Amazon Lex授权Flutter

Question

我想写一个与Amazon Lex REST API一起工作的颤振应用程序。Amazon有特定的方法来验证我使用的SigV4包来生成所需的头文件

  Sigv4Client client = Sigv4Client(
  keyId: kAccessKey,
  accessKey: kSecretKey,
  region: "us-east-1",
  serviceName: "lex",
);

final request = client.request(
  "https://runtime.lex.us-east-1.amazonaws.com/bot/myBotName/alias/BETA/user/myUserId/text",
  method: 'POST',
  body: jsonEncode({'inputText': 'hi'}),
);

var response=post(request.url, headers: request.headers, body: request.body);
print(response.body);

但我得到的信息是：

{"message":"The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details."}

我得到有效的回复邮递员相同的数据，唯一的部分是不同的邮递员，这个包是X-Amz-Content-Sha256值，当然签名值（它每次都改变）。"X-Amz-Content-Sha256"邮递员值：

beaead3198f7da1e70d03ab969765e0821b24fc913697e929e726aeaebf0eba3

“X-Amz-Content-Sha256”我的代码值：

ee9ef87bd5a357cff93b1d83d1e8a1b47fb3fa2e94251711c6a30250119e6369

我试图编写函数来计算验证字符串，但它对我来说太复杂了。

Answer 1

我也有类似的问题。我设置defaultContentType：'应用程序/json； charset=utf-8'在AwsSigV4Client和删除标头从SigV4Request：

AwsSigV4Client client=AwsSigV4Client(
  accessKey,
  secretKey,
  'https://runtime.lex.eu-west-2.amazonaws.com',
  region: 'eu-west-2',
  serviceName: 'lex',
  defaultContentType: 'application/json; charset=utf-8',
);

final signedRequest = new SigV4Request(
  client,
  method: 'POST',
  path: '/bot/MyBotName/alias/BETA/user/MyUser/text',
  body: new Map<String, dynamic>.from({"inputText": "hi"}),
);

Answer 2

我更改了包并使用了amazon-cognito-identity-dart-2

并按如下方式发送请求：

AwsSigV4Client client=AwsSigV4Client(
      kAccessKey,
      kSecretKey,
      'https://runtime.lex.us-east-1.amazonaws.com',
      region: 'us-east-1',
      serviceName: 'lex',
    );

final signedRequest = new SigV4Request(
      client,
      method: 'POST',
      path: '/bot/MyBotName/alias/BETA/user/MyUser/text',
      headers: new Map<String, String>.from({
        'Content-Type': 'application/json; charset=utf-8',
        'ACCEPT': 'application/json',
      }),
      body: new Map<String, dynamic>.from({"inputText": "hi"}),
    );

var response = await http.post(
      signedRequest.url,
      headers: signedRequest.headers,
      body: signedRequest.body,
    );

补充一点非常重要

'Content-Type': 'application/json; charset=utf-8',

在标题中。