[Laszlo-user] Could someone elaborate on this? XML binary encoding:

John Sundman jsundman at laszlosystems.com
Thu Mar 9 06:33:11 EST 2006


As the person responsible for the document in question I guess I must 
speak up.

I'm afraid that sentence you cite may be a vestigial artifact.

I plead guilty to copy-pasting that bit from an older source, pre 2003, 
and I'm not sure WHAT it meant.   I will try to find out what the 
original sense was, but so far as I know now, that statement is 
meaningless -- unless it means that you can compress stuff before 
sending it to the client, which is kind of a 'Well, duh" statement.

In this embarassing circumstance, let me tell the story, perhaps 
apocryphal, attributed to William Faulker.  It seems that there was one 
particularly dense passage in one of his more abstruse novels, let's 
say, The Sound and the Fury, or Absolom! Absolom!  in which punctuation 
and normal English semantics went by the board.  So whole generations 
of students spent endless hours trying to tease out the many layers of 
meaning in it.  There were partisans of this or that intepretation: "It 
means 'Great Taste'!" "No, it means 'Less Filling'!!"   So, one 
partisan wrote a whole Ph.D. dissertation explaining why his 
interpretation was the One True Explanation.

So he finishes that dissertation and what do you know but he gets the 
chance to meet Mr. Faulkner himself, and he asks him the meaning of 
that particular inscrutable, beguiling passage.

"I don't rightly know," says the great man of letters.  "As I 
recollect, I was pretty well corned up when I wrote that."

Well, I was not corned up when I put that passage in the Architecture 
chapter, but I may have been a bit lazy.

I'll get to the bottom of this soon.

jrs





On Mar 8, 2006, at 11:54 PM, Andrew Chandler wrote:

> Thanks Henry, however I wasn't asking anyone to debug it - we have a
> perfectly working solution as far as I'm aware.  I only wanted 
> explanation
> of a statement that is made on the laszlo overview or summary pages 
> that I
> quoted below.  I wanted to know what it meant - optional implies user 
> or
> programmer control and its not explained anywhere I could see.  Again 
> the
> caption right off the openlaszlo site is
> "Data transcoding
> Optionally transcode XML data responses to a compact binary format."
> The above statement can be found on this page:
> http://www.openlaszlo.org/architecture    down under the laszlo servlet
> section.
>
>
>
>   _____
>
> From: laszlo-user-bounces at openlaszlo.org
> [mailto:laszlo-user-bounces at openlaszlo.org] On Behalf Of Henry Minsky
> Sent: Wednesday, March 08, 2006 5:56 PM
> To: Andy Chandler
> Cc: Laszlo-user at openlaszlo.org
> Subject: Re: [Laszlo-user] Could someone elaborate on this? XML binary
> encoding:
>
>
> The Flash instruction set cannot support strings longer than 64 
> kbytes, but
> the runtime can certainly have longer strings in memory. We have code 
> in the
> XML encoder to split longer strings and reassemble them using byte 
> codes for
> push and string append. However, it is possible that the Java rpc 
> encoder,
> which shares code with the XML encoder,  is generating some kind of 
> overly
> long instruction byte codes. It would be best if you could send us a 
> test
> case with long strings that are failing, otherwise it's difficult for 
> anyone
> to get the motivation to debug this.
>
>
>
>
>
> On 3/8/06, Andy Chandler <achandler at visionael.com> wrote:
>
> I believe (and I'll have to double check with the tech lead on the 
> other
> project) that the way they have things working is that we have java 
> classes
> that return data as a single xml string on the tomcat server.   This 
> string
> is retrieved using javarpc from inside an lzx file - the "string" that 
> is
> retrieved is then assigned to a dataset and then the laszlo controls 
> are
> bound to the dataset.   The limit seems to be in the length of that 
> string -
> it can break something either in the browser or somewhere else if its 
> too
> long so they developed a mechanism to send it in "chunks" of say 1024
> characters and then reassemble it at the client before assigning it to 
> the
> dataset.  Is there a fundamentally better way?   I'm also still curious
> about the stament below I found on the architecture page.
>
>
>   _____
>
> From: Henry Minsky [mailto:henry.minsky at gmail.com]
> Sent: Wednesday, March 08, 2006 4:22 PM
> To: Andy Chandler
> Cc: Laszlo-user at openlaszlo.org
> Subject: Re: [Laszlo-user] Could someone elaborate on this? XML binary
> encoding:
>
>
>
>
>
>
> On 3/8/06, Andy Chandler <achandler at visionael.com> wrote:
>
> I found the following tidbit in the architecture document - could 
> someone
> point me to where this is elaborated ?    I know we've hit XML string
> response limits and implemented a "chunking" mechanism that retrieves 
> long
> responses in pieces but this sounds interesting and perhaps more 
> appropriate
> -
>
>
>
> What context are you talking about XML string limits? Laszlo currently
> proxies XML data by encoding the XML as a Flash byte-coded instruction
> stream, but we're moving to use the newer Flash client-side XML 
> parsing,
> because it is now fast enough. For DHTML, we use the XMLHTTPRequest 
> API, so
> the XML is sent as text, but it can be gzipped by the server , which 
> is a
> better idea all around than a separate binary encoding for XML.
>
>
>
>
> Data transcoding
> Optionally transcode XML data responses to a compact binary format.
>
>
> Andrew Chandler
>
> Manager DataCollection Group
>
>
> Visionael Corporation             Phone : (918) 388-8308
>
> 9717 E. 42nd Street               Fax   : (918) 663-1456
> <mailto:  <mailto:achandler at visionael.com> achandler at visionael.com>
>
> Suite 200                         Email : andy at visionael.com
> <mailto:  <mailto:achandler at visionael.com> achandler at visionael.com >
> Tulsa, OK 74146-3680              WEB   : www.visionael.com
> <  <http://www.visionael.com/> http://www.visionael.com/>
>
>
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>
>
>
>
>
> -- 
> Henry Minsky
> Software Architect
> hminsky at laszlosystems.com
>
>
>
>
>
>
> -- 
> Henry Minsky
> Software Architect
> hminsky at laszlosystems.com
>
>
>
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