Hi All,

I have created a REST class in which have the Parameter HandleCorsRequest = 1;

I can able to access the API using Postman, but not with my web application. It throws the below error.

Access to XMLHttpRequest at 'http://localhost:52773/IrisVSCode/app/test' from origin 'null' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

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Developing a Full-Stack JavaScript web app with Caché requires you to bring together the right building blocks. Previously, I outlined the basic steps to install and connect Node.js to Caché and make it's powerful multi-model database capabilites available for use with Node.js. You can use Caché as a NoSQL-, document- (with unique key-level access!), SQL- and object-database with Node.js. When developing JavaScript applications, you'll see how powerful this combination is and makes Caché a perfect fit for Node.js.

In the first part of this article series I will show how to get started with the React framework, one of the most popular frameworks currently taking over front-end development. In the next parts you'll learn how to connect a basic web app to a Caché back-end.

You'll see, it's very easy to get started with this technology - you can even compare the amount of basic knowledge you need to COS because you only need to know a few basic concepts to start!

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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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Article
Lily Taub · Mar 19, 2019 9m read
A Tutorial On WebSockets

Intro

Most server-client communication on the web is based on a request and response structure. The client sends a request to the server and the server responds to this request. The WebSocket protocol provides a two-way channel of communication between a server and client, allowing servers to send messages to clients without first receiving a request. For more information on the WebSocket protocol and its implementation in InterSystems IRIS, see the links below.

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I cannot connect to Cache from node.js  

I have installed in Windows 10 the following: CACHE 2016, node.js v 4.4.7 and  express .

-  where can I get cache.node? The link in the Intersystmes documentation  http://globalsdb.org/downloads/  doesn't work. I found cache0100.node and cache0120.node  in my Cache instance's  \bin directory. But I am not sure if I can use them or not.

 - how to install cache.node ? Where do I place it exactly? 

Can anyone recommend any tutorial or code example with installation instructions?

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Announcement
Nikita Savchenko · Jan 19, 2017
Caché WebTerminal v4 Release

Greetings, InterSystems community!

I am pleased to announce that the web terminal project, Caché WebTerminal version 4 gets its release! After long period of enhancing this web application from 2013, it came to the version 4, which features major stability and security improvements, intelligent autocomplete and syntax highlighting, convenient SQL mode and a lot of other useful features.

The goal of this article is to spread the knowledge about this project over the InterSystems community.

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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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Full-Stack JavaScript development allows you to create state-of-the-art applications with Caché. With any (web) app you build nowadays, one has to make a lot of architectural decisions and you want to make the right ones. With the Node.js connector available for Caché, you can create a very powerful server side application server, allowing you to use the latest JavaScript technology and frameworks client- and server-side.

With all these new technologies, the most important is to integrate them in the most efficient way and to create a very productive development experience. This article willl get you started step-by-step with Node.js technology.

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or "So you just got yelled at by your boss, for sending him an unformatted Hello World webpage"

Our previous lesson ended with us serving a Message value obtained from a Caché REST service to the client, using Angular as a runtime.  While there is a lot of moving parts involved in this process, the page is not especially exciting at the moment.  Before we can start adding new features, we should take a step back and review our tools.

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Hi-

I am trying to create a simple example of allowing binary (tiff) files to be selected and uploaded asynchronously to an IRIS for Health back-end.   I have managed to write the HTML and Javascript which works great with regular text / ascii files, but fails with binary files.

When I upload a binary file (tiff) image I get garbage like this on the database server 

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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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One of the most important features during application development is the ability to debug your code easily. Because of the asynchrnous nature, a standard Node.js application server works single-threaded by default. When you are developing applications using an IDE like Visual Studio Code, you can very easily debug your Node.js process:

First, download the free Visual Studio Code IDE (@code) and install it on your development machine.

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Hi,

I have been trying to implement SPA using routing between two components in a CSP page. 

If i use the line which i commented the page views and gets data from the vue instance (when not using the <route-view> and other 2 vue route functions below).

since i need to implement routing i am using as below, now the property "selectedYear" is not getting data from vue instane and i am getting the below error as well.

I dont know whether i am going down the right path.

please see my code below and help me

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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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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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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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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. 

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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?

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Has anyone called any outside Javascript code from inside their class files? I asked a long time ago if there was a way to manipulate an image within Cache Object Script, and since Cache doesn't have any image libraries its not really possible. However I have found Javascript to resize an image and wonder how hard it would be to mesh the two together.

Can anyone share any examples?

Thanks

Scott

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or "Bonus Breakage"

In our last lesson, we added a relationship between 2 persistent classes.  We are clearly going to need to start creating REST Services to expose CRUD operations for each of these classes, but before we do that, we should really finish defining our linkages.  We added code to our Widget toJSON to spool off related Accessory data, so we should really do the reciprocal and allow Accessories to return all Widgets that are compatible.

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