AllAccepted answers
Julius Kavay · Nov 17, 2022

First, the suggestion of Victor Gordillo  is correct.

do ##class(Some.Class).%BuildIndices()

solves most index related problems.

Second, there are a couple of things, we do not know, but you
- did you made an in-place-upgrade or a clean install + data transfer
- the class in question is the same on IRIS and Cache (i.e. no change was made)
- is the class re-compiled (on IRIS)
- what do you exactly mean when you say "Not opening an instance...": (1) you get an NULL-OREF or (2) you get an error
- what do you provide as a NULL value: (1) "", (2) $c(0), (3) " " or something else as open parameter

A shortened class definition (we don't need the whole definition) would be also helpfull, something like this

Class Problem.Class extends %Persistent
{
Property Field1 as %String;
Property Filed2 As %String;

Index composite on (Field1, Field2) [ Unique];
}
Julius Kavay · Nov 16, 2022

If your serial class is named Data.Serial (as in your example code) then you should use the same name for the serial property too

Class Data.Persistent Extends %Persistent
{
Property MPID as %Integer;
Property Name as Data.Serial;   <--- !!!!!
}

The correct way to set the values

Set Obj=##Class(Data.Persistent).%New()
Set Obj.MPID=MPID
Set Obj.Name.FirstName=FirstName   ; <----
Set Obj.Name.LastName=LastName     ; <----
Set tSC=Obj.%Save()
Julius Kavay · Nov 14, 2022

I think, I have a solution for you

ClassMethod GetImage()
{
	s req=##class(%Net.HttpRequest).%New()
	s req.Server="www.distrelec.de"
	s req.SSLConfiguration="SSL"
	s req.ReadRawMode=1        //  <<---- this is your solution
	d req.Get("/Web/WebShopImages/landscape_medium/_t/if/sortimentsboxen-1.jpg")
	q req.HttpResponse
}

To get the image

s rsp=##class(Some.Class).GetImage()
i rsp.StatusCode=200 {
    s file="c:\temp\imageName.jpg"
    o file:"nwu":0
    i $t u file d rsp.Data.Rewind(),rsp.Data.OutputToDevice()
    c file
}

 That's all...

Julius Kavay · Nov 14, 2022

To download that image, you need just a few lines of code

Class Some.Class Extends %RegisteredObject
{
ClassMethod GetImage()
{
	s req=##class(%Net.HttpRequest).%New()
	s req.Server="www.distrelec.de"
	s req.SSLConfiguration="SSL" // use your SSL-Config-Name
	d req.Get("/Web/WebShopImages/landscape_medium/_t/if/sortimentsboxen-1.jpg",1)
	q req.HttpResponse
}
}

So your code is more or less OK, but the rest of the process is ominous

set rsp=##class(Some.Class).GetImage()
zw rsp
rsp=7@%Net.HttpResponse  ; <OREF>
+----------------- general information ---------------
|      oref value: 7
|      class name: %Net.HttpResponse
| reference count: 3
+----------------- attribute values ------------------
|    ContentBoundary = ""
|        ContentInfo = "charset=UTF-8"
|      ContentLength = 17759
|        ContentType = "image/jpeg;charset=UTF-8"
|               Data = "8@%Stream.GlobalCharacter"
|Headers("CACHE-CONTROL") = "max-age=0"
|Headers("CONTENT-LENGTH") = 17759
|Headers("CONTENT-TYPE") = "image/jpeg;charset=UTF-8"
|    Headers("DATE") = "Mon, 14 Nov 2022 10:57:10 GMT"
|    Headers("ETAG") = "a919e895229c7883864aecbfa2717516"
|Headers("LAST-MODIFIED") = "Thu, 01 Jan 1970 00:00:01 GMT"
|Headers("SET-COOKIE") = "visid_incap_2373370=1U8JalxbRJOzRFviQpi05AYfcmMAAAAAQUIPAAAAAADRm"
|Headers("STRICT-TRANSPORT-SECURITY") = "max-age=31536000; includeSubDomains; preload"
|   Headers("X-CDN") = "Imperva"
| Headers("X-IINFO") = "5-19652015-0 0CNN RT(1668423430526 51) q(0 -1 -1 0) r(0 -1)"
|        HttpVersion = "HTTP/1.1"
|       ReasonPhrase = "OK"
|         StatusCode = 200
|         StatusLine = "HTTP/1.1 200 OK"
+-----------------------------------------------------

The sender says, content type is "image/jpeg", which is OK, but charset=UTF-8 is, I think, a problem. A jpeg-image usually starts with (hex) bytes:

FF D8 FF E0 00 10 4A 46 49 46 ...

The HTTP-Response gives us

do rsp.Data.Rewind()
zzdump rsp.Data.Read(10)

3F 3F 3F 10 4A 46 49 46 00 01                           ???.JFIF..

But I'm in no way a web-expert, but it seems to me, Cache tries to decode (according to content-type =image/jpg; charset=UTF-8) the incomming raw (jpeg) data. The first byte, FF, will already give an error (no utf-8 encoded byte can start with FF) and returns an "?" char as a replacement. The next two "?" (hex: 3F) chars are also arised from (inpossible) decoding. Why the same page works, if you try it with Chrome or Firefox: I think, they either ignore the charset=UTF-8 or just show the raw data after the first decoding error.

