Merge pull request #129 from DataONEorg/feature-126-objectmetadata-da…

…taclass

Feature-126: Refactor `ObjectMetadata` to be a dataclass

src/hashstore/__init__.py

@@ -16,6 +16,6 @@
     system.
 """
 
-from hashstore.hashstore import HashStore, HashStoreFactory, ObjectMetadata
+from hashstore.hashstore import HashStore, HashStoreFactory
 
-__all__ = ("HashStore", "HashStoreFactory", "ObjectMetadata")
+__all__ = ("HashStore", "HashStoreFactory")

src/hashstore/filehashstore.py

@@ -9,12 +9,13 @@
 import os
 import logging
 import inspect
+import fcntl
+import yaml
+from dataclasses import dataclass
 from pathlib import Path
 from contextlib import closing
 from tempfile import NamedTemporaryFile
-import fcntl
-import yaml
-from hashstore import HashStore, ObjectMetadata
+from hashstore import HashStore
 from hashstore.filehashstore_exceptions import (
     CidRefsContentError,
     CidRefsDoesNotExist,
@@ -2611,3 +2612,25 @@ def close(self):
             self._obj.close()
         else:
             self._obj.seek(self._pos)
+
+
+@dataclass
+class ObjectMetadata:
+    """Represents metadata associated with an object.
+
+    The `ObjectMetadata` class represents metadata associated with an object, including
+    a persistent or authority-based identifier (`pid`), a content identifier (`cid`),
+    the size of the object in bytes (`obj_size`), and an optional list of hex digests
+    (`hex_digests`) to assist with validating objects.
+
+    :param str pid: An authority-based or persistent identifier
+    :param str cid: A unique identifier for the object (Hash ID, hex digest).
+    :param int obj_size: The size of the object in bytes.
+    :param list hex_digests: A list of hex digests to validate objects
+        (md5, sha1, sha256, sha384, sha512) (optional).
+    """
+
+    pid: str
+    cid: str
+    obj_size: int
+    hex_digests: dict

src/hashstore/hashstore.py

@@ -1,7 +1,6 @@
 """Hashstore Interface"""
 
 from abc import ABC, abstractmethod
-from collections import namedtuple
 import importlib.metadata
 import importlib.util
 
@@ -28,19 +27,20 @@ def store_object(
     ):
         """Atomic storage of objects to disk using a given stream. Upon successful storage,
         it returns an `ObjectMetadata` object containing relevant file information, such as
-        the file's id, the file's size, and a hex digest dictionary of algorithms and checksums.
-        The method also tags the object, creating references for discoverability.
+        a persistent identifier that references the data file, the file's size, and a hex digest
+        dictionary of  algorithms and checksums. The method also tags the object, creating
+        references for discoverability.
 
         `store_object` ensures that an object is stored only once by synchronizing multiple calls
         and rejecting attempts to store duplicate objects. If called without a pid, it stores the
         object without tagging, and it becomes the caller's responsibility to finalize the process
         by calling `tag_object` after verifying the correct object is stored.
 
-        The file's id is determined by calculating the object's content identifier based on the
-        store's default algorithm, which is also the permanent address of the file. The file's
-        identifier is then sharded using the store's configured depth and width, delimited by '/',
-        and concatenated to produce the final permanent address. This address is stored in the
-        `/store_directory/objects/` directory.
+        The file's permanent address is determined by calculating the object's content identifier
+        based on the store's default algorithm, which is also the permanent address of the file.
+        The content identifier is then sharded using the store's configured depth and width,
+        delimited by '/', and concatenated to produce the final permanent address. This address
+        is stored in the `/store_directory/objects/` directory.
 
         By default, the hex digest map includes common hash algorithms (md5, sha1, sha256, sha384,
         sha512). If an additional algorithm is provided, the method checks if it is supported and
@@ -59,8 +59,8 @@ def store_object(
         :param str checksum_algorithm: Algorithm of the supplied checksum.
         :param int expected_object_size: Size of the object to verify.
 
-        :return: ObjectMetadata - Object containing the permanent address, file size, and
-            hex digest dictionary.
+        :return: ObjectMetadata - Object containing the persistent identifier (pid),
+        content identifier (cid), object size and hex digests dictionary (checksums).
         """
         raise NotImplementedError()
 
@@ -113,8 +113,9 @@ def store_metadata(self, pid, metadata, format_id):
         """Add or update metadata, such as `sysmeta`, to disk using the given path/stream. The
         `store_metadata` method uses a persistent identifier `pid` and a metadata `format_id`
         to determine the permanent address of the metadata object. All metadata documents for a
-        given `pid` will be stored in a directory (under ../metadata) that is determined by
-        calculating the hash of the given pid, with the document name being the hash of the pid
+        given `pid` will be stored in a directory that follows the HashStore configuration
+        settings (under ../metadata) that is determined by calculating the hash of the given pid.
+        Metadata documents are stored in this directory, and is each named using the hash of the pid
         and metadata format (`pid` + `format_id`).
 
