如何访问我定义的java grpc服务的请求元数据？

Question

对于某些背景,我试图使用grpc auth以便为我定义的某些服务提供安全性.

让我们看看我是否可以问这是一种有意义的方式.对于我的python代码,实现服务器端代码非常容易.

class TestServiceServer(service_pb2.TestServiceServer):

    def TestHello(self, request, context):

        ## credential metadata for the incoming request
        metadata = context.invocation_metadata()

        ## authenticate the user using the metadata

因此,正如您所知,我能够非常轻松地从"上下文"中获取元数据.对我来说更难的是在java中做同样的事情.

public class TestImpl extends TestServiceGrpc.TestServiceImplBase {

    @Override
    public void testHello(TestRequest req, StreamObserver<TestResponse> responseObserver) {

        // How do I get access to similar request metadata here?

        // from the parameter positions, it looks like it should be
        // "responseObserver" but that doesn't seem similar to "context"

    }

}

我承认我的问题来自几个方向.

1)我不熟悉Java

2)我大量使用python的"pdb"来调试类,看看我可以使用哪些方法.我不知道/我不熟悉java的类似工具.

3)此时文档似乎相当稀疏​​.它向您展示了如何在服务器端设置ssl连接,但是我找不到服务器的示例来查看请求元数据,正如我在python中所示.

有人可以给我一个如何做到这一点的想法,或者可能在python的pdb的同一环境中向我展示一个有用的java调试工具？

编辑/答案:

我需要先写一个实现接口ServerInterceptor的定义.

private class TestInterceptor implements ServerInterceptor {
    ....

然后,在实际绑定我的服务和构建我的服务器之前,我需要这样做.

TestImpl service = new TestImpl();
ServerServiceDefinition intercepted = ServerInterceptors.intercept(service, new TestInterceptor());

现在我能够创建服务器了.

server = NettyServerBuilder.forPort(port)

    // enable tls
    .useTransportSecurity(
        new File(serverCert),
        new File(serverKey)
    )
    .addService(
        intercepted  // had been "new TestImpl()"
    )
    .build();

server.start();

当我触发客户端请求时,这允许实际调用我的ServerInterceptor.

这个链接非常有助于搞清楚这一点.

Answer 1

使用a ServerInterceptor然后通过传播身份Context.这允许您具有用于身份验证的中央策略.

拦截器可以从中检索身份Metadata headers.然后它应该验证身份.然后可以testHello通过io.grpc.Context以下方式将经过验证的身份传达给应用程序(即):

/** Interceptor that validates user's identity. */
class MyAuthInterceptor implements ServerInterceptor {
  public static final Context.Key<Object> USER_IDENTITY
      = Context.key("identity"); // "identity" is just for debugging

  @Override
  public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(
      ServerCall<ReqT, RespT> call,
      Metadata headers,
      ServerCallHandler<ReqT, RespT> next) {
    // You need to implement validateIdentity
    Object identity = validateIdentity(headers);
    if (identity == null) { // this is optional, depending on your needs
      // Assume user not authenticated
      call.close(Status.UNAUTENTICATED.withDescription("some more info"),
                 new Metadata());
      return new ServerCall.Listener() {};
    }
    Context context = Context.current().withValue(USER_IDENTITY, identity);
    return Contexts.interceptCall(context, call, headers, next);
  }
}

public class TestImpl extends TestServiceGrpc.TestServiceImplBase {
  @Override
  public void testHello(TestRequest req, StreamObserver<TestResponse> responseObserver) {
    // Access to identity.
    Object identity = MyAuthInterceptor.USER_IDENTITY.get();
    ...
  }
}

// Need to use ServerInterceptors to enable the interceptor
Server server = ServerBuilder.forPort(PORT)
    .addService(ServerInterceptors.intercept(new TestImpl(),
        new MyAuthInterceptor()))
    .build()
    .start();