Re: Proper upload streaming? Not possible with WO!

After some more debugging and playing with the developer examples I  
came to the conclusion that truly streaming a request to WO is _not  
possible_!

Here's the output of a modified wis request, where the whole http  
request gets "streamed" directly to the disk - at least according to  
Apple docs:

[2006-04-25 11:15:21 CEST] <WorkerThread3> Application.createRequest 
(): /cgi-bin/WebObjects/FileUpload.woa/womp/instanceRequest
[2006-04-25 11:15:21 CEST] <WorkerThread3> Application.dispatchRequest()
[2006-04-25 11:15:21 CEST] <WorkerThread3> Application.awake()
[2006-04-25 11:15:38 CEST] <WorkerThread4> Application.createRequest 
(): /cgi-bin/WebObjects/FileUpload.woa/1/wis/ProcessRequestContent
[2006-04-25 11:15:38 CEST] <WorkerThread4> Data size: 571602
[2006-04-25 11:15:38 CEST] <WorkerThread4> Application.dispatchRequest()
[2006-04-25 11:15:38 CEST] <WorkerThread4> Application.awake()
===============================================
Direct Action Request Content Streaming Upload:
[2006-04-25 11:15:38 CEST] <WorkerThread4> 84585 bytes uploaded
[2006-04-25 11:15:38 CEST] <WorkerThread4> 142985 bytes uploaded
[2006-04-25 11:15:38 CEST] <WorkerThread4> 217445 bytes uploaded
[2006-04-25 11:15:38 CEST] <WorkerThread4> 253945 bytes uploaded
[2006-04-25 11:15:38 CEST] <WorkerThread4> 297745 bytes uploaded
[2006-04-25 11:15:38 CEST] <WorkerThread4> 332785 bytes uploaded
[2006-04-25 11:15:38 CEST] <WorkerThread4> 416005 bytes uploaded
[2006-04-25 11:15:38 CEST] <WorkerThread4> 472945 bytes uploaded
[2006-04-25 11:15:38 CEST] <WorkerThread4> 571602 bytes uploaded
Wrote file to '/var/tmp/DARCSUReq56899.tmp'

The first three lines are from wotaskd which checked to see if the  
app was alive. They don't have anything to do with my problem...  
except that I triggered the upload exactly at this time. Then, 17  
seconds later, my request finally arrived at the application. Now if  
the request would really be streamed directly to the disk, then I  
would be one happy owner of a very fast internet connection since the  
rest (uploading, streaming to disk of > 500kb) would have happened in  
less than a second - which would result in a 4Mbits/sec upload stream!

Now when you look at the method that gets called first by the  
woadaptor - createRequest() - you'll notice that this method already  
has an NSData object as parameter. According to the docs this  
parameter contains "the HTML content of the receiver", which i don't  
fully understand. But since it's size is exactly the total size of  
the whole request, I guess we know what this means. Looking at the  
time span between the moment I submitted the form and the moment the  
app got called by the adaptor (17 seconds) makes me believe that too  
that the upload actually happens _before_ the request is forwarded to  
the WO app which would definitely _not_ correspond to what is said in  
the docs and the samples:

"Because the request content is not displayed or read into memory,  
this page can be used to upload an arbitrarily large file."

Hm... if that NSData object containing the whole request data is not  
in memory, where is it then?

If I'm missing something please do tell me so. Otherwise I'm going to  
waste a Tech Support incident on this.

Thanks!

-Will

On 24.04.2006, at 16:15, Kevin Windham wrote:

>
> On Apr 24, 2006, at 4:41 AM, Will Scheidegger wrote:
>
>> I'm looking for a solution for proper upload streaming in WO. I  
>> want the user to be able to upload a lot of data (file upload) to  
>> my WO app and want
>> Result with all 3 attempts:
>> - A long period with no visible action at all
>> - Then the upload appears within a second
>
> I suspect what you are seeing here is the browser preparing the  
> post response. The format that browsers upload with requires a  
> boundary to be assigned in the headers preceding the data. This  
> boundary has to be checked to make sure it doesn't exist in the  
> file being uploaded. If it did, it would mess up the parsing of the  
> post data. The bigger the file the longer this check takes. I'm not  
> sure but there may be some implementations that use probability to  
> predetermine a boundary that doesn't exist in the file, but I've  
> noticed the slow start behavior on all the browsers I tested with  
> when writing my own parser for doing uploads a while back.
>
> HTH,
> Kevin
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