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New in release 0.2.0

This release implements basic tracking of short URL usage. It tracks the following data:

• IP address of request
• user agent of request
• time of request

It renders the number of hits against a short URL in the last month, and over all, in the show view. These values are calculated with a private class method on ShortUrlHit: ShortUrlHit::count_in_period(begin_date, end_date)–which should be called by public class methods, such as ShortUrlHit::count_last_30_days.

It also switches the app to using semantic versioning.

The weird roadblock I hit with a migration

I ran into a strange database migration behavior (Rails 5.1 and Postgres 9.6), where adding a reference inside a create_table block would fail. I used the in-built model generator to get the migration: rails g model ShortUrlHit ip_address:string user_agent:string short_url:references, which generated the following migration, to which I added the index bit:

# This doesn't work
class CreateShortUrlHits < ActiveRecord::Migration[5.1]
  def change
    create_table :short_url_hits do |t|
      t.reference :short_url, foreign_key: true
      t.string :ip_address
      t.string :user_agent

      t.timestamps
    end
    add_index :short_url_hits, :short_url_id
  end
end

Weirdly, every time I ran the migration, I got an error reporting that an index already existed on the column. I rammed my head against this for a but, but finally gave up and rewrote the migration as follows:

# This works
class CreateShortUrlHits < ActiveRecord::Migration[5.1]
  def change
    create_table :short_url_hits do |t|
      t.string :ip_address
      t.string :user_agent

      t.timestamps
    end
    add_reference :short_url_hits, :short_url, index:       true,
                                               foreign_key: true
  end
end

Moving the reference command outside the create_table block, and declaring that it needed to be indexed and it was a foreign key all at the same time seems to have worked.

I’m not 100% sure why it didn’t work the first way, but did the second, especially since the first was a Rails generated migration (other than the index), but… ¯\_(ツ)_/¯. It works fine the other way.

That said, if anyone can see an obvious error I’ve made, please do let me know.