Caché

It's well-known that namespace global mapping helps us to write code independent on database storage details (Caché instance name, directory path). But sometimes we can face problems accessing an unsubscripted global which has subscript level mapping (SLM) defined. Most of such cases are evident and associated with administrative tasks that should be done on database level, but some of them can confuse even an experienced developer. Just to start:

This code snippet provides a ZEN page that downloads a stream from its database directly:

/// We assume that you have stored your data within this schema:
/// MyApp.Model.Storage: Filename,FileSize,Content,ContentType
Class zen.downloadStream Extends (%ZEN.Component.page,%CSP.StreamServer)
{
 
    /// Wrapper to get the id of the download, we assume that the id is passed to this zen page
    /// as a URI parameter, i.e.: MyApp.Downloads.cls?OID=1234
    ClassMethod GetId()
    {
        Quit $Get(%request.Data("OID",1))
    }
     
    /// Set the appropriate header for the file.
    ClassMethod OnPreHTTP() As %Boolean
    {
        Set tId = ..GetId()
     
        If ##Class(MyApp.Model.Storage).%ExistsId(tId) {
            Set tStream = ##Class(MyApp.Model.Storage).%OpenId(tId)
            // You could "guess" the content type by its file extension
            // or you can store it (before) in the database separately (like in this example).
            // Set Extension = $Piece(tStream.Filename,".",$Length(tStream.Filename,"."))
            // Set ContentType = ..FileClassify(Extension)
     
            Set %response.ContentType = tStream.ContentType
            Do %response.SetHeader("content-disposition","attachment; filename="_tStream.Filename)
            Do %response.SetHeader("Content-Length",tStream.FileSize)
        }
        Else {
            Set %response.Status="404 File Not Found"
            Quit 0
        }
        Quit $$$OK
    }
     
    ClassMethod OnPage() As %Status
    {
        Set Download = ##Class(MyApp.Model.Storage).%OpenId(..GetId())
        Do Download.Content.OutputToDevice()
        Quit $$$OK
    }
 
}

Link to code on GitHub

Hi folks,

I've created a datatype class whoch extends from %Library.String with a REGEX parameter and the validation of the value against the regular expression. The class does not support Populate using the regular expression as a template for data population.

The following class method "test" contains code that can create a new class, create new properties for classes, or create new methods for classes. "test" runs all three of these processes once, and the code that performs each action is labelled by comments in the method:

ClassMethod test() As %Status
{
    set sc = $$$OK
    
    // Create a class
    set class = ##class(%ClassDefinition).%New("MyClass")
    set class.Description = "This is my test class"_$c(13,10)_"testing %ClassDefinition"
    set class.Super = "%Persistent"

    // Create a property and add it
    set property = ##class(%PropertyDefinition).%New("MyClass.MyProperty")
    set property.Type = "%String"
    set property.Description="This is a property"
    set sc1 = class.Properties.Insert(property)
    do:$$$ISERR(sc1) $system.Status.DisplayError(sc1)
    set sc = $$$ADDSC(sc, sc1)
    
    // Create a method and add it
    set method = ##class(%MethodDefinition).%New("MyClass.MyMethod")
    set method.ReturnType = "%Integer"
    set method.FormalSpec = "x:%Integer,y:%Integer=10"
    set method.Description = "Return product of x and y"
    set method.CodeMode = "code"
    set method.Code = " new result"_$c(13,10)_" set result=x*y"_$c(13,10)_" quit result"
    set sc2 = class.Methods.Insert(method)
    do:$$$ISERR(sc2) $system.Status.DisplayError(sc2)
    set sc = $$$ADDSC(sc, sc2)
    
    // Save the class definition
    set sc3 = class.%Save()
    do:$$$ISERR(sc3) $system.Status.DisplayError(sc3)
    set sc = $$$ADDSC(sc, sc3)
    
    return sc
}

Here's a link to the code on GitHub

or "Bonus Breakage"

In our last lesson, we added a relationship between 2 persistent classes.  We are clearly going to need to start creating REST Services to expose CRUD operations for each of these classes, but before we do that, we should really finish defining our linkages.  We added code to our Widget toJSON to spool off related Accessory data, so we should really do the reciprocal and allow Accessories to return all Widgets that are compatible.

