Exercise 1: XML On the start page of your Movie DB, show the title of a random movie that is coming soon to theaters. There's an XML feed for...
...no longer a "Year" field when creating a movie. It is automatically fetched and stored before the movie is created. When editing a movie there is a "Year" field that...
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...
...Learn to create test data effectively using factories. Decouple tests by having each test start with an empty database and create only the records needed for the test. Learn
...with every test. In our experience the use of fixtures can make a test suite hard to work with. In any non-trivial test suite there will be thousands of...
Debouncing a method call delays its execution until after a specified time has passed. If it's called again before that time has passed, its execution is delayed again.
...would be run more often than it needs to. One example for that are scroll event handlers in JavaScript: You want to react to a user scrolling, but it's...
...library => Google Drive) CLI tricks every developer should know Install the tldr tool using sudo apt install tldr. You can then get usage examples for every console command, e.g. tldr...
...ssh to get examples for the ssh command. (If there are no entries, run tldr -u and try again) Exercises Basic commands Experiment and do something useful with the following...
If you've stumbled over display: grid while reading the Flexbox material of the previous card - we've got you covered! Let's dive into this topic with a quote...
...dimensional layouts and Grid is made for two-dimensional layouts. You will learn more subtle differences in the linked material below, but you can remember this as a rule of...
Is your application doing something expensive every few seconds? Maybe an animated slider that rotates images? Maybe you are updating data over the network every five minutes?
...this if the your document tab is not even visible to the user. This saves your user's battery and data plan. You can ask document.visibilityState whether this tab is...
Are My Indexes Affected? If your database has been created on an operating system with glibc version < 2.28 and later upgraded to an operating system with glibc >= 2.28, you...
...affected. To find out which indexes in our database are affected, run the following slightly modified query from the PostgreSQL documentation: CREATE extension amcheck; SELECT bt_index_check(index => c.oid...
...in the context of our application. While you could roll out a custom authentication solution, this would likely expose you to the various risks of "homegrown crypto". In practice we...
...like clearance or devise for this task. Learn Read the article Rails Authentication from Scratch You don't need to do write any code, but you should be able to...
Rails wraps your parameters into an interface called StrongParameters. In most cases, your form submits your data in a nested structure which goes hand in hand with the strong parameters...
...However, there are cases where this does not fit your use case, or has side effects. If you do it differently, be extra careful not to introduce security issues.
Action Mailer Basics and Previews Chapter "Task H1: Sending Mail" from Agile Web Development with Rails 7.2 (in our library) Ensure that the receiving e-mail is valid
...the Truemail gem to validate e-mail addresses Ensure that development and staging are not sending out e-mails by accident Rails: How to write custom email interceptors
With Ubuntu 24.04 it's not longer possible to setup FDE with BTRFS The new installer won't offer you any options for manually created dm-crypt volumes
...btrfs subvolume snapshot . @ rmdir @/ext2_saved ls | grep -Ev "@|ext2_saved" | xargs rm -rf btrfs subvolume set-default @ Create additional subvolumes btrfs subvolume create @home cp -ax --reflink=always @/home/* @home...
Learn to treat files as an ActiveRecord attribute type, like :string or :integer Research Look at the README for the carrierwave gem Read about Common mistakes when storing file...
...the form where we can also fill in title, year, etc. On the movie show view, render a poster version that is 400 pixel wide, with a height that respects...
...has a very different disk usage on it's nodes you can use these steps to rebalance the shards. Before we begin it's important to understand how Elasticsearch defines...
The balance of the cluster depends only on the number of shards on each node and the indices to which those shards belong. It considers neither the sizes of...
Intel CPUs receive updates, including security relevant upgrades, through 2 channels: Firmware/UEFI BIOS updates can also update the microcode in CPUs. This is the preferred and persistent way
How to install an microcode update? If one is available and deemed sufficiently stable from Debian's or Ubuntu's perspective, the intel-microcode package is updated and...
...good thing. It's possible to configure this requirement at the web- or proxy server level, where nginx or apache will just redirect every request on http to https. Some...
...if the URL they've been called with contains the http or the https scheme and issue their own redirect response (usually 301 or 302) to https. This card is...
This card is a short summary on different ways of assigning multiple attributes to an instance of a class. Using positional parameters Using parameters is the default when assigning attributes...
...It works good for a small number of attributes, but becomes more difficult to read when using multiple attributes. Example: class User def initialize(salutation, first_name, last_name, street...
...Adding Records via XHR and JS Example For the following examples we use a simple data model where a user has zero or more tasks. class ExampleMigration < ActiveRecord::Migration...
...user.tasks.build } end def update load_user @user.attributes = user_params if @user.save flash[:notice] = 'User saved successfully.' redirect_to(edit_variant_1_user_path(@user)) else flash[:notice] = 'User could not...
A JavaScript error in an E2E test with Selenium will not cause your test to fail. This may cause you to miss errors in your frontend code. Using the BrowserConsole...
!!driver_logs_proc end def driver_logs_proc browser = page.driver.browser if browser.respond_to?(:logs) # selenium-webdriver >= 4 proc { browser.logs } elsif browser.respond_to?(:manage) && browser.manage.respond_to?(:logs) # selenium-webdriver...
Du weißt was copy-on-write ist und warum das in Zusammenhang mit Snapshots praktisch ist Du weißt was Fragmentierung ist und wann und wo es bedeutsam ist
Du weißt wie du einen Datenträger verschlüsselst Du weißt wie man ein Linux System verschlüsselt Du weißt wie man die Systeme jeweils wieder entschlüsselt Inhalte LinuxFilesystemsExplained (Achtung alt)
...if you do not know. How are cookies transferred between your browser and the server? Open the development tools in your browser for this page. Can you find the cookies...
...your browser stores for makandracards? In the network tab, can you see how the cookies are transferred to or from the server? Can you log yourself out by manipulating a...
...always is to prevent long-running queries in the first place, automatic timeouts can serve as a safety net to terminate problematic queries automatically if a set time limit is...
...statement due to statement timeout (PG::QueryCanceled)). If multiple SQL statements appear in a single simple-query message, the timeout is applied to each statement separately. Set the timeout globally...
While it might seem trivial to implement an invoice that sums up items and shows net, gross and vat totals, it actually involves a lot of rules and caveats. It...
...examples in Ruby and MySQL, the concepts apply to all programming languages and data stores. When to round There are exactly two spots where your invoice logic should round money...
If you want to switch to another ruby versions, you have several options, depending on what you want: Do you want to switch temporarily, per project, or globally?
Unlike RVM, rbenv does not offer a command like rvm use. By default, it respects your project's .ruby-version file. If you need to change manually...