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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or "Didn't you say you would cover Persistent Objects in Part 5, Chris?"

Yes, that was the plan. This is a pretty important topic, so it get's its own Article

Up until now, we've display widget JSON that has been created by a basic loop. Clearly this isn't of much value. Now we have our stack connected together, and we can see that the data is flowing to the Welcome page, it's time to complete the stack and start feeding our service from "real" data.

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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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If a picture is worth a thousand words, what's a video worth? Certainly more than typing a post.

Please check out my "Coding talks" on InterSystems Developers YouTube:

1. Analysing InterSystems IRIS System Performance with Yape. Part 1: Installing Yape

https://www.youtube.com/embed/3KClL5zT6MY
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Running Yape in a container.

2. Yape Container SQLite iostat InterSystems

https://www.youtube.com/embed/cuMLSO9NQCM
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Extracting and plotting pButtons data including timeframes and iostat.

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Article
· Jan 18, 2019 2m read
Free IRIS Community Edition in AWS

Good News!! You can use now the Free InterSystems IRIS Community Edition in the AWS Cloud

Hello,

It's very common that people new in InterSystems IRIS want to start to work in a personal project in a full free environment. If you are one of this, Good News!! You can use now the Free InterSystems IRIS Community Edition in the AWS Cloud.

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Last time we deployed a simple IRIS application to the Google Cloud. Now we’re going to deploy the same project to Amazon Web Services using its Elastic Kubernetes Service (EKS).

We assume you’ve already forked the IRIS project to your own private repository. It’s called <username>/my-objectscript-rest-docker-template in this article. <root_repo_dir> is its root directory.

Before getting started, install the AWS command-line interface and, for Kubernetes cluster creation, eksctl, a simple CLI utility. For AWS you can try to use aws2, but you’ll need to set aws2 usage in kube config file as described here.

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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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Article
· Dec 12, 2016 3m read
Generate and Validate Captcha Code

Suppose you have developed your own web app with InterSystems technologies stack and now want to perform a captcha validation on the client side in order to determine whether or not the user is human and make it safer. There are some modern frameworks to address the captcha issue, however most part of them needs internet access to generate codes and sometimes are complex to implement. Take this as basic example considering that image recognition has gotten too good. That's why you nowadays you tend to see more pattern recognition captchas than mere reading ones. (I.e.

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Article
· May 11, 2020 5m read
Work with SAML in IRIS

When a company is quite large and many different applications used by employees. But while those applications are mostly completely different, how to make it possible to not force users to enter credentials as many times as many applications they would like to use. The best way is to use SSO, so, it will be possible to have a portal, where users could launch any application used in a company. There are many different ways how to give access to your application by using the SSO mechanism, and some of them are:

  • OAuth2
  • Kerberos
  • SAML

InterSystems already supports OAuth2 and can be quite easily deal with Kerberos. But I would like to discuss about using SAML (Security Assertion Markup Language).

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Article
· Jul 4, 2016 8m read
Introduction to the iKnow REST APIs

After a five-part series on sample iKnow applications (parts 1, 2, 3, 4, 5), let's turn to a new feature coming up in 2017.1: the iKnow REST APIs, allowing you to develop rich web and mobile applications. Where iKnow's core COS APIs already had 1:1 projections in SQL and SOAP, we're now making them available through a RESTful service as well, in which we're trying to offer more functionality and richer results with fewer buttons and less method calls. This article will take you through the API in detail, explaining the basic principles we used when defining them and exploring the most important ones to get started.

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Index to Articles

Published 2018-05-11 Last edit -

Hi All

I this article I detail some strategic issues that a new development UI will need to address - these are the ones that I can think of now - others may come to light during this journey.

See the webinar by Eduard Lebedyuk here from the last Global Summit describing modern web development and Caché

And, as always, if I have missed something please comment....

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Article
· Nov 1, 2016 9m read
Reflection in Caché

The topic of reflection hasn't been raised in Caché forums or blogs too often. Perhaps, it happened because the notion of reflection is not explicitly defined in Caché. However, it exists in Caché and can be a very useful development tool.

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Sometimes, we need to copy part of the properties of an object into a different one.
The simplest thing would be to do the following:

Set obj1.FirstName = obj2.FirstName

Set obj1.SecondName = obj2.SecondName

What happens if the object contains a large number of properties? or we just want to extract an important group of data, and complement the information in another object?

