Hey Stuart,
thanks for start the thread. I just finished the review of your changes and have a few comments.
* FrameHandler:
I don't know if I like the fact that the same interface is used for "assembled Fragments" (when WebSocketSession.setAutomaticallyAssembleFragments(true) was used) and not assembled Fragments (when WebSocketSession.setAutomaticallyAssembleFragments(false) was used". I think we really should either use another interface or do the assemble work in an abstract implementation of the FrameHandler and just provide
abstract methods to implement that act on the "assembled Frame" then. Also with the current interface design it is up to the user to detect when the Frame is complete by check if he received all of the data. I think we should make it easier and just tell the user when it is complete.
Also I wonder if it is really useful to also get notified with the frame content for other frames then Binary and Text. My idea would be that we:
- automatically respond to a Ping with a Pong
- automatically echo back the Close Frame and after that close the connection
- Ignore Pong frames
The fact why I think we should just do this is that otherwise it is easy for the user to make the whole thing messed up and so not be conform with the RFC anymore. Do you think there are real use-cases for get the content of those in the high-level API ? If not we may not want to expose this at all.
* TextFrameSender / BinaryFrameSender
What about add an extra method to it which takes a FileChannel, offset, length and SendCallback as parameter. So we could make use of zero copy if a user want to send a file content in a frame.
Something like this:
void sendBinary(FileChannel, long offset, long length, SendCallback callback);
* WebSocketFrame
Should be renamed to WebSocketFrameHeader or something like this if we keep it like it is atm.
---
Norman Maurer
JBoss, by Red Hat
Hi guys,
Last night Norman and I had a bit of a talk about what the high level Websocket API should look like, and Norman came up with some interfaces as a prototype.
So after looking at Norman's prototype I had a bit more of a think about what our high level API should look like and this is what I have come up with:
https://github.com/stuartwdouglas/undertow/compare/websockets_high_level_api
I have been thinking about the use cases that we want to address with the high level API, and when you would want to use the high level API vs the low level XNIO API.
My thinking is that in general if you want to use async IO and deal with message bytes as soon as they arrive this is covered quite nicely by our existing low level API. The high level API should focus on async operations involving complete messages, and blocking operations.
The JSR 356 implementation will just be implemented as a fairly thin wrapper around our high level API.
Sending:
This is handled by (Text|Binary)FrameSender.
I think there are a few different use cases for the high level API in terms of sending messages:
- Complete message async, with a callback on completion
- Complete message blocking
- Complete message blocking with Stream / Writer
- Fragmented versions of all of the above.
There is one use case that is not covered here, and that is sending a partial messaged using async IO, as mentioned above the reason why I don't think we should have this as part of the high level API is because this is essentially what is provided by our low level API.
Receiving:
In terms of receiving I think that we should just have a single handler type:
https://github.com/stuartwdouglas/undertow/compare/websockets_high_level_api#diff-5
This just receives complete messages. I think this is preferable to having to register 5 different types of handler for every frame type.
These handlers just receive complete messages that are fully buffered.
In terms of fragmented messages I think we should provide 2 ways of dealing with them, and have a setting that controls which one is in use:
https://github.com/stuartwdouglas/undertow/compare/websockets_high_level_api#L9R98
If this is true then we will just assemble the fragmented messaged automatically and deliver it as 1 logical message. Otherwise they will just be delivered as they arrive.
I would have liked to provide a way to receive messages via an InputStream / Reader, to provide a way to get around fully buffering messaged when using blocking IO, however I can't really think of a nice way to do this.
What do you guys think? I know there is still some stuff missing (e.g. we need a way to propagate auth and session information from the original HTTP request).
Stuart