Qt for WebAssembly

Thank you @jsulm for the response. Here is my CMakeLists.txt below: CMakeLists.txt cmake_minimum_required(VERSION 3.16) project(demoApp VERSION 0.1 LANGUAGES CXX) set(CMAKE_CXX_STANDARD_REQUIRED ON) set(CMAKE_AUTOMOC ON) set(QT_QML_GENERATE_QMLLS_INI ON) find_package(Qt6 6.4 REQUIRED COMPONENTS Quick Network Sql WebSockets ) # find_package(MySQL REQUIRED) qt_standard_project_setup(REQUIRES 6.4) qt_policy(SET QTP0001 NEW) qt_add_executable(appdemoApp main.cpp ) qt_add_qml_module(appdemoApp URI demoApp VERSION 1.0 RESOURCE_PREFIX / SOURCES mainworker.h mainworker.cpp applogger.h applogger.cpp icons/Resource.qrc QML_FILES Main.qml Login.qml Userreg.qml ) # Qt for iOS sets MACOSX_BUNDLE_GUI_IDENTIFIER automatically since Qt 6.1. # If you are developing for iOS or macOS you should consider setting an # explicit, fixed bundle identifier manually though. set_target_properties(appdemoApp PROPERTIES # MACOSX_BUNDLE_GUI_IDENTIFIER com.example.appdemoApp MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION} MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR} MACOSX_BUNDLE TRUE WIN32_EXECUTABLE TRUE ) target_link_libraries(appdemoApp PRIVATE Qt6::Quick PRIVATE Qt6::Network PRIVATE Qt6::Sql PRIVATE Qt6::WebSockets ) include(GNUInstallDirs) install(TARGETS appdemoApp BUNDLE DESTINATION . LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR} ) I was thinking I could be linking to a wrong library and mysql include directory however, Cmake runs the configurations very well and indicated MYSQL:MYSQL is found.

@davidweisgerber hi, Since you dived in already, I would encourage you to submit a patch to improve the documentation on that aspect.

I think I might have a similar problem. Any update on your original issue?

If I remember well, this SharedArrayBuffer is needed when using wasm multithreading. If your app does not need multithreading, use Qt wasm single threading. If multithreading is needed, check https://forum.qt.io/post/765010

@mv-whw Thanks for answering Yes, that is the solution, putting inside my hosting public www folder all my resources: index.html main.wasm images/image0.png images/image1.png inside the wasm code: Image { source: "images/image0.png" } That worked well... and is very nice, this saves a lot of loading times..

@Jan-Bakker Hey, sorry for answering an answered qustion. Justo happy to read it, so, it is possible to load external images in Your web app so your wasm file is smaller?

@Caro You might start by Googling webassembly memory () could not allocate memory and read through the other reports and comments.

@SGaist said in Qt 6.8.2 for wasm on android, the keyboard always auto popup ?: Can you share the bug report ? https://bugreports.qt.io/browse/QTBUG-134917 https://bugreports.qt.io/browse/QTBUG-133781

I can't figure out how to build a lib for qzxing so I can link it with my application. I've tried cmake and qmake and nothing out of the box works. How did you compile qzxing? I am using qt 6.8.2 on windows 11.

There are two fantistic api in c++ #ifdef __EMSCRIPTEN__ #include <emscripten.h> // Required for calling JavaScript #endif #ifdef __EMSCRIPTEN__ // WebAssembly-specific code emscripten_run_script("console.log('Running in WebAssembly');"); #endif #ifdef __EMSCRIPTEN__ const char* url = emscripten_run_script_string("window.location.href"); qDebug() << "Current Page URL:" << url; #endif

For WebAssembly you cannot use theme icons directly but must use the Qt Ressource System

This might be QTBUG-133781, which release are you using ?

The solution to the problem is to add the header res.addHeader("Access-Control-Allow-Origin", "*"); to the HTTP server; hServer.route("/", QHttpServerRequest::Method::Get, []() { QString testAnswer = "TEST REPLY"; res.addHeader("Access-Control-Allow-Origin", "*"); // Added line QHttpServerResponse res(testAnswer, QHttpServerResponse::StatusCode::Ok); return res; }); After adding this line, the browser forwarded the reply to my application.

After some investigation, I don't believe the issue is related to the attribute method. The entire received reply is empty. There are no headers or body received by the application. The Wireshark capture shows that the entire message is properly sent out by my HTTP server and received by the browser, however, the application does not receive it. I checked if any error was reported by the reply and received an error QNetworkReply::ProtocolFailure (399). I believe the browser strips that information and does not propagate it further to the application. I tested this in Firefox and Chrome with the same results. As I mentioned in my original post, the communication works perfectly when compiled as a desktop application. The issue was only observed when compiled by WebAssembly. I will close this post and reopen a new one with a new question.

@lorn-potter Thank you, I think the OP needs help from someone who already built a Wasm project with Multimedia as he didn't manage to have his project built, on the pinned discussion almost all links are dead or out of date which doesn't help much.