如何从 .net 核心客户端生成 JWT Bearer Flow OAuth 访问令牌?

How to generate JWT Bearer Flow OAuth access tokens from a .net core client?

我无法让我的 .NET Core 客户端为需要 'JWT Bearer Flow'.

类型 OAuth 的 salesforce 端点生成 OAuth 访问令牌

似乎有有限的 .NET Framework 示例显示 .NET 客户端执行此操作,但是 none 显示 .NET Core 客户端执行此操作 例如 https://salesforce.stackexchange.com/questions/53662/oauth-jwt-token-bearer-flow-returns-invalid-client-credentials

所以在我的 .NET Core 3.1 应用程序中,我生成了一个自签名证书,在加载证书时将私钥添加到上面示例的代码中,但是此行出现 System.InvalidCastExceptionexception 异常:

var rsa = certificate.GetRSAPrivateKey() as RSACryptoServiceProvider;

异常:

System.InvalidCastException: 'Unable to cast object of type 'System.Security.Cryptography.RSACng' to type 'System.Security.Cryptography.RSACryptoServiceProvider'.'

这个私钥似乎在 JWT Bearer Flow 中用作签名的一部分,并且 RSACryptoServiceProvider 可能不像在 .NET Framework 中那样在 .NET Core 中使用。

我的问题是 - 在 .NET Core 中实际上有一种方法可以为 OAuth JWT Bearer Flow 生成访问令牌吗?

我正在使用的完整代码:

static void Main(string[] args)
    {
        Console.WriteLine("Hello World!");
        var token = GetAccessToken();
    }

    static dynamic GetAccessToken()
    {
        // get the certificate
        var certificate = new X509Certificate2(@"C:\temp\cert.pfx");

        // create a header
        var header = new { alg = "RS256" };

        // create a claimset
        var expiryDate = GetExpiryDate();
        var claimset = new
        {
            iss = "xxxxxx",
            prn = "xxxxxx",
            aud = "https://test.salesforce.com",
            exp = expiryDate
        };

        // encoded header
        var headerSerialized = JsonConvert.SerializeObject(header);
        var headerBytes = Encoding.UTF8.GetBytes(headerSerialized);
        var headerEncoded = ToBase64UrlString(headerBytes);

        // encoded claimset
        var claimsetSerialized = JsonConvert.SerializeObject(claimset);
        var claimsetBytes = Encoding.UTF8.GetBytes(claimsetSerialized);
        var claimsetEncoded = ToBase64UrlString(claimsetBytes);

        // input
        var input = headerEncoded + "." + claimsetEncoded;
        var inputBytes = Encoding.UTF8.GetBytes(input);

        // signature
        var rsa = (RSACryptoServiceProvider) certificate.GetRSAPrivateKey();

        var cspParam = new CspParameters
        {
            KeyContainerName = rsa.CspKeyContainerInfo.KeyContainerName,
            KeyNumber = rsa.CspKeyContainerInfo.KeyNumber == KeyNumber.Exchange ? 1 : 2
        };
        var aescsp = new RSACryptoServiceProvider(cspParam) { PersistKeyInCsp = false };
        var signatureBytes = aescsp.SignData(inputBytes, "SHA256");
        var signatureEncoded = ToBase64UrlString(signatureBytes);

        // jwt
        var jwt = headerEncoded + "." + claimsetEncoded + "." + signatureEncoded;

        var client = new WebClient();
        client.Encoding = Encoding.UTF8;
        var uri = "https://login.salesforce.com/services/oauth2/token";
        var content = new NameValueCollection();

        content["assertion"] = jwt;
        content["grant_type"] = "urn:ietf:params:oauth:grant-type:jwt-bearer";

        string response = Encoding.UTF8.GetString(client.UploadValues(uri, "POST", content));

        var result = JsonConvert.DeserializeObject<dynamic>(response);

        return result;
    }

    static int GetExpiryDate()
    {
        var utc0 = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
        var currentUtcTime = DateTime.UtcNow;

        var exp = (int)currentUtcTime.AddMinutes(4).Subtract(utc0).TotalSeconds;

        return exp;
    }

    static string ToBase64UrlString(byte[] input)
    {
        return Convert.ToBase64String(input).TrimEnd('=').Replace('+', '-').Replace('/', '_');
    }

