exceptions.rst

Exceptions

nacl.exceptions

All of the exceptions raised from PyNaCl-exposed methods/functions are subclasses of :pynacl.exceptions.CryptoError. This means downstream users can just wrap cryptographic operations inside a

try:
    # cryptographic operations
except nacl.exceptions.CryptoError:
    # cleanup after any kind of exception
    # raised from cryptographic-related operations

These are the exceptions implemented in :pynacl.exceptions:

PyNaCl specific exceptions

Base exception for all nacl related errors

Raised when the signature was forged or otherwise corrupt.

Raised on password/key verification mismatch

is a subclass of ~nacl.exceptions.RuntimeError, raised when trying to call functions not available in a minimal build of libsodium.

PyNaCl exceptions mixing-in standard library ones

Both for clarity and for compatibility with previous releases of the PyNaCl, the following exceptions mix-in the same-named standard library exception to :py~nacl.exceptions.CryptoError.

is a subclass of both CryptoError and standard library's RuntimeError, raised for internal library errors

is a subclass of both CryptoError and standard library's AssertionError, raised by default from :py~nacl.utils.ensure when the checked condition is False

is a subclass of both CryptoError and standard library's TypeError

is a subclass of both CryptoError and standard library's ValueError

Utility functions for exception handling

ensure(cond, *args, raising=nacl.exceptions.AssertionError)

Returns if a condition is true, otherwise raise a caller-configurable :pyException

param cond

the condition to be checked

type cond

bool

param sequence args

the arguments to be passed to the exception's constructor

param raising

the exception to be raised if cond is False

type raising

exception

Example usage:

nacl.exceptions.ensure(
    a == 1 or a == 2,
    "a must be either 1 or 2"
)