A few side notes...

The correct/best way to create a %Object from a %RegisteredObject (or vice versa) is $compose, not $fromObject (which has been marked as Internal in more recent builds). This is first available in 2016.2.

SAMPLES>set person = ##class(Sample.Person).%OpenId(1)
SAMPLES>set obj = {}.$compose(person)
SAMPLES>w obj.$toJSON()
{"Age":88,"DOB":31520,"FavoriteColors":["Blue"],"Home":{"City":"Youngstown","State":"CO","Street":"1360 Oak Avenue","Zip":74578},"Name":"Tillem,Terry Y.","Office":{"City":"Gansevoort","State":"KY","Street":"4525 Main Court","Zip":93076},"SSN":"132-94-8739"}

Also, you can get %RegisteredObjects as JSON more directly:

SAMPLES>set person = ##class(Sample.Person).%OpenId(1) 
SAMPLES>w person.$toJSON()
{"Age":88,"DOB":31520,"FavoriteColors":["Blue"],"Home":{"City":"Youngstown","State":"CO","Street":"1360 Oak Avenue","Zip":74578},"Name":"Tillem,Terry Y.","Office":{"City":"Gansevoort","State":"KY","Street":"4525 Main Court","Zip":93076},"SSN":"132-94-8739"}

Try:

Do $System.Process.Terminate(,exitCode)

See documentation for reference. On older versions I believe the equivalent is:

Do $zu(4,$job,exitCode)

But this shouldn't be used if the nicer method is available.

Actually - if you're going to do this after issuing the Get, you should use request.Get(,,0), then do this, then call Reset() on the request manually. Otherwise the parameters will get cleared out and the query string will always be blank.

I'd suggest something like this, after calling Get:

Set tParams = request.ReturnParams()
Set tQuery = $Case(tParams,"":"",:"?"_tParams)
Set tURL = $Select(request.Https:"https://",1:"http://")_request.Server_":"_request.Port_"/"
    _request.Location_tQuery

1/2. I use the "My Content" page to quickly get back to my own posts. I don't use "My Collaborations" or understand how the content that appears there is determined.

3. I'd expect to see my own posts (and perhaps answers) on "My Content" and for "My Collaborations" to show links to questions that I have answered and to posts/answers that I have commented on. Answers could fit in either category (or both); I'm not sure if those are best understood as content or as a particular type of comment.

4. Show the content described in (3) on these pages. Also, for answers, rather than showing "answer406256" as the title (for example), show "Answer: <title of question>" and link to the answer within the question page rather than the answer on its own. I think the same would also apply to comments shown on "My Collaborations" (if that approach is taken). If "My Collaborations" shows comments it might make sense to group them by post, in case there's a very active back-and-forth.

Here are two perspectives, from different development workflows:

My team (working on a large Caché-based application) does development on a newer Ensemble version than the version on which our software is released. We perform functional and performance testing against the older version. Most of the time, moving code from newer versions to older works just fine; when it does fail, it tends to be very obvious. The last class dictionary version change was in 2011.1, so that isn’t a concern for upgrades involving recent versions. These used to be much more frequent. Working this way provides a good sort of pressure for us to upgrade when we find new features that the old version doesn’t have or performance improvements on the newer version. It also eases concerns about future upgrades to the version on which the application has been developed.

For Caché-based internal applications at InterSystems, we have separate designated dev/test/live environments. Application code changes typically spend a relatively short time in dev, and a much shorter time in test, before going live. Upgrades are typically done in a short time frame and move through the environments in that order. It would be incredibly risky to upgrade the live environment first!  Rather, our process and validation for upgrades go through the same process as functional changes to these applications. The dev environment is upgraded first; this might take time if there are application issues found in testing after the upgrade. The test environment is upgraded next, typically a very short time before the live environment is upgraded. It's OK if code changes are made in dev before the test environment is upgraded, because changes will still be compiled and tested in the older Caché/Ensemble version prior to going live. Of course, if testing fails, the upgrade may become a prerequisite for the given change to the application. Additionally, we periodically clone the test environment for upgrades to and validation against field test versions. Using virtual machines makes this very easy.

