In communication outside of this thread, turns out the issue stemmed from a failed %Save() - something like:

Class DC.Demo.OREFOIDDemo Extends %Persistent
{

Property Foo As %String(VALUELIST = ",Bar");

ClassMethod RunDemo()
{
    Do ..%KillExtent()
    
    Set thingOne = ..%New()
    Set thingOne.Foo = "Bar"
    Do thingOne.%Save()
    Set thingOne.Foo = "Baz"
    Do thingOne.%Save()
    
    // Later, and elsewhere, because thingOne happens to be in memory,
    // it appears that the value "Baz" has been persisted:
    
    Set thingTwo = ..%OpenId(thingOne.%Id())
    
    Write !,"thingOne = ",thingOne
    Write !,"thingTwo = ",thingTwo
    Write !,"thingOne.Foo = ",thingOne.Foo
    Write !,"thingTwo.Foo = ",thingTwo.Foo
    
    Write !,"thingOne.FooGetStored(thingOne.%Id()) = ",thingOne.FooGetStored(thingOne.%Id())
    
    Do thingTwo.%Reload()
    Write !,"After thingTwo.%Reload(), thingOne.Foo = ",thingOne.Foo
    Write !,"After thingTwo.%Reload(), thingTwo.Foo = ",thingOne.Foo
}

}

Which produces output:

Do ##class(DC.Demo.OREFOIDDemo).RunDemo()
thingOne = 15@DC.Demo.OREFOIDDemo
thingTwo = 15@DC.Demo.OREFOIDDemo
thingOne.Foo = Baz
thingTwo.Foo = Baz
thingOne.FooGetStored(thingOne.%Id()) = Bar
After thingTwo.%Reload(), thingOne.Foo = Bar
After thingTwo.%Reload(), thingTwo.Foo = Bar

Poking around a bit, here's the best explanation I could find for how to implement such behavior: https://stackoverflow.com/a/7317311/2323797

Given that SQLCODE is 100 (in other comment thread), might you have an index on %ConfigName that has not been built?

What do you see from the following queries?

select * from X_X.X where %ConfigName IN ('X_X_X','Y_Y_Y')

select * from %IGNOREINDEX * X_X.X where %ConfigName IN ('X_X_X','Y_Y_Y')

Also, is X_X.X the table corresponding to the class where the property is defined?

Short answer: yes, ZPM can manage whatever you want other than ObjectScript, it just takes a little extra work.

Longer answer:

This "extra work" involves writing a class that extends %ZPM.PackageManager.Developer.Processor.Abstract and overrides OnBeforePhase or OnAfterPhase, then implementing whatever behavior you want. You can see a bunch of classes in the %ZPM.PackageManager.Developer.Processor package that do this.

I'd imagine being able to put something in the Resources element of module.xml like:

<Resource Name="/external-dependencies/some-package" ProcessorClass="MyPackage.AptGetInstall" />

Where MyPackage.AptGetInstall overrides OnAfterPhase and for the "Activate" phase runs apt-get install <name of resource following "/external-dependencies/"

The catch:

If you want to support all operating systems, think about what the Windows equivalent would be and/or add defensive coding to avoid trying to run the command on Windows.

Here's how I'd typically do something like that, going back to my example from one of your earlier questions and expanding a bit. The persistent class as a new %Boolean property named "Toggleable" (not a magical name - you can call it whatever you like), and the tablePane has <column> elements added. The query supplying data for the table has the ID and Toggleable columns added as well. The "Toggleable" column has OnDrawCell defined to provide custom HTML for the cells in the table; this references an ObjectScript method (which doesn't need to be, and in fact shouldn't be, a ZenMethod). That ObjectScript method renders HTML which calls a ZenMethod to actually do the update, using query results from the %query variable (which is a special thing that's available for use in OnDrawCell). No table refresh is needed, but if you refresh the page you'll see that the checkbox values have indeed been persisted.

