Package io.grpc

Class CallCredentials

  • Direct Known Subclasses:

    public abstract class CallCredentials
    extends Object
    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);

    The contents and nature of this class (and whether it remains an abstract class) is experimental, in that it can change. However, we are guaranteeing stability for the name. That is, we are guaranteeing stability for code to be returned a reference and pass that reference to gRPC for usage. However, code may not call or implement the CallCredentials itself if it wishes to only use stable APIs.

    • Constructor Detail

      • CallCredentials

        public CallCredentials()
    • Method Detail

      • applyRequestMetadata

        public abstract void applyRequestMetadata​(CallCredentials.RequestInfo requestInfo,
                                                  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.

        requestInfo - request-related information
        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.
      • thisUsesUnstableApi

        public void thisUsesUnstableApi()
        With this class now being stable this method moves from an abstract one to a normal one with a no-op implementation. This method is marked deprecated to allow extenders time to remove the method before it is removed here.