好吧 - 事实证明,发布到 Whosebug 会让大脑齿轮转动。

答案最终是深入研究以在此处找到类似问题并使用

中的解决方案

我最终替换了以下代码:

var cspParam = new CspParameters
{
      KeyContainerName = rsa.CspKeyContainerInfo.KeyContainerName,
      KeyNumber = rsa.CspKeyContainerInfo.KeyNumber == KeyNumber.Exchange ? 1 : 2
};
var aescsp = new RSACryptoServiceProvider(cspParam) { PersistKeyInCsp = false };
var signatureBytes = aescsp.SignData(inputBytes, "SHA256");
var signatureEncoded = ToBase64UrlString(signatureBytes);

使用 System.IdentityModel.Tokens.Jwt nuget 包的代码:

var signingCredentials = new X509SigningCredentials(certificate, "RS256");
var signature = JwtTokenUtilities.CreateEncodedSignature(input, signingCredentials);

解决后的完整代码:

static void Main(string[] args)
    {
        Console.WriteLine("Hello World!");
        var token = GetAccessToken();
    }

    static dynamic GetAccessToken()
    {
        // get the certificate
        var certificate = new X509Certificate2(@"C:\temp\cert.pfx");

        // create a header
        var header = new { alg = "RS256" };

        // create a claimset
        var expiryDate = GetExpiryDate();
        var claimset = new
        {
            iss = "xxxxx",
            prn = "xxxxx",
            aud = "https://test.salesforce.com",
            exp = expiryDate
        };

        // encoded header
        var headerSerialized = JsonConvert.SerializeObject(header);
        var headerBytes = Encoding.UTF8.GetBytes(headerSerialized);
        var headerEncoded = ToBase64UrlString(headerBytes);

        // encoded claimset
        var claimsetSerialized = JsonConvert.SerializeObject(claimset);
        var claimsetBytes = Encoding.UTF8.GetBytes(claimsetSerialized);
        var claimsetEncoded = ToBase64UrlString(claimsetBytes);

        // input
        var input = headerEncoded + "." + claimsetEncoded;
        var inputBytes = Encoding.UTF8.GetBytes(input);

        var signingCredentials = new X509SigningCredentials(certificate, "RS256");
        var signature = JwtTokenUtilities.CreateEncodedSignature(input, signingCredentials);

        // jwt
        var jwt = headerEncoded + "." + claimsetEncoded + "." + signature;

        var client = new WebClient();
        client.Encoding = Encoding.UTF8;
        var uri = "https://test.salesforce.com/services/oauth2/token";
        var content = new NameValueCollection();

        content["assertion"] = jwt;
        content["grant_type"] = "urn:ietf:params:oauth:grant-type:jwt-bearer";

        string response = Encoding.UTF8.GetString(client.UploadValues(uri, "POST", content));

        var result = JsonConvert.DeserializeObject<dynamic>(response);

        return result;
    }

    static int GetExpiryDate()
    {
        var utc0 = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
        var currentUtcTime = DateTime.UtcNow;

        var exp = (int)currentUtcTime.AddMinutes(4).Subtract(utc0).TotalSeconds;

        return exp;
    }

    static string ToBase64UrlString(byte[] input)
    {
        return Convert.ToBase64String(input).TrimEnd('=').Replace('+', '-').Replace('/', '_');
    }

我回答这个问题只是因为这样一个相似的答案在我第一次登陆这个页面时会对我有很大帮助。

首先,您不必从 C# 客户端生成 JWT。

要生成 JWT 令牌,您可以使用此网站:https://jwt.io/

有一个制作精良的视频展示了如何生成 JWT 令牌: https://www.youtube.com/watch?v=cViU2-xVscA&t=1680s

生成后,从您的 C# 客户端使用它来调用 get access_token 端点 https://developer.salesforce.com/docs/atlas.en-us.api_iot.meta/api_iot/qs_auth_access_token.htm (在 YT 上观看视频)

如果一切正确,您将得到 access_token

要 运行 API 调用,您只需要 access_token 而不是 JWT。

一旦你有了它,就把它添加到像这样的 HTTP 调用中

public static void AddBearerToken(this HttpRequestMessage request, string accessToken)
    {
        request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", accessToken);
    }

access_token 有时会过期。要检查其有效性,您可以调用令牌内省 api https://help.salesforce.com/s/articleView?id=sf.remoteaccess_oidc_token_introspection_endpoint.htm&type=5

您需要传递两个附加参数:client_id 和 client_secret

  • client_id 是消费者密钥。您可以从 Salesforce
  • 中的连接应用程序获取它
  • client_server 是消费者机密。您可以从 Salesforce
  • 中的 Connected App 获取它

如果内省标记 API returns 响应

{ active: false, ...  }

表示access_token已过期,您需要重新签发。 要发布新的 access_token,只需使用相同的 JWT 再次调用“/services/oauth2/token”即可。