Error <MAXSTRING> (Stream to %xsd.base64Binary)

Question

Question

Mathieu Van Sevenant · May 18, 2021

Hello everyone :-) A colleague wants to use data got from a stream into another type of object: %xsd.base64Binary (related to a webservice context).
His code works for regular data, but the following error appears when parsing large streams (~43 MB): "ERREUR #5002: Erreur Cache: <MAXSTRING>"

Here is below his code:

Class (...).StampDataRequest Extends Ens.Request [ ProcedureBlock ]
{
…

Property DocumentData As %xsd.base64Binary;
…

}

Method OnRequest(pRequest As Ens.StreamContainer, Output pResponse As Ens.Response) As %Status
{
...

set fileStream = ##class(%Stream.GlobalCharacter).%New()

do fileStream.CopyFromAndSave(pRequest.Stream)

//fileStream contains bytes from pRequest

set tsRequest = ##class((...).StampDataRequest).%New()
…

      do fileStream.Rewind()
       while 'fileStream.AtEnd {
                   set tsRequest.DocumentData = tsRequest.DocumentData_fileStream.Read(30000)
        }
        …

}

What should he change in this code for not to have this size limitation ?

Best regards,

Mathieu

Product version: HealthShare 2017.2

$ZV: Cache for Windows (x86-64) 2018.1.4 (Build 505_1U) Thu May 28 2020 10:01:40 EDT

Discussion (9)1

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PHILIPPE BOULANGER · May 20, 2021

Hello,

In the client classes of the external webservice, i changed for the "DocumentData" property, in several places, ,"%xsd.base64Binary" to "%Stream.GlobalCharacter". I recompiled the classes.

After this, in the "Ensemble" connector, i had to do the conversion to Base64 imyself.

Indeed, with "%xsd.base64Binary" the conversion to base64 was done automatically during the transfer.

Now, in my example, fileStream is a base64 stream, and here's how my "DocumentData" property is assigned:

do tsRequest.DocumentData.CopyFrom (fileStream)

I tested and the return from the remote webservice is correct with the same hashing values.

Thank you very much for your help.

0 0

score 0 · Answer 1 · 2021-05-18T13:59:51-04:00

I've read that some users have seen the <MAXSTRING> error when they have "Log Trace Events" enabled for a particular business host. Can you try disabling this and re-running your program?

http://docs.intersystems.com/ens201317/csp/docbook/DocBook.UI.Page.cls?K...

score 0 · Answer 2 · 2021-05-18T16:02:50-04:00

Hi

Your request class tsRequest has a property DocumentData which I assume has a data type of %String. There is one thing you need to check and to things you can do in the request class:

1) Make sure that the setting for "Support Long Strings" setting in your Cache Instance is set to true. The setting can be found in the Management Portal at System Administration > Configuration > System Configuration > Memory and Startup

2) in the class definition for your request class use the following definition for your DocumentData specify the definition as follows:

Property DocumentData as %String(MAXLEN="", TRUNCATE);

Turning on Long Srinngs enables you to store up to 3,641,144 characters.

The Attribute MAXLEN="" says the Maximum Length of the property is the maximum string length supported i.e. 3,641,144 characters.

The TRUNCATE attribute will chop off any characters that exceed the MAXLEN without throwing a MAXSTRING error

Nigel

score 0 · Answer 3 · 2021-05-18T16:23:42-04:00

David Hockenbroch · May 18, 2021

In his class definition, DocumentData is a %xsd.base64Binary, not a string.

0 0

score 0 · Answer 4 · 2021-05-18T17:18:25-04:00

Replace:

do fileStream.Rewind()
while 'fileStream.AtEnd {
           set tsRequest.DocumentData = tsRequest.DocumentData_fileStream.Read(30000)
}

with

do tsRequest.DocumentData.CopyFrom(fileStream)

or even:

do tsRequest.DocumentData.CopyFrom(pRequest.Stream)

score 0 · Answer 5 · 2021-05-19T04:39:49-04:00

Hi,

This line :

"do tsRequest.DocumentData.CopyFrom(fileStream)" don't work.

Error:

ERREUR #5002: Erreur Cache: <INVALID OREF>

tsRequest.DocumentData not recognized as a Stream !!! (In his class definition, DocumentData is a %xsd.base64Binary)

Thanks

Phil.

score 0 · Answer 6 · 2021-05-19T05:02:26-04:00

%xsd.base64Binary is essentially a string so you can't write more than 3,5 mb there.

Change property definition to %Stream.GlobalCharacter instead.

score 0 · Answer 7 · 2021-05-19T07:20:47-04:00

if i change property in the client webservice class, will the external webservice called still work ?

Thanks

score 0 · Answer 8 · 2021-05-19T09:04:50-04:00

Eduard Lebedyuk · May 19, 2021

It should but requires testing

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