#Code Snippet

Background

Caché 2016.1 introduced some very powerful JSON features.  Unfortunately, the syntax used in the 2016.1 release is going to be changed in the 2016.2 release to bring it closer to Caché ObjectScript syntax.  This will mean that code that works in 2016.1 may not be forwards compatible.   See this announcement and this article for more details about the changes.

This sample class will add parameter DSINTERVAL to each class containing the parameter DSTIME

To execute it from a Terminal :

SAMPLES>d ##class(adm.param).add(,,1)
[SAMPLES] parameter DSINTERVAL=5 added to class DeepSee.Study.CityRainfall (via adm.param)
[SAMPLES] parameter DSINTERVAL=5 added to class HoleFoods.Transaction (via adm.param)
[SAMPLES] parameter DSINTERVAL=5 added to class News.DeepSee.NewsArticle (via adm.param)
DSINTERVAL parameter was added to 3 classes

Checking if Directory or File Exists:

Outlined below is an example of how to check if a directory exists:

Set directoryName="c:\temp\nosuchdir"

/* Check for existence of a directory - Return Value:  0 - directory does not exist;  1 - directory does exist  */

Set directoryExists=##class(%File).DirectoryExists(directoryName)

If ('directoryExists)  // do the processing for when a directory does not exist

Outlined below is an example of how to check if a file exists:

Have you tried $Translate for date conversion?

USER>write $Translate("Dd.Mm.WwYy","WwYy-Mm-Dd","2015-08-02")

02.08.2015

Stolen from Russian forum and Alexander Koblov.

We're developing Ensemble PoC and one day our frontend developer (who doesn't have Ensemble production running) said that Populate just doesn't cut it and he needs to see the real data. He needed only one object, but the problem was - it's a big object. Still, I checked ids of everything related and wrote this command (parts omitted, but you get the idea):

Process-private Globals  can be used as a data global in storage definition. That way, each process can have its own objects for the class with ppg storage. For example lets define a pool, which can:

• add elements to a pool (ignoring duplicates)
• check if an element exists in the pool

Here's the class:

Date range queries going too slow for you?  SQL Performance got you down?  I have ANOTHER weird trick that SQL Developers don't want you to know!*

Cache tricks

Several years ago, long before Developer Community Portal was launched, I published a series of Caché tricks at one of Czech web sites. In this article, I’m posting translated version of one of them.

Capturing output of someone else’s methods or routines

Suppose you, or someone else created a useful method or routine, that was producing some computation that you’d like to benefit from, but the routine was writing output to process principal device.

You would like to use the data, but you need it not written to a device, but assigned to a variable. And, for any reason, you can’t modify the code. What can you do?

This article created as side effect of preparations to the longer set of articles about simple, but still handy MapReduce implementation in Caché. I was looking for relatively easy way to pass arguments to (potentially) multiple targets via remote calling facilities. And after several attempts I have realized that we do have very powerful mechanism in the Caché ObjectScript which might be of particular help here – dynamic dispatch for methods and properties.

Hi,

I am new to Cache and I am trying to convert a JSON string (msgdata) that contains a JSON payload to an object to be saved into a Driver. Entity table.  I am running into 2 issues and would appreciate any help:

1) It seems that when the 1st element of a list within the payload (Choices) is an empty string, after I call %ConvertJSONToObject, the obj.%data("payload").Choices contains just 1 empty element, removing the next 3 valid values (10,20,30). The same does not happen if I change the input to [10,20,"",30], in this case it works correctly.

Hello, everyone!

I opened one project and there I found such lines as 

$$Export^%occXMLExport(filename,"-d /diffexport",InternalName)

Do DecomposeStatus^%apiOBJ(sc,,"d")

The problem is I can't go to their definition and find them in documentation. It says that they don't exist on the server. However, the project works and these routines execute. 

How can I import them into my project? 

I've been trying to write a method to compare two local variables, which may be arrays, for "equality" - that is, to see if they have all the same subscripts (if they're arrays) and values. This is the best I've come up with so far - are there any better/simpler approaches out there?

I want to show my script which I use for a completion in bash, for ccontrol and csession. 

With this script bash helps to available (running or down) instances to ccontrol, or in csession

file
/usr/share/bash-completion/completions/ccontrol

Here's  a code snippet to calculate the length of a class or a package in lines of code:

Hi!

Here is small "How to" again.

Suppose you need to share something with source code. How can we manage it on DC?

Sharing code snippets

1. Add normal post (not Code Package).

2. Paste your code in the post and format it with highlighting as it is described here.

3. If you see that your COS code is highlighted wrong it means that autodetect missed with language. Open the post's HTML ("disable rich-text" button below the Editor) and put class=COS parameter into the code tag.

Example:

Hi!

Want to share with you code snippet of try catch block I usually use in methods which should return %Status. 

{ 
 try {
  	$$$TOE(sc,StatusMethod())
 }
 catch e {
 	set sc=e.AsStatus()
 	do e.Log()
 }

Quit sc 
}

Here $$$TOE is a short form of $$$TROWONERROR macro.

