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CRUNCHYROLL DOWNLOADER - CHALLENGE 3 SOLUTION
Chapter 2: Configuration Management
Challenge: Error Handling
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PROBLEM:
Add error handling for missing .env file and type conversion errors.

SOLUTION:
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File: config.py (with error handling)

import os
import re
import sys
from pathlib import Path
from dotenv import load_dotenv

class Config:
    """Configuration with comprehensive error handling."""

    def __init__(self):
        self.valid = False
        self.errors = []

        # Try to find and load .env file
        env_file = Path(__file__).parent / ".env"

        if not env_file.exists():
            self.errors.append(f".env file not found at {env_file}")
            print(f"⚠️  .env not found")
            print(f"    Copy .env.example to .env and edit it")
            return

        try:
            load_dotenv(env_file)
            print(f"✅ Loaded .env file")
        except Exception as e:
            self.errors.append(f"Failed to load .env: {e}")
            return

        # Load variables with error handling
        try:
            self.email = os.environ.get('CRUNCHYROLL_EMAIL')
            self.password = os.environ.get('CRUNCHYROLL_PASSWORD')
            self.api_base = os.environ.get('API_BASE_URL', 'https://api.crunchyroll.com')
            self.token_cache = os.environ.get('TOKEN_CACHE_FILE', 'token_cache.json')
            self.valid = True
        except ValueError as e:
            self.errors.append(f"Type conversion error: {e}")
        except Exception as e:
            self.errors.append(f"Unexpected error: {e}")

    def validate(self) -> bool:
        """Validate configuration."""

        # Check for loading errors
        if self.errors:
            for error in self.errors:
                print(f"❌ {error}")
            return False

        # Validate email
        if not self.email or not self.email.strip():
            print("❌ CRUNCHYROLL_EMAIL is empty")
            return False

        email_pattern = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'
        if not re.match(email_pattern, self.email):
            print(f"❌ Invalid email format: {self.email}")
            return False

        # Validate password
        if not self.password or not self.password.strip():
            print("❌ CRUNCHYROLL_PASSWORD is empty")
            return False

        if len(self.password) < 6:
            print("❌ Password too short (minimum 6 characters)")
            return False

        print("✅ Configuration is valid!")
        return True


# Test scenarios
if __name__ == "__main__":
    print("Testing configuration loading and validation...\n")

    config = Config()

    if not config.valid:
        print("❌ Failed to load configuration")
        sys.exit(1)

    if not config.validate():
        print("❌ Configuration validation failed")
        sys.exit(1)

    print("\n✅ Ready to use!")


ERROR SCENARIOS
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Scenario 1: Missing .env file
Output:
⚠️  .env not found
    Copy .env.example to .env and edit it
❌ .env file not found at /path/to/.env

Scenario 2: Invalid email
.env contains: CRUNCHYROLL_EMAIL=notanemail
Output:
✅ Loaded .env file
❌ Invalid email format: notanemail

Scenario 3: Missing password
.env contains: CRUNCHYROLL_PASSWORD=
Output:
✅ Loaded .env file
❌ CRUNCHYROLL_PASSWORD is empty

Scenario 4: Success
.env contains valid values
Output:
✅ Loaded .env file
✅ Configuration is valid!
✅ Ready to use!


PRODUCTION-READY ERROR HANDLING
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✅ File not found → helpful message
✅ Type conversion errors → caught and reported
✅ Validation errors → detailed feedback
✅ System exit with error code (1) on failure
✅ Clear error messages for debugging

This is enterprise-grade error handling!

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