Output from tests/test_demo_using_bagit_bags.py.
Imagine that we have a Bagit bag tests/testdata/bags/uaa_v1 that represents the initial state of an object. We can use --create to make a new OCFL object /tmp/obj with that content as the v1 state:
> python ocfl-object.py --create --objdir tmp/obj --srcbag tests/testdata/bags/uaa_v1 -v
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v1/data/my_content/dracula.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v1/data/my_content/poe.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v1/bagit.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v1/bag-info.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v1/manifest-sha512.txt
INFO:ocfl.object:Created OCFL object info:bb123cd4567 in tmp/obj
Now that we have the object it is of course valid.
> python ocfl-validate.py tmp/obj
INFO:ocfl.object:OCFL v1.1 Object at tmp/obj is VALID
Looking inside the object we see v1 with the expected 2 content files.
> python ocfl-object.py --show --objdir tmp/obj
WARNING:ocfl.object:OCFL v1.1 Object at tmp/obj has VALID STRUCTURE (DIGESTS NOT CHECKED)
WARNING:ocfl.object:Object tree
[tmp/obj]
├── 0=ocfl_object_1.1
├── inventory.json
├── inventory.json.sha512
└── v1
├── content (2 files)
├── inventory.json
└── inventory.json.sha512
If we have a bag tests/testdata/bags/uaa_v2 with updated content we can --update the object to create v2.
> python ocfl-object.py --update --objdir tmp/obj --srcbag tests/testdata/bags/uaa_v2 -v
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v2/data/my_content/a_second_copy_of_dracula.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v2/data/my_content/dracula.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v2/data/my_content/poe-nevermore.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v2/data/my_content/another_directory/a_third_copy_of_dracula.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v2/bagit.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v2/bag-info.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v2/manifest-sha512.txt
INFO:ocfl.object:Will update info:bb123cd4567 v1 -> v2
INFO:ocfl.object:Updated OCFL object info:bb123cd4567 in tmp/obj by adding v2
Looking inside the object we now see v1 and v2. There are no content files inside v2 because although this update added two files they have identical content (and hence digest) as one of the files in v1
> python ocfl-object.py --show --objdir tmp/obj
WARNING:ocfl.object:OCFL v1.1 Object at tmp/obj has VALID STRUCTURE (DIGESTS NOT CHECKED)
WARNING:ocfl.object:Object tree
[tmp/obj]
├── 0=ocfl_object_1.1
├── inventory.json
├── inventory.json.sha512
├── v1
│ ├── content (2 files)
│ ├── inventory.json
│ └── inventory.json.sha512
└── v2
├── inventory.json
└── inventory.json.sha512
Similarly we can --update with tests/testdata/bags/uaa_v3 to create v3.
> python ocfl-object.py --update --objdir tmp/obj --srcbag tests/testdata/bags/uaa_v3 -v
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v3/data/my_content/dracula.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v3/data/my_content/poe-nevermore.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v3/data/my_content/another_directory/a_third_copy_of_dracula.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v3/bagit.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v3/bag-info.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v3/manifest-sha512.txt
INFO:ocfl.object:Will update info:bb123cd4567 v2 -> v3
INFO:ocfl.object:Updated OCFL object info:bb123cd4567 in tmp/obj by adding v3
Looking inside again we see that v3 does add another content file.
> python ocfl-object.py --show --objdir tmp/obj
WARNING:ocfl.object:OCFL v1.1 Object at tmp/obj has VALID STRUCTURE (DIGESTS NOT CHECKED)
WARNING:ocfl.object:Object tree
[tmp/obj]
├── 0=ocfl_object_1.1
├── inventory.json
├── inventory.json.sha512
├── v1
│ ├── content (2 files)
│ ├── inventory.json
│ └── inventory.json.sha512
├── v2
│ ├── inventory.json
│ └── inventory.json.sha512
└── v3
├── content (1 files)
├── inventory.json
└── inventory.json.sha512
Finally, we can --update again with tests/testdata/bags/uaa_v4 to create v4.
> python ocfl-object.py --update --objdir tmp/obj --srcbag tests/testdata/bags/uaa_v4 -v
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v4/data/my_content/dracula.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v4/data/my_content/dunwich.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v4/data/my_content/poe-nevermore.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v4/data/my_content/another_directory/a_third_copy_of_dracula.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v4/bagit.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v4/bag-info.txt
INFO:bagit:Verifying checksum for file /home/runner/work/ocfl-py/ocfl-py/tests/testdata/bags/uaa_v4/manifest-sha512.txt
INFO:ocfl.object:Will update info:bb123cd4567 v3 -> v4
INFO:ocfl.object:Updated OCFL object info:bb123cd4567 in tmp/obj by adding v4
Taking the newly created OCFL object /tmp/obj we can --extract the v4 content as a Bagit bag.
> python ocfl-object.py --extract v4 --objdir tmp/obj --dstbag tmp/extracted_v4 -v
INFO:ocfl.object:Extracted v4 into tmp/extracted_v4
INFO:bagit:Creating bag for directory tmp/extracted_v4
INFO:bagit:Creating data directory
INFO:bagit:Moving my_content to tmp/extracted_v4/tmpq_2ho4cy/my_content
INFO:bagit:Moving tmp/extracted_v4/tmpq_2ho4cy to data
INFO:bagit:Using 1 processes to generate manifests: sha512
INFO:bagit:Generating manifest lines for file data/my_content/dracula.txt
INFO:bagit:Generating manifest lines for file data/my_content/dunwich.txt
INFO:bagit:Generating manifest lines for file data/my_content/poe-nevermore.txt
INFO:bagit:Generating manifest lines for file data/my_content/another_directory/a_third_copy_of_dracula.txt
INFO:bagit:Creating bagit.txt
INFO:bagit:Creating bag-info.txt
INFO:bagit:Creating tmp/extracted_v4/tagmanifest-sha512.txt
Extracted content for v4 saved as Bagit bag in tmp/extracted_v4
We note that the OCFL object had only one content file in v4 but the extracted object state for v4 includes 4 files, two of which have identical content (dracula.txt and another_directory/a_third_copy_of_dracula.txt). We can now compare the extracted bag /tmp/uaa_v4 that with the bag we used to create v4 tests/testdata/bags/uaa_v4 using a recursive diff.
> diff -r tmp/extracted_v4 tests/testdata/bags/uaa_v4
diff -r tmp/extracted_v4/bag-info.txt tests/testdata/bags/uaa_v4/bag-info.txt
1,2c1
< Bag-Software-Agent: bagit.py v1.8.1 <https://github.com/LibraryOfCongress/bagit-python>
< Bagging-Date: 2023-03-08
---
> Bagging-Date: 2020-01-04
diff -r tmp/extracted_v4/tagmanifest-sha512.txt tests/testdata/bags/uaa_v4/tagmanifest-sha512.txt
2c2
< fb20d9575bd2a36d589c32af7118552b96b2ca8500d8a90494be8f4354c31909a70a0b2792c9b89652f59725895b5326a57e423e2065d5edfe380f47a9c82c40 bag-info.txt
---
> 10624e6d45462def7af66d1a0d977606c7b073b01809c1d42258cfab5c34a275480943cbe78044416aee1f23822cc3762f92247b8f39b5c6ddc5ae32a8f94ce5 bag-info.txt
(last command exited with return code 1)
The only differences are in the bag-info.txt file and the checksum file for that file (tagmanifest-sha512.txt). The content matches.