sheller 0.4.0-dev4

Ergonomic scripting in Dart. Utilities for interacting with shells and converting output to Dart types.

sheller

Ergonomic scripting in Dart. Utilities for interacting with shells and converting output to Dart types.

List<File> files = await $("cd $dir && find . -maxdepth 1 -type f").lines();

Table of Contents

1. Example
2. Valid Conversion Types
3. Custom Conversion Types
4. Real Use Case - Protobuf Package Generation Script Example

Example

With Sheller you can esaily write sync or async Dart scripts that interact with the host platform.

import 'sheller/sheller_sync';
// import 'sheller/sheller_async'; // alternative

// Linux
void main() async {
  // int
  int number = $("echo 1")();
  assert(number == 1);
  // json
  String data ='{\\"id\\":1, \\"name\\":\\"lorem ipsum\\", \\"address\\":\\"dolor set amet\\"}';
  Map<String, dynamic> json = $('echo $data')();
  assert(json.entries.length == 3);
  // List<double>
  List<double> doubleList = $('echo 1 2 3').spaces();
  assert(doubleList.length == 3);
  // The class
  $ shellClass = $("echo 1");
  int id = shellClass.pid;
  int convertedResult = shellClass();
  assert(convertedResult == 1);
  // Writing to a file
  $("echo 1") > File("./temp"); // == $("echo 1 > ./temp")();
  // Appending to a file
  $("echo 2") >> File("./temp"); // == $("echo 2 >> ./temp")();
}

Valid Conversion Types

Convert stdout of successful shells to

int
double
num
BigInt
String
bool (empty is true)
Map<String, dynamic>
Object
FileSystemEntity
Directory
File
Link

Custom Conversion Types

class IntConverter extends Converter<String, int> {
  const IntConverter();

  @override
  int convert(String input) {
    int? result = int.tryParse(input);
    if (result == null) {
      throw ShellResultConversionException(int, input);
    }
    return result;
  }
}

ShellConversionConfig.add(const IntConverter());

Real Use Case - Protobuf Package Generation Script Example

Future<void> main() async {
  String osPathSeparator = path.separator;
  assert(Directory.current.path.split(osPathSeparator).last == "lib");
  var protoFilesDir = "../../../proto";
  var outputDir = "../../generated";
  var outputSrcDir = "../../generated/lib/src";
  Directory(outputDir).deleteSync(recursive: true);
  Directory(outputSrcDir).createSync(recursive: true);

  var protoFiles = Directory(protoFilesDir)
      .listSync()
      .whereType<File>()
      .where((file) => file.path.endsWith(".proto"))
      .map((file) => file.path)
      .toList();

  var command = "protoc -I=$protoFilesDir --dart_out=grpc:$outputSrcDir ${protoFiles.join(' ')} google/protobuf/empty.proto";
  print(await $(command)());

  var toCopyOver = "../to_copy_over";
  // Contains desired pubspec.yaml
  Directory(toCopyOver).copyToSync(Directory(outputDir));

  final generateBarrelFileCommand = "cd $outputDir && dart pub run index_generator";
  print(await $(generateBarrelFileCommand)());
}