[LINK] WebSockets

[Kim Holburn]

That comment was about a MS Exchange feature called EAS mentioned by Johann Kruse.  We had already talked about websockets.  

On 2011/Apr/06, at 8:48 PM, Martin Barry wrote:

> Replying to an old thread but I've just come back from a holiday so...
> 
> $quoted_author = "Kim Holburn" ;
>> 
>> I expect he means a TCP stream using a kind of embraced and extended HTTPS
>> apps layer protocol except instead of a browser at the client end you have
>> an exchange client and instead of a webserver at the server end you have
>> an exchange server.  So they can extend the protocol in a proprietary way
>> and there's no interoperability problems with other software.  And like
>> http you can keep the connection open for as long as you like.
> 
> The problem that WebSockets is trying to solve is not with TCP but with
> HTTP.

As I said, in that discussion the problem that websockets is trying to solve is that the clients control the flow of information which is the opposite of the traditional broadcast model and big media hate it and have tried before to find methods to push their data to mug punters.  They don't get it.  

That's not to say there aren't uses for such a thing but it comes with heaps of potential security problems.

I'm not sure that javascript can't open a connection and let itself get pushed anyway.

> HTTP is a request/response protocol. The client requests something, the
> server responds. There is no way for the server to push something. The usual
> workaround is have the client poll for new data instead. The neatest, lowest
> latency implementation of that is long polling (a subset of Comet
> http://en.wikipedia.org/wiki/Comet_%28programming%29 ).
> 
> It works something like:
> 
> - client requests data
> - server waits until is has new data to send before responding
> - if no new data is available just prior to the client timeout the server
>  responds with "no data"
> - the client immediately repeats the request in step 1
> 
> This gets you data as soon as it is available without polling more often
> than the timeout value if there is no new data.
> 
> WebSockets removes the need for these "crutches" by allowing the client to
> open a connection over which the server can push data at will.
> 
> cheers
> Marty
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Kim Holburn
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