Plugin System

class BasePlugin:
    def init_spec(self, spec: APISpec) -> None:
        """
        Initialize plugin with APISpec object.
        
        Parameters:
        - spec: APISpec object this plugin instance is attached to
        
        Called once when plugin is registered with APISpec instance.
        Use this to store references and initialize plugin state.
        """

def schema_helper(
    self, 
    name: str, 
    definition: dict, 
    **kwargs: Any
) -> dict | None:
    """
    Process schema component definition.
    
    Parameters:
    - name: Identifier by which schema may be referenced
    - definition: Schema definition dictionary
    - **kwargs: Additional keyword arguments sent to APISpec.components.schema()
    
    Returns:
    Modified schema definition dictionary or None
    
    Raises:
    - PluginMethodNotImplementedError: If method not implemented by plugin
    """

def response_helper(self, response: dict, **kwargs: Any) -> dict | None:
    """
    Process response component definition.
    
    Parameters:
    - response: Response definition dictionary
    - **kwargs: Additional keyword arguments sent to APISpec.components.response()
    
    Returns:
    Modified response definition dictionary or None
    
    Raises:
    - PluginMethodNotImplementedError: If method not implemented by plugin
    """

def parameter_helper(self, parameter: dict, **kwargs: Any) -> dict | None:
    """
    Process parameter component definition.
    
    Parameters:
    - parameter: Parameter definition dictionary  
    - **kwargs: Additional keyword arguments sent to APISpec.components.parameter()
    
    Returns:
    Modified parameter definition dictionary or None
    
    Raises:
    - PluginMethodNotImplementedError: If method not implemented by plugin
    """

def header_helper(self, header: dict, **kwargs: Any) -> dict | None:
    """
    Process header component definition.
    
    Parameters:
    - header: Header definition dictionary
    - **kwargs: Additional keyword arguments sent to APISpec.components.header()
    
    Returns:
    Modified header definition dictionary or None
    
    Raises:
    - PluginMethodNotImplementedError: If method not implemented by plugin
    """

def path_helper(
    self,
    path: str | None = None,
    operations: dict | None = None,
    parameters: list[dict] | None = None,
    **kwargs: Any
) -> str | None:
    """
    Process path definition and extract path string.
    
    Parameters:
    - path: Path to the resource  
    - operations: Dictionary mapping HTTP methods to operation objects
    - parameters: List of parameters for the path
    - **kwargs: Additional keyword arguments sent to APISpec.path()
    
    Returns:
    Path string or None. If string returned, it sets the path value.
    
    Raises:
    - PluginMethodNotImplementedError: If method not implemented by plugin
    
    Note:
    The last path helper returning a string sets the final path value.
    Plugin registration order matters for path helpers.
    """

def operation_helper(
    self,
    path: str | None = None,
    operations: dict | None = None,
    **kwargs: Any
) -> None:
    """
    Process operations dictionary, modifying operations in-place.
    
    Parameters:
    - path: Path to the resource
    - operations: Dictionary mapping HTTP methods to operation objects
    - **kwargs: Additional keyword arguments sent to APISpec.path()
    
    Raises:
    - PluginMethodNotImplementedError: If method not implemented by plugin
    
    Note:
    This method should modify the operations dictionary in-place.
    """

class PluginMethodNotImplementedError(APISpecError, NotImplementedError):
    """Raised when calling an unimplemented helper method in a plugin."""

from apispec import BasePlugin, APISpec

class CustomFrameworkPlugin(BasePlugin):
    def init_spec(self, spec: APISpec) -> None:
        """Initialize plugin with spec reference."""
        self.spec = spec
        self.framework_routes = self.discover_routes()
    
    def path_helper(self, path=None, operations=None, **kwargs):
        """Extract path from framework route object."""
        route_obj = kwargs.get('route')
        if route_obj:
            return route_obj.get_path_template()
        return path
    
    def operation_helper(self, path=None, operations=None, **kwargs):
        """Extract operations from framework route handlers."""
        route_obj = kwargs.get('route')
        if route_obj and operations:
            # Extract operation info from route handlers
            for method, handler in route_obj.get_handlers().items():
                if method.lower() in operations:
                    # Add framework-specific operation metadata
                    operations[method.lower()].update({
                        'operationId': handler.__name__,
                        'summary': getattr(handler, '__doc__', '').split('\n')[0]
                    })
    
    def discover_routes(self):
        """Framework-specific route discovery logic."""
        # Implementation depends on the framework
        pass

from apispec import APISpec
from apispec.ext.marshmallow import MarshmallowPlugin

# Create spec with multiple plugins
spec = APISpec(
    title="My API",
    version="1.0.0", 
    openapi_version="3.0.2",
    plugins=[
        CustomFrameworkPlugin(),
        MarshmallowPlugin()
    ]
)

# Plugins process components and paths during registration
spec.components.schema("User", schema=UserSchema)  # MarshmallowPlugin processes this
spec.path("/users", route=user_route_obj)  # CustomFrameworkPlugin processes this

class FlaskPlugin(BasePlugin):
    def path_helper(self, path=None, operations=None, **kwargs):
        """Extract path from Flask view function."""
        view_function = kwargs.get('view_function')
        if view_function:
            # Get Flask route rules for this view
            rules = [rule for rule in current_app.url_map.iter_rules() 
                    if rule.endpoint == view_function.__name__]
            if rules:
                return rules[0].rule
        return path
    
    def operation_helper(self, path=None, operations=None, **kwargs):
        """Extract operations from Flask view function."""
        view_function = kwargs.get('view_function')
        if view_function and operations:
            # Parse docstring for OpenAPI spec
            from apispec.yaml_utils import load_operations_from_docstring
            doc_operations = load_operations_from_docstring(view_function.__doc__ or '')
            operations.update(doc_operations)

# Usage with Flask
@app.route('/users/<int:user_id>')
def get_user(user_id):
    """Get user by ID.
    ---
    get:
      parameters:
        - name: user_id
          in: path
          schema:
            type: integer
      responses:
        200:
          description: User found
    """
    pass

# Register with APISpec
spec.path(view_function=get_user)

class SchemaValidationPlugin(BasePlugin):
    def schema_helper(self, name, definition, **kwargs):
        """Add validation metadata to schema definitions."""
        if definition and isinstance(definition, dict):
            # Add schema validation rules
            definition = definition.copy()
            definition.setdefault('additionalProperties', False)
            
            # Add pattern validation for string fields
            if 'properties' in definition:
                for prop_name, prop_def in definition['properties'].items():
                    if prop_def.get('type') == 'string' and 'email' in prop_name.lower():
                        prop_def['format'] = 'email'
            
            return definition
        return None