Rails: Comparison of assignable_values and Active Record enum types
We are using assignable_values for managing enum values in Rails. Nevertheless Rails is adding more support for enum attributes, allowing to have a closer look at the current feature set in comparison to our still preferred option assignable_values
.
Active Record enum attribute interface
By default Rails is mapping enum attributes to integers:
...
Updated: ActiveRecord: count vs size vs length on associations
- Added another caveat of #count
count looks directly into the database, neglecting already loaded elements. This becomes a problem when you use that "db count" when processing the loaded elements.
A common example is tests: Imagine a test that sets up a few records and finishes the test setup by asserting a number of associated records. If you use .count for that job, the assertion cannot see that the setup records have already loaded (i.e. cached) their associations. Tests relying on the setup will fail, because they will operate o...
Updated: How to write complex migrations in Rails
Added a general advise to migration models: Using reset_column_information
should prevent some common issues when migrating from scratch.
Text column sizes in MySQL
Postgres works differently
See PostgreSQL: Difference between text and varchar columns for PostgreSQL-specific info
MySQL has 4 different column sizes. They are actually different data types under the hood:
type | size limit | schema.rb option |
---|---|---|
TINYTEXT | 256 bytes | size: :tiny |
TEXT | 65,535 bytes | (default) |
MEDIUMTEXT | 16,777,215 bytes | size: :medium |
LONGTEXT | 4,294,967,... |
Using rack-mini-profiler (with Unpoly)
Debugging performance issues in your Rails app can be a tough challenge.
To get more detailed insights consider using the rack-mini-profiler gem.
Setup with Unpoly
Add the following gems:
group :development do
gem 'memory_profiler'
gem 'rack-mini-profiler'
gem 'stackprof'
end
Unpoly will interfere with the rack-mini-profiler widget, but configuring the following works okayish:
// rack-mini-profiler + unpoly
if (process...
Caution: rem in @media query definitions ignore your font-size
Note
Using rem only ever makes sense when the root font size is dynamic, i.e. you leave control to the user. Either by a) respecting their user agent defaults, or by b) offering multiple root font sizes in your application.
By defining @media queries in rem, they will accommodate to the root font size of your page. At a larger root font, breakpoints will be at larger widths, scaling with the font. However, there is a catch in case b) mentioned in the note above.
Relative length units in media queries are based on the initial value,...
Debug SAML in development using a local keycloak server
Developing or debugging SAML functionality can be a hassle, especially when you need to go back and forth with someone external who is managing the identity provider (IDP).
But you can setup a local keycloak server to act as your IDP to play around with. This might seam intimidating, but is actually quite simple when using docker and turning off some verification steps.
1. Start a keycloak instance using docker
`mkdir -p keycloak_data && docker run --network=host -e KEYCLOAK_ADMIN=admin -e KEYCLOAK_ADMIN...
Geordi 10.0.0 released
10.0.0 2024-03-07
Compatible changes
-
console
command: You can now globally disable the IRB multiline feature by settingirb_flags: --nomultiline
in~/.config/geordi/global.yml
. All configured irb_flags are automatically passed on to the console IRB. -
console
command:Ctrl + C
now properly exits a local Rails console -
rspec
andcucumber
commands: Run specs even if the automatic chromedriver update fails - Improve detection of IRB version
- Add new hints to 'Did you know'
Breaking changes
-
dump
command: Drop...
Chaining Capybara matchers in RSpec
You can chain multiple Capybara matchers on the page
or any element:
expect(page)
.to have_content('Example Course')
.and have_css('.course.active')
.and have_button('Start')
When you chain multiple matchers using and
, [Capybara will retry the entire chain](https://github.com/teamcapybara/capybara/blob/c0cbf4024c1abd48b0c22c2930e7b05af58ab284/lib/capybara/rspec/matc...
Accessibility: Making non-standard elements interactive
A common cause of non-accessible web pages are elements that were made interactive via JavaScript but cannot be focused or activated with anything but the mouse.
❌ Bad example
Let's take a look at a common example:
<form filter>
<input filter--query name="query" type="text">
<span filter--reset>Clear Search</span>
</form>
The HTML above is being activated with an Unpoly compiler like this:
up.compiler('[filter]', function(filterForm) {
const resetButton = filterForm.querySelec...
Top Accessibility Errors in 2023
These are the top ten accessibility errors as researched by TPGi, a company focusing on accessibility. See the linked article for details on each item, as well as instructions on how to do it correctly.
- No link text
- Non-active element in tab order
- Missing link alt attribute
- No alt text
- List not nested correctly
- Duplicate labels used
- Positive tabindex value
- Invalid aria-describedby
- No label for button element
- Invalid aria-labelledby
Generally, I am surprised by these items. I would have expected more complex i...
Be careful when checking scopes for blankness
Today I stumbled across a pretty harmless-looking query in our application which turned out to be pretty harmful and caused huge memory usage as well as downing our passenger workers by letting requests take up to 60 seconds. We had a method that received a scope and then checked, if the scope parameter was blank?
and aborted the method execution in this case.
def foo(scope)
return if scope.blank?
# Use scope, e.g.
scope.find(...)
end
We then called this method with an all
scope: foo(Media::Document::Base.all)
. *...
How to display an unsaved changes alert
All browsers implement an event named beforeunload. It is fired when the active window is closed and can be used to display an alert to warn the user about unsaved changes.