This should accomplish what you want:

var tablePane = zen('yourTablePaneId');

// Don't actually execute the query the next time the table is rendered.
tablePane.setProperty('initialExecute',false);

// Clear the snapshot (cached results of the query, used for quick pagination) before re-rendering.
// This is irrelevant if the tablePane isn't using snapshots.
tablePane.setProperty('clearSnapshot',true);

// Regenerate HTML for the tablePane - it'll be empty.
tablePane.refreshContents();

Or, a bit more simply:

var tablePane = zen('yourTablePaneId');

// Don't actually execute the query the next time the table is rendered.
tablePane.setProperty('initialExecute',false);

// Re-execute the query (this also clears the snapshot if snapshots are in use)
tablePane.executeQuery();

If refreshContents() / executeQuery() is called again, query results will be shown, because initialExecute is set to true each time the tablePane is drawn.

One solution would be to look at the audit database. It's not pretty, but there might not be any other way.

ClassMethod GetLoginService() As %String
{
    New $Namespace
    Zn "%SYS"
    
    Set tService = ""
    
    // Ensure that login events are being audited.
    Set tLoginEvent = ##class(Security.Events).Get("%System","%Login","Login",.tProps)
    If '$Get(tProps("Enabled")) {
        // Querying the audit DB probably won't do any good.
        Quit tService
    }
    
    // Warning: on systems with a lot of activity, this query might take a long time.
    // It might be worth filtering by recent UTCTimeStamp, assuming processes won't be that long-running.
    Set tRes = ##class(%SQL.Statement).%ExecDirect(,
        "select top 1 EventData from %SYS.Audit "_
        "where EventSource = '%System' and EventType = '%Login' and Event = 'Login' and PID = ? "_
        "order by UTCTimeStamp DESC, SystemID DESC, AuditIndex DESC",$Job)
    
    Set tHasResult = tRes.%Next()
    If (tHasResult) {
        Set tData = tRes.%Get("EventData")
        //NOTE: This makes assumptions about the format of EventData.
        //Particularly, that it looks something like:
        /*
        Service name:       %Service_Bindings
        Login roles:        %All
        $I:                 |TCP|1972|15396
        $P:                 |TCP|1972|15396
        */
        //
        Set tFirstLine = $Piece(tData,$c(13,10))
        
        //Presumably "Service name:" might be localized, but %Service_<something> would not be.
        Set:tFirstLine["%Service" tService = "%Service"_$Piece(tFirstLine,"%Service",2)
    }
    Quit tService
}

Note: if your application is using Caché security correctly, you'd probably need to define a privileged routine application to allow access to Security.Events and the audit database.

Specifics on %CSP.Page / cspbind error handling:

There are alternatives to modifying system-level error message translations. Even if the localization is changed, the end user would probably still see "SQLCODE -139," which isn't helpful. What you probably want to show the user is "Someone else has modified this record. Please reload the page and try again." or something similar.

Using %CSP.Page and a form with cspbind, there's no way to customize the error handling in the generated <form name>_save function. It seems to always show any error message in an alert. An alternative would be to use a similar approach to form.csp and formsubmit.csp in the SAMPLES namespace, submitting the form and calling the <form name>Submit method of the page rather than using a hyperevent (in form_save()). Note that you don't need a separate page to handle the form submit; one page can do it all.

Of course, if the form is saved with a POST rather than a hyperevent, and optimistic concurrency control is in use, it might be worth a separate call to the server immediately before submitting the form for an optimistic concurrency check. If someone else edited the record, the page could tell the user rather than submitting the form. This wouldn't prevent the error in question, but would at least make it much less likely.

(Side note: %CSP.Page/cspbind is very old technology. There are better tools available now, but if you're stuck with it in a large existing project, that's understandable.)

General thoughts on showing users friendly error messages:

The more general problem is: "Often, the error codes and messages the system produces are not helpful to an end user. How do you show the user the information they need when an error occurs?"

This gets more complicated because error messages can come from very different sources - for example, SQL, an object %Save, a variable being undefined, or the application detecting a user error.

