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Julius Kavay · Jul 12, 2021

The possibilities to get a corrupted file are:

- you do not read the (Base64) encoded file in chunks of N*4 (where N is an integer)
- your stream wasn't rewinded before starting with reading
- your (incoming) stream is (already) corrupted (but this would in some cases trigger an error in Base64Decode() method). 

Just for a test, try this

str = is your incoming Base64 stream

set filename = "test.tiff"
open filename:"nwu":1
if '$test write "Can't open",! quit

do str.Rewind()
use file
while 'str.AtEnd { write $system.Encryption.Base64Decode(str.Read(32000)) } // 32000 = 4 * 8000
close file

If the incoming stream is not corruoted, the right now created tiff file should be readable

Julius Kavay · Jun 8, 2021

Somehow I don't get you right. To save obj.%Size() in a variable, just do a simple assign

set myVariable = obj.%Size()

but I'm pretty shure, this was not your intended question.

I suppose, you have JSON formatted data (a string or a stream) and you want to store those data in a table. Am I right?

If yes, then follow the next steps:

1) create a class which describes your JSON objects (strings)

Class DC.SehindeRaji Extends (%Persistent, %JSON.Adaptor)
{
Property byr As %String(%JSONFIELDNAME = "byr:");
Property iyr As %String(%JSONFIELDNAME = "iyr:");
Property eyr As %String(%JSONFIELDNAME = "eyr:");
// do the same for all other fields

ClassMethod Import(data)
{
    set obj=..%New()                    // create a new DC.SehindeRaji object
    set sts=obj.%JSONImport(data,"")    // import the (JSON) data
    
    if sts {
        set sts = obj.%Save()
        if sts {
            write "Saved, ID=",obj.%Id(),!
            quit 1
            
        } else {
            write "Not saved, Err=",$system.Status.GetOneErrorText(sts),!
            quit 0
        }
        
    } else {
        write "Can't import: ",$system.Status.GetOneErrorText(sts),!
        quit 0
    }
}
}

2) You can create some test data (interactively) in a terminal session

set dynObj = {"byr:":"1937", "iyr:":"2017", "eyr:":"2020"}
set data = dynObj.%ToJSON()

or get your data somehow from an input (possibly from a file),  the only important thing is, your data should look like this

write data  -->  {"byr:":"1937","iyr:":"2017","eyr:":"2020"}

3) import those data

write ##class(DC.SehindeRaji).Import(data) --> Saved, ID=1

4) Now open the saved data and check the result

set oref =  ##class(DC.SehindeRaji).%OpenId(1)

write oref.byr  --> 1937
write oref.iyr  --> 2017

write oref.%JSONExportToString(.exported,"") --> 1
write exported  --> {"byr:":"1937","iyr:":"2017","eyr:":"2020"}

zw ^DC.SehindeRajiD
^DC.SehindeRajiD=1
^DC.SehindeRajiD(1)=$lb("","1937","2017","2020")

I hope, this is what yoy want to do...

Julius Kavay · Jun 8, 2021

The facts:
1) According to the error message: "The system cannot find the file specified."
2) Futhermore, the error message shows slashes and backslashes, mixing is rarely good, Windows uses "\", Unix "/"

What to do is:
1) check the filename, you want to send (including the path)
2) check the existence of the file
3) Under which user accont is IRIS/Cache running?
4) May this user read the file?

Julius Kavay · Jun 8, 2021

It's not clear to me what you want to do.

A property like

Property MyData as %(Global-or-File)Stream;

means, the size of MyData can be something between 0 and the free space on your (hard) drive.
That's the reason, why is MyData defined as a stream and not as a %String.

On the other hand, in an excel cell you can put no more then 32767 characters, hence the plan to extract those data to an spreadsheet will work only if the MyData properties do not have more then 32767 chars, see
https://support.microsoft.com/en-us/office/excel-specifications-and-limi...

