ion-hash-python

API documentation for the ion-hash-python GitHub repository.

ionhash.hasher module

Adds an ion_hash() method to all simpleion value classes, and provides readers/writers that hash Ion values according to the Ion Hash Specification.

class ionhash.hasher.HashEvent

Bases: enum.IntEnum

Events that may be pushed into a hash_reader or hash_writer coroutine, in addition to those allowed by the wrapped reader/writer.

Attributes:

DIGEST: produces bytes that represents the hash of the Ion values read/written

DIGEST = 0

class ionhash.hasher.IonHasher

Bases: abc.ABC

Abstract class declaring the hashing methods that must be implemented in order to support a hash function for use by hash_reader or hash_writer.

digest()

Returns a digest of the accumulated bytes passed to update, and resets the IonHasher to its initial state.

update(_bytes)

Updates the hash function with the specified _bytes.

ionhash.hasher.hashlib_hash_function_provider(algorithm)

A hash function provider based on hashlib.

<simpleion_class>.ion_hash(algorithm=None, hash_function_provider=None)

Given an algorithm or hash_function_provider, computes the Ion hash of this value.

Args:

algorithm:

A string corresponding to the name of a hash algorithm supported by the hashlib module.

hash_function_provider:

A function that returns a new IonHasher instance when called.

Note that multiple IonHasher instances may be required to hash a single value (depending on the type of the Ion value).

Returns:

bytes that represent the Ion hash of this value for the specified algorithm or hash_function_provider.

ionhash.hasher.hash_reader(reader, hash_function_provider)

Provides a coroutine that wraps an ion-python reader and adds Ion Hash functionality.

The given coroutine yields bytes when given HashEvent.DIGEST. Otherwise, the couroutine’s behavior matches that of the wrapped reader.

Notes:

The coroutine translates any amazon.ion.reader.SKIP_EVENTs into a series of amazon.ion.reader.NEXT_EVENTs in order to ensure that the hash correctly includes any subsequent or nested values.

Args:

reader(couroutine):

An ion-python reader coroutine.

hash_function_provider(function):

A function that returns a new IonHasher instance when called.

Note that multiple IonHasher instances may be required to hash a single value (depending on the type of the Ion value).

Yields:

bytes:

The result of hashing.

other values:

As defined by the provided reader coroutine.

ionhash.hasher.hash_writer(writer, hash_function_provider)

Provides a coroutine that wraps an ion-python writer and adds Ion Hash functionality.

The given coroutine yields bytes when given HashEvent.DIGEST. Otherwise, the couroutine’s behavior matches that of the wrapped writer.

Args:

writer(coroutine):

An ion-python writer coroutine.

hash_function_provider(function):

A function that returns a new IonHasher instance when called.

Note that multiple IonHasher instances may be required to hash a single value (depending on the type of the Ion value).

Yields:

bytes:

The result of hashing.

other values:

As defined by the provided writer coroutine.