#REST API

Hello again and welcome to the next tutorial on this series: Part 4 - Sharing data across router methods. Here we are going to learn how to share a object containing data that is available for read across every router methods.

You're required to complete at least the Part 1 before entering this one. Still, this is supposed to be a really short tutorial, since there isn't much to be said about data sharing.

Hello again! Welcome to the Part 2 - Handling payloads!

If you're new to this series, I'd recommend you to check out the Part 1 - Core concepts. You'll need a basic understanding about how Frontier works before continuing with the Part 2.

The Widgets Direct sample application highlights many aspects of how to use InterSystems technologies to build a modern web application. Features include:

Preface

Before we begin, I'd like to mention that I am by no means an Ensemble expert, so take this with a grain of salt and please feel free to offer any suggestions for improvement. That being said, I have enjoyed working with Ensemble and wanted to share the approach I took to poll an external REST API for patient data in the hopes that it might help others with a similar goal.

Hello.

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

REQUIREMENTS:

• Caché 2016.2 or higher.
• Frontier.

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.

In our last lesson, we added some formatting and validation to our Edit Widget form. So, now we are ready to add the ability to add new Widgets to our application. However, the great Widget Wars have come to an abrupt end, as Widget Direct has purchased its biggest competitor, WorldWideWidgets. In order to maintain some continuity, we need to display their catalog on our new application.

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:

In our last lesson, we implemented a linkage to our WidgetAccessory class, and debugged some errors we encountered along the way. We now have our data being returned by REST, but what if we want to update or add new data to our application?

or "Things are going to break"

We left our application over the weekend, secure in the knowledge that it was returning data from our primary persistent class, User.Widget. However, Widgets Direct are the premier supplier of both Widgets AND Widget Accessories, so we should really start working on adding these Accessories to our application.

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.

At the end of our last lesson, we ended with our page displaying a nice (but garish) Angular Material Toolbar, and our Widget data displaying in a list of Material cards. Our page feels a bit static, and we already know that the large number of Widgets that we will be dealing with will not be especially usable on a static list. What can we do to help?

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.

I've mentioned the QEWD project in this group before: it's a Node.js-based platform for web, Native and REST applications which tightly integrates with Cache. It uses a somewhat different philosophy to the use of Node.js than the norm, and I've now published an article that explains this approach and the unique benefits that arise as a result.

It turns out that, integrated via QEWD, Cache is an ideal bed-fellow for Node.js. QEWD makes the integration of Cache and Node.js exceptionally fast, simple and intuitive to use, but also extremely powerful.

Read the article here:

In this article I'll cover testing and debugging Caché web applications (mainly REST) with external tools. Second part covers Caché tools.

You wrote server-side code and want to test it from a client or already have a web application and it doesn't work. Here comes debugging. In this article I'll go from the easiest to use tools (browser) to the most comprehensive (packet analyzer), but first let's talk a little about most common errors and how they can be resolved.