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Error Handling

Complete guide to handling OAuth errors gracefully.

Common Errors​

SVATokenError​

Raised when token operations fail:

from sva_oauth_client.client import SVATokenError
from sva_oauth_client.utils import get_sva_claims

try:
    claims = get_sva_claims(request)
except SVATokenError:
    # Token expired or invalid
    # Handle error
    pass

Common causes:

  • Token expired
  • Invalid token signature
  • Token not found in session

SVAAuthorizationError​

Raised when authorization fails:

from sva_oauth_client.client import SVAAuthorizationError, SVAOAuthClient

try:
    tokens = client.exchange_code_for_tokens(code, code_verifier)
except SVAAuthorizationError:
    # Authorization failed
    pass

Common causes:

  • Invalid authorization code
  • Code already used
  • Code expired
  • Invalid redirect URI

Error Handling Patterns​

Basic Error Handling​

from sva_oauth_client.decorators import sva_oauth_required
from sva_oauth_client.utils import get_sva_claims
from sva_oauth_client.client import SVATokenError
from django.shortcuts import redirect
from django.contrib import messages

@sva_oauth_required
def my_view(request):
    try:
        claims = get_sva_claims(request)
        # Process claims...
    except SVATokenError:
        messages.error(request, 'Your session has expired. Please sign in again.')
        return redirect('sva_oauth_client:login')

Comprehensive Error Handling​

from sva_oauth_client.utils import get_sva_claims
from sva_oauth_client.client import SVATokenError, SVAAuthorizationError, SVAOAuthError
import logging

logger = logging.getLogger(__name__)

@sva_oauth_required
def my_view(request):
    try:
        claims = get_sva_claims(request)
        # Process claims...
    except SVATokenError as e:
        logger.warning(f"Token error: {e}")
        messages.error(request, 'Authentication failed. Please sign in again.')
        return redirect('sva_oauth_client:login')
    except SVAOAuthError as e:
        logger.error(f"OAuth error: {e}")
        messages.error(request, 'An error occurred. Please try again.')
        return redirect('/')
    except Exception as e:
        logger.exception(f"Unexpected error: {e}")
        messages.error(request, 'An unexpected error occurred.')
        return redirect('/')

Decorator Error Handling​

Automatic Error Handling​

The @sva_oauth_required decorator handles errors automatically:

  • Token errors → Redirects to login
  • Missing authentication → Redirects to login
  • Displays appropriate messages

Custom Error Messages​

from sva_oauth_client.decorators import sva_blocks_required
from sva_oauth_client.utils import get_sva_claims
from sva_oauth_client.client import SVATokenError

@sva_blocks_required('email', 'name')
def my_view(request):
    try:
        claims = get_sva_claims(request)
        # Process claims...
    except SVATokenError:
        # Decorator handles logout, but you can add custom logic
        messages.warning(request, 'Your session expired. Please sign in again.')
        return redirect('sva_oauth_client:login')

Token Refresh Errors​

Handling Refresh Failures​

from sva_oauth_client.client import get_client_from_settings, SVATokenError

def refresh_token_safely(request):
    """Safely refresh token with error handling"""
    refresh_token = request.session.get('sva_oauth_refresh_token')
    
    if not refresh_token:
        return False
    
    try:
        client = get_client_from_settings()
        new_tokens = client.refresh_access_token(refresh_token)
        
        # Update session
        request.session['sva_oauth_access_token'] = new_tokens['access_token']
        # ... update other tokens
        
        return True
    except SVATokenError as e:
        # Refresh failed - token expired or revoked
        logger.warning(f"Token refresh failed: {e}")
        clear_oauth_session(request.session)
        return False

OAuth Flow Errors​

Authorization Errors​

from sva_oauth_client.client import SVAOAuthClient, SVAAuthorizationError

def handle_oauth_callback(request):
    code = request.GET.get('code')
    error = request.GET.get('error')
    
    if error:
        # User denied authorization
        messages.error(request, 'Authorization was denied.')
        return redirect('/')
    
    if not code:
        messages.error(request, 'No authorization code received.')
        return redirect('/')
    
    try:
        client = SVAOAuthClient(...)
        tokens = client.exchange_code_for_tokens(code, code_verifier)
        # Process tokens...
    except SVAAuthorizationError as e:
        messages.error(request, 'Authorization failed. Please try again.')
        return redirect('sva_oauth_client:login')

Validation Errors​

Missing Blocks​

from sva_oauth_client.decorators import sva_oauth_required
from sva_oauth_client.utils import get_sva_claims

@sva_oauth_required
def my_view(request):
    claims = get_sva_claims(request)
    
    required_blocks = ['email', 'name', 'phone']
    missing = [block for block in required_blocks if block not in claims]
    
    if missing:
        messages.warning(
            request,
            f'Missing required data: {", ".join(missing)}. Please sign in again and approve these permissions.'
        )
        return redirect('sva_oauth_client:login')
    
    # All required blocks are present
    return render(request, 'template.html', {'claims': claims})

Logging Errors​

Error Logging​

import logging

logger = logging.getLogger(__name__)

@sva_oauth_required
def my_view(request):
    try:
        claims = get_sva_claims(request)
    except SVATokenError as e:
        logger.warning(f"Token error for user: {e}", exc_info=True)
        # Handle error...
    except Exception as e:
        logger.error(f"Unexpected error: {e}", exc_info=True)
        # Handle error...

User-Friendly Messages​

Error Messages​

from django.contrib import messages

# Token expired
messages.error(request, 'Your session has expired. Please sign in again.')

# Authorization denied
messages.warning(request, 'Authorization was denied. Please try again.')

# Missing blocks
messages.info(request, 'Please approve the requested permissions to continue.')

# General error
messages.error(request, 'An error occurred. Please try again.')

Error Recovery​

Retry Logic​

from sva_oauth_client.utils import get_sva_claims
from sva_oauth_client.client import SVATokenError

def get_claims_with_retry(request, max_retries=2):
    """Get claims with retry logic"""
    for attempt in range(max_retries):
        try:
            return get_sva_claims(request)
        except SVATokenError:
            if attempt < max_retries - 1:
                # Try to refresh token
                if refresh_token_safely(request):
                    continue
            # All retries failed
            raise

Best Practices​

  1. Always handle errors - Don't let errors crash your app
  2. Log errors - Help with debugging
  3. User-friendly messages - Don't expose technical details
  4. Graceful degradation - Handle missing data gracefully
  5. Retry logic - For transient errors

Next Steps​