12

我有一个 webviewer，只希望它只能访问我们的 webapps，为了实现这一点，我放置了一个我在 Qt 应用程序中寻找的 php 标头。这工作正常，但有一个例外，那就是 301 永久移动状态代码。现代浏览器会自动重定向您，但会在 http 请求的末尾添加一个“/”。

当输入我们的网络应用程序的 URL 时，它当前需要尾部斜杠才能检测到标头，但我希望它也能到达该标头，即使他们没有放置尾部斜杠。

这是我当前检索标头的方法：

QNetworkAccessManager *manager = new QNetworkAccessManager(this);
    QNetworkRequest request;
    request.setUrl(url);
    connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(onFinished(QNetworkReply*)));

    request.setRawHeader("User-Agent", "CytoViewer 1.0");
    request.setHeader(QNetworkRequest::ContentTypeHeader,"application/CytoViewer");
    QNetworkReply *reply = manager->get(request);
    reply->ignoreSslErrors();
    QEventLoop loop;

    connect(reply, SIGNAL(finished()), &loop, SLOT(quit()));
    loop.exec();
    qDebug() << "QLoop reply all: " << reply->readAll();
    qDebug() << "QLoop: " << reply->rawHeader("Cyto-Study-Manager");
    if(reply->rawHeader("OurWebApp") == "1"){
        //Header exists?(QEventLoop finish) Set arg[1]"url 'Found prouct: product header'"
        product = reply->rawHeader("Product");
        return true;
    } else {
        //Header doen't exist? Graceful error - not a valid PI product
        return false;
    }

为了解决首先点击 301 的问题，我发送了两个网络请求，第一个点击输入的 URL 并检查 301，如果有 301 状态代码，它通过该reply->attribute(QNetworkRequest::RedirectionTargetAttribute).toUrl();方法获取建议的 url，如果有则返回该 URL没有状态码，那么它只是返回用户输入的前一个 URL，然后发送另一个网络请求来检查标头。

我发出的第一个请求是检查状态码：

QUrl MainWindow::networkRequest(QUrl checkUrl){
    qDebug() << "checkURL: " << checkUrl;
    //
    QNetworkAccessManager *manager = new QNetworkAccessManager(this);
    QNetworkRequest request;
    request.setUrl(checkUrl);
    request.setRawHeader("User-Agent", "CytoViewer 1.0");
    request.setHeader(QNetworkRequest::ContentTypeHeader,"application/CytoViewer");
    QNetworkReply *reply = manager->get(request);
    reply->ignoreSslErrors();
    QEventLoop checkLoop;
    connect(reply, SIGNAL(finished()), &checkLoop, SLOT(quit()));
    checkLoop.exec();
    //Check status code
    if (reply->error() == QNetworkReply::NoError) {
        int statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
        if(statusCode == 301) {
            QUrl redirectUrl = reply->attribute(QNetworkRequest::RedirectionTargetAttribute).toUrl();
            return redirectUrl;
        }else {
            return checkUrl;
        }

    }
}

长话短说，我正在发送两个网络请求，1）检查 301 2）检查我们的应用程序标头。

有没有办法在一个请求中做到这一点？我是否缺少一种可以自动执行此重定向的方法？

问候

弥敦道

4

2 回答 2

26

如果您使用的是 Qt 6，请跳过阅读此答案，因为自动重定向是默认行为

如果您不使用 Qt 6，则旧答案：

QNetworkRequest::FollowRedirectsAttributeQt 5.6 ( )添加了自动重定向支持。

默认情况下未启用：

QNetworkRequest req(QUrl("https://example.com/"));
req.setAttribute(QNetworkRequest::FollowRedirectsAttribute, true);
于 2016-04-03T14:33:18.737 回答
12

显然没有。

在https://web.archive.org/web/20141101060340/http://developer.nokia.com/community/wiki/Handling_an_HTTP_redirect_with_QNetworkAccessManager上有一个官方的 HOWTO 条目

从上面的链接中提取：

void QNAMRedirect::replyFinished(QNetworkReply* reply) {
    /*
     * Reply is finished!
     * We'll ask for the reply about the Redirection attribute
     * http://doc.trolltech.com/qnetworkrequest.html#Attribute-enum
     */
    QVariant possibleRedirectUrl =
             reply->attribute(QNetworkRequest::RedirectionTargetAttribute);
 
    /* We'll deduct if the redirection is valid in the redirectUrl function */
    _urlRedirectedTo = this->redirectUrl(possibleRedirectUrl.toUrl(),
                                         _urlRedirectedTo);
 
    /* If the URL is not empty, we're being redirected. */
    if(!_urlRedirectedTo.isEmpty()) {
        QString text = QString("QNAMRedirect::replyFinished: Redirected to ")
                              .append(_urlRedirectedTo.toString());
        this->_textContainer->setText(text);
 
        /* We'll do another request to the redirection url. */
        this->_qnam->get(QNetworkRequest(_urlRedirectedTo));
    }
    else {
        /*
         * We weren't redirected anymore
         * so we arrived to the final destination...
         */
        QString text = QString("QNAMRedirect::replyFinished: Arrived to ")
                              .append(reply->url().toString());
        this->_textContainer->setText(text);
        /* ...so this can be cleared. */
        _urlRedirectedTo.clear();
    }
    /* Clean up. */
    reply->deleteLater();
}
 
QUrl QNAMRedirect::redirectUrl(const QUrl& possibleRedirectUrl,
                               const QUrl& oldRedirectUrl) const {
    QUrl redirectUrl;
    /*
     * Check if the URL is empty and
     * that we aren't being fooled into a infinite redirect loop.
     * We could also keep track of how many redirects we have been to
     * and set a limit to it, but we'll leave that to you.
     */
    if(!possibleRedirectUrl.isEmpty() &&
       possibleRedirectUrl != oldRedirectUrl) {
        redirectUrl = possibleRedirectUrl;
    }
    return redirectUrl;
}
于 2013-02-11T09:58:02.760 回答