Article
· Oct 6, 2016 4m read
RESTful Exception Handling

A beginner’s guide to Exception Handling in RESTful web services. The article gives an example how the various error conditions during processing a service request can be handled.

We expect our client – server communication working in a flawless operational condition, running error free software. But we are prepared to handle exceptions. Are we? So far in the examples of the previous sessions were not. We did not care about exceptions. The result? In any error incident it took ages to figure out what the problem is and more importantly how to fix it.

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Hi Community,

Did you know about OWASP and Top Ten Web Application security risks to your Web API or Web Apps?

OWASP is a community foundation created to help us to improve the security of web apps/web APIs. OWASP do the web apps more secure through its community-led open source software projects, hundreds of chapters worldwide, tens of thousands of members, and by hosting local and global conferences.

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Hi Community!

I think everyone keeps the source code of the project in the repository nowadays: Github, GitLab, bitbucket, etc. Same for InterSystems IRIS projects check any on Open Exchange.

What do we do every time when start or continue working with a certain repository with InterSystems Data Platform?

We need a local InterSystems IRIS machine, have the environment for the project set up and the source code imported.

So every developer performs the following:

  1. Check out the code from repo
  2. Install/Run local IRIS installation
  3. Create a new namespace/database for a project
  4. Import the code into this new namespace
  5. Setup all the rest environment
  6. Start/continue coding the project

If you dockerize your repository this steps line could be shortened to this 3 steps:

  1. Check out the code from repo
  2. Run docker-compose build
  3. Start/continue coding the project

Profit - no any hands-on for 3-4-5 steps which could take minutes and bring head ache sometime.

You can dockerize (almost) any your InterSystems repo with a few following steps. Let’s go!

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Introduction

InterSystems has recently completed a performance and scalability benchmark of IRIS for Health 2020.1, focusing on HL7 version 2 interoperability. This article describes the observed throughput for various workloads, and also provides general configuration and sizing guidelines for systems where IRIS for Health is used as an interoperability engine for HL7v2 messaging.

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Overview

Encryption of sensitive data becomes more and more important for applications. For example patient names, SSN, address-data or credit card-numbers etc..

Cache supports different flavors of encryption. Block-level database encryption and data-element encryption. The block-level database encryption protects an entire database. The decryption/encryption is done when a block is written/read to or from the database and has very little impact on the performance.

With data-element encryption only certain data-fields are encrypted. Fields that contain sensitive data like patient data or credit-card numbers. Data-element encryption is also useful if a re-encryption is required periodically. With data-element encryption it is the responsibility of the application to encrypt/decrypt the data.

Both encryption methods leverage the managed key encryption infrastructure of Caché.

The following article describes a sample use-case where data-element encryption is used to encrypt person data.

But what if you have hundreds of thousands of records with an encrypted datafield and you have the need to search that field? Decryption of the field-values prior to the search is not an option. What about indices?

This article describes a possible solution and develops step-by-step a small example how you can use SQL and indices to search encrypted fields.

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Article
· Mar 31, 2023 3m read
Using JSON in IRIS

Saw the other day an article with the usage of the %ZEN package when working with JSON and decided to write an article describing a more modern approach. At some recent point, there was a big switch from using %ZEN.Auxiliary.* to dedicated JSON classes. This allowed to work with JSONs more organically.

Thus, at this point there are basically 3 main classes to work with JSON:

  • %Library.DynamicObject - provides a simple and efficient way to encapsulate and work with standard JSON documents. Also, there is a possibility instead of writing the usual code for creating an instance of a class like
set obj = ##class(%Library.DynamicObject).%New()

it is possible to use the following syntax

set obj = {}
  • %Library.DynamicArray - provides a simple yet efficient way to encapsulate and work with standard JSON arrays. With arrays you can use the same approach as with objects, meaning that yu can either create an instance of the class
set array = ##class(%DynamicArray).%New()

or you can do it by using brackets []

set array = []
  • %JSON.Adaptor is a means for mapping ObjectScript objects (registered, serial or persistent) to JSON text or dynamic entities.
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For Global Summit 2016, I set out to showcase a Reference Architecture I had been working on for a National Provider Directory solution with State Level Instances and a National Instance all running HealthShare Provider Directory and all running on AWS Infrastructure.

In short, I wanted to highlight:

  • The implementation of Amazon Web Services to provision the infrastructure, including the auto-creation of the state level instances through Cloud Formation.
  • The use of the HSPD Broadcast functionality to Notify Upstream Systems Changes in Master Provider Data.
  • The implementation of a transformation of the standard Broadcast Object to HL7 MFN for interoperability.
  • The principals of Master Data Management applied to the Provider Directory.

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Those of you who keep an eye on developments in the mainstream of IT will be aware that a major upheaval has been occurring over the last 5 or so years, in which JavaScript has exploded in popularity and importance. Largely as a result of its server-side incarnation - Node.js - it has broken free of just being the scripting language that you use in web browser, to becoming the world's most popular language and enterprise technology of choice.

