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Display Google Calendars on your Mephisto Blog

2010-02-20T15:54:00Z

This plugin provides a liquid filter for the mephisto blog engine for inclusion of calendars hosted by Google.

Installation

Installation takes three simple steps.

Run ‘gem install runt’
Download the Plugin from Github and put it into your vendor/plugins folder.
Restart your server.

Usage

This plugin offers you a liquid filter. You may call this filter from every liquid template. Provide the liquid filter call with the private url of your calendars ical file. The number at the end specifies the number of items you may get. Example:

{{ 'https://www.google.com/calendar/ical/your.user.name/private-xxxxxxxxxxxxxxxxxxxxxxxxxxxxx/basic.ics' | gcal_shortlist, 7 }}

Augmented Bing Maps

2010-02-15T12:43:00Z

The video of Microsoft’s Bing Maps augmented reality demo at the TED conference last week shows how they integrate Flickr imagery, indoor panoramas, Worldwide Telescope and even live videos to allow a really impressive time travel for certain places.

“We see this space, three-dimensional environment as being a canvas on which all sorts of applications can play out,” said Bing Maps’ Blaise Aguera y Arcas.

A userlogin plugin for mephisto 0.8.2

2010-01-28T20:18:00Z

This little plugin provides you with a protected area for your users on your mephisto blog. Its built to use engines compatible mephisto available in the mephisto version 8.2.

To install this plugin, run:

script/generate plugin_migration
rake db:migrate RAILS_ENV=production

This will make some changes to your production database and will expose a new Userlogin tab to your Mephisto administration interface. From there you can create new userlogins. When creating new userlogins provide a username and a password (Attention! This is designed for ease of use and easy remebering. The passwords are NOT ENCRYPTED! Don’t use this for really important stuff) along with some sites you like to provide inside of the protected area.

You need to create a liquid template for every site you list as protected. So, if you list “family_gallery” as a protected site, you need to create a template called “family_gallery.liquid”. This page will be available at http://yoursite.com/protected/family_galery. The page http://yoursite.com/protected will show a login form (if not logged in) or the conten of “protected_index.liquid” (otherwise).

Ambiguity madness

2009-11-19T16:29:00Z

Coding in hastiness combined with a limited vocabulary late at night will certainly result in comprehension difficulties at the very next morning:

<%= "#{t("role.role")}" %>: <%= "#{t("role."+role.role)}" %>

Kids, don’t try this at home.

Inference on the Semantic Web

2009-11-05T11:36:00Z

This is a very informative slideshare on inference and the power of the Semantic Web. To emphasize the potential of the Semantic Web, Myungjin Lee used RDF and OWL constructs to represent the statements of his slides. Very impressive, though.

Inference on the Semantic Web

View more presentations from Myungjin Lee.

Sections and Pagination in Mephisto 0.8.2

2009-11-03T23:01:00Z

It is wildly known and even somewhat accepted, that the pagination mechanism of Mephisto 0.8.2 is very buggy and non-functional. However, paging blog posts is a feature that kills a blog engine if it does not work. Fortunately, James of Rails Talk wrote a nice tutorial for bringing up paging again. His description is easy done and works well, as long as you have only one section, the mandatory Home section.

However, blogs with multiple sections (like this one) faced a strange problem with doubled section names in URLs. A workaround with separate URL helpers for each section exists, but is utterly unhandy. After some investigation it turns out, that a small change to the original tutorial solves the whole section difficulty. The original instruction was to add the following to mephisto_paged_article_list/lib/paged_article_list/link_helpers.rb:

def path_for( path_info, page_number )
  return path_info[:path] + "/page/" + page_number.to_s
end

Now, when using this with multiple sections, path_info[:path] contains the name of the current section (or nothing, if the section is Home). Moreover, the produced path is a relative path, so that the returned string will be appended to the base URL that already contains the section name as the last part. This is where the doubled section names come from. To remove this behaviour, we need to change the code a little bit:

def path_for( path_info, page_number )
  path = path_info[:path] + '/page/' + page_number.to_s
  path_info[:path].blank? ? path : '/' + path
end

With this code, we assemble the path the same way, but precede it with a ’/’ whenever the section name is not empty. This gives us a non-relative URL without the doubled section name and thus correct pagination URLs for all sections.

