Gets the versions of Flutter from GitHub

README.md

Flutter Version Check

This will print out the versions of the three major Flutter branches on GitHub.

$ dart flutter_version.dart
Flutter beta is at v0.4.4
Flutter dev is at v0.5.4
Flutter master is at <NO TAG>

It's also possible to check only one branch, and to print out more detail about the branch and tag that is found: dart flutter_version.dart beta or dart flutter_version master -v.

flutter_version_check.dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';

void main(List<String> args) async {
  final String branchName =
      args != null && args.length > 0 ? args[0].toLowerCase() : null;

  final bool verbose = args.contains('--verbose') || args.contains('-v');

  final List<Map<String, dynamic>> branches =
      await getJson('https://api.github.com/repos/flutter/flutter/branches');
  final List<Map<String, dynamic>> tags =
      await getJson('https://api.github.com/repos/flutter/flutter/tags');

  if (branchName != null && branchName.trim() != '') {
    printBranchVersion(branches, tags, branchName, verbose);
  } else {
    Function printer =
        (String n) => printBranchVersion(branches, tags, n, verbose);
    ['beta', 'dev', 'master'].forEach(printer);
  }
}

void printBranchVersion(
    List<dynamic> branches, List<dynamic> tags, String branchName,
    [bool verbose]) {
  final Map<String, dynamic> branch =
      branches.firstWhere((x) => x['name'].toLowerCase() == branchName, orElse: () => null);

  if (branch == null) {
    print('No branch named $branchName');
    return;
  }

  final String branchSha = branch['commit']['sha'];

  if (verbose) {
    print(branch);
  }

  final Map<String, dynamic> tag = tags
      .firstWhere((x) => x['commit']['sha'] == branchSha, orElse: () => null);
  final String tagName = tag == null ? '<NO TAG>' : tag['name'];
  if (verbose) {
    print(tag);
  }

  print('Flutter $branchName is at ${tagName}');
}

Future<List<Map<String, dynamic>>> getJson(String uri) async {
  final HttpClient http = new HttpClient();
  final HttpClientRequest req = await http.getUrl(Uri.parse(uri));
  final HttpClientResponse resp = await req.close();

  assert(resp.statusCode == HttpStatus.OK);
  final List<dynamic> ret =
      json.decode(utf8.decode(await resp.expand((x) => x).toList()));
  http.close(force: true);
  return ret.cast<Map<String, dynamic>>();
}