Inside macro StatusMethod is any method you call which will return %Status value. This value will be placed into sc variable.

In case of sc contains error execution will be routed to try catch block. You can wrap any Status methods calls in your code if you need to catch the errors coming from them.

Hello,

Here's the code:

Hi all,

I've been looking for a way to extract the sorting  from the ^CacheTemp.zenData global that contain the tablePane snapshot data in order to use it on a report following the current UI sorting criteria.

I could see that if the column is sorted by one column, new entries with this structure are created:

^CacheTemp.zenData(<sessionId>,<snapShotId>,<tablePaneId>,"index",<columnId>,<value>,<dataId>)=""

Hi!

Does anyone have an example of subj?

I know there is google service for it. Anyone uses it in production? What is the feedback?

In case of positive feedback would you please post the code example?

TIA!

Hello.

For debugging purposes I  sometimes need to display stack information to the current device or save it (to a global for example).

There is this snippet offered in documentation:

ClassMethod StackToDisplay()
{
    For loop = 0:1:$Stack(-1) {
        Write !, "Context level:", loop, ?25, "Context type: ", $Stack(loop)
        Write !, ?5, "Current place: ", $Stack(loop, "PLACE")
        Write !, ?5, "Current source: ", $Stack(loop, "MCODE")
        Write !
    }
}

And to save stack to a global there's always an exception method:

I believe the I have followed the instructions to attach a document to the body of a post request but nothing is being sent out in the files{} port of the request.  I can either get the stream in "data", not visible at all, or visible but no form data. Any help would be appreciated, below is what I have:

There have been a few use cases recently within InterSystems where we've needed to connect to Caché-based web services from PHP. The first of these was actually the Developer Community itself, which uses web services as part of Single Sign-On with other InterSystems sites/applications. The following example demonstrates how to connect to a Caché-based web service (particularly, the web service in the SAMPLES namespace) from PHP, using password authentication.

RESTful API Call From Cache to Particle.io Electron

Tom Fitzgibbon | Multidata | 212-967-6700 x537 | tom@mul.com

Summary: Simple Blink Tutorial for Particle.io Electron Device from Cache

Electron device is a tiny ARM processor ($40-$60) that connects to Particle’s world wide leased 2G/3G network (about $3/mo) and runs off an included LiPo battery. Using Cache’s %Net.HttpRequest you can send/receive data, control hardware and read sensors.

Step by Step (about 1 hour)

1) Get the Electron from store.particle.io.

2) Set up the Electron from setup.particle.io.

Attached is an example of a web service client that can be used to do a lookup against the CMS NPPES database to validate and retrieve information about a given National Provider Identification (NPI).

C:\data\backup.bat :

C:\InterSystems\Ensemble\bin\cache -s"C:\InterSystems\Ensemble\Mgr" -U%%SYS ##Class(Backup.General).ExternalFreeze() <C:\data\login.scr 

echo %ERRORLEVEL%

rem note that we need to check errorlevel from highest to lowest here....

if errorlevel 5 goto OK

if errorlevel 3 goto FAIL

echo errorlevel returned wrong value

goto END

:OK

echo SYSTEM IS FROZEN

xcopy c:\InterSystems\Ensemble\mgr\ z:\backup\Ensemble /s /e /y /i

echo %ERRORLEVEL%

goto END

:FAIL

echo SYSTEM FREEZE FAILED

:END

rem Now unfreeze the system

The attached file contains an example of code generation using ObjectGenerators which builds a very simple homemade RuleEngine. 

Code generation is an excellent way of increasing performance moving run-time calculations to compile-time.

We could generate code creating routines or implemeting methods using ObjectGenerators. In this example we are using ObjectGenerators.

Update: Rule Engine is now on GitHub https://github.com/intersystems-ib/cache-iat-ruleengine

A very simple code generated method

For starters, let's begin with a very basic code generated method:

Here is my original query:

SELECT EventType, InitiatedAt, COUNT(*) as cnt
FROM HS_IHE_ATNA_Repository.Aggregation
WHERE EventType = 'LOGIN'
AND LocalDateTime > '2016-02-16 11:00:00'
GROUP BY EventType, InitiatedAt

This gives me data like this:

However, I need to get the data back as two columns with all but the last concatenated and delimited, more like this:

I tried this:

I'm writing some custom functions for use in a routing rule.  I have a few that are working, but right now I'm trying to use one that has no parameters.  Typically this would be a sub instead of a function, but I'm not familiar enough with Cache to know what I need to do here. 

Here is the code:

Given the following code:

I get <UNDEFINED>start+4^DeploymentTool *tstVar
 

I also tried setting the variable outside the start method but that doesn't work either.  I realize I could pass tstVar to the TestIt() routine but I'm trying to create a couple variables that will be reused repeatedly so that doesn't really work.

So calling this lookup manually from the console works as expected:

However, calling it from a method with some concatination to build the key is giving me problems: