Path Templates

def expand(tmpl, *args, **kwargs):
    """
    Expand a path template with variables.
    
    Args:
        tmpl (str): Path template with {variable} placeholders
        *args: Positional arguments for template variables
        **kwargs: Named arguments for template variables
        
    Returns:
        str: Expanded path with variables substituted
    """

def validate(tmpl, path):
    """
    Validate that a path matches a template pattern.
    
    Args:
        tmpl (str): Path template pattern
        path (str): Path to validate
        
    Returns:
        dict: Extracted variables if path matches, raises ValueError if not
    """

def get_field(request, field):
    """
    Get field value from request dict or protobuf Message.
    
    Args:
        request: Request dict or protobuf Message
        field (str): Field path (e.g., "user.name" for nested fields)
        
    Returns:
        Any: Field value
    """

def delete_field(request, field):
    """
    Delete field from request dict or protobuf Message.
    
    Args:
        request: Request dict or protobuf Message  
        field (str): Field path to delete
    """

def transcode(http_options, message=None, **request_kwargs):
    """
    Transcode gRPC request to HTTP format.
    
    Args:
        http_options: HTTP binding configuration
        message: gRPC request message
        **request_kwargs: Additional request parameters
        
    Returns:
        dict: HTTP request components (method, uri, body)
    """

from google.api_core import path_template

# Expand template with named parameters
template = "projects/{project}/instances/{instance}/databases/{database}"
path = path_template.expand(template, 
                           project="my-project",
                           instance="my-instance", 
                           database="my-db")
print(path)  # "projects/my-project/instances/my-instance/databases/my-db"

# Validate and extract parameters
extracted = path_template.validate(template, path)
print(extracted)  # {"project": "my-project", "instance": "my-instance", "database": "my-db"}