QR codes on-demand with MicroProfile

Introduction

This project will generate a QR code as an image and a PDF on demand.

What it does?

The project will generate a QR code based on the string passed in the URL (in this case "MyString"):

http://localhost:8181/qrcreator/qr/MyString/

Or a PDF file with the provided string in clear text and the QR code:

http://localhost:8181/qrcreator/qr/MyString/pdf

The QR code will contain a JSON object with the following structure:

{ 
    "Name", "MyString",
    "Key", "HashedStringWithSalt"
}

Where,

• Name is the string provided as the URL
• Key is the hashed Name with salt.

The contents of the QR code can be modified in QRCodeSupplier class, while the hashing algorithm is specified in SecretKeyProvider class.

Running the project

The generation of the executable jar file can be performed by issuing the following command:

mvn clean package

This will create an executable jar file qrcreator.jar within the target maven folder. This can be started by executing the following command:

java -jar target/qrcreator.jar

To launch the test page, open your browser at the following URL:

http://localhost:8181/qrcreator/index.html

MicroProfile Specification Examples

By default, there is always the creation of a JAX-RS application class to define the path on which the JAX-RS endpoints are available.

The application's endpoint is defined in class QRController.

More information on MicroProfile can be found here.

Config

Configuration of your application parameters (specification).

The example class SecretKeySupplier shows you how to configure and define default values for variables.

Health

The health status can be used to determine if the 'computing node' needs to be discarded/restarted or not (specification).

The class ServiceHealthCheck contains an example of a custom check which can be integrated to health status checks of the instance. The index page contains a link to the status data.

Metrics

The Metrics exports Telemetric data in a uniform way of system and custom resources (specification).

The class QRController contains an example how you can measure the execution time of a request. The index page also contains a link to the metric page (with all metric info).

Open API

Exposes the information about your endpoints in the format of the OpenAPI v3 specification (docs).

The index page contains a link to the OpenAPI information of the available endpoints for this project.

Author

Rustam Mehmandarov