev dependencies
dart_style ^1.0.7
test ^1.0.0
test_descriptor ^1.0.0