javascript - GreenAsh Poignant wit and hippie ramblings that are pertinent to javascript https://greenash.net.au/thoughts/topics/javascript/ 2022-08-28T00:00:00Z GDPR-compliant Google reCAPTCHA 2022-08-28T00:00:00Z 2022-08-28T00:00:00Z Jaza https://greenash.net.au/thoughts/2022/08/gdpr-compliant-google-recaptcha/ Per the EU's GDPR and ePrivacy Directive, you must ask visitors to a website for their consent before setting any cookies, and/or before collecting any user tracking data. And because the GDPR applies to all EU citizens (who are residing within the EU), regardless of where in the world a website or its owner is based, in order to fully comply, in practice you should seek consent for all visitors to all websites globally.

In order to be GDPR-compliant, and in order to just be a good netizen, I made sure, when building GreenAsh v5 earlier this year, to not use services that set cookies at all, wherever possible. In previous iterations of GreenAsh, I used Google Analytics, which (like basically all Google services) is a notorious GDPR offender; this time around, I instead used Cloudflare Web Analytics, which is a good enough replacement for my modest needs, and which ticks all the privacy boxes.

However, on pages with forms at least, I still need Google reCAPTCHA. I'd like to instead use the privacy-conscious hCaptcha, but Netlify Forms only supports reCAPTCHA, so I'm stuck with it for now. Here's how I seek the user's consent before loading reCAPTCHA.

ready(() => {
  const submitButton = document.getElementById('submit-after-recaptcha');

  if (submitButton == null) {
    return;
  }

  window.originalSubmitFormButtonText = submitButton.textContent;
  submitButton.textContent = 'Prepare to ' + window.originalSubmitFormButtonText;

  submitButton.addEventListener("click", e => {
    if (submitButton.textContent === window.originalSubmitFormButtonText) {
      return;
    }

    const agreeToCookiesMessage =
      'This will load Google reCAPTCHA, which will set cookies. Sadly, you will ' +
      'not be able to submit this form unless you agree. GDPR, not to mention ' +
      'basic human decency, dictates that you have a choice and a right to protect ' +
      'your privacy from the corporate overlords. Do you agree?';

    if (window.confirm(agreeToCookiesMessage)) {
      const recaptchaScript = document.createElement('script');
      recaptchaScript.setAttribute(
        'src',
        'https://www.google.com/recaptcha/api.js?onload=recaptchaOnloadCallback' +
        '&render=explicit');
      recaptchaScript.setAttribute('async', '');
      recaptchaScript.setAttribute('defer', '');
      document.head.appendChild(recaptchaScript);
    }

    e.preventDefault();
  });
});

(View on GitHub)

I load this JS on every page, thus putting it on the lookout for forms that require reCAPTCHA (in my case, that's comment forms and the contact form). It changes the form's submit button text from, for example, "Send", to instead be "Prepare to Send" (as a hint to the user that clicking the button won't actually submit the form, there will be further action required before that happens).

It hijacks the button's click event, such that if the user hasn't yet provided consent, it shows a prompt. When consent is given, the Google reCAPTCHA JS is added to the DOM, and reCAPTCHA is told to call recaptchaOnloadCallback when it's done loading. If the user has already provided consent, then the button's default click behaviour of triggering form submission is allowed.

{%- if params.recaptchaKey %}
<div id="recaptcha-wrapper"></div>
<script type="text/javascript">
window.recaptchaOnloadCallback = () => {
  document.getElementById('submit-after-recaptcha').textContent =
    window.originalSubmitFormButtonText;
  window.grecaptcha.render(
    'recaptcha-wrapper', {'sitekey': '{{ params.recaptchaKey }}'}
  );
};
</script>
{%- endif %}

(View on GitHub)

I embed this HTML inside every form that requires reCAPTCHA. It defines the wrapper element into which the reCAPTCHA is injected. And it defines recaptchaOnloadCallback, which changes the submit button text back to what it originally was (e.g. changes it from "Prepare to Send" back to "Send"), and which actually renders the reCAPTCHA widget.

<!-- ... -->

  <form other-attributes-here data-netlify-recaptcha>
    <!-- ... -->

    {% include 'components/recaptcha_loader.njk' %}
    <p>
      <button type="submit" id="submit-after-recaptcha">Send</button>
    </p>
  </form>

<!-- ... -->

(View on GitHub)

This is what my GDPR-compliant, reCAPTCHA-enabled, Netlify-powered contact form looks like. The data-netlify-recaptcha attribute tells Netlify to require a successful reCAPTCHA challenge in order to accept a submission from this form.

