Minify Font Awesome fonts with webpack
Font Awesome 5 is a comprehensive solution for vector icons on your website.
Originally, Font Awesome came as an icon font (plus stylesheets), but recently it can also be used as a pure JavaScript solution (which will render icons as inline <svg>
tags), or even as SVG sprites.
All solutions have their pros and cons:
Icon font:
- little CPU load (no JavaScript)
- fonts are relatively large
- 1 extra HTTP request
Javascript + inline SVG:
- higher CPU load (needs to watch the DOM via mutation observers to ad...
How to: Validate dynamic attributes / JSON in ActiveRecord
PostgreSQL and ActiveRecord have a good support for storing dynamic attributes (hashes) in columns of type JSONB
. But sometimes you are missing some kind of validation or lookup possibility (with plain attributes you can use Active Record's built-in validations and have your schema.rb
).
One approach about being more strict with dynamic attributes is to use JSON Schema validations. Here is an example, where a project has the dynamic attributes analytic_stats
, that we can use to store analytics from an external measurement tool.
- A g...
dbconsole in Rails 3 requires the environment as the first argument
There is a bug in Rails 3's dbconsole
script, which makes the following command open a database console for the development
environment:
rails dbconsole -p test
You need to write this instead:
rails dbconsole test -p
Rspec: How to write better specs
betterspecs.org is a documentation on how to write better RSpec tests.
Note that there are also other approaches like The Self-Contained Test, which is complementary to the dry-approches in betterspecs. Like usual you need to weight the different recommendation and there is no rule of thumb for all specs.
VCR and the webdrivers gem
If you're using the webdrivers gem and VCR together, depending on your configuration, VCR will yell at you regulary.
The webdrivers gem tries to update your webdrivers on your local machine. To do so, it checks the internet for newer versions, firing an HTTP-request to e.g. https://chromedriver.storage.googleapis.com
You can "fix" this in multiple ways:
-
Update your drivers on your machine with
RAILS_ENV=test rake webdrivers:chromedriver:update
-
Ignore the driver update-URL in your ...
Online tool to convert tables between different formats
https://tableconvert.com/ is an online tool to convert tables between different formats (e.g. json, markdown, csv).
It also has a button to transpose a table ("rotate" it by 90 degree).
The tool can be handy if you have tests with large markdown tables for testing contents of a flat json structure or csv.
Please note that you should not use it with sensitive data (like all online tools in general).
Silencing Deprecation Warnings in Rspec
If you’re testing the behavior of deprecated code in your Ruby project, the warning messages littered throughout your spec output is incredibly noisy.
You could silence all warnings with ::ActiveSupport::Deprecation.silenced = true, but you might miss out on an important warning in one of your dependencies. It’s tempting to remove the tests altogether (the code will be burned soon too, right?), but I figured out something a little nicer a little while back in Formtastic’s test suite.
Traversing the DOM tree with jQuery
jQuery offers many different methods to move a selection through the DOM tree. These are the most important:
$element.find(selector)
Get the descendants of each element in the current set of matched elements, filtered by a selector. Does not find the current element, even it matches. If you wanted to do that, you need to write $element.find(selector).addBack(selector)
.
$element.closest(selector)
Get the first ancestor el...
How to install packages from newer Ubuntu releases
We're usually running Ubuntu LTS versions. Sometimes newer hardware requires packages from more recent Ubuntu releases that only come with 6 months of support. If there is really no other way, it's possible to install packages from later Ubuntu releases
Caution: Pay really close attention to what you're doing. Depending on the package, this process may require upgrading a lot of dependencies, possibly breaking the system! You really should not do this unless you've carefully calculated the impact on your system
Preparation
First,...
Upgrading Cucumber and Capybara to the latest versions available for Rails 2
Specify these gem versions in your Gemfile:
gem 'cucumber', '~> 1.3.0'
gem 'cucumber-rails', '= 0.3.2' # max version for Rails 2
gem 'capybara', '< 2' # capybara 2+ requires Rails 3
gem 'mime-types', '< 2' # dependeny of capybara
gem 'nokogiri', '< 1.6' # dependency of capybara
gem 'rubyzip', '< 1' # dependency of selenium-webdriver, rubyzip 1+ requires Ruby 1.9
gem 'cucumber_factory'
gem 'database_cleaner', '< 1'
gem 'cucumber_spinner', '~> 0.2.5'
gem 'launchy', '~> 2.1.2'
With these versions set, `...
How to set up SMTP email delivery with a Gmail account
If you want to make your Rails application be capable of sending SMTP emails, check out the action mailer configuration section in the Ruby on Rails guide.
TL;DR you will end up having an smtp_settings
hash that looks something like this:
smtp_settings = {
address: ...,
domain: ...,
port: ...,
user_name: ...,
password: ...,
authentication: ...,
tls: ...,
enable_starttls_auto: ...,
}
This hash can be set as the `delivery_me...
Debugging cucumber feature with javascript + firefox vnc
TL;DR Debugging problems with javascript errors in cucumber tests is sometimes easier in the browser. Run the test, stop at the problematic point (with Then pause
from Spreewald 1.7+) and open VNC for Firefox.
Features:
- It does not freeze your server like when you're using a debugger. (Compared to the
Then console
step) - It enables interacting with the server. (Compared to taking screenshots in Capybara)
- It is a faster alternat...