To trigger the alert, you have to call preventDefault()
on the event.
Note
The
beforeunload
event is only dispatched when the user navigation makes a full page load, or if it closes the tab entirely. It will not be dispatched when navigating via JavaScript. In this case you need to ...
Heads up: You should always use "current_window.resize_to" to resize the browser window in tests
I recently noticed a new kind of flaky tests on the slow free tier GitHub Action runners: Integration tests were running on smaller screen sizes than specified in the device metrics. The root cause was the use of Selenium's page.driver.resize_window_to
methods, which by design does not block until the resizing process has settled:
We discussed this issue again recent...
Where to keep project files that should not go to Git
Sometimes you have a file that is related to a project, while not actually being part of it. You'd like to keep them around, but others won't need them – e.g. some notes, a log, or a database dump.
Sure, you have a project directory – but all of it is tracked by Git. A project's tmp/ directory is usually not tracked, but by definition it is not a good place to keep things.
An excluded directory for related files
I suggest you keep your related files in a related-files/ directory within your project(s).
To keep this directory u...
Best practices: Writing a Rails script (and how to test it)
A Rails script lives in lib/scripts and is run with bin/rails runner lib/scripts/...
. They are a simple tool to perform some one-time actions on your Rails application. A Rails script has a few advantages over pasting some prepared code into a Rails console:
- Version control
- Part of the repository, so you can build on previous scripts for a similar task
- You can have tests (see below)
Although not part of the application, your script is code and should adhere to the common quality standards (e.g. no spaghetti code). However, a script...
Rails: Testing the number of database queries
There are a few tools to combat the dreaded n+1 queries. The bullet gem notifies you of missing eager-loading, and also if there is too much eager-loading. strict_loading in Rails 6.1+ forces developers to explicitly load associations on individual records, for a single association, for an entire model, or globally for all models.
But you can also actually **write spe...
Unpoly 3.7.1, 3.7.2 and 3.7.3 released
Version 3.7.0 broke some things in complex forms. Sorry for that. Concurrent user input is hard.
3.7.1
This change fixes two regressions for form field watchers, introduced by 3.7.0:
- When a change is detected while waiting for an async callback, prevent the new callback from crashing with
Cannot destructure property { disable } of null
. - When a change is detected while waiting for an async callback, the full debounce delay of that new change is honored.
...
Disable PostgreSQL's Write-Ahead Log to speed up tests
The linked article suggests an interesting way to speed up tests of Rails + Postgres apps:
PostgreSQL allows the creation of “unlogged” tables, which do not record data in the PostgreSQL Write-Ahead Log. This can make the tables faster, but significantly increases the risk of data loss if the database crashes. As a result, this should not be used in production environments. If you would like all created tables to be unlogged in the test environment you can add the following to your...
Migrate searchkick from Elasticsearch client to Opensearch client without Downtime
General
A general overview about why and how we migrate can be found under Migrating from Elasticsearch to Opensearch
This card deals with specifics concerning the use of searchkick.
Step 1: Make Opensearch available for Searchkick
In your Gemfile
# Search
gem 'searchkick' # needs to be > 5, to use Opensearch 2
gem 'elasticsearch'
gem 'opensearch-ruby'
in config/initializers/searchkick.rb
(or wherever you have configured your Searchkick settings) add:
SEARCHKICK_CLIENT_T...
Capistrano: creating a database dump if migrating
In Capistrano 3, your Capfile requires 'capistrano/rails/migrations'
, which brings two Capistrano tasks: deploy:migrate
and deploy:migrating
. The former checks whether migrations should be performed. If so, the latter is invoked, which performs the actual migrations.
Knowing this, it is easy to dump the db only if migrations will run. First, enable conditional migrations:
# config/deploy.rb
set :conditionally_migrate, true # Only attempt migration if db/migrate changed
Then hook up the dump task to deploy:migrating
:
Rails: Pluck across associated tables
#pluck
is commonly used as a performant way to retain single database values from an ActiveRecord::Relation
Book.pluck(:title, :price) #=> [["The Hobbit", "8.99"], ["The Alchemist", "7.89"]]
But #pluck
can do more: you can query multiple tables as well!
Book.joins(:author).pluck("books.title, books.price, authors.name") #=> [["The Hobbit", "8.99", "J. R. R. Tolkien"], ["The Alchemist", "7.89", "Paulo Coelho"]]
Note the use of :author
for the joins, and then authors
for the pluck clause. The first corresp...
Transfer records to restore database entries (with Marshal)
If you ever need to restore exact records from one database to another, Marshal
might come in handy.
Marshal.dump
is part of the ruby core and available in all ruby versions without the need to install anything. This serializes complete ruby objects including id
, object_id
and all internal state.
Marshal.load
deserializes a string to an object. A deserialized object cannot be saved to database directly as the the dumped object was not marked dirty, thus rails does not see the need to save it, even if the object is not present in...
Ruby: Using `sprintf` to replace a string at fixed named references
The sprintf
method has a reference by name format option:
sprintf("%<foo>d : %<bar>f", { :foo => 1, :bar => 2 }) # => 1 : 2.000000
sprintf("%{foo}f", { :foo => 1 }) # => "1f"
The format identifier %<id>
stands for different data types to be formatted, such as %f
for floats:
sprintf('%f', 1) # => 1.000000
Example:
This is quite useful to replace ...