Use the command geordi migrate to migrate your databases and to prepare them before running tests. The abbrevation geordi m works as well.

• It will run rake db:migrate if parallel_tests does not exist in your Gemfile
• Otherwise it runs b rake db:migrate and then executes b rake parallel:prepare if parallel_tests was found in your Gemfile.

Removing features and merging those changes back can be painful. Here is how it worked for me.\
tl;dr: Before merging back: reinstate reverted features in a temporary branch, then merge that branch.

Scenario

Consider your team has been working on several features in a branch, made many changes over time and thus several commits for each feature.\
Now your client wants you to deploy while there are still stories that were rejected previously and can't be deployed.
...

Our gitpt script to generate git commits from Pivotal Tracker stories has been tweaked and polished and is now part of the geordi gem.

Install the freshly released version 0.7 now:

gem install geordi

This update will bring you commit with an initial "setup wizard" (that asks for your PT API key and initials) and prettier output: stories are colored by their state and thos...

When selecting records in a date range, take care not to do it like this:

start_date = Date.parse('2007-05-01')
end_date = Date.parse('2007-05-31')
LogItem.where(:created_at => start_date .. end_date)

The problem is that created_at is a datetime (or Time in Ruby), while start_date and end_date are simple dates. In order to make sense of your query, your database will cast your dates to datetimes where the time component is 00:00:00. Because of this the query above will lose records created from `2007-05-31 00:00:0...

Basically, you now need to know if your project uses a "real" time zone or :local, and if config.active_record.time_zone_aware_attributes is set to false or not.

• With time zones configured, always use .current for Time, Date, and DateTime.

  ActiveRecord attributes will be time-zoned, and .current values will be converted properly when written to the database.
  Do not use Time.now and friends. Timezone-less objects will not be converted properly when written to the database.

• With no/local time zone use Time.now, `...

The tagged_with scope comes with many awesome options to modify your search:

User.tagged_with("awesome", "cool")                     # Users that are tagged with awesome and cool
User.tagged_with("awesome", "cool", :exclude => true)   # Users that are not tagged with awesome or cool
User.tagged_with("awesome", "cool", :any => true)       # Users that are tagged with awesome or cool
User.t...

This might seem obvious, but I'm rejecting stories because of this on a regular basis.

Whenever a list (e.g. an index of records or the options of a select box) is visible in the UI that list must be sorted. Unsorted lists are completely unusable once they contain more than 5 items.

The unix command line tool less is a good choice for browsing logfiles. In the standard configuration, though, it does not interpret the escape sequences used in the rails logfiles. To enable this type:

less -R my_logfile.log

You can also have an alias to save yourself the typing

alias less='less -R'

When internationalizing your Rails app, you'll be replacing strings like 'Please enter your name' with t('.name_prompt'). You will be adding keys to your config/locales/*.yml files over and over again. Not to miss any key and place each at the right place is a challenging task.

The gem i18n-tasks has you covered. See its README for a list of things it will do for you.

Note

The i18n-tasks gem does not understand aliases and will duplicate all referenced data when it writes locales. If yo...

For university I have to stay up-to-date with lecture documents. Since my university doesn't offer RSS feeds, I wrote a little script that collects files from web pages.

You want this, if you have several web pages that offer downloads that you don't want to check manually. Just register the URL and a CSS snippet to retrieve the files in the attached script and run it – it will fetch all your files. It will store all files in a single place or sort them into respective directories.

Edit the header of the file (providing your data), save it...

The SQL code generated by Graticule's spherical distance computation is insufficient and can lead to NULL distances in edge cases.

The reason for this is that MySQL is performing several sine and cosine computations which can result in slight rounding errors -- which is usually okay. Rarely, though, for the exact center of the given circle, it is then asked to compute the arc cosine of a result like 1.0000000001.

Since this i...

Seems like a useful gem for cases where ActiveRecord is overkill but you don't want to do everything by hand either.

