initialize method

void initialize(
  1. String aliOSSAccessKeyId,
  2. String aliOSSKeySecret, {
  3. String? policyText,
})

必须先初始化

Implementation

void initialize(String aliOSSAccessKeyId, String aliOSSKeySecret,
    {String? policyText}) {
  final String text = policyText ??
      '{"expiration": "2050-01-01T12:00:00.000Z","conditions": [["content-length-range", 0, 1048576000]]}';

  /// 进行base64编码
  _policyBase64 = text.utf8Encode.base64Encode;

  /// 再次进行utf8编码
  final List<int> policy = _policyBase64!.utf8Encode;

  /// 进行utf8 编码
  final List<int> key = aliOSSKeySecret.utf8Encode;

  /// 通过 HMAC ,使用sha1进行加密
  final List<int> signatureHMAC = Hmac(sha1, key).convert(policy).bytes;

  /// 最后一步，将上述所得进行base64 编码
  _signature = signatureHMAC.base64Encode;
  _aliOSSAccessKeyId = aliOSSAccessKeyId;
}