Get an idea of the varying support for HTML/CSS/JavaScript features in different browsers like Chrome, Firefox, Internet Explorer, Edge...
While working on a Rails application, your code base will grow a collection of different file types including: Ruby (business...
Congratulations, you just made it through about half of our curriculum deck! 🎉 We've covered the basics of your future...
We are using the BEM pattern ("Block, Element, Modifier") to structure our CSS in all new projects. We try to...
Stepping forward from JavaScript Basics, the goal of this card is for you to be able to read and write...
Understand how asynchronous JavaScript works: Read Henning's presentation about asynchronous Javascript (there's also a German video presentation...
Just like we use gems on the server, we use third party JavaScript libraries in the browser. These typically provide...
Rubymonk training Read the following Rubymonk articles: Ruby Primer: Ascent (archived copy) Metaprogramming Ruby (archived copy) Metaprogramming Ruby: Ascent (archived...
Method lookup Understand all the terms in How Ruby method lookup works, in particular: include extend singleton class
Your MovieDB gained traction and is now a popular tool among cineasts. This comes with a downside: You noticed a...
Exercise 1: Maps In MovieDB, add a new field “Principal filming location”. In a movie’s show view, geocode that...
Exercise 1: XML On the start page of your Movie DB, show the title of a random movie that is...
Jasmine is a great tool to unit test your JavaScript components without writing an expensive end-to-end test for...
If you've stumbled over display: grid while reading the Flexbox material of the previous card - we've got you...
Many of our clients can't or don't want to design their user interfaces. In the absence of a...
Adopting legacy Rails apps Talk to your mentor about how we're approaching applications that are either old or abandoned...
Some tasks in a web application are better not done live when a user request a page, but in the...
Resources Rails Guide: Internationalization API Guide to localizing a Rails application Locale-aware helpers in ActionView::Helpers::NumberHelper
Action Mailer Basics and Previews Chapter "Task H1: Sending Confirmation Emails" from Agile Web Development with Rails (in our...
For each movie in MovieDB, we want to track which other movie it was inspired by. For...
While the Software Design Basics card tried to make a point about writing self explanatory code, it's still...
Rails ships with two separate build pipelines: Sprockets ("asset pipeline") and Webpacker. Webpacker has many more moving parts, but allows...
We've already learned how to integrate user-provided images uploads to our application in 205 basic file uploads and...
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When you load a with a nonce, that script can await import() additional sources from any hostname. The nonce is propagated automatically for the one purpose of importing more scripts. This is not related to strict-dynamic, which propagates nonces for any propose not limited to imports (e.g. inserting elements). Example We have a restrictive CSP that only allows nonces: Content-Security-Policy: default-src 'none'; script-src 'nonce-secret123' Our HTML loads script.js using that nonce: Our script.js imports other.js without a nonce: let other = await import('other.js') console.log("Look, script.js has imported %o", other) The import succeeds without a nonce, due to implicit nonce propagation. Why this is useful In modern build pipelines, code splitting (chunking) is implemented using dynamic imports. Nonce propagation allows us to use automatic chunking with restrictive, nonce-based CSPs without using strict-dynamic. E.g. esbuild automatically groups dynamically imported modules into chunks, and writes that chunk to disk. The compiled build has an await import('assets/chunk-NAXSMFJV.js'). There's no way to inject a nonce into that import(), but implicit nonce propagation still allows the request. Should I worry about this? It would require some truly strange code for user input to make it into an import() argument. I wouldn't lose sleep over this. Is this a browser bug? It is by design. Here are some sources: HTML Spec Section 8 (Web Application APIs) (search for "descendant script fetch options") Chromium test ensuring none propagation Firefox bug implementing nonce propagation CSP issue: Someone concerned about propagation being a vulnerability CSP issue: Proposal for import-src that went nowhere Are other CSP sources also propagated? No, only nonces. In particular host-based CSPs do not propagate trust. For example, you only allow scripts from our own host (no nonces): Content-Security-Policy: default-src 'none'; script-src 'self' Our HTML loads script.js from our own host: Our script.js imports other.js from a different host: let other = await import('https://other-host.com/other.js') This fails with a CSP violation: Executing inline script violates the following Content Security Policy directive 'script-src 'self''
When working with file uploads, we sometimes need to process intrinsic properties like the page count or page dimensions of...