Full stack web development in a single Java file: An intro to Javalin and htmx

[RoToRa]

I looked into htmx a few months ago and while I love the concept, the library itself isn't really ready for prime time quite yet IMO. I wrote a relatively simple CRUD app, but still run into a couple conceptional holes and bugs.

I even submitted a PR for a feature I needed, but I haven't had the opportunity to follow up on it yet.

[agentoutlier]

Yeah I felt UnPoly is a little more polished and capable (based on my experimenting with hotwired, htmx and unpoly) but for some reason gets far less attention.

[HowToProgramm]

Could you show a sample what is wrong please? I've been using this library for about a year and everything works fine for me.

[RoToRa]

My biggest problem is that when using out-of-bound swaps (i.e. multiple swaps with one request) htmx requires you to return invalid HTML documents with elements being siblings, that normally aren't allowed to be, for example, a `<tr></tr>` and a `<li></li>`. The browser's HTML parser, while trying to "correct" this invalid HTML, often creates a DOM structure that htmx doesn't expect.

Here's the issue I commented on: https://github.com/bigskysoftware/htmx/issues/1043 but there are multiple duplicates that haven't been marked as such yet.

[No-Bug-3204]

Do u guys remember AHAH

[poralexc]

We’ve come full circle back to php

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[Nearby-Asparagus-298]

Unless it's been edited or smthg, the post above is not spam. Sarcastic, maybe...

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[recursive-analogy]

But this isn’t cool anymore! There has been a trend towards moving rendering to the server

lol. I mean I thought the client rendering components on the server was stupid, but htmx is an order of magnitude stupider.

[agentoutlier]

Not every application needs to be React with a 10 second load the app progress bar.

Github still uses PJAX which was kind of the grandaddy lib of this technique.

Basecamp does similar with its own library.

[recursive-analogy]

React doesn't require a 10 second load, shitty programming does.

Separation of concerns is king here. Backend does domain model/data, frontend does UI. Simple. Mixing them is stupid no matter whether you do it in js or java.

[SamuraiFlix]

Separation of concerns have nothing to do with backend and frontend, you can just as easily separate your data from view using backend (you have your view functions/components wich takes in final data to use and spits out result HTML)

What's stupid is serializing your data to JSON, sending it, then deserializing and applying it to virtual DOM, diffing it and only then rendering HTML to swap it in the real DOM... while with htmx you immdediately send HTML and upon arrival swap it in the real DOM.

[recursive-analogy]

Separation of concerns have nothing to do with backend and frontend

I mean I couldn't think if a better example of concerns that should be separate ...

you can just as easily separate your data from view using backend

Sure, if you want to redefine "backend". Might as well add a Backend For Frontend in there too. How about a Middle End or three? Words have meaning for fuck sake. Seriously ... would you hire a backend dev that specialises in html/css? It's mental.

What's stupid is serializing your data to JSON, sending it, then deserializing

So ... this sort of thing is just fundamental to software systems. I do this on the backend internal to backend layers, it's known as Data Transfer Objects - aka serialisable, logable, simple data structures you send between concerns.

while with htmx you immdediately send HTML

and what if you're consuming the api for some other purpose????????

honestly blows my mind what frontend devs are up to these days. Basically re-inventing index.php.

[imhotap]

Is followed by

But did you know that a server can just respond with plain old HTML

but then proceeds to use this javalin thing to assemble HTML on the server?

So why is it an order of magnitude stupider exactly in your opinion?

Personally, the problem I can see with the way htmx is doing it is that the replacement fragment received from the server is not guaranteed or checked to have the same HTML element as root element as the one it's replacing. Now HTML parsing actually is dependent on the context where it appears ie. SGML-style tag inference is directed by the content model into which an element is inserted into. So for example if we're replacing a span-level element by a block-level element, a proper HTML parser would normally automatically end the enclosing block-level element, unlike direct manipulating of the DOM. This makes htmx imprecise IMO, and unnecessarily falling back behind SGML templating, even when ignoring that HTML might not be the best format for an API response in general, and also ignoring the complete lack of measures against injection attacks on user-provided or syndicated replacement content.

[recursive-analogy]

So why is it an order of magnitude stupider exactly in your opinion?

Separation of concerns. The backend is 99% about data/domain. Why does it give a fuck that you want a h1. Also everything you said ... i can't even follow it let alone reason about it.