APEX + MLE

An APEX app which demonstrates the power of server-side JavaScript via MLE & GraalVM

App

Download app.sql, and import it into an APEX 20.2 instance, on an Always Free 21c DB.

Examples

Name	Description	Libraries Used
Form Validation	Use form validations such as isEmail or isCreditCard	validator
QR Code Generation	Generate a QR Code as a blob or base64 encode string	qrcode
Markdown to HTML	Convert Markdown to HTML serverside. Integration with dompurify would also be wise	marked
HTML Sanitization	Clean HTML of XSS vunrabilities and other issues	text-encoding, mle-jsdom, dompurify
Image Manipulation	Experimental example for cropping, flipping, and watermarking images	jimp
Sentiment Analysis	Output a "sentiment score" based on a block of text	sentiment.js

Libraries

To be able to run the examples, navigate to the Modules page and create extermal modules for the following libraries. On save, the actual code will be downloaded automatically.

Library name	URL
dompurify	https://cdnjs.cloudflare.com/ajax/libs/dompurify/2.2.7/purify.min.js
jimp	https://cdn.jsdelivr.net/npm/jimp@0.16.1/browser/lib/jimp.js
marked	https://cdnjs.cloudflare.com/ajax/libs/marked/1.2.9/marked.min.js
mle-jsdom	https://raw.githubusercontent.com/stefandobre/mle-jsdom/main/jsdom.js
qrcode	https://cdnjs.cloudflare.com/ajax/libs/qrcode-generator/1.4.4/qrcode.min.js
text-encoding	https://cdn.jsdelivr.net/npm/text-encoding@0.6.4/lib/encoding.min.js
validator	https://cdnjs.cloudflare.com/ajax/libs/validator/13.5.2/validator.min.js
mle-sentiment	https://raw.githubusercontent.com/stefandobre/mle-sentiment/main/dist/mle-sentiment.js

Loading modules

You will notice an application process called Setup MLE that runs After Page Submission. This process exposes 2 global helper functions: requireModule and loadScript. Based on a module name, these functions will fetch the CLOB code out of the MLE_MODULE table and execute it. We can then use these functions in After Submit computations, validations, processes etc.

• requireModule is meant to be used with CommonJS (Node JS-like) modules. Example var qrcode = requireModule('qrcode');
• loadScript simply loads the script as is (IIFE or Browser-like). Example loadScript('text-encoding');

Some libraries are bundled in such a way that either way of loading will work. Some libraries on the other hand might need extra wrapping.

Further notes

Some libraries can be used without a hitch (see validator). Some libraries need extra attention (see dompurify).

If a library is meant to be used in node-js, you might have to "browserify" it. If a library is meant to be used in the browser, it might just work (validator), you might have to fake things like setTimeout or window (jimp), or you might have to fake a browser environment altogether (dompurify)

I am confident however that this process will get better with time, as MLE progresses, and more developers come up with better ways to bundle and ship libraries.