HTML5 and Semantics

2009-11-03T21:16:00Z

If you ever did a web project that featured dated entries, like articles in a blog, you may have typed something like


  
    Home
    Link 1
    Link 2
    Link 3

and

2009-11-03

Now, this is higly understandable for any developer and for most of your users, but not for crawlers and the like. As this is the central issue in the field of the semantic web, there are already some solutions that address this problem. You could, for example, enhance your code with semantic markup like RDFa or microformats.

But then, that may be overkill. Why not just use the possibilities that come with the shiny new HTML5? Most of the modern browsers already support at least some of the new features. Features, in this case, are new text-level semantic tags that allow a lightweight semantic annotation of content. With the use of these new tags, our first example would read:


  
    Home
    Link 1
    Link 2
    Link 3

This enables screen readers, mostly used by people with limited sight, to jump directly to the sites menu and allow a quick navigation. Even more fun comes with the second example:

2009-11-03

This promotes the human readable string to a full machine readable timestamp that tells every crawler/browser/whatever the publication date of the embracing document.

If you want to learn more about these two and all the other cool new tags, please have a look at Dive into HTML5, a clearly structured and neatly designed publication by the great Mark Pilgrim.

Martian Notation for Topic Maps

2009-11-02T13:41:00Z

Many people tend to understand structures much better when they are properly visualized. So it comes to no surprise that there were some proposals for a Graphical Topic Map notation (GTM) made in the past. The guys from musicDNA recently stepped into the spotlight with their latest publication that illustrates Topic Maps by using a Martian as example. Unsurprisingly, they call it Topic Map Martian Notation.

Topic Maps Lab moves

2009-11-01T11:42:00Z

In the past days, the Topic Maps Lab has moved in different ways. First of all, we had to leave our own 9th floor offices in downtown and moved to the ground floor of the computer science department building. The new offices have a sgnificant lack of look-out but give us much shorter paths to the rest of the department. Fotos will follow, but don’t expect something spectacular.

Aside from moving geographically, we constantly move forward to TMRA 2009. With only ten days to go, the conference organization and proceedings are moving towards completion. I, for my part, finished the proceedings on last thursday and will rouse the print office on tuesday, so you all will have a freshly printed proceedings book in your conference package.

NB: If you are coming to TMRA 2009 and are in need of getting something to eat (beyond the great conference catering), I strongly recommend a visit at the newly opened Vapiano Restaurant in downtown Leipzig. They serve great italian food, freshly made before your eyes with fair prizes.

Simon's cat: Hot Spot

2009-09-29T08:40:00Z

A demanding cat goes to great lengths in order to warm up and become the centre of attention.

Simon's Cat: The Fly Guy

2009-08-02T11:10:00Z

The cat is back. Simon Tofields lates masterpiece pictures a scene that every cat owner is familiar with. A playful cat and an agile fly is always good for some wrecking.

Howto write your own plugin for mephisto

2009-08-01T07:00:00Z

On my crusade on gaining more insight into mephisto, I felt it would be helpful to see how this plugin thingy works. I found, that writing your own mephisto plugin is not as hard as you would think. In fact, it is real easy. Start with generating the plugin skeleton.

# ruby script/generate plugin NameOfYourPlugin

Now, define your method inside lib/name_of_your_plugin.rb.

module NameOfYourPlugin

  def link_to_something_strange(object_to_yield)
    url =  'http://example.com/api?'
    url += "id=#{object_to_yield['some_attribute']}" 
    content_tag :a, 'foobar', :href => url
  end
end

After that, open init.rb and paste in the following:

require 'name_of_your_plugin'
Liquid::Template.register_filter NameOfYourPlugin

The first line is the standard registration you need for every rails plugin. The second line registers whatever method you defined as a global liquid filter. If you like to add another filter, just put the method inside lib/name_of_your_plugin.rb and it will be automagically registered.

The last step is to include your fresh filter into the liquid template.

{{ object_to_yield | link_to_something_strange }}

That’s all folks. Really. Be sure to check the first fruit of this new gained insights.

A gravatar plugin for mephisto

2009-07-31T07:00:00Z

Although the mephisto blog system contains a possibility to display a gravatar for a specific comment, I decided to do my own gravatar plugin, because I wanted to display gravatars not just on comments. You can download the first version from GitHub.

Installation

Installation is real simple. Just download it and put it into your vendor/plugins folder. After that, restart your server.

