Re: [hybi] hum #3: Message

[Julian Reschke <[e-mail]>]

On 06.08.2010 13:26, Arman Djusupov wrote:
> Pieter Hintjens wrote:
>> Agree with both these points. If a sender does fragment a large
>> message, they ALSO need to specify the full size up front, for the
>> same reasons we specify the frame size up front. You want to avoid
>> sentinel-based reads.
>
> If the sender knows the size of the message upfront then there is no
> point to fragment it. The sender can just specify the total length of
> the message and keep pumping data into the connection, while the reader
> can count the received bytes and so know where the message ends. The
> whole reason of having fragmentation and framing is to remove the need
> to know the full size of the message prior to sending it.
> Arman

There are more reasons. Just stating the length upfront and then sending 
the data as-is does not allow signaling an error when something bad 
happens (except by dropping the connection). This requires chunking, or 
some other way to signal the error condition.

Best regards, Julian