We use foreman to start all necessary processes for an application, which are declared in a Procfile. This is very...

Building application assets with esbuild is the new way to do it, and it's great, especially in combination with...

When Capybara locates elements in the DOM, by default it allows only accessing visible elements -- when you are using a...

Since Rails 6.1, if we use where.not with multiple attributes, it applies logical NAND (NOT(A) OR NOT(B)) instead...

You can use RSpec::Matchers.define_negated_matcher to define a negated version of an existing matcher. This is particularly useful...

In my case [...] the catalog is an XML that contains all kinds of possible products, categories and vendors and it...

Field error steps Spreewald's The...

...field should have an error and The...

...field should have the error...

...steps now...

The Interactive Advertising Bureau (IAB) is a European marketing association which has introduced a standard how advertising can be served...

Similar to the Webpack Bundle Analyzer, Chrome's new Lighthouse feature … … shows a visualisation of your JavaScript bundles. It's...

From Exploring ES6: Module imports are hoisted (internally moved to the beginning of the current scope). Therefore, it doesn’t...

Since GitLab 10.3. you can use Mermaid in GitLab comments: Gitlab Doc. With Mermaid you can create diagrams based on...

A flaky test is a test that is often green, but sometimes red. It may only fail on some PCs...

Within development and test environments, Rails is usually configured to show a detailed debug page instead of 404s. However, there...

This RailsCast demonstrated a very convenient method to activate VCR for a spec by simply tagging it with :vcr.

You want to use fields in your applications. However, your desktop users may encounter some weird quirks: Aside from allowing...

Event delegation is a pattern where a container element has a single event listener that handles events for all descendants...

Besides their default styling properties, HTML elements have a semantic meaning. For example, an h1 tag is usually styled with...

git --fixup is very handy to amend a change to a previous commit. You can then autosquash your commits with...

We are using Spring in our tests for sequential test execution but not for parallel test execution. And Rails requires...

It is generally discouraged to load your JavaScript by a tag in the : The reason is that a tag will pause the DOM parser until the script has loaded and executed. This will delay the browser's first contentful paint. A much better default is to load your scripts with a tag: A deferred script has many...

The attached compiler() function below applies JavaScript behavior to matching HTML elements as they enter the DOM. This works like...

Given you have a strict CSP that only allows elements from your own domain: Content-Security-Policy: script-src 'self' This will block JavaScript handlers inlined as attribute into your HTML elements. Clicking on the following link will only log an error with a strict CSP: click me click me Solution 1: Move the handler into your JavaScript The recommended solution is to move the handler from the HTML to the allowed JavaScript file that we loaded via . In the example above we could invent a new [data-alert] attribute with the alert message: click me Then our JavaScript intercepts clicks on elements with that attribute: document.addEventListener('click', function(event) { let link = event.target.closest('[data-alert]') if (link) { let message = link.dataset.alert alert(message) event.preventDefault() } }) Solution 2: Allow that one handler in your CSP Some browsers allow the CSP directive script-src-attr. This lets you allow the hashes of actual JavaScript code. The SHA256 hash of alert('hello') is vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE= (in Base64). We can allow this one event handlers like this: Content-Security-Policy: script-src 'self'; script-src-attr 'unsafe-hashes' 'sha256-vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE=' Note the sha256- prefix. This event handler now works when clicked: click me But any other script will still be blocked: click me Dealing with legacy browsers Currently (November 2023) about 75% of browsers support script-src-attr. Here is a forward-looking compromise that many users use with new CSP features: Have a liberal CSP with old directives supported by all browsers Make your CSP stricter with new, more specific directives for browsers that support it The CSP spec supports that approach in that using newer, more specific directives disable older, more general features. In our case this means: For old browsers, allow all inline scripts For new browsers, disallow inline scripts but allow inline handlers with given hashes Here is a CSP directive that works like this: Content-Security-Policy: script-src 'self' 'unsafe-inline'; script-src-elem 'self'; script-src-attr 'unsafe-hashes' 'sha256-vIsp2avtxDy0157AryO+jEJVpLdmka7PI7o7C4q5ABE=' Old browsers will only use script-src. New browsers will use script-src-elem (for tags) and script-src-attr (for inline event handlers), which override the more liberal rules from script-src.

We had a card that described how to install multiple mysql versions using mysql-sandbox. Nowadays with the wide adoption...