Re: [hybi] hum #3: Message

[Maciej Stachowiak <[e-mail]>]

On Aug 5, 2010, at 2:09 PM, Maciej Stachowiak wrote:

> 
> On Aug 5, 2010, at 1:43 PM, Jack Moffitt wrote:
> 
>>>> Sending a file from disk to the network without processing it in any way
>>>> is more efficient than cutting it into slices and interleaving with headers.
>>>> The IP layer is already going to cut it into slices, in a way that almost
>>>> certainly won't line up with WebSocket-level fragment boundaries.
>>> 
>>> There's no way to "send a file over the network without processing". You
>>> need to read it into memory, and then write it to the network. Of course
>>> adding frame headers *is* overhead, but it's really identical or close to
>>> the overhead on the wire, nothing more.
>> 
>> The kernel's sendfile() is responsible for a lot of the HTTP server
>> optimization for static resources, and for this case, I think it is
>> true that doing any framing that shows up in the middle of the file
>> would lead to a big inefficiency.
>> 
>> I'm not sure how useful this pattern is with dynamic data though. I
>> think people will continue to send most static resources via regular
>> HTTP because it is very, very good at it.
> 
> I think there's definitely use cases for transferring large static resources over WebSocket. Consider syncing a media library where items may have been added on either end.  Sync seems like a pretty likely target for WebSocket. You will want to do large static transfers in both directions, and it seems better to use the existing warmed-up WebSocket TCP connection than to make fresh HTTP connections.

If it's an optional extension that intermediaries could ignore, that makes it unlikely that there will be a default expectation that it should be sent and have a correct value.

Regards,
Maciej