The prompt before the reCAPTCHA in action
The prompt before the reCAPTCHA in action

That's all there is to it! Not rocket science, but I just thought I'd share this with the world, because despite there being a gazillion posts on the interwebz advising that you "ask for consent before setting cookies", there seem to be surprisingly few step-by-step instructions explaining how to actually do that. And the standard advice appears to be to use a third-party script / plugin that implements an "accept cookies" popup for you, even though it's really easy to implement it yourself.

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On Tina 2021-06-25T00:00:00Z 2021-06-25T00:00:00Z Jaza https://greenash.net.au/thoughts/2021/06/on-tina/ Continuing my foray into the world of Static Site Generators (SSGs), this time I decided to try out one that's quite different: TinaCMS (although Tina itself isn't actually an SSG, it's just an editing toolkit; so, strictly speaking, the SSG that I took for a spin is Next.js). Shiny new toys. The latest and greatest that the JAMstack has to offer. Very much all alpha (I encountered quite a few bugs, and there are still some important features missing entirely). But wow, it really does let you have your cake and eat it too: a fast, dumb, static site when logged out, that transforms into a rich, Git-backed, inline CMS when logged in!

Yes, it's named after that Tina, from Napoleon Dynamite.
Yes, it's named after that Tina, from Napoleon Dynamite.
Image source: Pinterest

Pressing on with my recent tradition of converting old sites of mine from dynamic to static, this time I converted Daydream Believers. I deliberately chose that site, because its original construction with Flask Editable Site had been an experiment, trying to achieve much the same dynamic inline editing experience as that provided by Tina. Plus, the site has been pretty much abandoned by its owners for quite a long time, so (much like my personal sites) there was basically no risk involved in touching it.

To give you a quick run-down of the history, Flask Editable Site was a noble endeavour of mine, about six years ago – the blurb from the demo sums it up quite well:

The aim of this app is to demonstrate that, with the help of modern JS libraries, and with some well-thought-out server-side snippets, it's now perfectly possible to "bake in" live in-place editing for virtually every content element in a typical brochureware site.

This app is not a CMS. On the contrary, think of it as a proof-of-concept alternative to a CMS. An alternative where there's no "admin area", there's no "editing mode", and there's no "preview button".

There's only direct manipulation.

That sounds eerily similar to "the acronym TinaCMS standing for Tina Is Not A CMS" (yes, yet another recursive acronym in the IT world, in the grand tradition of GNU), as explained in the Tina FAQ:

Tina introduces an entirely new paradigm to the content management space, which can make it difficult to grasp. In short, Tina is a toolkit for making your website its own CMS. It's a suite of packages that enables developers to build a customized content management system into the website itself.

(Who knows, maybe Flask Editable Site was one of the things that inspired the guys behind Tina – if so, I'd be flattered – although I don't believe they've heard of it).

Flask Editable Site boasted essentially the same user experience – i.e. that as soon as you log in, everything is editable inline. But the content got saved the old-skool CMS way, in a relational database. And the page(s) got rendered the old-skool CMS way, dynamically at run-time. And all of that required an old-skool deployment, on an actual server running Nginx / PostgreSQL / gunicorn (or equivalents). Plus, the Flask Editable Site inline components didn't look as good as Tina's do out-of-the-box (although I tried my best, I thought they looked half-decent).

So, I rebuilt Daydream Believers in what is currently the recommended Tina way (it's the way the tinacms.org website itself is currently built): TinaCMS running on top of Next.js, and saving content directly to GitHub via its API. Although I didn't use Tina's GitHub media store (which is currently the easiest way to manage images and other media with Tina), I instead wrote an S3 media store for Tina – something that Tina is sorely lacking, and that many other SSGs / headless CMSes already have. I hope to keep working on that draft PR and to get it merged sometime soon. The current draft works, I'm running it in production, but it has some rough edges.

Daydream Believers with TinaCMS editing mode enabled.
Daydream Believers with TinaCMS editing mode enabled.

The biggest hurdle for me, in building my first Tina site, was the fact that a Tina website must be built in React. I've dabbled in React over the past few years, mainly in my full-time job, not particularly by choice. It's rather ironic that this is my first full project built in React, and it's a static website! It's not that I don't like the philosophy or the syntax of React, I'm actually pretty on board with all that (and although I loathe Facebook, I've never held that against React).

