[HN Gopher] Wt - C++ Web Toolkit
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Wt - C++ Web Toolkit
Author : gtirloni
Score : 123 points
Date : 2020-07-12 17:00 UTC (5 hours ago)
(HTM) web link (www.webtoolkit.eu)
(TXT) w3m dump (www.webtoolkit.eu)
| mjs33 wrote:
| Is this just CGI?
| c-smile wrote:
| Am I right that this is close to ASP.NET thing
| <asp:textbox text="hello world" runat=server />
|
| In particular to that runat=server part?
|
| So widget gets rendered to HTML on server side with events sent
| to it from client? That may work for logical events like click
| but not for mousemove (too expensive) ...
| doteka wrote:
| While certainly impressive, the Hello World example in their
| documentation is in no way preferable to writing JavaScript.
| cbsmith wrote:
| I always liked Wt. I haven't used it in quite a while. What's it
| like these days?
| nikki93 wrote:
| With 'modern C++' you can make APIs way nicer than the Java-like
| API going on here. Lambdas really help, along with RAII which has
| already been around. I have an API going where the following
| syntax creates a div with a 'toolbar' class and a toggle button
| with the 'edit' class and updates the DOM (C++ running in WASM,
| using IncrementalDOM for the DOM access):
| ui.div()("toolbar")([&]() {
| ui.button()("edit")("selected", editing)("click",
| [&](emscripten::val target) { editing = !editing;
| }); });
|
| This works by having `.div()` etc. return an `Elem` type whose
| constructor opens an HTML element and destructor closes it, with
| various overloads of `operator()` letting you set attributes,
| bind events or add child elements.
|
| Here's a video of some results with C++ and CSS:
| https://twitter.com/snikhilesh/status/1279913032471031809
|
| I should do a writeup about this soon...
| jordigh wrote:
| So what do the compiler errors look like when you mess this up?
| Say, you use the wrong argument passing for one of the lambdas.
| cocoa19 wrote:
| It's hard to compete with Open Source Libre libraries and lower
| C++ interest in new developers, not to mention developing in C++
| is harder than many other languages.
|
| My employer still struggles to this day finding good recent grads
| remotely interested in C++. In contrast, Java and Javascript
| skills are easy to find in the market.
|
| Edit: Added "Libre"
| rch wrote:
| > Wt is licensed under the GNU GPL Version 2
|
| That excludes it from my use, but I believe that license is
| what is implied by 'Libre' generally.
| cocoa19 wrote:
| I think you are right, what I wanted to say is free for
| commercial uses without restrictions like LGPL's dynamic
| linking requirement.
|
| I'm thinking something like MIT or BSD licenses. Not sure if
| there's a term for this, "permissive" license maybe.
| mehrzad wrote:
| I am a recent grad interested in C++ but from my perspective,
| very few employers want to hire recent grads for C++.
| jonwalch wrote:
| Investment banks and trading shops are always looking for new
| grads for C++.
| wojtczyk wrote:
| Agreed. Also, robotics & controls
| einpoklum wrote:
| Sure, if you have an anti-social bent and want to profit
| almost directly from usury, arbitrage and speculation.
| ncmncm wrote:
| They can afford to demand competence, and they need it. But
| they don't always get it.
|
| They are the reason it can be hard to hire qualified C++
| programmers elsewhere. You compete for the rest who find
| Wall Street and monopolists both morally repugnant.
| beached_whale wrote:
| I would say programming is really difficult and it is
| hard to find competent(pick an arbitrary line in the
| sand) for any skill let alone programming. Pick a field,
| and the web is stuffed full of people with battle stories
| of cleaning up after other people. This is actually a
| point or two against C++ as the breadth of it is so
| large. The trick, as in any practice, is to find
| motivated people willing to learn that are not stubborn
| in their set ways.
| vikinghckr wrote:
| Google and Facebook -- two of the biggest software companies
| are incredibly C++ focused -- especially in backend/infra. To
| a lesser extent Microsoft and Amazon are the same. And as
| others mentioned, trading farms love C++ too.
|
| Essentially, in 2020, the highest paying software companies
| in the world all are heavily invested in modern C++. Knowing
| modern C++ is the biggest advantage you can have in the
| market. But you won't know that from reading the HN comments
| section.
| [deleted]
| doliveira wrote:
| That's nice to hear! I need some C++ projects to show, then
| zelly wrote:
| C++ people don't do CRUD webshit. C++ is for compilers, HFT,
| machine learning, browsers, search engines, robotics. When C++
| touches "the web" it's in the form of something like Envoy or
| HAProxy, not exactly application layer. For CRUD webshit, there
| are literally hundreds of options out there that largely
| automate the entire process (Rails/Django/Spring). There is no
| reason to use C++ for it not just because of the timesink but
| because the lack of safety makes it an aggressively bad idea.
| You would get all kinds of "I thought that wasn't a problem in
| the 21st century anymore" type of problems.
| fbmac wrote:
| That's the illusion that got me into C. Reality I found is,
| where I live at least, C is for legacy code and code that
| runs in very bad hardware.
| zelly wrote:
| What illusion are you talking about?
| guruz wrote:
| It's all possible :-)
|
| I can recommend the "app server" POCOPRO
| https://pocoproject.org/pocopro.html
| smt1 wrote:
| People do need to write UIs in C++ though (sometimes as
| frontends for some of the purposes you mentioned), and Qt is
| probably the most used UI toolkit for C++.
|
| Wt is basically Qt for the web. I've used a lot of UI
| toolkits across many languages, and Qt with modern-ish C++ is
| fairly productive, doubly so if you're slapping something
| together for an existing C++ codebase you have.
| roywiggins wrote:
| This is the exact use-case where I've used Wt. Existing C++
| codebase, needs an admin interface, needs to be accessible
| over the corporate intranet. Wt is perfect for that.
| codr7 wrote:
| I've written several applications using this approach
| lately, administrative systems.
|
| None in C++ yet, but Java & Go.
|
| Integrating the UI tightly with the backend has a lot of
| advantages and I strongly prefer working in a sane
| language to both template engines and JSON APIs.
| giancarlostoro wrote:
| You are better served using D and Vibe.d or other D web
| frameworks if you really want a compiled web stack. Also the
| other obvious choice is Go and probably Rust but I havent
| found a web framework for Rust that doesnt annoy me to no end
| yet.
| stjo wrote:
| Making a front end library/framework/toolkit without screenshots
| and example code should be made punishable by law.
| ssutch3 wrote:
| https://www.webtoolkit.eu/widgets
| Jaxan wrote:
| There is a link to the gallery. That suffices, right?
| beached_whale wrote:
| The whole site is run on it, and your working examples are
| there just had to click on documentation
| https://www.webtoolkit.eu/wt/documentation
| einpoklum wrote:
| So, Wt is about having the server do a bunch of computational
| work for rendering the UI. Now, I'm not a web developer, so I may
| be talking nonsense, but I don't see how that's reasonable:
|
| 1. It doesn't scale, or if you're rich - it's annoying to scale.
| 2. It interferes with the client/user's ability (albeit
| theoretical) to decide how they want to present the information
| 3. It seems to go against what are, or used to be, the principles
| of the web: Interlinked, clear-text, markup which the client
| renders as it sees fit.
| marta_morena_25 wrote:
| I find it irritating that even after reading their front-page and
| the "How you can use WT" I still have no clue what it is supposed
| to be. Is this an embedded browser? Is it a C++ app GUI that
| allows you to use HTML like construction? Is it an emscripten
| application? How can it work without JS enabled? Is it compiled
| into pure WebASM? What the heck do they mean by connection? What
| connection? What does have PDF and DB to do with all that? Etc.
|
| Very poor marketing imo. After reading all this I have even less
| clue what it is supposed to do.
| roywiggins wrote:
| It works without JavaScript because it can render everything
| server-side. If the user has JavaScript it uses websockets or
| Ajax to fetch updates from the server, but if it doesn't have
| those it can just reload the whole page like you would with a
| CGI application.
|
| "Qt, but for web applications" would be a short and basically
| accurate descriptor. You slot together widgets in C++ and it
| works out how to lay them out and connect actions taken by the
| user to your event-handling code, which lives on the server.
|
| The PDF thing is for rendering reports to PDF, instead of HTML.
| Not useful unless you're in a corporate sort of space, but when
| you want a PDF report you do want something like that. The DB
| thing is an ORM that makes basic CRUD operations on your
| database easier.
| hellofunk wrote:
| Oh strange, I completely assumed from the start that it was
| referring to front end C++ using Webassembly, similar to how
| some rust libraries do it. Never occurred to me this is
| server side.
| chrismorgan wrote:
| Wt comes from many years before WebAssembly.
| marta_morena_25 wrote:
| Yeah it dawned on me the moment I hit sent... That this is
| probably something like ASP.NET for C++. Probably some people
| still need that :). Legit use case, just I think they need to
| work a lot on their messaging.
| shayas wrote:
| Why some people can't liberate themselves from C++?
| mister_hn wrote:
| Because the alternatives aren't better
| PaulDavisThe1st wrote:
| Because we're already free.
| znpy wrote:
| Best comment
| vikinghckr wrote:
| Because:
|
| a) Modern C++ is amazing. b) The highest paying software jobs
| require C++.
| imafish wrote:
| a) it really isn't. b) yes, COBOL developers are also highly
| paid. does not make the language amazing.
| vikinghckr wrote:
| a) It really is. b) I didn't say point (a) is why modern
| C++ is amazing. But it is one of the motivations for
| learning modern C++.
| varbhat wrote:
| What's the real advantage of using this over HTML template
| rendering?
| roywiggins wrote:
| You don't have to write JavaScript, and it generates a page
| that acts like an SPA and does all the AJAXy stuff for you in
| the background. So you can just say "I want a button that does
| this server action on click" and it manages all the
| communication between the browser and the back end. It even
| gracefully degrades to full page reloads if the user doesn't
| have JavaScript turned on.
| rsecora wrote:
| I will try to be brief and go to the point.
|
| Wt is different to templating. It's server side rendering and
| the widgets communication is transparent, based on slots and
| receivers in the server side.
|
| If you came from java it has similarities to Vaadin.
|
| It has more goodies, websockets, DB...
| Jeaye wrote:
| I tried using Wt for a site almost a decade ago, it seems. The
| layout managers would make the site so terribly jittery that it
| could cause motion sickness.
|
| My use case for Wt at the time as "I know C++ well and I don't
| want to learn anything else." I don't think I'll ever have a
| better use case for it and I don't think that one was very good
| to begin with.
|
| The best use case I can imagine is something like "We have a lot
| of existing C++ code which we need to turn into a web app." But
| even then, why does the C++ code need to manage the DOM? It
| almost certainly doesn't.
| jokoon wrote:
| Wait, is this using http/html, or something else? I'm not sure I
| understand the "web" part in this.
| nephanth wrote:
| It is. But it is abstracting over
| http/HTML/JavaScript/rpc(ajax) with c++ classes
| afranchuk wrote:
| I used Wt about a year ago for an application at work. I was able
| to write a GUI program that could be accessed at a web address or
| with a native Qt application, and Wt was equivalent enough (API-
| wise) that I was able to template between the two. Really neat
| actually. There was one place where the GUI was defined and you
| could choose whether you wanted web, native, or both! Only
| stumbling block was when I needed some opengl (webgl), but with a
| fairly minimal abstraction I was and to get that working in both
| two.
|
| Wt felt very polished and worked exactly as I expected.
| guruz wrote:
| A propos Qt.
|
| There is Qt for Web Assembly. https://www.qt.io/qt-examples-
| for-webassembly
|
| And WebGL streaming https://www.qt.io/blog/2018/11/23/qt-quick-
| webgl-release-512...
| esprehn wrote:
| Unfortunately the Qt demos all take 8-10 seconds to load on a
| phone for me and several of them fail with out of memory even
| on high end devices like a Pixel 4 XL. Certainly I'd expect a
| Pizza Ordering app to work on mobile (and to not show a flash
| style loading spinner for 10 seconds).
|
| WT is doing all the logic server side so the client ends up
| being lighter weight and will work on more devices, and with
| better performance.
| mwcampbell wrote:
| The Qt port for WebAssembly still has zero accessibility
| support, e.g. for blind people with screen readers. Assuming
| Wt is using standard HTML form controls, it shouldn't get in
| the way of accessibility. Of course, the app developer still
| needs to follow good accessibility practices, such as
| labeling images and not conveying information through color
| alone.
| InfiniteRand wrote:
| A lot of the comments question the use case but I think your
| story captures the ideal use case, a hybrid C++ / web app where
| you want to or need to share some of the functionality between
| web / c++ sides
| roywiggins wrote:
| It's not a bad way to build a web interface for a C++
| application that needs to be configured over an intranet. It
| makes tying "click on a button on a web site" to "run an
| administrator action on my application" very easy, and you
| can use your Qt muscle memory to lay out a simple admin
| interface with relatively little mucking about.
|
| You can do all that with CGI scripts or whatever, but if you
| already have a bunch of C++ running on the server it isn't
| nuts to use Wt to build your CRUDy admin interface.
| beached_whale wrote:
| In addition, I have used the templating in the library and it
| works really well. Let the UI/UX people do their thing and
| get the best performing back end.
| einpoklum wrote:
| But for a modern-C++ developer, Qt is so outdated... it's based
| on what the language was like 20 years ago. I would really
| rather not be limited to writing UI that way.
| briandilley wrote:
| painful
| dang wrote:
| If curious see also
|
| 2013 https://news.ycombinator.com/item?id=5997034
|
| 2010 https://news.ycombinator.com/item?id=1098282
|
| 2009 https://news.ycombinator.com/item?id=886900
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