starting http server with error handling

main.cpp

@@ -33,6 +33,7 @@ static QWidget *loadUI(QWidget *parent, std::string filename) {
 }
 
 int main(int argc, char *argv[]) {
+    srand(time(0));
 
     QApplication app(argc, argv);
 
@@ -92,10 +93,6 @@ int main(int argc, char *argv[]) {
     OCRScene *ocrscene = new OCRScene();
     OFDScene *ofdscene = new OFDScene();
 
-    // ofdscene->startHttpServer();
-    // get_local_ip_address();
-
-
     sceneLayout->addWidget(mainwindowscene);
     sceneLayout->addWidget(emailTextScene);
     sceneLayout->addWidget(ocrscene);

ofdscene.cpp

@@ -17,6 +17,8 @@ OFDScene::OFDScene(QWidget *parent)
     : QWidget(parent)
     , ui(new Ui::OFDScene) {
     ui->setupUi(this);
+
+    QObject::connect(this, &OFDScene::httpErrorOccured, this, &OFDScene::notifyHttpServerFailure);
 }
 
 OFDScene::~OFDScene() {
@@ -25,6 +27,7 @@ OFDScene::~OFDScene() {
 
 void OFDScene::startHttpServer() {
     std::string localIp = "";
+
     try {
         localIp = get_local_ip_address();
     } catch(std::exception e) {
@@ -32,13 +35,29 @@ void OFDScene::startHttpServer() {
         return;
     }
 
-    httplib::Server svr;
-    //TODO: generate random port from 1024 to 65535 and check if its used.
-    svr.Get("/", [&](const httplib::Request &, httplib::Response &res){
-        res.set_redirect("http://"+ localIp +":8080/", 301);
-    });
+    unsigned short number_of_retries = 0;
 
-    svr.listen("0.0.0.0", 8080);
+    do {
+        if (number_of_retries == 10) {
+            emit httpErrorOccured();
+            return;
+        }
+        this->port = rand() % (65535 - 1024) + 1024;
+
+        httplib::Server svr;
+
+        svr.Get("/", [&](const httplib::Request &, httplib::Response &res){
+            res.set_redirect("http://"+ localIp +":"+ std::to_string(port) +"/", 301);
+        });
+
+        number_of_retries ++;
+        std::cerr << "Listening on port: " << this->port << std::endl;
+        if (!svr.listen("0.0.0.0", this->port)) {
+            std::cerr << "Random port seems to be occupied. Trying to generate another one" << std::endl;
+            number_of_retries ++;
+            continue;
+        }
+    } while(true);
 }
 
 void OFDScene::on_choose_image_button_clicked() {
@@ -53,7 +72,6 @@ void OFDScene::on_choose_image_button_clicked() {
         return;
     }
 
-
     ui->info_label->setText(tr("Selected image: ") + filename);
 
     AdjustPictureDialog dialog = AdjustPictureDialog(this, filename.toStdString());
@@ -145,6 +163,19 @@ void OFDScene::on_parse_button_clicked() {
 
 
 void OFDScene::on_binary_eye_button_clicked() {
-
+    http_thread = new std::thread(&OFDScene::startHttpServer, this);
+}
+
+void OFDScene::notifyHttpServerFailure() {
+    QMessageBox *infoDialog = new QMessageBox();
+    infoDialog->setText(tr("Could not start http server. 10 times in a row random port was occupied. Either you should run for a lottery ticket, or the problem is in the program. If the lottery ticket wasn't lucky, please, contact the developer."));
+    infoDialog->setIcon(QMessageBox::Warning);
+    infoDialog->setWindowTitle(tr("Could not start http server."));
+    infoDialog->exec();
+    delete infoDialog;
+}
+
+unsigned int OFDScene::getPort() {
+    return port;
 }
 

ofdscene.h

@@ -2,6 +2,7 @@
 #define OFDSCENE_H
 
 #include <QWidget>
+#include <thread>
 
 namespace Ui {
 class OFDScene;
@@ -15,6 +16,8 @@ public:
     explicit OFDScene(QWidget *parent = nullptr);
     ~OFDScene();
     void startHttpServer();
+
+    unsigned int getPort();
 private slots:
     void on_choose_image_button_clicked();
     void onDataDecode(std::string data);
@@ -22,9 +25,16 @@ private slots:
     void on_parse_button_clicked();
 
     void on_binary_eye_button_clicked();
+    void notifyHttpServerFailure();
+
+signals:
+    void httpErrorOccured();
 
 private:
     Ui::OFDScene *ui;
+    std::thread *http_thread;
+
+    unsigned int port;
 };
 