It's just that: React is quite a big learning curve; it bloats a web front-end with its gazillion dependencies; and every little thing in the front-end has to be built (or rebuilt) in React, because it doesn't play nicely with any non-React code (e.g. old-skool jQuery) that touches the DOM directly. Anyway, I've now learnt a fair bit of React (still plenty more learning to go); and the finished site seems to load reasonably fast; and I managed to get the JS from the old site playing reasonably nicely with the new site (some via a hacky plonking of old jQuery-based code inside the main React "app" component, and some via rewriting it as actual React code).

TinaCMS isn't really production-ready just yet: I had to fix some issues just to get started with it, including bugs in the official docs and in the beginner guides.

Nevertheless, I'm super impressed with it. This is the kind of delightful user experience that I and many others were trying to build 15+ years ago in Drupal. I've cared about making awesome editable websites for an awfully long time now, and I really am overjoyed to see that awesomeness evolving to a whole new level with Tina.

Compared to the other SSGs that I've used lately – Hugo and Eleventy – Tina (slash Next.js) does have some drawbacks. It's far less mature. It has a slower build time. It doesn't scale as well. The built front-end is fatter. You can't just copy-paste legacy JS into it. You have to accept the complexity cost of React (just to build a static site!). You have to concern yourself with how everything looks in edit mode. Quite a lot of boilerplate code is required for even the simplest site.

You can also accompany traditional SSGs, such as Hugo and Eleventy, with a pretty user-friendly (and free, and SaaS) git-based CMS, such as Forestry (PS: the Forestry guys created Tina) or Netlify CMS. They don't provide any inline editing UI, they just give you a more traditional "admin site". However, they do have pretty good "live preview" functionality. Think of them as a middle ground between a traditional SSG with no editing UI, and Tina with its rich inline editing.

So, would I use Tina again? For a smaller brochureware site, where editing by non-devs needs to be as user-friendly as possible, and where I have the time / money / passion (pick approximately two!) to craft a great experience, sure, I'd love to (once it's matured a bit more). For larger sites (100+ pages), and/or for sites where user-friendly editing isn't that important, I'd probably look elsewhere. Regardless, I'm happy to be on board for the Tina journey ahead.

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On Eleventy 2021-04-14T00:00:00Z 2021-04-14T00:00:00Z Jaza https://greenash.net.au/thoughts/2021/04/on-eleventy/ Following on from my last experiment with Hugo, I decided to dabble in a different static site generator (SSG). This time, Eleventy. I've rebuilt another one of my golden oldies, Jaza's World, using it. And, similarly, source code is up on GitHub, and the site is hosted on Netlify. I'm pleased to say that Eleventy delivered in the areas where Hugo disappointed me most, although there were things about Hugo that I missed.

11ty!
11ty!

First and foremost, Eleventy allows virtually all the custom code you might need. This is in stark contrast to Hugo, with which my biggest gripe was its lack of support for any custom code whatsoever, except for template code. The most basic code hook that Eleventy supports – filters – will get you pretty far: I whipped up some filters for date formatting, for array slicing, for getting parent pages, and for getting subsets of tags. Eleventy's custom collections are also handy: for example, I defined a collection for my nav menu items. I didn't find myself needing to write any Eleventy plugins of my own, but my understanding is that you have access to the same Eleventy API methods in a plugin, as you do in a regular site-level .eleventy.js file.

One of Eleventy's most powerful features is its pagination. It's implemented as a "core plugin" (Pagination.js is the only file in Eleventy core's Plugins directory), but it probably makes sense to just think of it as a core feature, period. Its main use case is, unsurprisingly, for paging a list of content. That is, for generating /articles/, /articles/page/2/, /articles/page/99/, and so on. But it can handle any arbitrary list of data, it doesn't have to be "page content". And it can generate pages based on any permalink pattern, which you can set to not even include a "page number" at all. In this way, Eleventy can generate pages "dynamically" from data! Jaza's World doesn't have a monthly archive, but I could have created one using Eleventy pagination in this way (whereas a dynamically-generated monthly archive is currently impossible in Hugo, so I resorted to just manually defining a page for each month).

