ISO8583 Tutorial - Interactive Learning Platform

A complete Ktor web application designed to teach ISO8583 financial messaging through interactive tutorials and a live message simulator.

Overview

This application provides:

• Comprehensive Tutorials: Learn about MTI, Bitmaps, and Data Fields
• Interactive Simulator: Build and send real ISO8583 messages
• Mock Payment Host: See how transactions are approved/declined
• Visual Breakdown: Understand hex encoding and bitmap structures

Technical Stack

• Framework: Ktor 3.4.0
• Language: Kotlin 2.3.0
• ISO8583 Library: JPOS 3.0.1
• Templating: Ktor HTML DSL
• Build Tool: Gradle with Kotlin DSL

Project Structure

src/main/kotlin/com/divora/
├── Application.kt              # Main application entry point
├── Routing.kt                  # Route configuration
├── iso8583/
│   ├── BitmapHelper.kt        # Bitmap generation and parsing
│   ├── ISO8583Message.kt      # Message building and parsing
│   └── MockHostService.kt     # Payment processor simulation
├── routes/
│   ├── TutorialRoutes.kt      # Tutorial page routes
│   └── SimulatorRoutes.kt     # Simulator and processing routes
└── views/
    ├── CommonLayout.kt        # Shared HTML layout and CSS
    ├── TutorialPages.kt       # Tutorial content pages
    └── SimulatorPages.kt      # Interactive simulator pages

Features

Tutorial Pages

1. Introduction: Overview of ISO8583 standard
2. MTI (Message Type Indicator): 4-digit message classification
3. Bitmap: Visual hex-to-binary conversion examples
4. Data Fields: Common field descriptions and formats

Interactive Simulator

• Build 0200 (Authorization Request) messages
• Input fields: Processing Code, Amount, STAN, Terminal ID, Merchant ID
• Real-time hex message generation
• Visual field breakdown

Mock Host Logic

• Processes authorization requests
• Approval Rule: Amounts ending in "00" (e.g., $10.00) → Approved (Code 39='00')
• Decline Rule: All other amounts → Declined (Code 39='05')
• Returns 0210 (Authorization Response) with echoed fields

Building & Running

To build or run the project, use one of the following tasks:

Task	Description
./gradlew test	Run the tests
./gradlew build	Build everything
./gradlew buildFatJar	Build an executable JAR of the server with all dependencies included
./gradlew buildImage	Build the docker image to use with the fat JAR
./gradlew publishImageToLocalRegistry	Publish the docker image locally
./gradlew run	Run the server
./gradlew runDocker	Run using the local docker image

If the server starts successfully, you'll see the following output:

2024-12-04 14:32:45.584 [main] INFO  Application - Application started in 0.303 seconds.
2024-12-04 14:32:45.682 [main] INFO  Application - Responding at http://0.0.0.0:8080