Over the past year or so, my team (Application Services at InterSystems - tasked with building and maintaining many of our internal applications, and providing tools and best practices for other departmental applications) has embarked on a journey toward building Angular/REST-based user interfaces to existing applications originally built using CSP and/or Zen. This has presented an interesting challenge that may be familiar to many of you - building out new REST APIs to existing data models and business logic.

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In this article I would like to present the RESTForms project - generic REST API backend for modern web applications.

The idea behind the project is simple -after I wrote several REST APIs I realized that generally, REST API consists of two parts:

  • Work with persistent classes
  • Custom business logic

And, while you'll have to write your own custom business logic, RESTForms provides all things related to working with persistent classes right out of the box.
Use cases

  • You already have a data model in Caché and you want to expose some (or all) of the information in a form of REST API
  • You are developing a new Caché application and you want to provide a REST API
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So, one day you're working away at WidgetsDirect, the leading supplier of widget and widget accessories, when your boss asks you to develop the new customer facing portal to allow the client base to access the next generation of Widgets..... and he wants you to use Angular 1.x to read into the department's Caché server.   

There's only one problem:  You've never used Angular, and don't know how to make it talk to Caché.

This guide is going to walk through the process of setting up a full Angular stack which communicates with a Caché backend using JSON over REST.  

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While reviewing our documentation for our ^pButtons (in IRIS renamed as ^SystemPerformance) performance monitoring utility, a customer told me: "I understand all of this, but I wish it could be simpler… easier to define profiles, manage them etc.".

After this session I thought it would be a nice exercise to try and provide some easier human interface for this.

The first step in this was to wrap a class-based API to the existing pButtons routine.

I was also able to add some more "features" like showing what profiles are currently running, their time remaining to run, previously running processes and more.

The next step was to add on top of this API, a REST API class.

With this artifact (a pButtons REST API) in hand, one can go ahead and build a modern UI on top of that.

For example -

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Something that shot up the popularity stakes last week was this article on a very interesting initiative: RealWorld:

https://medium.com/@ericsimons/introducing-realworld-6016654d36b5

I decided it would be a good idea to use this as a way of creating an exemplar implementation of a RESTful back-end using QEWD against their published API (https://github.com/gothinkster/realworld/tree/master/api)

The results are here:

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Hi Community,
 
OpenAPI-Client Gen has just released, this is an application to create an IRIS Interoperability Production client from Swagger 2.0 specification.
 
Instead of the existing tool ^%REST that creates a server-side REST application, OpenAPI-Client Gen creates a complete REST Interoperability Production client template.

 

Install by ZPM:

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So, one day you're working away at WidgetsDirect, the leading supplier of widget and widget accessories, when your boss asks you to develop the new customer facing portal to allow the client base to access the next generation of Widgets..... and he wants you to use Angular 1.x to read into the department's Caché server.   

There's only one problem:  You've never used Angular, and don't know how to make it talk to Caché.

This guide is going to walk through the process of setting up a full Angular stack which communicates with a Caché backend using JSON over REST.  

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Developing a Full-Stack JavaScript web app with Caché requires you to bring together the right building blocks. In the previous part, we created a basic front-end React application. In the second part of this article series I will show how to choose the right back-end technology for your application. You will see Caché allows you to use many different approaches to link your front-end to your Caché server, depending on your application's needs. In this part we will set up a back-end with Node.js/QEWD and CSP/REST. In the next part we will enhance our basic web app and connect it to Caché using these technologies.

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Article
Eduard Lebedyuk · 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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Hello.

The idea of this post is to introduce Frontier: An abstraction layer that allows Rapid REST development.

REQUIREMENTS:

Why?

Have you ever found yourself dealing with repetitive tasks like mounting objects, serializing them and eventually handling multiple errors for multiple cases? Frontier can boost your development by making you focus on what really matters: your application.
 

Frontier is made to stop you from WRITE'ing by instead forcing your methods to return values.
It's designed to make you code clean, and you'll see the why pretty soon.

This is the Part 1, where you'll learn he basics about how to work with Frontier. That means at the end of this part you should be capable of 

creating GET requests without difficulties. Since this also serves as a way to introduce the framework, I'll be calling this part: Core concepts.