Using rename_column, remove_column, etc. more than once in a migration makes that migration run slower than it should. Use change_table instead.

Consider this migration:

add_column :users, :name, :string
remove_column :users, :first_name
remove_column :users, :last_name
rename_column :users, :cool, :awesome

Migrating in this case means that all those commands are processed step by step, causing 4 SQL statements to change the table. In turn, your database needs to modify the table structure 4 times. When working on hu...

For performance improvements (and to remove the need for eager loading), the ActsAsTaggableOn gem supports caching your tag lists directly in your model. To enable this, simply add a cached_tag_list column to your table.

Example:

class Company < ActiveRecord::Base
  acts_as_taggable_on :categories
end

The cache column has to be named cached_category_list.

Existing data

If you already have existing data, you have to save all records with tags once, after you've added the ...

When you have objects in your database that hold latitude and longitude and you want to find others that are close to given coordinates you can use the Graticule gem.

Graticule

Graticule offers several methods to compute the distance between two geo-dated objects but fetching records from the database that are within a given radius of a location is a bit trickier:

def close_destinations(latitude, longitude)
  distance_sql = Graticule::Distance::Spherical.to_sql(:latitude => l...

Instead of running all missing migrations on your test database with rake db:migrate RAILS_ENV=test you can also use a handful of rake tasks to prepare the database structure directly. They can produce different results, though.

In a nutshell, to ensure your test database gains the correct structure:

• Don't use rake db:test:prepare carelessly
• or use rake db:test:clone_structure ← preferred :)
• or use rake db:migrate RAILS_ENV=test and don't mix it with other ways, like some of the rake tasks.

rake db:test:prepare
------------...

When using state_machine you sometimes need to know whether an object may execute a certain transition. Let's take an arbitrary object such as a blog article as an example that has those states:

A -> B -> C -> D

Additionally, you have transitions between the states as shown above. Let's call the transition between 'A' and 'B' transition_ab for simplicity. \
Given an object in state 'A'. You can call object.transition_ab but calling object.transition_bc! will obviously fail because ...

• Forms with many inputs (600+ in my case) become extremely unresponsive on an iPad, up to the point where it can take several seconds for a control to respond to touch commands.
• This is true for both iPad 1 and iPad 2 models.
• While certain CSS styles can lead to performance issues, removing those styles won't help if the form simply is very large.
• A workaround is to only show a limited number of form inputs at the time, e. g. by toggling groups of form...

Two new methods on and off are the new way of declaring event handlers. bind, delegate and live area deprecated. Also better performance for delegated events.

Note: This applies specifically to MySQL. In PostgreSQL for example, this is not an issue.

If you care about performance, never use a query like

UPDATE users SET has_message = 1 WHERE users.id IN (SELECT user_id FROM messages)

MySQL does not optimize this and seems to scan the temporary table, which isn't indexed, for every row in the update statement. This applies to other statements than UPDATE as well.

Instead, either use a JOIN like

UPDATE users INNER JOIN messages ON messages.user_id = users.id SET has_message =...

Clearance is a gem that provides authentication functionality (e.g. login, logout). This note explains, how the clearance login, logout and (in old Clearances) remember me functionality works.

Login

Clearance defines a database column called "remember_token". When you login in, that token will be saved in a cookie. For that reason you don't have to re-sign-in when you close and open the browser again.
This also means that you can be logged in in more than a single browser. Also see [When ses...

Look here for informations how you can show the MySQL default character set.

At first you need the Amazon RDS Command Line Toolkit

• download and unzip the [Amazon RDS Command Line Toolkit](http://aws.amazon.com/developertools/A...

Web fonts are awesome. After being restricted to Arial for two decades there is finally a cross-browser way to embed fonts into web pages.

Unfortunately while web fonts look awesome on Linux and MacOS, they look horrible on Windows, a problem that gets worse with smaller font sizes.

The culprit is something called font hinting:

...