Having the following classes:

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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
· Dec 7, 2016 3m read
Enable CORS for CSP/ ZEN Applications

As web application gets more complex, more technologies are involved into the application development. Once it gets deployed in large scale the configuration gets more complex too. For sure one of the most difficult part of the story is the security. In a complex solution when independent servers are feeding single web pages with contents, it is indeed challenging to keep the integrity of such system. HTML5 introduced a (weak) security constraint, the Cross Origin Resource Sharing (CORS). This article tells how to enable CORS for CSP/ ZEN applications.

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At least three different ways to process errors (status codes, exceptions, SQLCODE etc is given in ObjectScript. Most systems have status, but for a range of reasons exceptions are more convenient to manage. You spend some time translating between the various techniques dealing with legacy code. For reference, I use several of these excerpts. It is hoped that they will also support others.

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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.

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Last time we launched an IRIS application in the Google Cloud using its GKE service.

And, although creating a cluster manually (or through gcloud) is easy, the modern Infrastructure-as-Code (IaC) approach advises that the description of the Kubernetes cluster should be stored in the repository as code as well. How to write this code is determined by the tool that’s used for IaC.

In the case of Google Cloud, there are several options, among them Deployment Manager and Terraform. Opinions are divided as to which is better: if you want to learn more, read this Reddit thread Opinions on Terraform vs. Deployment Manager? and the Medium article Comparing GCP Deployment Manager and Terraform.

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Here is an ObjectScript snippet which lets to create database, namespace and a web application for InterSystems IRIS:

    set currentNS = $namespace

    zn "%SYS"

    write "Create DB ...",!
    set dbName="testDB"
    set dbProperties("Directory") = "/InterSystems/IRIS/mgr/testDB"
    set status=##Class(Config.Databases).Create(dbName,.dbProperties)
    write:'status $system.Status.DisplayError(status)
    write "DB """_dbName_""" was created!",!!


    write "Create namespace ...",!
    set nsName="testNS"
    //DB for globals
    set nsProperties("Globals") = dbName
    //DB for routines
    set nsProperties("Routines") = dbName
    set status=##Class(Config.Namespaces).Create(nsName,.nsProperties)
    write:'status $system.Status.DisplayError(status)
    write "Namespace """_nsName_""" was created!",!!


    write "Create web application ...",!
    set webName = "/csp/testApplication"
    set webProperties("NameSpace") = nsName
    set webProperties("Enabled") = $$$YES
    set webProperties("IsNameSpaceDefault") = $$$YES
    set webProperties("CSPZENEnabled") = $$$YES
    set webProperties("DeepSeeEnabled") = $$$YES
    set webProperties("AutheEnabled") = $$$AutheCache
    set status = ##class(Security.Applications).Create(webName, .webProperties)
    write:'status $system.Status.DisplayError(status)
    write "Web application """webName""" was created!",!

    zn currentNS

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Hi Developers!

Recently we launched InterSystems Package Manager - ZPM. And one of the intentions of the ZPM is to let you package your solution and submit into the ZPM registry to make its deployment as simple as "install your-package" command.

To do that you need to introduce module.xml file into your repository which describes what is your InterSystems IRIS package consists of.

This article describes different parts of module.xml and will help you to craft your own.

I will start from samples-objectscript package, which installs into IRIS the Sample ObjectScript application and could be installed with:

zpm: USER>install samples-objectscript

It is probably the simplest package ever and here is the module.xml which describes the package:

<?xml version="1.0" encoding="UTF-8"?>
<Export generator="Cache" version="25">
  <Document name="samples-objectscript.ZPM">
    <Module>
      <Name>samples-objectscript</Name>
      <Version>1.0.0</Version>
      <Packaging>module</Packaging>
      <SourcesRoot>src</SourcesRoot>
      <Resource Name="ObjectScript.PKG"/>
    </Module>
  </Document>
</Export>

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Introduction

In the first article, a simple tutorial helped you to set up your FHIRaaS deployment.

Now, let's move forward and introduce a JS library to access the FHIR resource.

In the end, two examples of usage of this library will be presented, exploring the Appointment FHIR resource type.

SMART on FHIR JavaScript Library

FHIR is a REST API, so you can use any HTTP client in order to use it. But, it’s always a good idea to have help.

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Article
· Feb 25, 2019 4m read
Using Grafana directly from IRIS

There have been some very helpful articles in the community that show how to use Grafana with IRIS (or Cache/Ensemble) by using an intermediate database.

But I wanted to get at IRIS structures directly. In particular, i wanted to access the Cache History monitor data that is accessible by SQL as described here

https://community.intersystems.com/post/apm-using-cach%C3%A9-history-mon...

and didn't want anything between me and the data.

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