This code snippet determines the day of the week associated with a date. The class method "test" takes a date as a string in "mm/dd/yyyy" format, and returns an integer corresponding to a day of the week:

Class cartertiernan.getDayfromDate Extends %RegisteredObject
{
    classmethod test(date) as %Integer {
        //Set date = $ZDATE(date) //  Looks like: mm/dd/yyyy
     
        Set monthList = $LISTBUILD(0,3,3,6,1,4,6,2,5,0,3,5) // (Jan,Feb,Mar,Apr,...)
        Set centuryList = $LISTBUILD(6,4,2,0) // first two digits divisiable by 4, then subsequent centuries. EX (2000, 2100, 2200, 2300)
        Set dayList = $LISTBUILD("Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday") // Index goes from 0-6
         
        Set day = $PIECE(date,"/",2) // get the day 
        Set monthVal = $LIST(monthList,($PIECE( date,"/",1 ))) // get the month value
        Set first2DigsYear = $PIECE( date,"/",3 ) \ 100 // get the last 2 digits of the year
        Set last2DigsYear = $PIECE( date,"/",3 ) # 100 // get the first 2 digits of the year
         
        // Used for DEBUG perpouses
        /*write !,"day: ",day
        write !,"Month: ",monthVal
        write !,"last2: ",last2DigsYear
        write !,"first2: ",first2DigsYear
        write !,"cen Val: ",$LIST(centuryList,(first2DigsYear # 4) + 1),!!*/
         
        // Look here for formula explination (its the "Basic method for mental calculation")
        // http://en.wikipedia.org/wiki/Determination_of_the_day_of_the_week
        Set dayOfWeekVal = ( day + monthVal + last2DigsYear + (last2DigsYear\4) + $LIST(centuryList,(first2DigsYear # 4) + 1 ) ) # 7
     
        Quit dayOfWeekVal
    }
}

Here's a link to the code on GitHub

(originally posted to CODE by Carter Tiernan, 6/18/14)

Generally speaking, InterSystems products supported dynamic objects and JSON for a long while, but version 2016.2 came with a completely new implementation of these features, and the corresponding code was moved from the ObjectScript level to the kernel/C level, which made for a substantial performance boost in these areas. This article is about innovations in the new version and the migration process (including the ways of preserving backward compatibility).

This code snippet allows for a file on the web to be saved into the file system. Specify the server and GET request, as well as the directory the file should be saved to. The class method "test" runs the code:

Class objectscript.saveFileHTTP Extends %RegisteredObject
{
    classmethod test() {
        Set httprequest = ##class(%Net.HttpRequest).%New()
        Set httprequest.Server = "docs.intersystems.com"
        Do httprequest.Get("documentation/cache/20172/pdfs/GJSON.pdf")
        
        Do $System.OBJ.Dump(httprequest.HttpResponse)
         
        Set stream=##class(%FileBinaryStream).%New()
        Set stream.Filename="c:\test.pdf"

        Write stream.CopyFrom(httprequest.HttpResponse.Data)
        Write stream.%Save()
    }
}

Here's a link to the code on GitHub

Have you ever thought why the code that you write in Caché Object Script is exported to an XML file?

This is the third article (see Part 1 and Part 2) where I continue to introduce you to the internal structure of Caché databases. This time, I will tell you a few interesting things and explain how my Caché Blocks Explorer project can help make your work more productive.

Hi ISC Community!

I'm pleased to announce new release of Caché Web Terminal 3.1.4.

What's new:

1. Drag'n'drop to Studio installation: just import xml in any namespace.

2. After import and comilation access your web terminal app on URL  server:port/terminal/.

F.e. localhost:57772/terminal/       

Slash is mandatory.

3. No need to use %CACHELIB anymore - please feel free to update your Caché and continue using CWT.

The following code snippet is a REGEX that validates characters that are not in English, as well as English characters. The class method "test" takes an email address and validates it based on this additional criteria:

The following code snippet uses GZIP to compress/decompress a file. Choose a file by specifying a file path in the "filename" variable.

The following code allows a user to view the audit settings of their instance. Run the code by running the class method "test":