Nevertheless, you could use the following stored procedure to extrac the first 32767 chars from those stream data:

Class Your.Table Extends %Persistent
{
Property StreamData As %GlobalCharacterStream;
// other properties
ClassMethod StreamDataAsText(ID) As %String [ SqlProc ]
{
    set obj = ..%OpenId(ID,0), text = ""
    if obj { do obj.StreamData.Rewind() set text obj.StreamData.Read(32767) }
    quit text
}
}

Now you can get, beside the other data, the first 32767 chars of those stream data too

select Your.Table_StreamDataAsText(ID), * from Your.Table
Julius Kavay · Jun 2, 2021

If you can call a JavaScript function, then you could do something like this...

<html>
<head><title>Test</title>
<link id="fav" rel="icon" href="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAIAAACQkWg2AAAABnRSTlMAAAAAAABupgeRAAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAF0lEQVQokWP8z0AaYCJR/aiGUQ1DSAMAQC4BH5CRCM8AAAAASUVORK5CYII=">

<script>
    function changeFavicon() {
        var lid=document.getElementById("fav");
        if (lid) {
            lid.setAttribute("href","data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAIAAACQkWg2AAAABnRSTlMAAAAAAABupgeRAAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAGElEQVQokWNk+M9AEmAiTfmohlENQ0kDAD8vAR+xLJsiAAAAAElFTkSuQmCC");
        }
    }
</script>
</head>
<body>
<button onclick="changeFavicon();")>Change my favicon</button><br>
</body>
</html>

The (red and green) icons are just a demo example.

Julius Kavay · May 21, 2021

[1,2,,3] is equally arguably as [1,2,3,,] or [1,2,3,,,,,] and IRIS/Cache accepts all of them.

Nothing against a system which is input tolerant (forgiving, with your words) but then this tolerance should be obvious and in some way logical. An example, I tolerate trailing comma(s), becuse they could be leftovers of editing. So I would say, all the arrays

[1,2,3]
[1,2,3,]
[1,2,3,,,]

have a size of 3 - there are three elements, no more. But IRIS/Cache says the sizes are 3, 4 and 6. So let check  the last one

set obj=[].%FromJSON("[1,2,3,,,]")
write obj.%Size() --> 6
for i=0:1:9 write i,?3,obj.%Get(i),?7,obj.%GetTypeOf(i),!

The output of the FOR-Loop is:

0  1   number
1  2   number
2  3   number
3      unassigned
4      unassigned
5      unassigned
6      unassigned
7      unassigned
8      unassigned
9      unassigned


The elements with index 3, 4 and 5 are unassigned and in some kind, I can understand that. But if the higher indices, like 6, 7, 88 or 1000 etc. are also unassigned then I ask you, why is the size 6 and not, say 12 or 573?
For me the logical size should be 3 because there are three intendeed elements, the others are a result of tolerated delimiters! 

Finally, I don't want to start a war, how to interpret JSON strings. It was just my 2cc to a theme, which is out-of-round, according to my opinion.

Julius Kavay · May 20, 2021

OK, take a more simple case:

set obj=[1,2,,3]  // again, this is a SYNTAX
set obj=[].%FromJSON("[1,2,,3]") // this is OK

but in both cases, the problem was the bouncing comma-key on my keyboard.

The first was told by compiler the second was "forgiven" by JSON-Reader! BUT the real question is, WHAT IS the third item in the above array? The latter shows obj has a size of 4, so the, and the desired thrid element could be null, 3 or maybe something else!

I wrote my very first program somewhere in 1971 or 1972, I can't remember anymore. But one thing I have learned is, one should accept checked data only.

Imagine, you accept those incorrect (aka forgiven) data and beside processing, store the data in your database, then later, for whatever reason, you send the (original string) data to an external party.... bang! They can't read it, because it's not JSON conform.

Julius Kavay · May 20, 2021

For the sake of completness, there is one more validator: https://jsonlint.com/  (which shows the above settings.json file as incorrect).

One more problem, it seems IRIS (and Cache) speaks with a forked tongue (but has nothing to do with the above problem) :

set string = "{""Value"":123, }"    // note the extra comma!
set stream=##class(%Stream.TmpCharacter).%New()
do stream.WriteLine(string)
set obj1={"Value":123, }  --> gives a SYNTAX
set obj2={}.%FromJSON(string) --> accepts the incorrect (json)string!