Here's the Zen XData change:

<tablePane id="myTable" OnCreateResultSet="CreateResultSet" valueColumn="ID">
<parameter value="" />
<parameter value="" />
<parameter value="" />
<column colName="ID" hidden="true" />
<column colName="Name" />
<column colName="SomeDate" />
<column colName="Toggleable" OnDrawCell="DrawToggleCell" />
</tablePane>

And corresponding ObjectScript methods:

/// Note: this doesn't need to be a ZenMethod.
ClassMethod DrawToggleCell(pTable As %ZEN.Component.tablePane, pColName As %String, pSeed As %String) As %Status
{
    &html<<input type="checkbox" #($Case(%query("Toggleable"),1:"checked",:""))# onchange="zenPage.Toggle(#(..QuoteJS(%query("ID")))#,this.checked)" />>
    Quit $$$OK
}

ClassMethod Toggle(pID As %String, pValue As %Boolean) [ ZenMethod ]
{
    Set obj = ##class(DC.Demo.SampleData).%OpenId(pID,,.sc)
    $$$ThrowOnError(sc)
    Set obj.Toggleable = pValue
    $$$ThrowOnError(obj.%Save())
}

Here's the full sample:

Class DC.Demo.SampleData Extends (%Persistent, %Populate)
{

Property Name As %String;

Property SomeDate As %Date;

Property Toggleable As %Boolean;

}

Class DC.Demo.ZenPage Extends %ZEN.Component.page
{

XData Contents [ XMLNamespace = "http://www.intersystems.com/zen" ]
{
<page xmlns="http://www.intersystems.com/zen">
<fieldSet legend="Filter" layout="horizontal">
<text label="Name Starts With:" onchange="zen('myTable').setProperty('parameters',1,zenThis.getValue())" />
<dateText label="Start Date:" onchange="zen('myTable').setProperty('parameters',2,zenThis.getValue())" />
<dateText label="End Date:" onchange="zen('myTable').setProperty('parameters',3,zenThis.getValue())" />
</fieldSet>
<tablePane id="myTable" OnCreateResultSet="CreateResultSet" valueColumn="ID">
<parameter value="" />
<parameter value="" />
<parameter value="" />
<column colName="ID" hidden="true" />
<column colName="Name" />
<column colName="SomeDate" />
<column colName="Toggleable" OnDrawCell="DrawToggleCell" />
</tablePane>
<button onclick="zenPage.Populate()" caption="Repopulate Data" />
</page>
}

ClassMethod CreateResultSet(Output pSC As %Status, pInfo As %ZEN.Auxiliary.QueryInfo) As %SQL.Statement
{
    Set nameFilter = pInfo.parms(1)
    Set startDateFilter = pInfo.parms(2) // Will be in ODBC format
    Set endDateFilter = pInfo.parms(3) // Will be in ODBC format
    Set query = ##class(%SQL.Statement).%New()
    Set query.%SelectMode = 1
    Set sql = "select ID, Name, SomeDate, Toggleable from DC_Demo.SampleData"
    Set conditions = ""
    If (nameFilter '= "") {
        Set conditions = conditions_$ListBuild("Name %STARTSWITH ?")
        Set parameters($i(parameters)) = nameFilter
    }
    If (startDateFilter '= "") && (endDateFilter '= "") {
        // Yes, this could just be independent AND'ed conditions on start/end date,
        // which would reduce code complexity, but you wanted to see BETWEEN, so... :)
        Set conditions = conditions_$ListBuild("SomeDate BETWEEN ? and ?")
        Set parameters($i(parameters)) = startDateFilter
        Set parameters($i(parameters)) = endDateFilter
    } ElseIf (startDateFilter '= "") {
        Set conditions = conditions_$ListBuild("SomeDate >= ?")
        Set parameters($i(parameters)) = startDateFilter
    } ElseIf (endDateFilter '= "") {
        Set conditions = conditions_$ListBuild("SomeDate <= ?")
        Set parameters($i(parameters)) = endDateFilter
    }
    If (conditions '= "") {
        Set sql = sql _ " where "_$ListToString(conditions," and ")
    }
    Set pSC = query.%Prepare(sql)
    If $$$ISERR(pSC) {
        Quit $$$NULLOREF
    }
    
    //Important: Reduce to only the parameters specified/used.
    Kill pInfo.parms
    Merge pInfo.parms = parameters
    Quit query
}