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Article
Stefan Wittmann · Aug 14, 2019 9m read
Introducing InterSystems API Manager

As you might have heard, we just introduced the InterSystems API Manager (IAM); a new feature of the InterSystems IRIS Data Platform™, enabling you to monitor, control and govern traffic to and from web-based APIs within your IT infrastructure. In case you missed it, here is the link to the announcement.

In this article, I will show you how to set up IAM and highlight some of the many capabilities IAM allows you to leverage.

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In this article you will have access to the curated base of articles from the InterSystems Developer Community of the most relevant topics to learning InterSystems IRIS. Find top published articles ranked by Machine Learning, Embedded Python, JSON, API and REST Applications, Manage and Configure InterSystems Environments, Docker and Cloud, VSCode, SQL, Analytics/BI, Globals, Security, DevOps, Interoperability, Native API. Learn and Enjoy!

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Those of you who are following the FullStack competition here in the Developer Community will know that I submitted an entry named qewd-conduit.  I wanted to summarise why I think it's something worth you taking a bit of time to check out.

qewd-conduit uses the Node.js-based QEWD framework alongside IRIS to implement the back-end REST APIs for something known as the RealWorld Conduit application:

https://github.com/gothinkster/realworld

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Earlier this year, the AppS.REST package was released. AppS.REST is a framework for easily exposing existing persistent classes in IRIS as REST resources. AppS.REST-enabled classes support CRUD operations with little effort from the developer, bridging the gap between persistent data in IRIS and data consumers, such as an Angular front end application.

But IRIS classes are much more than just a definition for loading and saving individual records! This article aims to highlight a few ways to leverage the power of IRIS in your REST applications.  Using the Phone.Contact sample app, we'll look at out-of-the-box query support, use of class queries and finally ObjectScript methods.

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Article
Istvan Hahn · Sep 21, 2016 7m read
REST in Pieces

A beginners guide to develop Ensemble RESTful web services.

Background

Before you start reading this short introduction please go through the on-line documentation of Ensemble with special attention to chapter “Creating REST services and clients with Ensemble”.

The approach in the documentation is undisputable the fastest and easiest way to create RESTful services. As a beginner I went through the documentation and I had several questions. This short article is listing those questions plus my humble answers.

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Some time ago I got a WRC case transferred where a customer asks for the availability of a raw DEFLATE compression/decompression function built-in Caché.

When we talk about DEFLATE we need to talk about Zlib as well, since Zlib is the de-facto standard free compression/decompression library developed in the mid-90s.

Zlib works on particular DEFLATE compression/decompression algorithm and the idea of encapsulation within a wrapper (gzip, zlib, etc.).
https://en.wikipedia.org/wiki/Zlib

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In this article, I would like to talk about the spec-first approach to REST API development.

While traditional code-first REST API development goes like this:

  • Writing code
  • REST-enabling it
  • Documenting it (as a REST API)

Spec-first follows the same steps but reverse. We start with a spec, also doubling as documentation, generate a boilerplate REST app from that and finally write some business logic.

This is advantageous because:

  • You always have relevant and useful documentation for external or frontend developers who want to use your REST API
  • Specification created in OAS (Swagger) can be imported into a variety of tools allowing editing, client generation, API Management, Unit Testing and automation or simplification of many other tasks
  • Improved API architecture.  In code-first approach, API is developed method by method so a developer can easily lose track of the overall API  architecture, however with the spec-first developer is forced to interact with an API from the position if API consumer which usually helps with designing cleaner API architecture
  • Faster development - as all boilerplate code is automatically generated you won't have to write it, all that's left is developing business logic.
  • Faster feedback loops - consumers can get a view of the API immediately and they can easier offer suggestions simply by modifying the spec

Let's develop our API in a spec-first approach!

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Hi guys.

Recently, I get interest in FHIR in order to run for the IRIS for Health FHIR
contest
. As a beginner on this topic, I've heard somewhat about it, but I didn't know how complex and powerful was FHIR. As pointed out by @Henrique Dias here, you can model several aspects of the patient history and other related entities.

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