ChequeFlow: Enterprise Cheque Generation and Audit Dashboard

ChequeFlow is a precision-engineered internal tool designed for the automated synchronization, enrichment, and generation of bank-standard cheques. The system bridges legacy IBM DB2 data with a modern web-based audit interface, ensuring high-fidelity PDF output and secure data management.

System Architecture

The application follows a modular three-tier architecture to ensure scalability and maintainability:

1. Data Integration Tier: Connects to IBM DB2 (AS/400) to retrieve raw transaction records from tstkdp.WCHKSP. It performs real-time relational enrichment using ameriben.bankfile to fetch employer and banking institution metadata.
2. Service & Persistence Tier: Utilizes a local SQLite database as a high-performance cache for enriched records. Business logic is encapsulated in a dedicated service layer:
   • SyncService: Manages DB2 connectivity, data transformation, and upsert logic.
   • SqliteService: Handles paginated data retrieval, complex filtering, and sensitive data masking (SSN).
   • ChequeService: Orchestrates on-demand PDF generation using the ReportLab engine.
3. Presentation Tier: A FastAPI-powered web dashboard provides an interactive interface for administrators to review, preview, and download individual cheques.

Core Technical Specifications

• PDF Rendering: Generates Letter-sized (8.5" x 11") documents including a high-detail Remittance Advice (top 2/3) and a standard bank cheque (bottom 1/3).
• Security Compliance: Implementation of multi-level SSN masking. Sensitive data is never fully exposed in the browser; full decryption/retrieval only occurs server-side during the on-demand PDF rendering process.
• MICR Precision: Utilizes the E13B font for bank-standard MICR line generation, with glyph-to-account mapping compliant with modern banking scanners.
• Dynamic Voiding: Includes customizable void logic and background watermarking to prevent unauthorized reproduction.
• Signature Processing: Advanced image processing for digital signatures, including background transparency subtraction and contrast optimization for high-quality printing.

Installation and Configuration

Prerequisites

• Python 3.9+
• IBM iSeries Access ODBC Driver
• pip install -r requirements.txt

Environment Configuration

Create a .env file in the project root with the following variables:

DB2_HOST=your_host_address
DB2_PORT=your_port
DB2_DATABASE=your_database_name
DB2_USER=your_username
DB2_PASSWORD=your_password

Operational Workflows

1. Database Initialization

Ensure the local cache schema is prepared:

python src/db_init.py

2. Data Synchronization

Retrieve and enrich data from the DB2 environment:

python src/sync_db2.py

3. Launching the Audit Dashboard

Start the FastAPI server:

python src/app.py

The dashboard will be available at http://localhost:8000.

Project Directory Structure

• src/: Primary application source code.
  • services/: Core business logic and database access objects.
  • templates/: Web dashboard frontend assets.
• assets/: Required fonts (E13B.ttf), signatures, and static resources.
• outputs/: Default directory for generated PDF documents.
• cheques.db: Local SQLite persistent cache.
• .env: Environment configuration (not committed).

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