Fiscguy

A Python library for integrating with ZIMRA (Zimbabwe Revenue Authority) fiscal devices. Provides a simple, Pythonic API for managing fiscal operations including device registration, receipt generation, and fiscal day management.

Features

• Secure Device Integration - Certificate-based authentication with ZIMRA FDMS
• Receipt Management - Create and submit receipts with multiple tax types
• Fiscal Day Operations - Open and close fiscal days with automatic counter management
• Device Status - Query device status and configuration
• Configuration Management - Fetch and manage device configuration
• Tax Support - Supports standard, zero-rated, exempt, and withholding taxes
• Fully Tested - Comprehensive unit tests with 90%+ code coverage

Installation

pip install fiscguy

Or from source:

git clone https://github.com/cassymyo-spec/zimra.git
cd zimra
pip install -e .

Quick Start

Important: Register a Device First

Before using Fiscguy, you must register and initialize a fiscal device:

python manage.py init_device

This interactive command will guide you through:

• Device information entry
• Certificate generation
• Device registration with ZIMRA
• Configuration and tax synchronization

Important: Environment Switching

When running python manage.py init_device:

If switching FROM TEST TO PRODUCTION:

• Safe to proceed - All test data will be automatically deleted
• The command will warn you and require confirmation (YES)
• All the following test data will be permanently deleted:
  • Fiscal Days
  • Fiscal Counters
  • Receipts & Receipt Lines
  • Device Configuration
  • Certificates
  • Device record itself
  • Taxes

If switching FROM PRODUCTION TO TEST:

• NOT ADVISABLE - This will delete your production records
• Only do this if you're absolutely sure you want to lose all production data
• The command will warn you and require confirmation (YES)

How to switch safely:

1. Run python manage.py init_device
2. Answer the environment question (yes=production, no=test)
3. If different from current environment, you'll see a warning
4. Review the warning carefully
5. Type YES to confirm deletion and switch

Using Fiscguy with Django REST Framework

Fiscguy is built as a Django REST Framework-first library. After device registration, integrate it into your Django project:

Important: First Sale Automatically Opens Fiscal Day

When you submit your first receipt without an open fiscal day, Fiscguy will automatically open a new fiscal day. This means:

• You don't need to manually call open_day() before submitting the first receipt
• The fiscal day will be opened silently and a 5-second delay is applied for ZIMRA processing
• Subsequent receipts will use the already-open fiscal day
• You only need to call close_day() when you're done with sales for the day

Example Flow:

1. Submit first receipt → Fiscal day automatically opens
2. Submit more receipts → Use the same open fiscal day
3. Call close_day() → Close the fiscal day when done

1. Add to Django Settings

# settings.py
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    
    'rest_framework',
    'fiscguy',  # Add fiscguy here
]

2. Make Migrations

Create migration files for fiscguy models:

python manage.py makemigrations fiscguy

3. Migrate the Database

Apply migrations to your database:

python manage.py migrate fiscguy

4. Include fiscguy URLs in Your Project

Add fiscguy URL endpoints to your Django project:

# urls.py
from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('api/', include('fiscguy.urls')),  # Add this line
]

5. Access API Endpoints

Fiscguy provides the following REST API endpoints:

• POST /api/open_day/ - Open a new fiscal day
• POST /api/close_day/ - Close the current fiscal day
• POST /api/receipts/ - Create and submit a receipt
• GET /api/status/ - Get device and fiscal status
• GET /api/configuration/ - Get device configuration
• GET /api/taxes/ - Get available tax types
• GET /api/receipts/ - List all receipts
• GET /api/receipts/{id}/ - Get receipt details

Example API Requests

Open a Fiscal Day:

curl -X POST http://localhost:8000/api/open_day/ \
  -H "Content-Type: application/json"

Submit a Receipt:

curl -X POST http://localhost:8000/api/receipts/ \
  -H "Content-Type: application/json" \
  -d '{
    "receipt_type": "fiscalinvoice",
    "currency": "USD",
    "total_amount": "100.00",
    "payment_terms": "cash",
    "lines": [
      {
        "product": "Test Item",
        "quantity": 1,
        "unit_price": "100.00",
        "tax_name": "standard rated 15.5%"
      }
    ]
  }'

Get Device Status:

curl -X GET http://localhost:8000/api/status/ \
  -H "Content-Type: application/json"

Models

Fiscguy provides Django ORM models for:

• Device - Fiscal device information
• FiscalDay - Fiscal day records
• FiscalCounter - Receipt counters for fiscal days
• Receipt - Receipt records
• ReceiptLine - Individual receipt line items
• Taxes - Tax type definitions
• Configuration - Device configuration
• Certs - Device certificates and keys
• Buyer - Buyer/customer information

Error Handling

from fiscguy import submit_receipt
from rest_framework.exceptions import ValidationError

try:
    result = submit_receipt(receipt_data)
except ValidationError as e:
    print(f"Validation error: {e.detail}")
except RuntimeError as e:
    print(f"Runtime error: {e}")

Testing

# All tests
pytest

# With coverage
pytest --cov=fiscguy

# Specific test
pytest fiscguy/tests/test_api.py::SubmitReceiptTest::test_submit_receipt_success

Development

# Clone and setup
git clone https://github.com/cassymyo-spec/zimra.git
cd zimra
python -m venv venv
source venv/bin/activate
pip install -e ".[dev]"

# Run tests
pytest

# Code formatting
black fiscguy
isort fiscguy

# Linting
flake8 fiscguy
pylint fiscguy

# Type checking
mypy fiscguy

Architecture

Public API (api.py)
- open_day, close_day, submit_receipt, etc.
         |
Services Layer
- ReceiptService
- ClosingDayService
         |
Handler Layer
- ZIMRAReceiptHandler
         |
Client Layer
- ZIMRAClient (FDMS API)
- ZIMRACrypto (Signing)

Key Components

• fiscguy/api.py - Public library interface (6 functions)
• fiscguy/services/ - Business logic (ReceiptService, ClosingDayService)
• fiscguy/zimra_base.py - ZIMRA FDMS HTTP client
• fiscguy/zimra_receipt_handler.py - Receipt formatting and signing
• fiscguy/zimra_crypto.py - Cryptographic operations
• fiscguy/models.py - Django ORM models
• fiscguy/serializers.py - DRF serializers
• fiscguy/tests/ - Unit tests (22+ tests)

Contributing

1. Fork the repository
2. Create a feature branch
3. Add/adjust tests
4. Submit a PR

See CONTRIBUTING.md for detailed guidelines.

License

MIT License

Support

• Email: cassymyo@gmail.com
• Issues: https://github.com/cassymyo-spec/zimra/issues
• Documentation: See README.md, INSTALL.md