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PORun several url requests in a loop in Qt
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copied!<p>In Qt I need to connect and check for updates on several servers and for this I'm using QNetworkAccessManager. The problem is that I don't want to connect to the next url until the current request has replied and is finished. My first idea was to use a loop like below, but then I have the problem with that I don't want to connect to the next url until the current is finished.</p> <pre><code>void connect() { for (int index = 0; index < 20; index++) { //I need to use this QSqlQuery to get some data here QSqlQuery query; QString sqlString = getSql(index); query.exec(sqlString); ..... if (needUpdate(index)) { //Check if I need to connect to this url QNetworkAccessManager *networkAccessManager = new QNetworkAccessManager(this); connect(networkAccessManager, SIGNAL(finished(QNetworkReply*)),this, SLOT(finishedSlot(QNetworkReply*))); QUrl url = getUrl(index); //Get the url based on the current index networkAccessManager->get(QNetworkRequest(url)); } } } void finishedSlot(QNetworkReply* reply) { </code></pre> <p>//Do more stuff }</p> <p>My other idea to solve the problem was to build it like this instead:</p> <pre><code>int index; void connect() { /*I need to use this QSqlQuery to get some data here, it works perfect when just looping like before, but when using this solution I get memory problems, it seems like it doesn't delete the query*/ QSqlQuery query; QString sqlString = getSql(index); query.exec(sqlString); ..... if (needUpdate(index)) { //Check if I need to connect to this url QNetworkAccessManager *networkAccessManager = new QNetworkAccessManager(this); connect(networkAccessManager, SIGNAL(finished(QNetworkReply*)),this, SLOT(finishedSlot(QNetworkReply*))); QUrl url = getUrl(index); //Get the url based on the current index networkAccessManager->get(QNetworkRequest(url)); } else { index++; connect(); //Request next url } } void finishedSlot(QNetworkReply* reply) { //Do more stuff index++; connect(); //Request next url } </code></pre> <p>Now the next url will not be requested before the current url is finished. The problem with this solution is that I have some problems with that as many connection() and finishedSlot() will be opened at the same time the stuff that I create in these methods wont get deleted and this will cause memory problems. I know it has something to do with query.exec(sqlString), because without this everything works like it should. But why would this differ so much between these two solutions?</p> <p>How would you solve this?</p>

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