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Manually Merging Day One Journals

My first Day One entry is from January 24, 2012. I used it often to take note about what I was doing during my PhD with the #wwid tag (what was I doing, an idea from Brett Terpstra, I think), and sometimes to clarify some thoughts.

When Day One went The Way of the Subscription, I didn’t bother too much because Dropbox sync still worked. Until it didn’t. I somehow didn’t realized it and kept adding entries to both the iOS and the macOS versions. Not good. It’s been on my to do list for a while to find a way to merge the two journals. I could probably subscribe to the Day One sync service and have it figure out the merging but I didn’t want to subscribe just for that.

I learned somewhere that Day One 2 could export journals as a folder of photos and a JSON file. I figure I could probably write a script to do the merging. So I downloaded Day One 2 on my iPhone and Mac, imported my Day One Classic journals, exported them as JSON to a folder on my Mac, and unzipped them. I also created a merged/ folder where to put the merged journal. The hierarchy looks like this:

$ tree -L 2
├── Journal-JSON-ios/
│   ├── Journal.json
│   └── photos/
├── Journal-JSON-mac/
│   ├── Journal.json
│   └── photos/
└── merged/

I first copied the photo folder from Journal-JSON-ios/ to merged/ and the photos from Journal-JSON-mac/photos/. I was pretty confident that I would end up with the union of all the photos because Day One uses UUIDs to identify each photo. The -n option to cp prevents overwriting files.

$ cp -r Journal-JSON-ios/photos merged/
$ cp -n Journal-JSON-mac/photos merged/photos/

I then ran the script (below) to do a similar merge of the entries, based on the UUIDs. The merging happens by building a dictionary with UUID of each entry as the key and the entry itself as the value. It’s two loops over the iOS and the macOS entries. Entries with the same UUID should have the same contents, unless I’ve edited some metadata on one platform but not the other. I’m not too worried about that.

The output dictionary will be written to the Journal.json file. The entries are sorted chronologically because that’s how it was in the exported journal files, but I doubt it matters.

The output dictionary is written to disk without enforcing the conversion to ASCII since the exported journals are encoded using UTF-8. The indent is there to make the output more readable and diff-able with the exported journals.

import json

with open('./Journal-JSON-ios/Journal.json') as f:
    ios = json.load(f)
with open('./Journal-JSON-mac/Journal.json') as f:
    mac = json.load(f)

# Extract and merge UUIDs
uniques = {entry['uuid']: entry for entry in ios['entries']}
for entry in mac['entries']:
    uniques[entry['uuid']] = entry

# Create the output JSON data structure
output = {}
output['metadata'] = mac['metadata']
output['entries'] = list(uniques.values())
# I'm not sure it matters, but Day One usually exports the entries
# in chronological order
output['entries'].sort(key=lambda e: e['creationDate'])

# ensure_ascii print unicode characters as-is.
with open('merged/Journal.json', 'w', encoding='utf-8') as f:
    json.dump(output, f, indent=True, ensure_ascii=False)

The last step is to zip the journal and photos together, which tripped me up a few times. The Journal.json and the photos/ folder must be at the top level of the archive, so I zip the file from within the merged/ folder and then move it back up one level.

$ cd merged
$ zip -r *
$ mv ..

I could then import in Day One, which created a new Journal, and delete the old one.

I guess I could somewhat automate this to roll my own, DIY, sync between versions of Day One, but I’d rather pay them money once I decide to use Day One frequently again. Still, I really appreciate that the Day One developers picked formats that could be manipulated so easily.