On This Day

A WordPress plugin that shows historical events which happened on today's date, and people born on it — 15 of each by default (configurable), pulled from Wikipedia's "On this day" API, sorted oldest to newest. Use it as a shortcode on any page/post, or drop it in as a widget.

Features

• Shortcode: [on_this_day] — add it to any page or post.
• Widget: "On This Day" widget under Appearance > Widgets, backed by the same renderer as the shortcode.
• Data source: Wikipedia's public onthisday/events REST API, queried for the current month/day.
• Random selection, sorted by year: the API returns a full day's pool of events (often 40+); the plugin randomly picks the configured number from that pool, then displays them sorted by year, oldest to newest.
• Born on this day: below the events, the same number of people born on today's date, picked at random from Wikipedia's births list (often 200+) and sorted by birth year. If the births list can't be loaded, the events still show.
• Faith entries: entries about church history and people of faith can be favoured or shown on their own. An entry counts as faith-related when its text, or a Wikipedia article it links to, contains one of the faith keywords (editable in Settings). By default about a third of each list are faith entries when the day has them; faith="1" puts them first and onlyfaith="1" shows only them.
• Today in the Church: with faith="1" or onlyfaith="1", a short section between the events and the births gives the day's celebrations from the Roman Catholic liturgical calendar (including movable feasts such as Easter, Pentecost and the Advent Sundays), the church season and week, and up to five Christian feast days from Wikipedia.
• Daily caching: each day's Wikipedia lists are downloaded once and shared by every shortcode and widget on the site, whatever their count or mode, and the day's selection is cached until local midnight, so every visitor sees the same list and the plugin isn't hitting Wikipedia on every page load. If Wikipedia can't be reached, the plugin waits 15 minutes before trying again rather than slowing every page view.
• Attribution footer: the list ends with "WP On This Day news sourced from Wikipedia (CC BY-SA 4.0) -sysop- · Source on GitHub", where Wikipedia links to that day's Wikipedia article, CC BY-SA 4.0 links to the license, and Source on GitHub links to this repository; -sysop- is plain text. It appears wherever the shortcode or widget is used. Wikipedia's text is available under the Creative Commons Attribution-ShareAlike 4.0 license, so the footer credits the source and links to that license; the Wikipedia article it links to lists its authors in the page history.
• Admin setting: Settings > On This Day lets you set the default number of events shown (1-100, default 15); the births section uses the same number. A shortcode's count attribute overrides this per instance.

Usage

Shortcode

Add to a page or post:

[on_this_day]

Override the count for a single instance:

[on_this_day count="10"]

Faith entries

Each list (events and births) can favour faith-related entries. There are three modes:

If both are given, onlyfaith wins. They combine with count, e.g. [on_this_day onlyfaith="1" count="10"]. These switches accept 1, true, yes or on; anything else, such as 0, no or off, means off. How many faith entries a day has varies a lot: on a quiet day there may be only two or three in each list, which is why the default and faith="1" fill the rest at random.

The keywords are whole words, not case-sensitive, and are matched against both the entry text and the short descriptions of the Wikipedia articles it links to (which is how "Johann Sebastian Bach leads a cantata" is recognised: the cantata's article is described as a church cantata). The defaults are:

church, pope, priest, theologian, bishop, archbishop, cardinal, pastor, lutheran, protestant, catholic, missionary, nun, abbot, evangelist

"Minister" is deliberately left out, because almost every match is a government minister. Edit the list under Settings > On This Day; clearing it restores the defaults.

Today in the Church

With faith="1" or onlyfaith="1" (and the widget's matching choices), a "Today in the Church" section appears as the second section, between "On This Day" and "Born on This Day". It is not shown in the default mix. The church option overrides that:

For example:

Today in the Church: October 22 ⚪ Saint John Paul II, pope (optional memorial) Thursday, 29th week in Ordinary Time Also commemorated: Abercius of Hieropolis · Cordula of Cologne · Donatus of Fiesole · Marcus of Jerusalem · Mellonius

• The day's celebrations come from the Church Calendar API, which computes the Roman Catholic General Roman Calendar in English, including the feasts whose dates move every year. Each celebration shows its rank (solemnity, feast, memorial, optional memorial) and a dot in its liturgical colour. On a plain weekday only the season line shows.
• Also commemorated lists up to five Christian feast days for the date from Wikipedia's "On this day" holidays list (Catholic, Anglican, Lutheran and Orthodox commemorations), each linked to its article, leaving out any saint the calendar already named.
• Both parts are cached until midnight. If one source fails, the other still shows; if both fail, the section is hidden and the rest of the page is unaffected. A failed request is retried after an hour rather than on every page load.
• When the calendar is shown, the footer adds "Liturgical calendar from the Church Calendar API".

The Church Calendar API is free software (LGPL 3) run by a volunteer, Jakub Pavlík, and is intended for "developers of websites and other Internet applications". It is only available over plain http://. The plugin fetches it server-side and escapes everything it displays, so this causes no mixed-content warnings, but the request itself is not encrypted.

Widget

Add the "On This Day" widget to any widget area (Appearance > Widgets). It has an optional title, an optional count override (leave blank to use the site-wide default), a "Faith entries" choice with the same three modes as the shortcode, and a "Today in the Church" choice: Automatic (shown with the two faith choices, as the shortcode does by default), Always show or Never show.

