使用QNetworkAccessManager的Qt应用程序在为WebAssembly构建时崩溃

我正在尝试制作一个简单的应用程序，通过RESTapi从服务器下载信息。对于下载数据，我使用QNetworkAccessManager。我的应用程序在为桌面构建时运行良好，我正在尝试为WebAssembly构建它。

我正在使用：

• Qt版本5.15.2
• Emscripten版本1.39.8(如本网站所写，为特定Qt版本的已知好版本(

我用-feature-thread从源代码构建了Qt-webassembly，以支持多线程，内存/工作线程(线程(设置为

QMAKE_WASM_PTHREAD_POOL_SIZE = 8
QMAKE_WASM_TOTAL_MEMORY = 3GB

当我把它用作本地桌面时，一切都很好。当我通过浏览器(WebAssembly(启动它时，应用程序启动，GUI出现，我可以输入连接地址。当我编写一个有效的请求(支持CORS的服务器(时，请求会顺利进行并返回有效的JSON文档。但是当我键入无效地址时，应用程序将崩溃。

崩溃是由Qt(调用堆栈(中某个位置的abort()函数引起的。此外，应用程序的行为也不一致——有时第一个请求会崩溃，有时第三个请求也会崩溃。

我可能遇到两个错误——Uncaught RuntimeError: abort(undefined)和Uncaught RuntimeError: abort(Runtime error: The application has corrupted its heap memory area (address zero)!)。

我尝试了QNetworkAccessManager的多个教程，但结果相同。

main.cpp

#include "DummyRequestManager.h"
#include <QGuiApplication>
#include <QQmlApplicationEngine>
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
DummyRequestManager c;
c.init();
return app.exec();
}

DummyRequestManager.hpp

#ifndef DUMMYREQUESTMANAGER_H
#define DUMMYREQUESTMANAGER_H
#include <QQuickView>
#include <QObject>
#include <QNetworkAccessManager>
#include <QJsonDocument>
#include <memory>
enum HttpRespStatus
{
NoResponse = 0,
Ok = 200,
NoContent = 204,
BadRequest = 400,
Unauthorized = 401,
Forbidden = 403,
NotFound = 404,
MethodNotAllowed = 405,
NotAcceptable = 406, // Shouldn't be used.
Conflict = 409,
Gone = 410,
UnsupportedMediaType = 415,
InternalError = 500,
NotImplemented = 501,
ServiceUnavailable = 503
};

class DummyRequestManager : public QNetworkAccessManager
{
Q_OBJECT
Q_PROPERTY(QString url READ url WRITE setUrl NOTIFY urlChanged)
public:
DummyRequestManager();
void init();
QString url() const { return url_; }
public slots:
QNetworkReply *createRequest(Operation op, const QNetworkRequest &request, QIODevice *outgoingData);
QNetworkReply* get(QNetworkRequest &request);
void sendRequest();
public slots:
// Setters
void setUrl(QString url);
signals:
void urlChanged(QString url);
private:
int port_{0};
QString scheme_{"https"};
QString url_{""};
QString finalUrl_{""};
QQuickView view_;
};
#endif // DUMMYREQUESTMANAGER_H

DummyRequestManager.cpp

#include "DummyRequestManager.h"
#include <QQmlContext>
#include <QNetworkReply>
#include <QJsonObject>
DummyRequestManager::DummyRequestManager()
{
connect(this, &DummyRequestManager::urlChanged, this, [=](){
QStringList split = url_.split(":");
QString addr = "";
if(split.size() == 2)
{
addr = split.first();
port_ = split.last().toInt();
finalUrl_ = QString("https://%1:%2/api").arg(addr).arg(QString::number(port_));
qDebug() << finalUrl_;
}
});
}
void DummyRequestManager::init()
{
port_ = 8080;
// WARNING Code below is supposed to be only for testing, it's necessary to add certificate
#ifndef QT_NO_SSL
QSslConfiguration sslConf = QSslConfiguration::defaultConfiguration();
sslConf.setPeerVerifyMode(QSslSocket::VerifyNone);
QSslConfiguration::setDefaultConfiguration(sslConf);
#endif
scheme_ = "https";
view_.rootContext()->setContextProperty("dummy", this);
view_.setSource(QUrl(QStringLiteral("qrc:/main.qml")));
view_.show();
}
QNetworkReply *DummyRequestManager::createRequest(QNetworkAccessManager::Operation op, const QNetworkRequest &request, QIODevice *outgoingData)
{
return QNetworkAccessManager::createRequest(op, request, outgoingData);
}
QNetworkReply *DummyRequestManager::get(QNetworkRequest &request)
{
qDebug() << "request url" << request.url();
request.setRawHeader("accept", "application/json");
request.setAttribute(QNetworkRequest::HttpPipeliningAllowedAttribute, true);
return QNetworkAccessManager::get(request);
}
void DummyRequestManager::sendRequest()
{
QUrl url(finalUrl_ + QString("/info"));
url.setScheme(scheme_);
QNetworkRequest request(url);
QNetworkReply *reply = get(request);
QObject::connect(reply, &QNetworkReply::finished, [=] {
qDebug() << reply->header(QNetworkRequest::ContentTypeHeader).toString();
qDebug() << reply->header(QNetworkRequest::LastModifiedHeader).toDateTime().toString();;
qDebug() << reply->header(QNetworkRequest::ContentLengthHeader).toULongLong();
qDebug() << reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
qDebug() << reply->attribute(QNetworkRequest::HttpReasonPhraseAttribute).toString();
QByteArray data = reply->readAll();
QJsonDocument doc = QJsonDocument::fromJson(data);
qDebug().noquote() << doc.toJson(QJsonDocument::Indented);
reply->deleteLater();
});
}
void DummyRequestManager::setUrl(QString url)
{
if (url_ == url)
return;
url_ = url;
emit urlChanged(url_);
}

main.qml

import QtQuick 2.12
Item {
width: 640
height: 480
visible: true
Rectangle {
id: centerRect
width: 200
height: 200
anchors.centerIn: parent
color: "blue"
MouseArea {
anchors.fill: parent
onClicked: {
dummy.sendRequest()
}
}
Text {
anchors.centerIn: parent
text: qsTr("Send")
color: "white"
}
}
Rectangle {
color: "gray"
width: centerRect.width
height: 50
anchors.top: centerRect.top
anchors.horizontalCenter: centerRect.horizontalCenter
TextInput {
anchors.fill: parent
onTextChanged: {
dummy.url = text
}
}
}
}

你知道问题出在哪里吗？

谢谢你的帮助！

编辑：当我删除lambda函数中的reply->deleteLater()时，它不会崩溃。