Safe Operations

def safe_load(stream):
    """
    Parse the first YAML document in a stream and produce the corresponding Python object.
    
    Resolve only basic YAML tags. This is known to be safe for untrusted input.
    
    Args:
        stream (str | bytes | IO): YAML content as string, bytes, or file-like object
        
    Returns:
        Any: Python object representing the YAML document
        
    Raises:
        YAMLError: If the document cannot be parsed
        MarkedYAMLError: If there's a syntax error with position information
    """

def safe_load_all(stream):
    """
    Parse all YAML documents in a stream and produce corresponding Python objects.
    
    Resolve only basic YAML tags. This is known to be safe for untrusted input.
    
    Args:
        stream (str | bytes | IO): YAML content containing multiple documents
        
    Yields:
        Any: Python objects representing each YAML document
        
    Raises:
        YAMLError: If any document cannot be parsed
        MarkedYAMLError: If there's a syntax error with position information
    """

import yaml

# Load a single document
config = yaml.safe_load("""
database:
  host: localhost
  port: 5432
  name: myapp
  credentials:
    username: user
    password: secret
""")

print(config['database']['host'])  # localhost

# Load multiple documents
documents = yaml.safe_load_all("""
---
name: Development Config
database:
  host: dev.example.com
---
name: Production Config  
database:
  host: prod.example.com
""")

for doc in documents:
    print(f"Config: {doc['name']}")
    print(f"Host: {doc['database']['host']}")

def safe_dump(data, stream=None, **kwds):
    """
    Serialize a Python object into a YAML stream.
    Produce only basic YAML tags.
    
    Args:
        data (Any): Python object to serialize
        stream (IO, optional): Output stream. If None, return as string
        **kwds: Additional keyword arguments for formatting
        
    Keyword Arguments:
        default_flow_style (bool): Use flow style for collections (default: False)
        canonical (bool): Produce canonical YAML (default: False)
        indent (int): Number of spaces for indentation (default: 2)
        width (int): Maximum line width (default: 80)
        allow_unicode (bool): Allow unicode characters (default: True)
        line_break (str): Line break character(s) (default: platform default)
        encoding (str): Output encoding for byte streams (default: 'utf-8')
        explicit_start (bool): Write document start marker (default: False)
        explicit_end (bool): Write document end marker (default: False)
        version (tuple): YAML version to use (default: (1, 1))
        tags (dict): Custom tag mappings
        sort_keys (bool): Sort dictionary keys (default: True)
        
    Returns:
        str | None: YAML string if stream is None, otherwise None
        
    Raises:
        RepresenterError: If an object cannot be represented
    """

def safe_dump_all(documents, stream=None, **kwds):
    """
    Serialize a sequence of Python objects into a YAML stream.
    Produce only basic YAML tags.
    
    Args:
        documents (Iterable[Any]): Sequence of Python objects to serialize
        stream (IO, optional): Output stream. If None, return as string
        **kwds: Additional keyword arguments (same as safe_dump)
        
    Returns:
        str | None: YAML string if stream is None, otherwise None
        
    Raises:
        RepresenterError: If any object cannot be represented
    """

import yaml

data = {
    'application': 'MyApp',
    'version': '1.0.0',
    'features': ['auth', 'api', 'ui'],
    'settings': {
        'debug': False,
        'max_connections': 100
    }
}

# Dump to string with default formatting
yaml_output = yaml.safe_dump(data)
print(yaml_output)

# Dump with custom formatting
yaml_formatted = yaml.safe_dump(
    data,
    default_flow_style=False,
    indent=4,
    width=120,
    sort_keys=False
)
print(yaml_formatted)

# Dump multiple documents
documents = [
    {'name': 'Config 1', 'value': 100},
    {'name': 'Config 2', 'value': 200}
]

yaml_multi = yaml.safe_dump_all(
    documents,
    explicit_start=True,
    explicit_end=False
)
print(yaml_multi)

# Dump to file
with open('config.yaml', 'w') as f:
    yaml.safe_dump(data, f, default_flow_style=False)