The change_column method for rails migrations support casting with a custom SQL statement. This allows us to change a column type and keep the former content as the new...
...number, 'int USING CAST(rating AS int)' end end Warning This migration's rollback strategy will fail, if any existing entry can't be casted. This is likely to happen...
When your public-facing application has a longer downtime for server maintenance or long migrations, it's nice to setup a maintenance page to inform your users. When delivering the...
...maintenance page, be very careful to send the correct HTTP status code. Sending the wrong status code might get you kicked out of Google, or undo years of SEO work...
There is a practical short list for valid/invalid example email addresses - Thanks to Florian L.! The definition for valid emails (RFC 5322) can be unhandy for some reasons, though.
...provides a built-in email regex URI::MailTo::EMAIL_REGEXP. That's the best solution to work with. /\A[a-zA-Z0-9.!\#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0...
...yml files. You may override those application-wide error messages using model or attribute scope like this: en: activerecord: errors: messages: invalid: is invalid # used for any invalid attribute in...
If you migrate a Rails application from Sprockets to Webpack(er), you can either transpile your CoffeeScript files to JavaScript or integrate a CoffeeScript compiler to your new process. This...
...to the global namespace, define them on window directly: -class @User +class window.User Replace Sprocket's require statement with Webpacker's import statement to load dependencies. -#= require ./person +import './person...
To work with other type of nodes (like text, comment or CDATA sections) you need to: Retrieve child nodes contents() (which behaves like children() except that it returns...
...element and returns an array of all child nodes that are text nodes: function selectTextNodes($container) { return $container.contents().filter(function() { return this.nodeType === 3; }); } Also check out this list of existing...
Download buttons can be difficult to test, especially with Selenium. Depending on browser, user settings and response headers, one of three things can happen: The browser shows a "Save as...
...dialog. Since it is a modal dialog, we can no longer communicate with the browser through Selenium. The browser automatically downloads the file without prompting the user. For the test...
...PATH << File.expand_path('../../lib', __FILE__) require 'my_cli' MyCli.run! However, if you create a symlink to this file, this will no longer work. __FILE__ will resolve to the path of...
...the symlink, not to its target. One solution is to use File.realpath(__FILE__). In Ruby 2+ you can also use this: $LOAD_PATH << File.expand_path('../lib', __dir__) __dir__ is simply...
By activating strict_loading you force developers to address n+1 queries by preloading all associations used in the index view. Using an association that is not preloaded will raise...
...an ActiveRecord::StrictLoadingViolationError. I think it's a good default to activate strict_loading in your controllers' #index actions. This way, when a change introduces an n+1 query, your...
...much faster than the configured up.form.config.observeDelay. Therefore, it may happen that you already entered something into the next field before unpoly updates that field with a server response, discarding your...
The steps I wait for active ajax requests to complete (if configured) and capybara-lockstep can catch some of these cases, but not all. Both of these only wait...
RubyMine has a collaboration feature called "Code With Me". Using it, you can invite someone into your local editor to work together. This is nicer to the eyes and much...
...more powerful than sharing code through some video chat. How to Getting started is really simple: Click the "add person" icon in the top-right editor corner (or hit Ctrl...
Compiling Sass is probably the slowest part of your build, so this is worth a try if you're using Sass...
...If you're using the sass npm package to compile your SASS/SCSS, consider switching to sass-embedded. It should be a drop-in replacement in a large app and it...
...ZIP archive, you basically have two options: Write a ZIP file to disk and send it as a download to the user. Generate a ZIP archive on the fly while...
...streaming it in chunks to the user. This card is about option 2, and it is actually fairly easy to set up. We are using this to generate ZIP archives...
We use foreman to start all necessary processes for an application, which are declared in a Procfile. This is very convenient, but the outputs of all processes get merged together...
...Especially while debugging you might not want other processes to flood your screen with their log messages. The following setup allows you to start Terminator in a split view with...
...on a Rails record is converted to UTC using to_s(:db) to be stored, and converted back into the correct time zone when the record is loaded from the...
...This is now UTC Problem That will blow up in your face when you send times to attributes that expect dates, just because those times will also be converted using...
Ask the admins to turn on SSL (they will set an HSTS header for SSL-only sites) Make cookies secure and http_only Never hard-code the http protocol...
...into URLs that point to your application, which makes you vulnerable to SSL-stripping. When linking to internal resources, just use the path without protocol or URL When linking to...
...index do |person, index| person.award_trophy(index + 1) end Ruby's map with index Similarly, you may need an index when using other methods, like map, flat_map, detect (when...
...you need the index for detection), or similar. Here is an example for map: people.map.with_index do |person, index| person.at_rank(index + 1)
...group using Ruby's def keyword or define_method method: describe "example" do def sum(a, b) a + b end it "has access to methods defined in its group" do...
...expect(sum(3, 4)).to be(7) end end The helper method is also available to groups nested within that group. The helper method is not available to parent or...
If you need a sample video with certain properties for a test you can create one using ffmpeg. You might want a very low bitrate file to speed up processing...
...ffmpeg -t 21 -s 10x10 -r 1 -f rawvideo -pix_fmt rgb24 -i /dev/zero sample_21_seconds.mp4 Option Explanation -t 21 set the length to 21s -s 10x10
When your site is on HTTPS and you are linking or redirecting to a HTTP site, the browser will not send a referrer. This means the target site will see...
Clients SHOULD NOT include a Referer header field in a (non-secure) HTTP request if the referring page was transferred with a secure protocol.
When you have a Cucumber step like Then I should see "Did you see those \"quotation marks\" over there?" you'll run into trouble. Cucumber won't take your...
...escaped quotation marks. Workarounds One workaround is to write the step as regex (since there is a step taking a regex): Then I should see /Did you see those "quotation...
geordi cucumber path/to/features -r2 Background and how to rerun manually Cucumber will save a file tmp/parallel_cucumber_failures.log containing the filenames and line number of the failed scenarios after a...
...full test run. Normally you can say cucumber -p rerun (rerun is a profile defined by default in config/cucumber.yml) to rerun all failed scenarios. Here are a few alternative ways...
Occasionally you need to do something directly on the server -- like having all records recalculate something that cannot be done in a migration because it takes a long time.
...s say you do something like this: Project.all.each(&:recalculate_statistics!) Even though you may have been successful with this on your development machine or the staging server, keep in mind...
Line-height and vertical-align are simple CSS properties. So simple that most of us are convinced to fully understand how they work and how to use them. But it...
...less-known feature of CSS: inline formatting context. For example, line-height can be set as a length or a unitless value 1, but the default is normal. OK, but...