Options

You may configure the following options in lib/mephisto_gravatar_plugin.rb:

default = 'identicon'

The guys at gravatar.com offer you three default avatars, in case there is no gravatar associated with that email address. Correct values for would be identicon, monsterid and wavatar.

rating = 'pg'

As you may know, all gravatars include a rating, done by the holder of the email. This rating may be one of the following: g, pg, r or x. To get only the gravatars you want, set the correct rating.

Usage

You can stuff any email into the filter, in order to get its gravatar. Sample usages:

{{ article.author.email | get_gravatar }}
{{ comment.author_email | get_gravatar, 30 }}

Note the object independence. An email address is all you need. You may deliver the desired size as an option to the filter. Leaving that out brings up the standard size of 80×80px.

There is still work to do. I think about pre-caching all gravatars for the registered bloggers. But that is subject to later exploration.

A weekly calendar plugin for rails

2009-07-29T18:56:00Z

Something that bugged me with its non-existence in the past was a rails plugin that would display a weekly calendar, while being highly configurable. And by saying highly configurable, I mean it should have options for its look, its operation and, beyond that, it should accept any kind of data to display. As there was no such plugin, I did it myself. So today, I proudly present you the weekly_schedule plugin for rails.

Installing

This plugin is really easy to install. Just download it from GitHub and place it into the vendor/plugins directory.

Usage

The simplest possible call in your code would be

schedule()

which generates a plain calendar (which can then be customized using CSS) for the current week. However, this may be customized in a variety of ways—changing the default CSS classes, populating the individual day entries with appointments, and so on. Generating a calendar that shows the whole christmas week 2009, starting from monday, would require the following call:

schedule(:day => Date.civil(2009, 12, 25), :first_day_of_week => 1)

A more typical use case for schedules is to show what happening today or the very next time. The following code generates a calendar that always starts with today:

schedule(:first_day_of_week => Date.today.cwday)

A more convenient variant of this is the following:

schedule(:first_day_of_week => Date.today.cwday - 3)

This calendar starts three days earlier and therefore keeps today right in the middle of the display

Options

As I said earlier in this post, I wanted this plugin to be as customizable as possible. So it is now packed with different options for the CSS classes:

:table_class
:month_name_class
:day_name_class
:day_class

An additional ‘weekend’ class is applied to weekend days.

The following options are available for customizing the behaviour of the calendar:

:day

This option specifies the day, whose week shall be displayed. Defaults to Date.today

:abbrev

This option specifies how the day names should be abbreviated. Use (0..2) for the first three letters, (0..0) for the first, and (0..-1) for the entire name.

:first_day_of_week

This renders a calendar starting on a specific weekday. Use 1 for Monday up to 7 for Sunday. This option applies only if :only_workdays is set to false.

:show_today

Highlights today on the calendar using the CSS class ‘today’. Defaults to true.

:only_workdays

Turns off weekend display. Defaults to false. When turned on, the value of :first_day_of_week is fixed to 1 (monday). If :day is a saturday or sunday, the following week is shown.

:show

Now, this gives us a hint where to search for info to show and is handed over to details(). Defaults to nil (showing no info).

A word about details()

This function evaluates if something is given in in the :show option. The following should give you a rough idea how this may be useful. Imagine, you’ve given @this_weeks_appointments as an array via the :show option. The value in date is the currently processed day as a Date object.

def details(date, options)
    if options[:show]
      appointments = options[:show].select{|a| a.date == date}.sort_by{|t| t.time}
      appointments.map{|a| "#{a.time} #{a.place}"}
  else
    'Nothing to do today'
  end
end

Feel free to download the plugin from GitHub. If you have some comment or a great idea, please let me know.

The Semantic Web Landscape 2009

2009-07-19T12:52:00Z

Long time no post. Learning for exams keeps me busy. But while learning, I found this neat presentation that was created by Lee Feigenbaum of Cambridge Semantics.

These slides were originally a tutorial presented for the SIG preceding the May 2009 meeting of the PRISM Forum. They attempt to give a survey of the technologies, tools, and state of the world with respect to the Semantic Web as of the first half of 2009. You may note the complete absence of topic maps, which clearly says, that more topic maps evangelization is needed.

Semantic Web Landscape 2009

View more presentations from LeeFeigenbaum.