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Article
· Dec 7, 2017 3m read
Asynchronous REST

In this article I'd like to discuss asynchronous REST and approaches to implementing it.

Why do we need asynchronous REST? Simply put - answering the request takes too much time. While most requests usually can be satisfied immediately, some can't. The reasons are varied:

  • You need to perform time-consuming calculations
  • Performing action actually takes time (for example container creation)
  • etc.

The solution to these problems is asynchronous REST. Asynchronous REST works by separating request and real response. Here's an example, let's consider the following simple async REST broker:

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Article
· Aug 2, 2022 8m read
Data models in InterSystems IRIS

Before we start talking about databases and different data models that exist, first we'd better talk about what a database is and how to use it.

A database is an organized collection of data stored and accessed electronically. It is used to store and retrieve structured, semi-structured, or raw data which is often related to a theme or activity.

At the heart of every database lies at least one model used to describe its data. And depending on the model it is based on, a database may have slightly different characteristics and store different types of data.

To write, retrieve, modify, sort, transform or print the information from the database, a software called Database Management System (DBMS) is used.

The size, capacity, and performance of databases and their respective DBMS have increased by several orders of magnitude. It has been made possible by technological advances in various areas, such as processors, computer memory, computer storage, and computer networks. In general, the development of database technology can be divided into four generations based on the data models or structure: navigational, relational, object and post-relational.

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Article
· May 16, 2016 11m read
Accelerate Ensemble

Introducing non-persistent messages. eXpert-to-eXpert

Background

InterSystems Ensemble as a tool does a lot for the Developer. One of the nice features is the Message trace utility. It shows a message flow diagram. The diagram shows the progress of the message processing real time. You can get many-many useful information from the production. In any case, someone needs to find a bug in a production implementation, without the Message trace utility it could turn into a real nightmare.

On the other hand, keeping message “traceability” is not for free. A heavy loaded production can very quickly run out of resources just because of the house keeping functions of Ensemble. House keeping functions such as maintaining message header, log entries, message queue generates a significant load on the Caché database used by Ensemble.

This article is about to show how to force Ensemble work more for the everyday life, instead of being prepared for “any-time-debugging”.

This is an eXpert-to-eXpert article. Therefore, I assume the deep understanding of Ensemble.

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We finished our last lesson with our Widgets Direct page iterating over a list of widgets, displaying an ID and a Name value. While we have been able to achieve this with only a small amount of coding, the page itself is not the most visually appealing place to be. The AngularJS framework is providing a powerful Model-View-Controller framework for our structure and logic, but it does not implement anything that will provide a nice UI experience.

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Article
· Apr 9, 2019 3m read
IRIS/Ensemble as an ETL

IRIS and Ensemble are designed to act as an ESB/EAI. This mean they are build to process lots of small messages.

But some times, in real life we have to use them as ETL. The down side is not that they can't do so, but it can take a long time to process millions of row at once.

To improve performance, I have created a new SQLOutboundAdaptor who only works with JDBC.

BatchSqlOutboundAdapter

Extend EnsLib.SQL.OutboundAdapter to add batch batch and fetch support on JDBC connection.

Open Exchange app
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Greetings! This article describes yet another simple way of creating installers for the solutions based on InterSystems Caché. The topic covers applications, which can be installed or completely removed from Caché with one action only. If you are still documenting installation instructions that have more than one step to do to install your application — it’s high time you automated this process.

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If I have defined a class query in one of my classes and I want to use that query from a method of another class, what are the pros and cons of using the %SQL.Statement interface versus the %Library.ResultSet interface?

I believe %SQL.Statement is the newer interface.

So if the old way is:

USER>s rs=##class(%Library.ResultSet).%New("%Library.File:FileSet")
 
USER>s sc=rs.Execute("c:\s\","*.txt")
 
USER>w sc
1
USER>while rs.%Next() {w !,rs.Data("Name")}

...

then the new way is:

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Article
· Jun 12, 2017 1m read
Setting the Windows service account

I recently helped a site investigate a problem that appeared after they upgraded their Windows instance of Caché from 2015.1 to 2017.1. A terminal session launched from the server's desktop cube was unable to run OS-level commands using the $ZF(-1) function. For instance, using the no-op command "REM" as follows:

write $zf(-1,"rem")

was returning -1, indicating that the Windows command could not be issued.

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Hi Community,

This article is a continuation of my article about Getting to know Python Flask Web Framework

In this article, we will cover the basics of topics listed below:

1. Routing in Flask Framework
2. Folder structure for a Flask app (Static and Template)
3. Getting and displaying data in the Flask application from IRIS.

So, let's begin.

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Article
· May 26, 2016 1m read
Windows, Caché and virus scanners

I have seen a customer problem recently where the use of a virus scanner running over Caché databases was causing intermittent application slow downs and bad user response times.

This is a surprisingly common problem, so this short post is just a reminder to exclude key Caché components from your virus scanning.

Generally virus scanning must exclude the CACHE.DAT database files and Caché binaries. If an anti-virus is scanning CACHE.DATs and InterSystems files then system performance will be significantly impacted.

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