"On This Day" page

Create a normal WordPress Page, add the [on_this_day] shortcode to its content, and publish. The page will always reflect the current day's events automatically — no further setup needed.

Settings

Go to Settings > On This Day to set the default number of events (1-100, default 15) shown by the shortcode and widget, and to edit the faith keywords.

Requirements

• WordPress 5.0+
• Outbound HTTPS access to en.wikipedia.org from the server
• For the "Today in the Church" section only: outbound HTTP access to calapi.inadiutorium.cz

Installation

Option A: Upload the zip via wp-admin

1. Download the plugin zip (e.g. WP-on-this-day-1.0.1.zip).
2. In wp-admin, go to Plugins > Add New Plugin > Upload Plugin.
3. Choose the zip file and click Install Now.
4. Click Activate Plugin.
5. Add the [on_this_day] shortcode to a page, or add the "On This Day" widget to a widget area.

Option B: Manual install (FTP / local dev)

1. Unzip the plugin so you have a WP-on-this-day/ folder containing on-this-day.php, includes/, and assets/.
2. Copy that folder into your site's wp-content/plugins/ directory (via FTP/SFTP, or directly on disk for a local dev site, e.g. Local by Flywheel: app/public/wp-content/plugins/).
3. In wp-admin, go to Plugins and click Activate under "On This Day".
4. Add the [on_this_day] shortcode to a page, or add the "On This Day" widget to a widget area.

Installing from GitHub

The repository root is the plugin (no build step, no dependencies), so GitHub's Code > Download ZIP works for a quick install. GitHub names the folder WP-On-this-day-main, so WordPress installs it under that name; uploading a differently named zip later installs a second copy instead of updating the first. For a clean install that updates in place, build a release zip (below).

A git clone carries files a web server should not serve. Chiefly .git, which holds the project's entire history. (GitHub's Download ZIP is an export, so it has no .git; this applies to a working copy you cloned or copied from your own machine.) Release zips leave out this README and the docs/ folder, so an installed plugin has no Markdown files for anyone to read. For copies installed some other way, the plugin ships an .htaccess that refuses .git, *.md, logs and editor leftovers, and every directory has an index.php so nothing can be listed. (An index.php only stops a folder being listed; it cannot stop a file being requested by name, which is why the server rules below are needed.) .htaccess is read by Apache only, so on nginx add this to the server block:

location ~ /wp-content/plugins/.*/\.(git|svn)(/|$) { deny all; }
location ~ /wp-content/plugins/.*\.(md|log|ya?ml|lock)$ { deny all; }

The surest fix is not to deploy .git at all: install a release zip built as below.

If you zip the plugin by hand

Building with git archive (below) is strongly preferred. If you make the zip manually from a clone or working copy, do not include any of these:

• .git/ (the whole project history), .svn/, and .github/
• .gitignore and .gitattributes
• docs/ and README.md (documentation for the repository, not part of the plugin; read them on GitHub)
• any .zip files, such as an earlier build sitting in the same folder
• editor and OS leftovers: .idea/, .vscode/, .DS_Store, Thumbs.db, desktop.ini
• logs, backups and scratch files: *.log, *.bak, *.orig, *.rej, *.swp
• anything of your own: notes, test files, credentials or .env files

What belongs in the zip is on-this-day.php, uninstall.php, LICENSE, .htaccess, the index.php files, and the includes/ and assets/ folders. Put them inside a single top-level folder named WP-on-this-day, so the zip contains WP-on-this-day/on-this-day.php. Check the finished zip by opening it before you upload. The plugin's Install health panel will warn you if a stray .git, .gitignore or .gitattributes slips through.

Install health

The plugin checks itself, because documentation only helps people who read it. Settings > On This Day has an Install health panel, and an administrator sees a notice on the Plugins screen, if:

• the folder is not named WP-on-this-day (for example WP-On-this-day-main from Download ZIP), which would make the next proper install a second copy;
• a second copy of the plugin is installed in wp-content/plugins;
• repository-only files such as .gitignore, .gitattributes or .github are present, which a release zip never contains and usually means the zip was made by hand from a working copy;
• a .git directory is present. The plugin makes one request to your own site to test whether the server actually serves it (the result is cached for a day), and reports an error if it does.

After activating

• Optionally visit Settings > On This Day to change the default number of events shown (default 15).
• Create a Page, add the [on_this_day] shortcode to its content, and publish. The page will always reflect the current day automatically.

Building a release zip

There is nothing to compile. A release zip is the tracked files inside a WP-on-this-day/ folder. From the repository root (requires Git):

git archive --format=zip --prefix=WP-on-this-day/ -o WP-on-this-day-<version>.zip HEAD

Use the version from the plugin header in on-this-day.php. This builds from the last commit (so uncommitted or stray files never ship), writes the forward-slash paths WordPress requires, and leaves out repo-only files (.gitignore, .gitattributes, docs/, README.md). Upload the result via Plugins > Add New Plugin > Upload Plugin; if a previous version is installed, choose Replace current with uploaded.

Avoid building the zip with PowerShell's Compress-Archive on Windows. It can write backslash path separators, which produce broken installs on Linux hosts.

Documentation

• Setting up WordPress for a BBS experience: site setup, security, membership and menu guidance for running this and the other BBS-style plugins.

The docs/ folder is for the repository only and is left out of release zips. If it ends up on a site anyway (a hand-made zip), its index.php stops it being listed and the plugin's .htaccess refuses .md files, so visitors still cannot read it.