Julius Kavay · Nov 12, 2022

OK, no punctuation, no empty words, etc.... My lowest bid: 74 chars

ClassMethod Order(s)
{
	f  s p=$p(s," ",$i(i)),w=$tr(p,1/17),$p(z," ",$tr(p,w))=w ret:p=w $g(z)
}

By the way, the following three variants all have the same size of 74

	f  s p=$p(s," ",$i(i)),w=$tr(p,1/17),$p(z," ",$tr(p,w))=w ret:p=w $g(z)
	f{s p=$p(s," ",$i(i)),w=$tr(p,1/17),$p(z," ",$tr(p,w))=w ret:p=w $g(z)}
1	s p=$p(s," ",$i(i)),w=$tr(p,1/17),$p(z," ",$tr(p,w))=w q:p=w $g(z) g 1
Julius Kavay · Nov 11, 2022

A small complaint:
- possible word delimiters weren't specified (space, tab, etc.)
- no specification about punctuation marks (allowed or disallowed)
- no specification about empty words (allowed or disallowed) and how to handle them, if allowed

So my question is, are the following examples legal or not:

"O2K. I'1m" --> "I'm OK."
"spac4es are2    1There     ma3ny" --> "There are many spaces."

Julius Kavay · Nov 10, 2022

Putting all in one line saves one byte

ClassMethod Order(s As %String) As %String
{
	s d=" ",z="" f i=1:1:$l(s,d){s b=$p(s,d,i),c=$zstrip(b,"*n"),$p(z,d,$tr(b,c))=c} q z
}

Changing $zstrip() to a $tr() saves one more byte

ClassMethod Order(s As %String) As %String
{
	s d=" ",z="" f i=1:1:$l(s,d){s b=$p(s,d,i),c=$tr(b,1E20/17),$p(z,d,$tr(b,c))=c} q z
}

So I end up with 86 bytes

Julius Kavay · Nov 9, 2022

One of the possible solutions

/// You can change the s:b]"" to an comma if there is always exact one space between the words
/// and remove the ,1) from $lts() if all word are numbered from 1..N with no number missing
ClassMethod WordOrder(s)
{
    s z="" f i=1:1:$l(s," ") s b=$p(s," ",i) s:b]"" $li(z,$zstrip(b,"*ap"))=$zstrip(b,"*n")
    q $lts(z," ",1)
}

This is a working solution and maybe not the shortest

Julius Kavay · Nov 7, 2022

You can it enter via terminal, no question about, but it's a little bit cumbersome

// create the class
s cls=##class(%Dictionary.ClassDefinition).%New()
s cls.ProcedureBlock=1
s cls.Super="%RegisteredObject"
s cls.Name="ObjectScript.RightTriangle"

// add one method
s mth=##class(%Dictionary.MethodDefinition).%New()
s mth.Name="Main"
s mth.Description="Compute area and hypotenuse of a right triangle"
d mth.Implementation.WriteLine($c(9)_"write !,""Compute the area and hypotenuse of a right triangle"",")
d mth.Implementation.Write($c(9,9)_"!,""given the lengths of its two sides.""")
d cls.Methods.Insert(mth)

// add one more method
s mth=##class(%Dictionary.MethodDefinition).%New()
s mth.Name="Area",mth.Description="Area, computed from sides 'a' and 'b'"
s mth.FormalSpec="a,b"
d mth.Implementation.WriteLine($c(9)_"quit a*b/2")
d cls.Methods.Insert(mth)

// save the class (it's NOT compiled!)
w cls.%Save()

As you may see, creating a class via an IDE is simpler... but yes, in an emergency case you can do it also via a console access

Julius Kavay · Nov 5, 2022

First, ##class(%PopulateUtils).StringMin(16,16)    generates random printable chars for testing (as replacement for user input) and is not ment to be used to generate cryptographic random chars. If you need cryptographic random chars, use $system.Encryption.GenCryptRand(length). This is just a hint and is not a reason for your current problem.

Second, despite my very limited C# experience, there is one thing in your code, I do not understand. If the initial vector (IV) is used, then it should be used (for enryption and decryption) the same IV on both sides, but you create an IV on Cache side (with the populate utils) and an other one on the C# side: byte[] IV = new byte[16]; (new Random()).NextBytes(IV);

That your decryption can't work.

To have a successful comunication, agree with the other party on
- a passphrase (the key), padding is done inside the encoding function 
- an IV (or left it empty on both sides)
- and on how the data will be sent:  either as the encoded (binary) data or as a readable (base64) data.ISC's implementation of AESCBCEncrtypt/Decrypt works well. One of my application uses it to communicate with an Windows application written in Delphi, without any problem since more the 15 years (we do not use the IV). So your problem will be some kind of a home-made problem:
- not using the same keys on both sides
- applying some kind of transformation (utf-8, base64, etc.)
- something suchlike

Julius Kavay · Nov 4, 2022

One of the problems could be the Bas64 encoding. This function inserts after each 76th byte a CRLF which possibly confuses the other party. Try with 

Set EncryptedBase64=$SYSTEM.Encryption.Base64Encode(encrypted, 1)

The parameter 1 says, do not insert CRLFs. Also, the text you encrypt must be an ANSI (8bit) text. If you are on a unicode system, you should call

Set encrypted=$SYSTEM.Encryption.AESCBCEncrypt($zcvt(text,"O","UTF8"),key,iv)
Julius Kavay · Nov 3, 2022

I understand your answer (#2) the way as this is a one time job. The simplest and quickest way to do this is:

- disable all indices (comment them out),
- compile the class or classes
- do the bulk insert
- enable all indices (by removing comment markers)
- compile the class or classes
- rebuild the indices

Class My.Class
{
    /*  disable all indices
    index1 someindex1 on someprop1;
    index2 someindex2 on someprop2;
    */
}