io.grpc

Interface CallCredentials

@ExperimentalApi(value="https//github.com/grpc/grpc-java/issues/1914")
public interface CallCredentials

Carries credential data that will be propagated to the server via request metadata for each RPC.

This is used by CallOptions.withCallCredentials(io.grpc.CallCredentials) and withCallCredentials() on the generated stub, for example:

 FooGrpc.FooStub stub = FooGrpc.newStub(channel);
 response = stub.withCallCredentials(creds).bar(request);
 

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	CallCredentials.MetadataApplier The outlet of the produced headers.

Field Summary

Fields

Modifier and Type	Field and Description
static Attributes.Key<String>	ATTR_AUTHORITY The authority string used to authenticate the server.
static Attributes.Key<SecurityLevel>	ATTR_SECURITY_LEVEL The security level of the transport.

Method Summary

Modifier and Type	Method and Description
void	applyRequestMetadata(MethodDescriptor<?,?> method, Attributes attrs, Executor appExecutor, CallCredentials.MetadataApplier applier) Pass the credential data to the given CallCredentials.MetadataApplier, which will propagate it to the request metadata.

Field Detail

ATTR_SECURITY_LEVEL

static final Attributes.Key<SecurityLevel> ATTR_SECURITY_LEVEL

The security level of the transport. It is guaranteed to be present in the attrs passed to applyRequestMetadata(io.grpc.MethodDescriptor<?, ?>, io.grpc.Attributes, java.util.concurrent.Executor, io.grpc.CallCredentials.MetadataApplier). It is by default SecurityLevel.NONE but can be overridden by the transport.

ATTR_AUTHORITY

static final Attributes.Key<String> ATTR_AUTHORITY

The authority string used to authenticate the server. Usually it's the server's host name. It is guaranteed to be present in the attrs passed to applyRequestMetadata(io.grpc.MethodDescriptor<?, ?>, io.grpc.Attributes, java.util.concurrent.Executor, io.grpc.CallCredentials.MetadataApplier). It is by default from the channel, but can be overridden by the transport and CallOptions with increasing precedence.

Method Detail

applyRequestMetadata

void applyRequestMetadata(MethodDescriptor<?,?> method,
                          Attributes attrs,
                          Executor appExecutor,
                          CallCredentials.MetadataApplier applier)

Pass the credential data to the given CallCredentials.MetadataApplier, which will propagate it to the request metadata.

It is called for each individual RPC, within the Context of the call, before the stream is about to be created on a transport. Implementations should not block in this method. If metadata is not immediately available, e.g., needs to be fetched from network, the implementation may give the applier to an asynchronous task which will eventually call the applier. The RPC proceeds only after the applier is called.

Parameters:

method - The method descriptor of this RPC

attrs - Additional attributes from the transport, along with the keys defined in this interface (i.e. the ATTR_* fields) which are guaranteed to be present.

appExecutor - The application thread-pool. It is provided to the implementation in case it needs to perform blocking operations.

applier - The outlet of the produced headers. It can be called either before or after this method returns.