curl returning none of the HTML content

hecker

Hi, I'm having a problem with curl, the content of the HTML being written is: "".
I believe that the problem is related to the installation since the same code works perfectly in visual studio code.

My curl installation:

QT       += core gui sql

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++17

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
LIBS += "C:/Users/uique/AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Qt/6.4.0/MinGW 11.2.0 (64-bit)/lib/libcurl.a"
LIBS += "C:/Users/uique/AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Qt/6.4.0/MinGW 11.2.0 (64-bit)/lib/libcurl.dll.a"
INCLUDEPATH += "C:/Users/uique/AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Qt/6.4.0/MinGW 11.2.0 (64-bit)/includer/curl"


SOURCES += \
    add_order.cpp \
    login.cpp \
    main.cpp \
    mainwindow.cpp \
    wallet.cpp

HEADERS += \
    Global_variables.h \
    add_order.h \
    login.h \
    mainwindow.h \
    wallet.h

FORMS += \
    add_order.ui \
    login.ui \
    mainwindow.ui \
    wallet.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

RESOURCES += \
    Resources.qrc

my function that is using curl:

void MainWindow::update_tb(){
    CURL *curl;
    CURLcode res;
    std::string HTMLcontent;
    curl = curl_easy_init();
    if(curl){
        curl_easy_setopt(curl, CURLOPT_URL, "https://api.binance.com/api/v3/ticker/price");
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeHTML);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &HTMLcontent);
        res = curl_easy_perform(curl);

        curl_easy_cleanup(curl);
        qDebug() << QString::fromStdString(HTMLcontent);
    }
    //qDebug() << QString::fromStdString(HTMLcontent);
    QSqlQuery query;
    std::string content = HTMLcontent;
    std::string pattern = "\\{\"symbol\":\"(.+?)\",\"price\":\"(.*?)\"\\}";
    std::regex rule(pattern);
    std::smatch match;

    while(std::regex_search(content, match, rule)){

        query.prepare("update coins_tb set VALUE='"+QString::fromStdString(match.str(2))+"' where TOKEN='"+QString::fromStdString(match.str(1))+"'");
        if(!query.exec()){
            QMessageBox::warning(this, "Erro", "Erro ao atualizar banco de dados");
        }
    }


    int row = 0;


    query.prepare("select VALUE from coins_tb where TOKEN like'%"+ui->lineEdit_filter->text()+"%'");
    if(!query.exec()){
    }else{
        query.first();
        do{
            ui->tw_tokens_list->setItem(row, 1, new QTableWidgetItem(query.value(0).toString()));
            row++;
        }while(query.next());

         if(ui->tw_tokens_list->currentRow() > -1){
            ui->label_value->setText(Global_var::token_value);
         }

    }
}

function responsible for writing the HTML count in the variable:

size_t writeHTML(char* HTML_content, size_t char_size, size_t char_amount, char* buffer_in) {
    size_t bytes = char_size * char_amount;
    ((std::string*)buffer_in)->append((char*)HTML_content, bytes);


    return bytes;
}

include and function prototype:


#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "add_order.h"
#include "Global_variables.h"
#include "login.h"
#include "wallet.h"
#include <QDebug>
#include "curl/curl.h"
#include <regex>


QString Global_var::current_token;
QString Global_var::token_value;
bool Global_var::login = false;

size_t writeHTML(char* HTML_content, size_t char_size, size_t char_amount, char* buffer_in);

Christian Ehrlicher

Use a debugger, see what's happening.
Also please don't post pictures but text.

hecker

@Christian-Ehrlicher Debugg returns "" from HTMLcontent

Christian Ehrlicher

@hecker said in curl returning none of the HTML content:

Debugg returns "" from HTMLcontent

I said you should use a debugger, not print something out.
Make a breakpoint in your writeHTML()m function to see if it's called and what's going on in there.

Don't know whjat this has to do with Qt though...