dart-cloud-vision.dart

library vision;

import 'dart:io';
import 'package:crypto/crypto.dart';
import 'package:http/http.dart' as http;
import 'package:jsonx/jsonx.dart';

encodeFile(file) {
  var contents = new File(file).readAsBytesSync();
  String encoded = CryptoUtils.bytesToBase64(contents);
  return encoded;
}

main() async {
  String filepath = "/path/124015.jpg";
  var content = encodeFile(filepath);

  Map data = {
    'requests': {
      'image': {'content': content},
      'features': {'type': 'LABEL_DETECTION', 'maxResults': 20}
    }
  };

  String jsonData = encode(data);

  var url = "https://vision.googleapis.com/v1alpha1/images:annotate?key=your-key";

  var response = await http.post(
      url, headers: {'Content-Type': 'application/json'}, body: jsonData);

  Map parsedJson = decode(response.body);
  List dig = parsedJson["responses"][0]["labelAnnotations"];
  String keywords = "";
  for (var i in dig) {
    keywords = keywords + i["description"] + ", ";
  }

  String enhanced = keywords.replaceRange(keywords.length - 2, keywords.length, "");
  print(enhanced);
}

dependencies:
crypto: any
http: any
jsonx: any