Streaming Thrift

Streaming Thrift allows requests or responses to be streamed over TChannel.

Streaming Thrift will uses a separate as header: sthrift, and is based on the standard Thrift arg scheme, with the only exception being the encoding of arg3 in both the call req and call res.

Streaming Thrift methods have the following restrictions:

• If the request is streamed, the method IDL should only specify a single argument which should be a struct.
• If the response is streamed, the return type of the method should be a struct.
• Thrift exceptions must be returned before any streaming results have been sent.

The encoding of data for streaming arg3 is a 4 byte length-prefixed chunk:

chunk~4 chunk~4 chunk~4 ...

Arguments

When streaming request arguments, each arg3 chunk is the encoded payload for the method's first (and only) argument. For example, if a method defines a single argument that is a string, then each chunk is just a Thrift encoded string.

Responses

When streaming successful (OK) responses, each arg3 chunk is the encoded payload for the method's result type. For example, if a method returns a string, then each chunk should be a Thrift encoded string.

If the response is not OK, arg3 is encoded in the same manner as non-streaming Thrift. E.g. if the response returned a Thrift exception, arg3 contains a TBinaryProtocol encoded version of a struct containing the exception field and struct.