# SADI Python 3.12 Compatibility Update

## Overview
This update makes the SADI Python project fully compatible with Python 3.12 by removing deprecated Python 2 constructs and updating dependencies.

## Changes Made

### 1. Removed `buffer()` Function Calls
**Issue**: The `buffer()` function was removed in Python 3.
**Files affected**: `frir/frir.py`
**Changes**: 
- Replaced `base64.urlsafe_b64encode(buffer(packl(value)))` with `base64.urlsafe_b64encode(packl(value))`
- Replaced `urlsafe_b64encode(buffer(m.digest()))` with `urlsafe_b64encode(m.digest())`
- **Rationale**: In Python 3, `packl()` and `m.digest()` already return bytes objects, so `buffer()` is unnecessary.

### 2. Removed Future Library Dependencies
**Issue**: The `future` library was used for Python 2/3 compatibility but is no longer needed.
**Files affected**: `frir/frir.py`, `sadi/sadi.py`, `sadi/serializers.py`, `sadi/mimeparse.py`, `tests.py`
**Changes**:
- Removed `from future import standard_library` and `standard_library.install_aliases()`
- Removed `from builtins import str, object, hex, map` (these are built-in in Python 3)
- Removed `from past.builtins import basestring`

### 3. Replaced `basestring` with `str`
**Issue**: `basestring` doesn't exist in Python 3.
**Files affected**: `sadi/sadi.py`
**Changes**: 
- Replaced `isinstance(identifier, basestring)` with `isinstance(identifier, str)`
- **Rationale**: In Python 3, `str` is the string type (equivalent to Python 2's `unicode`).

### 4. Updated setup.py
**Changes**:
- Added `python_requires='>=3.8'`
- Added explicit Python version classifiers including Python 3.12
- Removed `future` from `install_requires`
- Added comprehensive metadata for PyPI

### 5. Added .gitignore
**Added**: `.gitignore` file to exclude build artifacts (`.eggs/`, `__pycache__/`, etc.)

## Testing
Created comprehensive test suite that verifies:
- ✅ All `buffer()` calls have been removed
- ✅ All future library imports have been removed or commented
- ✅ No `basestring` references remain
- ✅ All Python files have valid Python 3.12 syntax
- ✅ Core encoding functions work correctly
- ✅ setup.py properly specifies Python 3.12 support

## Results
- **All tests pass** ✅
- **Package compiles without errors** in Python 3.12 ✅
- **Core functionality works** as expected ✅
- **Dependencies reduced** (no longer requires `future` library) ✅

## Compatibility
- **Supports**: Python 3.8, 3.9, 3.10, 3.11, 3.12
- **Dropped**: Python 2.x support (was already deprecated)

## Installation
```bash
cd python/sadi.python
pip install -e .
```

The package now works seamlessly with Python 3.12 while maintaining backward compatibility with Python 3.8+.