Qt for WebAssembly

@ericg_97477 I ended up trying an alternate way to use emrun... $ emrun --no_browser --port 8080 ./default.html Web server root directory: /Users/ericg/depot_qt/default/build Now listening at http://0.0.0.0:8080/ I then went to http://0.0.0.0:8080/ in the browser. I was shown the expected page: Directory listing for / with all of the files in my build folder. When I clicked on default.html, I saw the QT icon and it a message that it was downloading the program. Eventually, I saw the the hello world message appear. I assume I would eventually be able to take control over the loading screen. So, that worked. Why didn't emrun — browser=firefox *.html?

I don't know, sorry. I only tried WASM a few times, years ago.

Kinda... I documented my findings on https://github.com/jpgehrig/nextqt.

@SGaist said in How best to deploy a WebAssembly app: nginx Thank you!...Am a complete beginner. Just the help I needed! I'll try out nginx or something akin. :)

Hi Yes. Due to the sandbox nature, I have not seen any WebAssem that could save the DB as local file , only in memory which clearly won't fit your use case. However, it does seem possible to save to a array and and load from it. If your db is not big, it might be useful https://sql.js.org/#/ I wonder if it would be possible to save and load the DB with javascript and then access it from c++ as in-mem db. However, I never tried it.

Tested: EMSDK 1.38.9: OpenSSL cannot be compiled, since the packed gcc is older than requested EMSDK 1.39.16: Could compile but become frozen. EMSDK 2.0.6: Compiled, but every time I add QQuickView *view = new QQuickView(), the console log says: -- constructing QQuickView qtloader.js:382 Blocking on the main thread is very dangerous, see https://emscripten.org/docs/porting/pthreads.html#blocking- on-the-main-browser-thread and the execution hangs. It is possible that I oversee something, but every other modules are fine: multithreading is running, QGraphicsScene is there and works fine. I have only issue with this QML part.

@JKSH true, my bad. than thats not an option.

Hi, I am currently using EMSDK 2.0.6 with Qt 5.15.2, but IIRC it was possible to compile Qt with ESMDK 2.0.14 as well. The 2.x version of EMSDK greatly reduces the compilation time and feels to be more mature.

after contact the qt support, they suggest me to replace win32: LIBS += -L$$PWD/../../TinyLib/build-TinyLib-Qt_5_15_0_WebAssembly-Debug/ -lTinyLib with wasm:LIBS += -L$$PWD/../../TinyLib/build-TinyLib-Qt_5_15_0_WebAssembly-Debug/ -lTinyLib

It did not work. I used this line to configure: ./configure -DCMAKE_TOOLCHAIN_FILE='$HOME'/Library/emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake -qt-host-path /home/anon/Library/qt6.2/qtbase -xplatform wasm-emscripten -debug -prefix $PWD/qtbase -device-option QT_WASM_SOURCE_MAP=1 When I upload the Qt version into QtCreator, the ABI is always x86-linux-generic-elf-64bit Instead of asmjs-unknown-unknown-emscripten-32bit Preventing any build.

@SimonR Did you check the Compiler tab to see whether there are any warnings/errors?

No, that's the proper way to do it. The Qt logo and all the HTML, JS files generated in a project are just some example/ boilerplate code. You are free to replace it.

You can use emscripten API to read the JavaScript window.location object. #include <emscripten/val.h> ... emscripten::val location = emscripten::val::global("location"); auto host = location["hostname"].as<std::string>(); auto port = location["port"].as<std::string>();