Render iCalendar feeds on the web

We all use calendars. Some digital calendars have a standardized interface called iCalendar (see Wikipedia). An example are Meetup.com Groups or Google Calendar.

Let's dig into one use case: Meetup is great to organize your local meetup. Meetup also has great sharing and API options. They do support embedding the meetup group together with the next meetup. However, there is no out-of-the-box support to embed your schedule to another website.

At 200ok, we support some websites that do want this kind of integration. Therefore we have written a simple microservice in Ruby with the Sinatra framework which solves this issue by accessing the Meetup calendar feeds API. This iCalendar2web microservice is for the times when you do have an iCalendar feed (for example a meetup group or a Google calendar), and you want to show them quickly on a website. The microservice either yields a ready to use HTML table that you can inject, or it returns the events in a simplified JSON structure.

You can host this project yourself or you can use a hosted SaaS version (see below).

Please find the repository here: https://github.com/twohundredok/iCalendar2web

Demo

For example Lambda Zen Temple posts the daily meditation schedule and several other events to Meetup and integrates the same events into their website. You can see this as a demo here.

Plain

Integrated into a website

JSON Response

Request:

GET https://icalendar-to-web.herokuapp.com/calendar/Zen-Meditation-Schweiz?filter=retreat&format=json

Results:

[
  {
    "name": "One-Day-Retreat",
    "start_time": "2019-08-25T10:00:00.000+02:00",
    "end_time": "2019-08-25T17:00:00.000+02:00"
  },
  ...
]

Alternative use case

You can do the same for any calendar application that exports iCalendar via HTTP. For example, if you want to embed a Google calendar filtered down to specific keywords to your website.

Use as a Service

iCalendar2web is generic in that it can render any public Meetup schedule. Instead of installing iCalendar2web yourself, you can use this hosted version:

https://icalendar-to-web.herokuapp.com/calendar/YourQualifier

With YourQualifier being the Meetup Group URL, eg "Zen-Meditation-Schweiz".

iFrame

If you want to embed it to your own website, use an iframe - similar to Youtube:

<iframe width="800px" height="800px"
    src="https://icalendar-to-web.herokuapp.com/calendar/Zen-Meditation-Schweiz"
    frameborder="0">
</iframe>

Load via Ajax

You can also load the html via Ajax into your page. For example if you want to show a loading spinner upfront. The required access-control headers are set on this service, so no worries about CORS.

$.get("https://icalendar-to-web.herokuapp.com/calendar/MyMeetupGroup", function(data) {
  $("#my-schedule").html(data);
});

Configuration

For iCalendar2web to run, you need to set a base URL. Most generic calendar applications will export their various calendars using a URL scheme.

For example for meetup.com:

export ICALENDAR_URL="https://www.meetup.com/PLACEHOLDER/events/ical/"

For example for a Google calendar:

export ICALENDAR_URL="https://calendar.google.com/calendar/ical/PLACEHOLDER.calendar.google.com/public/basic.ics"

The PLACEHOLDER is the param you enter via YourQualifier.

Parameters

iCalendar2web takes the following parameters:

filter: takes a RegExp to filter the name of the meetup
show_from_to: when set, this changes the default table columns from

date time

to

date from date to
limit: set a limit of how often a specific meetup shall be repeated in the table, the default is 25. This flag is not supported for the json response.
format: when set to json, it returns the results as JSON and not as an HTML table

Examples

/calendar/YourQualifier
- will show all events with the table columns
  
  date time
/calendar/YourQualifier?format=json
- will show all events rendered in a JSON list
/calendar/YourQualifier?limit=5
- will show up to 5 events per category with the table columns
  
  date time
/calendar/YourQualifier?limit=5&filter=retreat
- will show up to 5 events that include 'retreat' in the title with the table columns
  
  date time
/calendar/YourQualifier?limit=5&filter=retreat&show_from_to=1
- will show up to 5 events that include 'retreat' in the title with the table columns
  
  date from date to

Deployment

Heroku

Please refer to the documentation of Heroku to install

https://devcenter.heroku.com/articles/rack

Running

Install Ruby (using rbenv in this example):

rbenv install

Install dependencies:

gem install bundler
bundle

Configure your iCalendar target URL by setting (more information see Configuration):

export ICALENDAR_URL="https://www.meetup.com/PLACEHOLDER/events/ical/"

Run the application:

rackup config.ru

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