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Julius Kavay · Aug 5, 2021

First of all, if you want to transform a hex string into base64 (or whatever), then first you have to say, WHAT IS that hex string?

According to your example

set hexString = "4C5803040101020179C3913EC3BA7C4C580708010101021824584D4C"

the string has 56 hex chars, so if you decode those 56 hex chars, the resulting string could be:
a) 28 eigth bit characters or
b) 14 sixteen bit chars or even
c)  7 characters, each 32 bits wide.

For cases b) and c) you also have to define the endianness (big- or little-endian).

Second, I assume, your hex-string represents 8-bit chars, so we get 28 characters after converting the hex-chars into a string.

Converting to base64 means, you get for every 3 (8bit) chars four printable (8bit) chars.

We add two padding chars to the 28 byte string, so we have 30 chars,  now which are divisible by 3. This gives you  40 base64 encoded characters. But your Base64 encoding has 44 characters, which must be wrong.

Here is a simple and working solution:

Class DC.Util Extends %RegisteredObject
{
/// Hex to Base64
ClassMethod HexToB64(hex)
{
   if $length(hex)#2 zt "ELEN" // trap, two hex chars should make up each byte
   set str=""
   for i=1:2:$length(hex) set str=str_$char($zhex($extract(hex,i,i+1)))
   quit $system.Encryption.Base64Encode(str,1)
}
/// Base64 to Hex
ClassMethod B64ToHex(b64)
{
   set str=$system.Encryption.Base64Decode(b64), hex=""
   for i=1:1:$length(str) set hex=hex_$extract($zhex($ascii(str,i)+256),2,3)
   quit hex
}
}

and a short test

set hexString = "4C5803040101020179C3913EC3BA7C4C580708010101021824584D4C"
set b64String=##class(DC.Util).HexToB64(hexString)
write b64String, !, ##class(DC.Util).B64ToHex(b64String), !,hexString

TFgDBAEBAgF5w5E+w7p8TFgHCAEBAQIYJFhNTA==
4C5803040101020179C3913EC3BA7C4C580708010101021824584D4C
4C5803040101020179C3913EC3BA7C4C580708010101021824584D4C
Julius Kavay · Aug 5, 2021

For such a task, the Horner's method was introduced. Fast and simple.

ClassMethod BinToDec(bin)
{
   if $translate(bin,10)="" { // formal check, bin should only contain '1' and '0'
      set res=0
      for i=1:1:$length(bin) set res=res*2+$extract(bin,i)
      quit res
   } else { ztrap "NBIN" }
}


Hardcore ObjectScript programer place those few commands into one line

bin2dec(bin) { s res=0 f i=1:1:$l(bin) { s res=res*2+$e(bin,i) } q res }


and doesn't care about errors ;-))

Julius Kavay · Jul 28, 2021

OK, this is the correct(ed) version:

ClassMethod RemoveNull(obj)
{
   set iter=obj.%GetIterator(),  rem=[]
   while iter.%GetNext(.key,.val) {
      if $isobject(val) { do ..RemoveNull(val) } elseif obj.%GetTypeOf(key)="null" { do rem.%Push({"o":(obj), "k":(key)}) }
   }
   for i=rem.%Size()-1:-1:0 set tmp=rem.%Get(i) do tmp.o.%Remove(tmp.k)
}
Julius Kavay · Jul 28, 2021

Just create a simple method like this:

ClassMethod RemoveNull(obj)
{
   set iter=obj.%GetIterator()
   while iter.%GetNext(.key,.val) {
   if $isobject(val) { do ..RemoveNull(val) } elseif obj.%GetTypeOf(key)="null" { do obj.%Remove(key) }
}

gives you

set json={"recipients": [{ "name":"Utsavi", "email":"utsavi@gmail.com"},{ "name":"Utsavi 1", "email":"utsavi1@gmail.com"},null, null],"content":[null, {"title":"Test.pdf", "data":"ygwehfbnwfbhew"} ]}

write json.%ToJSON() --> {"recipients":[{"name":"Utsavi","email":"utsavi@gmail.com"},{"name":"Utsavi 1","email":"utsavi1@gmail.com"},null,null],"content":[null,{"title":"Test.pdf","data":"ygwehfbnwfbhew"}]}

write ##class(some.class).RemoveNull(json) --> {"recipients":[{"name":"Utsavi","email":"utsavi@gmail.com"},{"name":"Utsavi 1","email":"utsavi1@gmail.com"},null],"content":[{"title":"Test.pdf","data":"ygwehfbnwfbhew"}]}
Julius Kavay · Jul 20, 2021

Just a hint, I would take $ZD($h,2). For today, my development system (and systems at customers site) shows:

Write $horolog - $zdate($horolog, 4) + 1 --> 65925.93
Write $zdate($horolog,4) --> 20.07.2021
Write $horolog - $zdate($horolog, 2) + 1  --> 65926 // expected value

Later, this value (65925.93), as a $zdate() argument,  gives you an <ILLEGAL VALUE> 

For $zdate($horolog,4), the link you provided says:

4 DD/MM/[YY]YY (01/07/97 or 27/03/2002) — European numeric format. You must specify the correct dateseparator character (/ or .) for the current locale.
Julius Kavay · Jul 17, 2021

Hello Matjaž,

I have a suspicion...

