Frames is a simple multiplexing protocol I use when I need to ask for a lot of different things concurrently between two servers and I don’t want to burn lots of file descriptors or rely on pipelining timings and such things to do it.
This should be usable anywhere you use a net.Conn today. There’s
some convenience support for HTTP as I’m using it quite a bit as an
HTTP transport.
The protocol is really simple, just a 6 byte header followed by 0 or more bytes of data (maximum data size of 2^16).
| Field | Type | Byte Offset | Byte Len |
|---|---|---|---|
| Data Length | unsigned 16-bit int | 0 | 2 |
| Channel | unsigned 16-bit int | 2 | 2 |
| Command | byte | 4 | 1 |
| Status | byte | 5 | 1 |
| Command | ID |
|---|---|
| Open | 0x00 |
| Close | 0x01 |
| Data | 0x02 |
| Status | ID |
|---|---|
| Success | 0 |
| Error | 1 |
A client begins by establishing a TCP connection. To do anything
useful, it must first issue an Open command to get a new channel
assigned. If this is successful (Status = Success), the client
will get a response with the Command set to Open and the channel
ID set to the new channel.
A client may open as many channels as necessary and then send Data
packets along with the corresponding data.
A client MUST Close the channel when you’re done with it if you
intend to continue using the service. If the client is completely
done, it MAY drop the underlying TCP connection and the server MUST
clean up after you.