Org-mode Email Reminders via XSLT
Posted: 8th March 2025
About
Relying more and more on org-mode to organise my life, I have been
looking for ways to remind myself of TODO deadlines beyond GNU
Emacs. I have been finding the following solution useful for sending
myself email reminders every morning, both for work and home TODOs.
In short, this is a simple cronjob 2 that:
- retrieves my org files from a private git repository,
- converts them to XML 1 ,
- transforms them into a nicely formatted HTML email with XSLT 3 , and
- sends them using mutt (via msmtp)
Currently the email displays the number of days until certain deadline, as I find this way of thinking about time a bit easier.
Anyway, this was another excuse for me to practice writing XSL(T) stylesheets. Hopefully others might find this kind of approach useful as well 🙂.
Stylesheet
Here is the current iteration of the stylesheet generated with the
help of a certain LLM chatbot. It takes a single parameter type that
populates the title of the table. I hope to keep improving this as my
knowledge of XSLT gets better. (Up to date version can be sourced via
GitHub.)
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:org="https://nwalsh.com/ns/org-to-xml"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs org">
<xsl:output method="html" indent="yes"/>
<xsl:variable name="today" select="current-date()"/>
<xsl:param name="type"/>
<xsl:template match="/">
<xsl:text disable-output-escaping="yes"><!DOCTYPE html></xsl:text>
<html>
<head>
<title>TODO Reminder</title>
</head>
<body style="font-family: Arial, sans-serif; margin: 20px;">
<h1 style="color: #333366;"><xsl:value-of select="$type"/></h1>
<table style="border-collapse: collapse; width: 100%; margin-top: 20px;">
<tr>
<th style="width: 33%; border: 1px solid #ddd; padding: 10px; text-align: left;
background-color: #f4f4f4;">Title</th>
<th style="width: 33%; border: 1px solid #ddd; padding: 10px; text-align: left;
background-color: #f4f4f4;">Days Left</th>
<th style="width: 33%; border: 1px solid #ddd; padding: 10px; text-align: left;
background-color: #f4f4f4;">Date</th>
</tr>
<xsl:apply-templates select="//org:headline[@todo-keyword='TODO']/org:deadline">
<xsl:sort select="xs:date(concat(org:timestamp/@year-start, '-',
format-number(org:timestamp/@month-start, '00'), '-',
format-number(org:timestamp/@day-start, '00')))"
data-type="text" order="ascending"/>
</xsl:apply-templates>
</table>
</body>
</html>
</xsl:template>
<xsl:template match="org:headline[@todo-keyword='TODO']/org:deadline">
<xsl:variable name="month" select="format-number(org:timestamp/@month-start, '00')"/>
<xsl:variable name="day" select="format-number(org:timestamp/@day-start, '00')"/>
<xsl:variable name="hour" select="format-number(org:timestamp/@hour-start, '00')"/>
<xsl:variable name="minute" select="format-number(org:timestamp/@minute-start, '00')"/>
<xsl:variable name="hour-end" select="format-number(org:timestamp/@hour-end, '00')"/>
<xsl:variable name="minute-end" select="format-number(org:timestamp/@minute-end, '00')"/>
<xsl:variable name="deadline-date"
select="xs:date(concat(org:timestamp/@year-start, '-', $month, '-', $day))"/>
<xsl:variable name="days-left" select="days-from-duration($deadline-date - $today)"/>
<xsl:variable name="full-timestamp">
<xsl:choose>
<xsl:when test="org:timestamp/@hour-start and
org:timestamp/@minute-start and
org:timestamp/@hour-end and
org:timestamp/@minute-end">
<xsl:variable name="start-time">
<xsl:value-of select="format-dateTime(xs:dateTime(concat(
org:timestamp/@year-start, '-', $month, '-', $day,
'T', $hour, ':', $minute, ':00Z')),
'[FNn], [D1o] [MNn] [Y0001], [h01]:[m01] [P]'
)"/>
</xsl:variable>
<xsl:variable name="end-time">
<xsl:value-of select="format-time(xs:time(concat($hour-end, ':', $minute-end, ':00Z')),
'[h01]:[m01] [P]')"/>
</xsl:variable>
<xsl:value-of select="concat($start-time, ' to ', $end-time)"/>
</xsl:when>
<xsl:when test="org:timestamp/@hour-start and org:timestamp/@minute-start">
<xsl:value-of select="format-dateTime(xs:dateTime(concat(
org:timestamp/@year-start, '-', $month, '-', $day, 'T',
org:timestamp/@hour-start, ':', org:timestamp/@minute-start, ':00Z')),
'[FNn], [D1o] [MNn] [Y0001], [h01]:[m01] [P]'
)"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="format-date(xs:date(concat(
org:timestamp/@year-start, '-', $month, '-', $day)),
'[FNn], [D1o] [MNn] [Y0001]')"/>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:if test="$days-left lt 0">
<tr>
<td style="width: 33%; border: 1px solid #ddd; padding: 10px;">
<xsl:value-of select="../org:title"/>
</td>
<td style="width: 33%; border: 1px solid #ddd; padding: 10px;">
<span style="color: red; font-weight: bold;">Overdue!</span>
</td>
<td style="width: 33%; border: 1px solid #ddd; padding: 10px;">
<xsl:value-of select="$full-timestamp"/>
</td>
</tr>
</xsl:if>
<xsl:if test="$days-left ge 0">
<tr>
<td style="width: 33%; border: 1px solid #ddd; padding: 10px;">
<xsl:value-of select="../org:title"/>
</td>
<td style="width: 33%; border: 1px solid #ddd; padding: 10px;">
<xsl:choose>
<xsl:when test="$days-left eq 0">
<span style="color: red; font-weight: bold;">Due Today!</span>
</xsl:when>
<xsl:when test="$days-left eq 1">
<span style="color: red; font-weight: bold;">1 day left!</span>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$days-left"/> days left
</xsl:otherwise>
</xsl:choose>
</td>
<td style="width: 33%; border: 1px solid #ddd; padding: 10px;">
<xsl:value-of select="$full-timestamp"/>
</td>
</tr>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
Elisp
As I have set this up as a shell script, I convert my org files using Emacs in batch mode and call a specific function, for example:
(defun convert-org-to-xml ()
(let ((directory (expand-file-name "org/path" default-directory)))
(when (file-directory-p directory)
(dolist (file (directory-files directory t "\\.org$"))
(when (file-regular-p file)
(with-current-buffer (find-file-noselect file)
(om-to-xml)
(save-buffer)
(kill-buffer)))))))
emacs \ -Q \ --batch \ -l "./el/transform-org.el" \ -f convert-org-to-xml
Shell
The converted files can then be transformed using an XSLT processor and sent via email, for example:
java -cp saxon-he-12.5.jar net.sf.saxon.Transform \
-t \
-s:TODO.xml \
-xsl:org-notifications.xsl \
-o:TODO-HOME.html \
type="HOME TODO"
mutt -e "set content_type=text/html" \
-s "TODO Reminder" \
user@email.com < TODO-HOME.html
Footnotes
| [1] | https://github.com/ndw/org-to-xml |
| [2] | In this case running on a Rasberry Pi. |
| [3] | I generally use Saxon HE for this kind of stuff. |