ClassMethod Populate() [ ZenMethod ]
{
    Do ##class(DC.Demo.SampleData).%KillExtent()
    Do ##class(DC.Demo.SampleData).Populate(20,,,,0)
    &js<zen('myTable').executeQuery();>
}

/// Note: this doesn't need to be a ZenMethod.
ClassMethod DrawToggleCell(pTable As %ZEN.Component.tablePane, pColName As %String, pSeed As %String) As %Status
{
    &html<<input type="checkbox" #($Case(%query("Toggleable"),1:"checked",:""))# onchange="zenPage.Toggle(#(..QuoteJS(%query("ID")))#,this.checked)" />>
    Quit $$$OK
}

ClassMethod Toggle(pID As %String, pValue As %Boolean) [ ZenMethod ]
{
    Set obj = ##class(DC.Demo.SampleData).%OpenId(pID,,.sc)
    $$$ThrowOnError(sc)
    Set obj.Toggleable = pValue
    $$$ThrowOnError(obj.%Save())
}

}

For IIS, see https://docs.intersystems.com/latest/csp/docbook/Doc.View.cls?KEY=GCGI_w... - you need to set up a wildcard entry for the REST application's path.

If the CSPGateway is configured properly you should certainly be able to make a REST request to the webserver rather than needing to use the private webserver port. Reading this again I think the issue isn't the header you saw but actually is mixed content - see e.g. https://www.howtogeek.com/443032/what-is-mixed-content-and-why-is-chrome...

In the browser developer tools this will show up as:

So you really need to make the request via https - which is what you said in the first place, of course! And the best way to do that will be via your IIS webserver, which might already be configured correctly, and (if it's not) can be configured using the instructions I linked to above.

@Evgeny Shvarov I think in this context it's a request from the browser, not from the server (e.g., using %Net.HttpRequest)

What are the file permissions? Does the "Effective user for Caché superserver and its jobs" have read permission?

Here's a quick sample:

Class DC.Demo.XDataDemo
{

ClassMethod Driver()
{
    Set array = ..GetXDataContents("DC.Demo")
    zw array
}

ClassMethod GetXDataContents(package As %String) As %Library.ArrayOfObjects
{
    $$$ThrowOnError($System.OBJ.GetPackageList(.classes,package))
    Set array = ##class(%Library.ArrayOfObjects).%New()
    Set class = ""
    For {
        Set class = $Order(classes(class))
        Quit:class=""
        Set xDataName = ""
        For {
            Set xDataName = $$$defMemberNext(class,$$$cCLASSxdata,xDataName)
            Quit:xDataName=""
            Set xdata = ##class(%Dictionary.XDataDefinition).IDKEYOpen(class,xDataName,,.sc)
            $$$ThrowOnError(sc)
            Do array.SetAt(xdata.Data,class_":"_xDataName)
        }
    }
    Quit array
}

XData Foo
{
}

XData Bar
{
}

}

Note that this gets XData blocks defined in a class; if you want to get "inherited" XData blocks listed for each subclass along with the inherited content it's only slightly more complex:

ClassMethod GetXDataContents(package As %String) As %Library.ArrayOfObjects
{
    $$$ThrowOnError($System.OBJ.GetPackageList(.classes,package))
    Set array = ##class(%Library.ArrayOfObjects).%New()
    Set class = ""
    For {
        Set class = $Order(classes(class))
        Quit:class=""
        Set xDataName = ""
        For {
            Set xDataName = $$$comMemberNext(class,$$$cCLASSxdata,xDataName)
            Quit:xDataName=""
            Set origin = $$$comMemberKeyGet(class,$$$cCLASSxdata,xDataName,$$$cXDATAorigin)
            Set xdata = ##class(%Dictionary.XDataDefinition).IDKEYOpen(origin,xDataName,,.sc)
            $$$ThrowOnError(sc)
            Do array.SetAt(xdata.Data,class_":"_xDataName)
        }
    }
    Quit array
}

First off, you should strongly consider using a production webserver, not the built-in one. On configuring the CSPGateway for this, see https://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY...

You might also need to investigate CORS settings - https://docs.intersystems.com/latest/csp/docbook/Doc.View.cls?KEY=GREST_... is helpful reading on this.