You can use the if $i to do some stuff within loops too. For example, if you enter the following to commands in a terminal:

set a = 5
for{if $i(a,-1){w a,!}else{quit}}

This will subtract 1 from a and write its value until it reaches 0, then quit the loop. Of course you could just as easily use for a=4:-1:1 {w a,!} to produce the same output a little more nicely, so you don't see that as much.

Queries to linked tables will fail if there is an issue with the connection, but when it's up, you've got the current data. Copying it over would help with potential connection issues, though you would still have a problem if the connection can't be established when you're trying to copy the data over. But if you're doing that once a day, your data is going to be a day old at times. I think the question you need to be asking is, for your specific application, how important is it that the data you're getting from the external database is current?

Your login request technically is an unauthenticated request, which means it uses the account UnknownUser. Since the web application /api/atelier requires user permission on the %Development resource, the request is failing. You could address this by either removing that restriction from the web app or by assigning the %Developer role to UnknownUser. In my opinion, though, neither of those is really ideal.

When you see something that starts with a ..# that's a parameter that's defined in a class. If you look at the source of the %CSP.REST class, you'll see:

Parameter HTTP401UNAUTHORIZED As %String = "401 Unauthorized";

So you could try either set the %response.Status "401 Unauthorized" or add that parameter to your class and use it as you have before in %CSP.REST classes.

If you want to do all files in a directory, including recursively going into all subfolders, the command should be something like:

zip -r test001.zip /path/to/folder/

If you're trying to do this from inside ObjectScript, you'd have to use $ZF -100 to do that:

set args(1) = "-r"
set args(2) = "test001.zip"
set args(3) = "/path/to/folder/"
do $ZF(-100,"","zip",.args)

We haven't tried using it for ObjectScript, but we do have some customers who use Crystal Reports who have tried using it to help set those up, and it has been very questionable for that. It definitely doesn't understand what's where in the database structure, and even basic formula fields seem to be far more complicated than necessary.

If you want to treat them as lists, you probably want to use $LISTFROMSTRING along with $LISTGET, $LISTFIND, and $LISTLENGTH. All of which can be abbreviated to their initials, by the way - $LFS, $LG, $LF, $LL.

set y = $LFS("Red,Green,Orange,Yellow")
set x = $LFS("Purple,Black,Yellow,Pink")
for i=1:1:$LL(x){
    if $LF(y,$LG(x,i)) > 0 { 
        write $LG(x,i)_" found in both lists!",!
        //Or whatever else you want to do when you find a match here . . .
    }
}

By the time I started learning ObjectScript, I had already been exposed to varying degrees to Java, javascript, PHP, C#, C++, Visual Basic, Python, and ActionScript, so to me it was different, but I was kind of used to finding my way around the quirks of a new object-oriented language.

One thing that does make it more difficult with ObjectScript in this community, though, is that so many things can be abbreviated in code, and that makes it harder for beginners to read and follow up on. For example, you might see {}.%New() or {}.%FromJSON(). It might take some time to figure out that if you want to look up further documentation on what that is, you have to look at the %Library.DynamicObject class, and that you could also use ##class(%Library.DynamicObject).%New(). Commands like set, do and for get shortened to s, d, and f. Functions like $ZDATETIME get shortened to $ZDT. We mention things like $$$ThrowStatus assuming you'll know that if you're writing a routine, you have to have #include %occStatus at the top to use that.

It's something that, once you figure it out, it's easy to understand, but those of us writing articles on here could also do a better job of writing our code samples to be readable.

If it's null, your code might not even be getting to the Post method. Are you running this in the terminal, and are you getting any other errors there? Is your RTLS SSL configuration set up in the management portal?

Also, when the response comes back, it's JSON, so if you want to get just the token, you'd have to:

set tokenObj = ##class(%Library.DynamicObject).%FromJSON(AuthToken.HttpResponse.Data)
set AuthTokenValue = tokenObj.%Get("access_token")