scheduled_resource

#ScheduledResource

This gem is for displaying how things are used over time -- a schedule for a set of "resources". You can configure the elements of the schedule and there are utilities and protocols to connect them:

• Configuration (specification and management),
• Query interfaces (a REST-like API and internal protocols to query the models), and
• A basic Rails controller implementation.

We have a way to configure the schedule, internal methods to generate the data, and a way to retrieve data from the client. However this gem is largely view-framework agnostic. We could use a variety of client-side packages or even more traditional Rails view templates to generate HTML.

In any case, to get a good feel in a display like this we need some client-side code. The gem includes client-side modules to:

• Manage time and display geometries with "infinite" scroll along the time axis.
• Format display cells in ways specific to the resource models.
• Update text justification as the display is scrolled horizontally.

Configuration

A scheduled resource is something that can be used for one thing at a time. So if "Rocky & Bullwinkle" is on channel 3 from 10am to 11am on Saturday, then 'channel 3' is the resource and that showing of the episode is a resource-use block. Resources and use-blocks are typically Rails models. Each resource and its use-blocks get one row in the display. That row has a label to the left with some timespan visible on the rest of the row.

Something else you would expect see in a schedule would be headers and labels -- perhaps one row with the date and another row with the hour. Headers and labels also fit the model of resources and use-blocks. Basic timezone-aware classes (ZTime*) for those are included in this gem.

Config File

The schedule configuration comes from config/resource_schedule.yml which has three top-level sections:

• ResourceKinds: A hash where the key is a Resource and the value is a UseBlock. (Both are class names),
• Resources: A list where each item is a Resource Class followed by one or more resource ids, and
• visibleTime: The visible timespan of the schedule in seconds.

The example file config/resource_schedule.yml (installed when you run schedulize) should be enough to display a two-row schedule with just the date above and the hour below. Of course you can monkey-patch or subclass these classes for your own needs.

The schedule API

The 'schedule' endpoint uses parameters t1 and t2 to specify a time interval for the request. A third parameter inc allows an initial time window to be expanded without repeating blocks that span those boundaries. The time parameters plus the configured resources define the data to be returned.

More About Configuration Management

The ScheduledResource class manages resource and use-block class names, id's and labels for a schedule according to the configuration file. A ScheduledResource instance ties together:

1. A resource class (eg TvStation),
2. An id (a channel number in this example), and
3. Strings and other assets that will go into the DOM.

The id is used to

• select a resource instance and
• select instances of the resource use block class (eg Program instances).

The id could be a database id but more often is something a little more suited to human use in the configuration. In any case it is used by model class method (resource_use_block_class).get_all_blocks() to select the right use-blocks for the resource. A resource class name and id are are joined with a '_' to form a tag that also serves as an id for the DOM.

Once the configuration yaml is loaded that data is maintained in the session structure. Of course having a single configuration file limits the application's usefulness. A more general approach would be to have a user model with login and configuration would be associated with the user.

Installation

Add this line to your application's Gemfile:

gem 'scheduled_resource'

And then execute:

$ bundle

Or install it yourself as:

$ gem install scheduled_resource

Then from your application's root execute:

$ schedulize .

This will install a few image placeholders, client-side modules and a stylesheet under vendor/assets, an example configuration in config/resource_schedule.yml and an example controller in app/controllers/schedule_controller.rb.

Also, if you use

$ bundle show scheduled_resource

to locate the installed source you can browse example classes lib/z_time_*.rb and the controller helper methods in lib/scheduled_resource/helper.rb

Testing

This gem also provides for a basic test application using angularjs to display a minimal but functional schedule showing just the day and hour headers in two different timezones (US Pacific and Eastern). Proceed as follows, starting with a fresh Rails app:

$ rails new test_sr

As above, add the gem to the Gemfile, then

$ cd test_sr
$ bundle
$ schedulize .

Add lines such as these to config/routes.rb

get "/schedule/index" => "schedule#index"
get "/schedule"       => "schedule#schedule"

Copy / merge these files from the gem source into the test app:

$SR_SRC/app/views/layouts/application.html.erb
$SR_SRC/app/views/schedule/index.html.erb
$SR_SRC/app/assets/javascripts/{angular.js,script.js,controllers.js}

and add //= require angular to application.js just below the entries for jquery.

After you run the server and browse to

http://0.0.0.0:3000/schedule/index

you should see the four time-header rows specified by the sample config file.

More Examples

A better place to see the use of this gem is at tv4. Specifically, models app/models/event.rb and app/models/station.rb give better examples of implementing the ScheduledResource protocol and adapting to a db schema organized along somewhat different lines.

Contributing

1. Fork it ( https://github.com/emeyekayee/scheduled_resource/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request