author / date info from git

[skwde]

Description

Is it possible to get author / date from git?

A possible use case is a webpage, were

• published corresponds to the first commit of the file
• last modified to the latest commit date

Similarly for authors.

For mkdocs similar functionality is available via plugins:

• https://github.com/ojacques/mkdocs-git-committers-plugin-2/
• https://github.com/timvink/mkdocs-git-revision-date-localized-plugin

[mcanouil]

Write your own filter or pre-render script to populate date and author metadata.

[Steinthal]

@skwde, have a look at quarto-rev-history. It's three years old, but you can probably use it as a starting point.

[mcanouil]

Here is a quick & dirty Lua filter (no checks for nil values, if Git is available, if there is a commit, etc.):

---
title: "Git Author Date"
filters:
  - path: filter.lua
    at: pre-ast
---

{{< lipsum 1 >}}

--[[
# MIT License
#
# Copyright (c) 2025 Mickaël Canouil
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
]]
function Meta(meta)
  -- Get the input file path
  local input_file = quarto.doc.input_file

  if not input_file then
    return meta
  end

  -- Get the author of the first commit
  local author_handle = io.popen(
    string.format(
      'git log --reverse --format="%%an" -- "%s" | head -n 1',
      input_file
    )
  )
  local author = author_handle:read("*a"):gsub("%s+$", "")
  author_handle:close()

  -- Get the date of the first commit
  local date_handle = io.popen(
    string.format(
      'git log --reverse --format="%%ad" --date=short -- "%s" | head -n 1',
      input_file
    )
  )
  local date = date_handle:read("*a"):gsub("%s+$", "")
  date_handle:close()

  -- Set metadata only if not already defined
  if author ~= "" and not meta.authors then
    meta.authors = pandoc.MetaInlines(pandoc.Str(author))
  end
  if date ~= "" and not meta.date then
    meta.date = pandoc.MetaInlines(pandoc.Str(date))
  end

  return meta
end

[coatless]

@mcanouil would you be okay if I promote this over to an extension?

[mcanouil]

Yes. Go ahead!