How to avoid ActiveRecord::EnvironmentMismatchError on "rails db:drop"
After loading a staging dump into development, you might get an ActiveRecord::EnvironmentMismatchError
when trying to replace the database (like rails db:drop
, rails db:schema:load
).
$ rails db:drop
rails aborted!
ActiveRecord::EnvironmentMismatchError: You are attempting to modify a database that was last run in `staging` environment.
You are running in `development` environment. If you are sure you want to continue, first set the environment using:
bin/rails db:environment:set RAILS_ENV=development
Starting with R...
Show the character set and the collation of your MySQL tables
To show the collation of your tables you have to login to the MySQL console and execute SHOW TABLE STATUS FROM database;
mysql> SHOW TABLE STATUS FROM test;
+-------------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+-----------------+----------+----------------+---------+
| Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_leng...
Cucumber Webrat steps
Most of these will not work in newer projects because these use the Capybara/Rack::Test combo in lieu of Webrat.
Find input fields
Then /^there should be a "([^"]+)" field$/ do |name|
lambda { webrat.current_scope.send(:locate_field, name) }.should_not raise_error(Webrat::NotFoundError)
end
Then /^there should be no "([^"]+)" field$/ do |name|
lambda { webrat.current_scope.send(:locate_field, name) }.should raise_error(Webrat::NotFoundError)
end
Find html content
Then /^I should see "([^\"]*)...
Capybara 'fill_in': Ambiguous match for different input names
When you have two inputs, where one contains the name of the other (eg. Name
and Name with special treatment
), Capybara's fill_in
method will fail with the following message:
Ambiguous match, found 2 elements matching visible field "Name" that is not disabled (Capybara::Ambiguous)
You can force Capybara to match exactly what you are typing (which makes your tests better anyways) with match: :prefer_exact
:
name = 'Name'
value = 'Bettertest Cucumberbatch'
fill_in(field, with: value, match: :prefer_exact)
Furthermore...
Performance analysis of MySQL's FULLTEXT indexes and LIKE queries for full text search
When searching for text in a MySQL table, you have two choices:
- The LIKE operator
- FULLTEXT indexes (which currently only work on MyISAM tables, but will one day work on InnoDB tables. The workaround right now is to extract your search text to a separate MyISAM table, so your main table can remain InnoDB.)
I always wondered how those two methods would scale as the number of records incr...
Copy to clipboard without flash (clipboard.js)
We used zeroclipboard.js
in some of our projects but now we switched to clipboard.js
because it does not rely on flash. Flash support of the major browsers has ended.
Some more advantages of clipboard.js:
- it consists only of a single javascript file, so it does not trigger additional requests with rails
- it automagically provides user feedback by selecting the text it has copied
- it provides callbacks for success and error which make it easier to add custom behaviour after copying to the clipboar...
ActiveRecord::Store: migrate data in store
When you need to store structured data (like Ruby hashes) in a single database column with ActiveRecord, a simple way is to use PostgreSQL's jsonb
columns. ActiveRecord will automatically serialize and deserialize your Hash to and from JSON, and you can index JSON paths for fast reads.
As an alternative, ActiveRecord::Store
offers a way to store hashes in a single database column. This card will show you how to migrate those hashes in an ActiveRecord::Migration
by example:
...
Synchronize a Selenium-controlled browser with Capybara
When you click a link or a press a button on a Selenium-controlled browser, the call will return control to your test before the next page is loaded. This can lead to concurrency issues when a Cucumber step involves a Selenium action and a Ruby call which both change the same resources.
Take the following step which signs in a user through the browser UI and then sets a flag on the user that was just signed in:
Given /^the user "([^"]*)" signed in (\d) days ago$/ do |name, days|
visit new_session_path
fill_in 'Username', :w...
How to change will_paginate's "per_page" in Cucumber features
The will_paginate
gem will show a default of 30 records per page.
If you want to test pagination in a Cucumber feature, you don't want to create 31 records just for that.
Instead, you probably want to modify the number of items shown, by saying something like this:
Given we paginate after 2 users
Using the following step definition, you now can! :)
require 'cucumber/rspec/doubles'
Given /^paginate after (\d+) (.*)$/ do |per_page, model_name|
model = model_name.singularize.gsub(/...
Freeze (vendor, unpack) a single Ruby gem with and without Bundler
When you need to patch an existing gem, one way is to "vendor" the gem by copying it into the vendor/gems
directory of your Rails project. You can then make any changes you require and Rails will use the vendored version of the gem after a server restart. Unfortunately you need to perform some additional steps to marry Rails and the copied gem. This notes describes what to do.
With Bundler
This is super-painful. If you just copy the gem to vendor/gems
, Rails will complain:
Unpacked gem foolib in vendor/gems has no s...
Rails logs are not flushed automatically (in Rake tasks)
The Rails logger will store its content in a buffer and write it into the file system every 1000 lines. This will come back to bite you when using Rails.logger.info
to write log output during Rake tasks or on a production console.
You often won't notice this because for the development
and test
environments auto_flushing
is set to write after each line. On production environments the Rails logger writes only every 1000 lines -- and not upon shell or script ter...
Consul 0.9 lets you optimize records checks
Consul 0.9 comes with many new features to optimize powers that only check access to a given record. e.g. Power.current.post?(Post.last)
. See below for details.
Powers that only check a given object
Sometimes it is not convenient to define powers as a collection. Sometimes you only want to store a method that
checks whether a given object is accessible.
To do so, simply define a power that ends in a question mark:
class Power
...
power :upd...