Jaza's World migrated to 11ty
Jaza's World migrated to 11ty

Eleventy's pagination still has a few rough edges. In particular, it doesn't (really) currently support "double pagination". That is, /section-foo/parent-bar-generated-by-pagination/child-baz-also-generated-by-pagination/ (although it's the same issue even if parent-bar is generated just by a permalink pattern, without using pagination at that parent level). And I kind of needed that feature, like, badly, for the Gallery section of Jaza's World. So I added support for this to Eleventy myself, by way of letting the pagination key be determined dynamically based on a callback function. As of the time of writing, that PR is still pending review (and so for now, on Jaza's World, I'm running a branch build of Eleventy that contains my change). Hopefully it will get in soon, in which case the enhancement request for double pagination (which is currently one of three "pinned" issues in the Eleventy issue tracker) should be able to be considered fulfilled.

JavaScript isn't my favourite language. I've been avoiding heavy front-end JS coding (with moderate success) for some time, and I've been trying to distance myself from back-end Node.js coding too (with less success). Python has been my language of choice for yonks now. So I'm giving Eleventy a good rap despite it being all JS, not because of it. I like that it's a minimalist JS tool, that it's not tied to any massive framework (such as React), and that it appears to be quite performant (I haven't formally benchmarked it against Hugo, but for my modest needs so far, Eleventy has been on par, it generates Jaza's World with its 500-odd pages in about 2 seconds). And hey, JS is as good a language as any these days, for the kind of script snippets you need when using a static site generator.

Eleventy has come a long way in a short time, but nevertheless, I don't feel that it's worthy yet of being called a really solid tool. Hugo is certainly a more mature piece of software, and a more mature community. In particular, Eleventy feels like a one-man show (Hugo suffers from this too, but it seems to have developed a slightly better contributor base). Kudos to zachleat for all the amazing work he has done and continues to do, but for Eleventy to be sustainable long-term, it needs more of a team.

With Jaza's World, I played around with Eleventy a fair bit, and got a real site built and deployed. But there's more I could do. I didn't bother moving any of my custom code into their own files, nor into separate plugins, I just left them in .eleventy.js. I also didn't bother writing JS unit tests – for a more serious project, what I'd really like to do, is to have tests that run in a CI pipeline (ideally in GitHub Actions), and to only kick off a Netlify deployment once there's a green build (rather than the usual setup of Netlify deploying as soon as the master branch in GitHub is updated).

Site building in Eleventy has been fun, I reckon I'll be doing more of it!

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First experiences developing a single-page JS-driven web app 2014-08-26T00:00:00Z 2014-08-26T00:00:00Z Jaza https://greenash.net.au/thoughts/2014/08/first-experiences-developing-a-single-page-js-driven-web-app/ For the past few months, my main dev project has been a custom tool that imports metric data from a variety of sources (via APIs), and that generates reports showing that data in numerous graphical and tabular formats. The app is private (and is still in alpha), so I'm afraid I can't go into more detail than that at this time.

I decided (and I was encouraged by stakeholders) to build the tool as a single-page application, i.e. as a web app where almost all of the front-end is powered by JavaScript, and where the page is redrawn via AJAX calls and client-side templates. This was my first experience developing such an app; as such, I'd like to reflect on the choices I made, and on my understanding of the technology as it stands now.

Drowning in frameworks

I never saw one before in my life, and I hope I never see one of those fuzzy miserable things again.
I never saw one before in my life, and I hope I never see one of those fuzzy miserable things again.
Image source: Memory Alpha (originally from Star Trek TOS Season 2 Ep 13).

Building single-page applications is all the rage these days; as such, a gazillion frameworks have popped up, all promising to take the pain out of the dev work for you. In reality, when your problem is that you need to create an app, and you think: "I know, I'll go and choose a JS framework", now you have two problems.

Actually, that's not the full story either. When you choose the wrong JS* framework – due to it being unsuitable for your project, and/or due to your failing to grok it – and you have to look for a framework a second time, and port the code you've already started writing… now you've got three problems!

(* I'd prefer to just refer to these frameworks as "JS", rather than use the much-bandied-about term "MVC", because not all such frameworks are MVC, and because one's project may be unsuitable for client-side MVC anyway).

Ah, the joy of first-time blunders.

I started by choosing Ember.js. It's one of the most popular frameworks at the moment. It does everything you could possibly need for your funky new JS app. Turns out that: (a) Ember was complete overkill for my relatively simple app; and (b) despite my best efforts, I failed to grok Ember, and I felt that my time would be better spent switching to something else and thereafter working more efficiently, than continuing to grapple with Ember's philosophy and complexity.

