Adding planted and last tended dates to pages in my digital garden

planted: 29/03/2024last tended: 10/04/2024

1. Why

It's a nice practice to display the date that a page was created, and, more importantly, last modified, in your digital garden. It gives the reader a clue as to the status of the information contained in the page.

2. How

I already have 'This page last updated: …' at the very bottom of every page.

But I'd prefer it right at the top. And I'd also like to indicate when the page was created, too. I don't want it to be be too prominent/distracting, but at the same time I have some pretty old pages knocking around now and I'd like people to be aware that they might be outdated.

It'll be a matter of (a) pulling the times out from somewhere; and (b) being able to render them.

2.1. Pulling times out

I'm currently using the date value for modified time that you get when you use the :with-date flag in org-publish. But it doesn't provide creation time.

I have ctimes and mtimes on all files(?), courtesy of the org-roam-timestamps package. So in theory I can use those. They are file-level properties name ctime and mtime. As far as I can tell, they don't exist in the info plist that's passed around during the export process.

So, for now, I've cobbled together a way to pull them out from the buffer using org-property-values.

(let* ((ctime-property (car (org-property-values "ctime")))
       (mtime-property (car (org-property-values "mtime")))
       (ctime-date (if ctime-property
                       (car (split-string ctime-property))
                     nil))
       (mtime-date (if mtime-property
                       (car (split-string mtime-property))
                     nil))
       )

2.2. Rendering them

So the rendering is going to be in my override of org-html-template (of which I have a note to self saying that I shouldn't really be overriding it…)

As a simple example:

(defun commonplace/format-date (date-str)
  (let ((year (substring date-str 0 4))
        (month (substring date-str 4 6))
        (day (substring date-str 6 8)))
    (format "%s/%s/%s" day month year)))

(defun commonplace/org-html-template (contents info)
  (let* ((ctime-property (car (org-property-values "ctime")))
         (mtime-property (car (org-property-values "mtime")))
         (ctime-date (if ctime-property
                         (car (split-string ctime-property))
                       nil))
         (mtime-date (if mtime-property
                         (car (split-string mtime-property))
                       nil))
         )
    (concat "<html>"
            (if ctime-date (concat "ctime: " (commonplace/format-date ctime-date)))
            " "
            (if mtime-date (concat "mtime: " (commonplace/format-date mtime-date)))
            "</html>")))

Check out my publish.el for the real function that I'm using.

3. Elsewhere

3.1. In my garden

Notes that link to this note (AKA backlinks).

3.2. In the Agora

Anagora - Adding planted and last tended dates to pages in my digital garden