         Upon successful storage of metadata, the method returns a string representing the file's
@@ -239,25 +240,3 @@ def get_hashstore(module_name, class_name, properties=None):
         raise AttributeError(
             f"Class name '{class_name}' is not an attribute of module '{module_name}'"
         )
-
-
-class ObjectMetadata(
-    namedtuple("ObjectMetadata", ["pid", "cid", "obj_size", "hex_digests"])
-):
-    """Represents metadata associated with an object.
-
-    The `ObjectMetadata` class represents metadata associated with an object, including
-    a persistent or authority-based identifier (`pid`), a content identifier (`cid`),
-    the size of the object in bytes (`obj_size`), and an optional list of hex digests
-    (`hex_digests`) to assist with validating objects.
-
-    :param str pid: An authority-based or persistent identifier
-    :param str cid: A unique identifier for the object (Hash ID, hex digest).
-    :param int obj_size: The size of the object in bytes.
-    :param list hex_digests: A list of hex digests to validate objects
-        (md5, sha1, sha256, sha384, sha512) (optional).
-    """
-
-    # Default value to prevent dangerous default value
-    def __new__(cls, pid, cid, obj_size, hex_digests=None):
-        return super(ObjectMetadata, cls).__new__(cls, pid, cid, obj_size, hex_digests)

tests/test_filehashstore.py

@@ -4,7 +4,7 @@
 import os
 from pathlib import Path
 import pytest
-from hashstore.filehashstore import FileHashStore
+from hashstore.filehashstore import FileHashStore, ObjectMetadata
 from hashstore.filehashstore_exceptions import (
     NonMatchingChecksum,
     NonMatchingObjSize,
@@ -1135,3 +1135,26 @@ def test_check_string(store):
     tab_line = "\t"
     with pytest.raises(ValueError):
         store._check_string(tab_line, "tab_line")
+
+
+def test_objectmetadata():
+    """Test ObjectMetadata class returns correct values via dot notation."""
+    pid = "hashstore"
+    ab_id = "hashstoretest"
+    obj_size = 1234
+    hex_digest_dict = {
+        "md5": "md5value",
+        "sha1": "sha1value",
+        "sha224": "sha224value",
+        "sha256": "sha256value",
+        "sha512": "sha512value",
+    }
+    object_metadata = ObjectMetadata(pid, ab_id, obj_size, hex_digest_dict)
+    assert object_metadata.pid == pid
+    assert object_metadata.cid == ab_id
+    assert object_metadata.obj_size == obj_size
+    assert object_metadata.hex_digests.get("md5") == hex_digest_dict["md5"]
+    assert object_metadata.hex_digests.get("sha1") == hex_digest_dict["sha1"]
+    assert object_metadata.hex_digests.get("sha224") == hex_digest_dict["sha224"]
+    assert object_metadata.hex_digests.get("sha256") == hex_digest_dict["sha256"]
+    assert object_metadata.hex_digests.get("sha512") == hex_digest_dict["sha512"]

tests/test_hashstore.py

@@ -2,7 +2,7 @@
 
 import os
 import pytest
-from hashstore.hashstore import ObjectMetadata, HashStoreFactory
+from hashstore.hashstore import HashStoreFactory
 from hashstore.filehashstore import FileHashStore
 
 
@@ -156,26 +156,3 @@ def test_factory_get_hashstore_filehashstore_nonconflicting_dir(factory, tmp_pat
     }
 
     factory.get_hashstore(module_name, class_name, properties)
-
-
-def test_objectmetadata():
-    """Test ObjectMetadata class returns correct values via dot notation."""
-    pid = "hashstore"
-    ab_id = "hashstoretest"
-    obj_size = 1234
-    hex_digest_dict = {
-        "md5": "md5value",
-        "sha1": "sha1value",
-        "sha224": "sha224value",
-        "sha256": "sha256value",
-        "sha512": "sha512value",
-    }
-    object_metadata = ObjectMetadata(pid, ab_id, obj_size, hex_digest_dict)
-    assert object_metadata.pid == pid
-    assert object_metadata.cid == ab_id
-    assert object_metadata.obj_size == obj_size
-    assert object_metadata.hex_digests.get("md5") == hex_digest_dict["md5"]
-    assert object_metadata.hex_digests.get("sha1") == hex_digest_dict["sha1"]
-    assert object_metadata.hex_digests.get("sha224") == hex_digest_dict["sha224"]
-    assert object_metadata.hex_digests.get("sha256") == hex_digest_dict["sha256"]
-    assert object_metadata.hex_digests.get("sha512") == hex_digest_dict["sha512"]