In the end, I settled on Sammy.js. This is one of the lesser-known frameworks out there. It boasts far less features than Ember.js (and even so, I haven't used all that Sammy.js offers either). It doesn't get in the way of my app's functionality. Many of its features are just a thin wrapper on top of jQuery, which I already know intimately. It adds a few bits 'n' pieces into my existing JS ecosystem, to give my app more structure and more interactivity; rather than nuking my existing ecosystem, and making me feel like single-page JS is a whole new language.

My advice to others who are choosing a whiz-bang JS framework for the first time: don't necessarily go with the most popular or the most full-featured framework you find (although don't discard such options either); think long and hard about what your app will actually do (more on that below), and choose an appropriate framework for your use-case; and make liberal use of online resources such as reviews (I also found TodoMVC extremely useful, plus I used its well-written code samples as the foundation for my own code).

What seems to be the problem?

Nothing to see here, people.
Nothing to see here, people.
Image source: Funny Junk (originally from South Park).

Ok, so you're going to write a single-page JS app. What will your app actually do? "Single-page JS app" can mean anything; and if we're trying to find the appropriate tool for the job, then the job itself needs to be clearly defined. So, let's break it down a bit.

Is the app (mainly) read-write, or is it read-only? This is a critical question, possibly more so than anything else. One of the biggest challenges with rich JS apps, is synchronising data between client and server. If data is only flowing one day (downstream), that's a whole lot less complexity than if data is flowing upstream as well.

Turns out that JS frameworks, in general, have dedicated a lot of their feature set to supporting read-write apps. They usually do this by having "models" (the "M" in "MVC"), which are the "source of truth" on the client-side; and by "binding" these models to elements in the DOM. When the value of a DOM element changes, that triggers a model data change, which in turn (often) triggers a server-side data update. Conversely, when new data arrives from the server, the model data is updated accordingly, and that update then propagates automatically to a value in the DOM.

Even the quintessential "Todo app" example has two-way data. Turns out, however, that my app only has one-way data. My app is all about sending queries to the server (with some simple filters), and receiving metric data in response. What's more, the received data is aggregate data (ready to be rendered as charts and tables), not individual entities that can easily be stored in a model. So, turns out that my life is easier without worrying about models or event bindings at all. Receive JSON, pipe it to the chart renderer (NVD3 for most charts), end of story.

Can displayed data change dynamically within a single JS route, or can it only change when the route changes? Once again, the former entails a lot more complexity than the latter. In my app's case, each JS route (handled by Sammy.js, same as with other frameworks, as "the part of the URL after the hash character") is a single report (containing one or more graphs and tables). The report elements themselves aren't dynamic (except that hovering over various graph elements shows more info). Changing the filters of the current report, or going to a different report, involves executing a new JS route.

So, if data isn't changing dynamically within a single JS route, why bother with complex event bindings? Some simple "old-skool" jQuery event handlers may be all that's necessary.

In summary, in the case of my app, all that it really needed in a JS framework was: client-side routing (which Sammy.js provides using nice, simple callbacks); local storage (Sammy.js has a thin wrapper on top of the HTML5 local storage API); AJAX communication (Sammy.js has a thin wrapper on top of jQuery for this); and templating (out-of-the-box Sammy.js supports John Resig's JS micro-templating system). And that's already a whole lot of funky new client-side components to learn and use. Why complicate things further?

Early days

There be dragons here.
There be dragons here.
Image source: Stormy Horizon Picture.

All in all, I enjoyed building my first single-page JS app, and I'm reasonably happy with how it turned out to be architected. The front-end uses Sammy.js, D3.js/NVD3, and Bootstrap. The back-end uses Flask (Python) and MongoDB. Other than the login page and the admin pages, the app only has one non-JSON server-side route (the home page), and the rest is handled with client-side routes. The client-side is fairly simple, compared to many rich JS apps being built today; but then again, every app is unique.

I think that right now, we're still in Wild West times as far as building single-page apps goes. In particular, there are way too many frameworks in abundance; as the space matures, no doubt most of these frameworks will die off, and only a handful will thrive in the long-term. There's also a shortage of good advice about design patterns for single-page apps so far, although Mixu's book is a great foundation resource.

Single-page JS technology has plenty of advantages: it can lead to a more responsive, more beautiful app; and, when done right, its JS component can be architected just as cleanly and correctly as everything would be (traditionally) architected on the server-side. Remember, though, that it's just one piece in the puzzle, and that it only needs to be as complex as the app you're building.

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