The standard for the large Caché-based application I work on is:

• Within UI classes (class-based CSP or Zen, in our case), server-side code is wrapped in try-catch blocks.
• Different types of exceptions (subclasses of %Exception.AbstractException) are thrown for the different types of errors that occur. These may be:
  • SQLCODEs and associated messages from embedded or dynamic SQL
  • Error %Status codes from object %Saves and various other things
  • General internal errors in application business logic
  • User errors detected in business logic. (These are treated differently for logging purposes; user errors may be more common than system errors and might not be logged.)
  • System errors (<UNDEFINED>, <SUBSCRIPT>, etc.)
• Any of these types of exceptions. except system errors, may include a user-friendly message explaining what went wrong.
• If an exception is caught, a method is called to (1) log that an error occurred and (2) either provide a description of the error that the user can understand, or else just say that an error happened (with the confusing details omitted, although they are logged).
  • If the exception already has a friendly message for the user, it's returned.
  • Otherwise, for error SQLCODEs and error %Status codes, we provide general messages for concurrency-related errors and some other common error codes. We also have a system for interpreting foreign and unique key violations (from an SQLCODE or %Status) and providing more descriptive messages based on those.
  • Worst case, the message "An internal error occurred (log ID _____)" is returned.
• The message is shown to the user in red text, an alert dialog (ideally not a vanilla JavaScript alert), or however else makes sense in context.
• There are macros for the different types of exceptions and for getting the user-friendly message, for ease of maintainability.

This has been bothering me a little bit; %Dictionary.* should really be a last-resort option, in my opinion, and it isn't easy to use it to get the full picture from an SQL perspective.

Here are some alternative/possibly-better solutions, using %SQL.StatementMetadata and INFORMATION_SCHEMA. It looks like INFORMATION_SCHEMA is more exactly what you were looking for, if you're running on a recent enough Caché version (2015.1+). I haven't been able to find documentation on it other than the class reference, though.

/// NOTE: It could be good to validate pTableName to avoid SQL injection. (Outside the scope of this demo.)
/// This works pre-2015.1 (since %SQL.Statement was introduced - maybe 2012.2+?)
ClassMethod GetTableColumns(pTableName As %String) As %List
{
    #dim tResult As %SQL.StatementResult
    #dim tMetadata As %SQL.StatementMetadata
    Set tStmt = ##class(%SQL.Statement).%New()
    $$$ThrowOnError(tStmt.%Prepare("select top 0 * from "_pTableName))
    Set tResult = tStmt.%Execute(), tMetadata = tResult.%GetMetadata()
    Set tCols = ""
    For i=1:1:tMetadata.columnCount {
        Set tCols = tCols_$ListBuild(tMetadata.columns.GetAt(i).colName)
    }
    Quit tCols
}

/// This will only work on 2015.1+; INFORMATION_SCHEMA is a new feature. For more information, see the class reference for it in the documentation.
ClassMethod GetTableColumnsNew(pTableName As %String) As %List
{
    #dim tResult As %SQL.StatementResult
    Set tStmt = ##class(%SQL.Statement).%New()
    Set tSchema = $Piece(pTableName,".")
    Set tTableName = $Piece(pTableName,".",2)
    $$$ThrowOnError(tStmt.%Prepare("select COLUMN_NAME from INFORMATION_SCHEMA.COLUMNS where TABLE_SCHEMA = ? and TABLE_NAME = ?"))
    Set tResult = tStmt.%Execute(tSchema,tTableName)
    Set tCols = ""
    While tResult.%Next(.tSC) {
        Set tCols = tCols_$ListBuild(tResult.%Get("COLUMN_NAME"))
    }
    $$$ThrowOnError(tSC)
    Quit tCols
}

Using this:

SAMPLES>set cols = ##class(Demo.TableColumns).GetTableColumns("Sample.Person")
SAMPLES>w $lts(cols)
ID,Age,DOB,FavoriteColors,Name,SSN,Spouse,Home_City,Home_State,Home_Street,Home_Zip,Office_City,Office_State,Office_Street,Office_Zip
SAMPLES>set cols = ##class(Demo.TableColumns).GetTableColumnsNew("Sample.Person")
SAMPLES>w $lts(cols)                                                            ID,Age,DOB,FavoriteColors,Name,SSN,Spouse,Home_City,Home_State,Home_Street,Home_Zip,Office_City,Office_State,Office_Street,Office_Zip