I tested your case with a 16201607 bytes large PNG file (and it worked).

First, to be able to do this, I had to made a change in the User.API class:

//Do model.%JSONExportToString(.json)
//Quit json

Do model.%JSONExportToStream(.str)
Quit str

so you get back a STREAM instead of a string.

As for IRIS and Cache, a string can't have more then 3641144 chars!

And take into account, a base64 encoded string is 33% longer then the orginal (exact: newSize = oldSize  + 2 \ 3 * 4), so you can use stringvariables up to an original picture size of (roughly, not counting the padding(s)): 

3641144 - 19 - $l(identname)  \ 4 * 3  //  19 bytes for {Ident:"","PNG":""}

By the way, can you output the encoded size (i.e. the length) of the JSONString you send and then the size of the same string in C#? Are they the same?

Julius Kavay · Jul 17, 2021

Zdravo Matjaž,

for the first glance, the above methods should work. Although I don't understand why you need the User.Model class? You can achieve the same thing by defining

Class User.Data Extends (%Persistend, %JSONAdapter) { }

and then 

ClassMethod Load(Ident As %String) As %String [ Language = objectscript ]
{
  Set data=##class(User.Data).%OpenId(Ident)
  Quit:data="" "null"

  Do data.%JSONExportToString(.json)
  Quit json
}

By the way, in the User.Data class, you can shorten the index definition to

Index Ident On Ident [ IdKey ];

because an IdKey is ALWAYS unique.

If you say, your C# gets a garbage PNG, then I would check two things:

1) does the PNG property (in User.Data) contain a valid PNG? Issue in a terminal session following commands: 

set data=##class(User.Data).%OpenId("...")
do data.PNG.Rewind() // not necessary straight after an open
zzdump data.PNG.Read(16)

the output should be:
0000: 89 50 4E 47 0D 0A 1A 0A 00 00 00 0D 49 48 44 52         .PNG........IHDR

2) are you sure, C# gets the JSON-string returned by Load() method? Are you sure, no intermediate process (a middleware) changes this string by applying extra encoding or decoding?

 

Pozdrav z Beča (Dunaja)

Julius Kavay · Jul 16, 2021 

Class Test.JD Extends (%Persistent, %JSON.Adaptor) [ Language = objectscript ]
{
Property Name As %String;
Property Type As %String;
Property Image As %Stream.GlobalBinary;
}

set obj=##class(Test.JD).%New()
set obj.Name="Joe"
do obj.Image.Write($system.Encryption.Base64Decode("iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAIAAACQkWg2AAAABnRSTlMAAAAAAABupgeRAAAACXBIWXMA"))
do obj.Image.Write($system.Encryption.Base64Decode("AA7EAAAOxAGVKw4bAAAAGElEQVQokWNk+M9AEmAiTfmohlENQ0kDAD8vAR+xLJsiAAAAAElFTkSuQmCC"))

if obj.%JSONExportToString(.string) write string --> 

{"Name":"Joe","Image":"iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAIAAACQkWg2AAAABnRSTlMAA
AAAAABupgeRAAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAGElEQVQokWNk+M9AEmAiTfmohlENQ0kDAD8vA
R+xLJsiAAAAAElFTkSuQmCC"}

As you see in the above example, the export works and does Base64Encoding for the appropriate property (in my example this is 16x16 pixel green rectangle). Please show the relevant part (property) of your class (definition).

Julius Kavay · Jul 15, 2021

Obviously, the response.Data does not contain valid JSON. You can simply check the received data by putting the data aside in a temporary global, something like this:

do request.HttpResponse.Data.Rewind()
set ^temp.debug($j,"size")=request.HttpResponse.Data.Size
set ^("data")=request.HttpResponse.Data.Read(request.HttpResponse.Data.Size)  // or just the first 1000 bytes
zw ^temp.debug

Now you can take a look on the incoming data, maybe there is an encoding problem or the data do not adhere to JSON specification

Julius Kavay · Jul 13, 2021

According to your code,  the variable obx5 contains the base64 encoded tiff image. There is one thing I do not understand: what are those "\.br\" char-sequences, how they came into the base64 stream?

Anyway, I suppose they are OK (those "\.br\"s), so put all those pieces together and decode all at once:

set input = ""
for i=1:1:$L(obx5,"\.br\") { set input = input _ $P(obx5,"\.br\",i)) }

Do obj.Write($system.Encryption.Base64Decode(input))

Now you should have a correct decoded image, provided, the obx5 variable really contains the original base64 encoded tiff image with randomly inserted "\.br\" chars (for whatever reason).