Class BidirectionalStreamingBase<TRequest, TResponse> (4.4.0) 

public abstract class BidirectionalStreamingBase<TRequest, TResponse> : IDisposable

Base class for bidirectional streaming RPC methods. This wraps an underlying call returned by gRPC, in order to provide a wrapper for the async response stream, allowing users to take advantage of 

await foreach
 support from C# 8 onwards. Additionally, it wraps the request stream in a buffer, allowing multiple requests to be written without waiting for them to be transmitted.

Inheritance

object > BidirectionalStreamingBase<TRequest, TResponse>

Implements

IDisposable

Namespace

Google.Api.Gax.Grpc

Assembly

Google.Api.Gax.Grpc.dll

Type Parameters
Name Description
TRequest

RPC request type
TResponse

RPC response type

Remarks

To avoid memory leaks, users must dispose of gRPC streams. Additionally, you are strongly advised to read the whole response stream, even if the data is not required - this avoids effectively cancelling the call.

Properties

GrpcCall

public virtual AsyncDuplexStreamingCall<TRequest, TResponse> GrpcCall { get; }

The underlying gRPC duplex streaming call. Warning: DO NOT USE GrpcCall.RequestStream at all if using TryWriteAsync(TRequest), WriteAsync(TRequest), TryWriteAsync(TRequest, WriteOptions) , or WriteAsync(TRequest, WriteOptions). Doing so will cause conflict with the write-buffer used within the [Try]WriteAsync methods.

Property Value
Type Description
AsyncDuplexStreamingCall

Methods

Dispose()

public virtual void Dispose()

Disposes of the underlying gRPC call. There is no need to dispose of both the wrapper and the underlying call; it's typically simpler to dispose of the wrapper with a

using
 statement as the wrapper is returned by client libraries.
Remarks

The default implementation just calls Dispose on the result of GrpcCall.

GetResponseStream()

public virtual AsyncResponseStream<TResponse> GetResponseStream()

Async stream to read streaming responses, exposed as an async sequence. The default implementation will use GrpcCall to extract a response stream, and adapt it to AsyncResponseStream<TResponse>.

Returns
Type Description
AsyncResponseStream
Remarks

If this method is called more than once, all the returned enumerators will be enumerating over the same underlying response stream, which may cause confusion. Additionally, the sequence returned by this method can only be iterated over a single time. Attempting to iterate more than once will cause an InvalidOperationException.

TryWriteAsync(TRequest)

public virtual Task TryWriteAsync(TRequest message)

Writes a message to the stream, if there is enough space in the buffer and WriteCompleteAsync() hasn't already been called. The same write options will be used as for the previous message.

Parameter
Name Description
message TRequest

The message to write.
Returns
Type Description
Task

null if the message queue is full or the stream has already been completed; otherwise, a Task which will complete when the message has been written to the stream.

TryWriteAsync(TRequest, WriteOptions)

public virtual Task TryWriteAsync(TRequest message, WriteOptions options)

Writes a message to the stream, if there is enough space in the buffer and WriteCompleteAsync() hasn't already been called.

Parameters
Name Description
message TRequest

The message to write.
options WriteOptions

The write options to use for this message.
Returns
Type Description
Task

null if the message queue is full or the stream has already been completed.

TryWriteCompleteAsync()

public virtual Task TryWriteCompleteAsync()

Completes the stream when all buffered messages have been sent. Only the first call to this method on any instance will have any effect; subsequent calls will return null.

Returns
Type Description
Task

A Task which will complete when the stream has finished being completed; or null if this method has already been called.

WriteAsync(TRequest)

public virtual Task WriteAsync(TRequest message)

Writes a message to the stream, if there is enough space in the buffer and WriteCompleteAsync() hasn't already been called. The same write options will be used as for the previous message.

Parameter
Name Description
message TRequest

The message to write.
Returns
Type Description
Task

A Task which will complete when the message has been written to the stream.
Exceptions
Type Description
InvalidOperationException

There isn't enough space left in the buffer, or WriteCompleteAsync() has already been called.

WriteAsync(TRequest, WriteOptions)

public virtual Task WriteAsync(TRequest message, WriteOptions options)

Writes a message to the stream, if there is enough space in the buffer and WriteCompleteAsync() hasn't already been called.

Parameters
Name Description
message TRequest

The message to write.
options WriteOptions

The write options to use for this message.
Returns
Type Description
Task

A Task which will complete when the message has been written to the stream.
Exceptions
Type Description
InvalidOperationException

There isn't enough space left in the buffer, or WriteCompleteAsync() has already been called.

WriteCompleteAsync()

public virtual Task WriteCompleteAsync()

Completes the stream when all buffered messages have been sent. This method can only be called once, and further messages cannot be written after it has been called.

Returns
Type Description
Task

A Task which will complete when the stream has finished being completed.
Exceptions
Type Description
InvalidOperationException

This method has already been called.