 #endif // OFDSCENE_H

translations/en_US.ts

@@ -367,47 +367,57 @@
         <translation>Parse</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="49"/>
+        <location filename="../ofdscene.cpp" line="178"/>
+        <source>Could not start http server. 10 times in a row random port was occupied. Either you should run for a lottery ticket, or the problem is in the program. If the lottery ticket wasn&apos;t lucky, please, contact the developer.</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location filename="../ofdscene.cpp" line="180"/>
+        <source>Could not start http server.</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location filename="../ofdscene.cpp" line="72"/>
         <source>Please, select a picture where QR code that contains info about check is present</source>
         <translation>Please, select a picture where QR code that contains info about check is present</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="51"/>
+        <location filename="../ofdscene.cpp" line="74"/>
         <source>Picture was not selected</source>
         <translation>Picture was not selected</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="57"/>
+        <location filename="../ofdscene.cpp" line="80"/>
         <source>Selected image: </source>
         <translation>Selected image: </translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="116"/>
+        <location filename="../ofdscene.cpp" line="139"/>
         <source>Captcha was not solved correctly!</source>
         <translation>Captcha was not solved correctly!</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="118"/>
+        <location filename="../ofdscene.cpp" line="141"/>
         <source>Captcha is incorrect</source>
         <translation>Captcha is incorrect</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="123"/>
+        <location filename="../ofdscene.cpp" line="146"/>
         <source>Internal server error. Please, try again later.</source>
         <translation>Internal server error. Please, try again later.</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="125"/>
+        <location filename="../ofdscene.cpp" line="148"/>
         <source>Internal server error</source>
         <translation>Internal server error</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="130"/>
+        <location filename="../ofdscene.cpp" line="153"/>
         <source>Check not found. Please, ensure correctness of entered data.</source>
         <translation>Check not found. Please, ensure correctness of entered data.</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="132"/>
+        <location filename="../ofdscene.cpp" line="155"/>
         <source>Check was not found</source>
         <translation>Check was not found</translation>
     </message>

translations/ru_RU.ts

@@ -367,47 +367,57 @@
         <translation>Парсить</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="49"/>
+        <location filename="../ofdscene.cpp" line="178"/>
+        <source>Could not start http server. 10 times in a row random port was occupied. Either you should run for a lottery ticket, or the problem is in the program. If the lottery ticket wasn&apos;t lucky, please, contact the developer.</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location filename="../ofdscene.cpp" line="180"/>
+        <source>Could not start http server.</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location filename="../ofdscene.cpp" line="72"/>
         <source>Please, select a picture where QR code that contains info about check is present</source>
         <translation>Пожалуйста, выберете изображение, содержащее QR код с информацией о чеке</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="51"/>
+        <location filename="../ofdscene.cpp" line="74"/>
         <source>Picture was not selected</source>
         <translation>Изображение не было выбрано</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="57"/>
+        <location filename="../ofdscene.cpp" line="80"/>
         <source>Selected image: </source>
         <translation>Выбранное изображение: </translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="116"/>
+        <location filename="../ofdscene.cpp" line="139"/>
         <source>Captcha was not solved correctly!</source>
         <translation>Капча была решена неверно!</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="118"/>
+        <location filename="../ofdscene.cpp" line="141"/>
         <source>Captcha is incorrect</source>
         <translation>Капча введена неверно</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="123"/>
+        <location filename="../ofdscene.cpp" line="146"/>
         <source>Internal server error. Please, try again later.</source>
         <translation>Внутренняя ошибка сервера. Пожалуйста, попробуйте снова позже.</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="125"/>
+        <location filename="../ofdscene.cpp" line="148"/>
         <source>Internal server error</source>
         <translation>Внутренняя ошибка сервера</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="130"/>
+        <location filename="../ofdscene.cpp" line="153"/>
         <source>Check not found. Please, ensure correctness of entered data.</source>
         <translation>Чек не найден. Пожалуйста, убедитесь в правильности введённых данных.</translation>
     </message>
     <message>
-        <location filename="../ofdscene.cpp" line="132"/>
+        <location filename="../ofdscene.cpp" line="155"/>
         <source>Check was not found</source>
         <translation>Чек не найден</translation>
     </message>