c++ - C++ libcurl 控制台进度条

Question

我希望在下载文件时在控制台窗口中显示一个进度条。我的代码是这样的：在 C/C++ 中使用 libcurl 下载文件。

如何在 libcurl 中有一个进度条？

Answer 1

你的仪表。

#include <math.h>

int progress_func(void* ptr, double TotalToDownload, double NowDownloaded, 
                    double TotalToUpload, double NowUploaded)
{
    // ensure that the file to be downloaded is not empty
    // because that would cause a division by zero error later on
    if (TotalToDownload <= 0.0)) {
        return 0;
    }

    // how wide you want the progress meter to be
    int totaldotz=40;
    double fractiondownloaded = NowDownloaded / TotalToDownload;
    // part of the progressmeter that's already "full"
    int dotz = (int) round(fractiondownloaded * totaldotz);

    // create the "meter"
    int ii=0;
    printf("%3.0f%% [",fractiondownloaded*100);
    // part  that's full already
    for ( ; ii < dotz;ii++) {
        printf("=");
    }
    // remaining part (spaces)
    for ( ; ii < totaldotz;ii++) {
        printf(" ");
    }
    // and back to line begin - do not forget the fflush to avoid output buffering problems!
    printf("]\r");
    fflush(stdout);
    // if you don't return 0, the transfer will be aborted - see the documentation
    return 0; 
}

Answer 2

来自curl 文档

CURLOPT_PROGRESSFUNCTION

应该匹配 curl_progress_callback 原型的函数指针在 . 这个函数被 libcurl 调用，而不是它的内部等效函数，在操作期间（大约每秒一次），无论是否正在传输数据。传递给回调的未知/未使用参数值将设置为零（例如，如果您只下载数据，则上传大小将保持为 0）。从此回调返回非零值将导致 libcurl 中止传输并返回 CURLE_ABORTED_BY_CALLBACK。

所以：

您提供了一个看起来像这样的函数

int progress_func(void* ptr, double TotalToDownload, double NowDownloaded, double TotalToUpload, double NowUploaded)
{
    // It's here you will write the code for the progress message or bar
}

以及现有选项之后的一些额外选项

curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);  // already there
// Internal CURL progressmeter must be disabled if we provide our own callback
curl_easy_setopt(curl, CURLOPT_NOPROGRESS, FALSE);
// Install the callback function
curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, progress_func); 

这就是所有需要做的

Answer 3

喜欢apt进度条

#include <iostream>
#include <fstream>
#include <include/curl/curl.h>//Or #include <curl/curl.h>
#include <windows.h>
#include <math.h>

using namespace std;

int nb_bar;
double last_progress, progress_bar_adv;

HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);

int progress_bar (void *bar, double t, double d)
{
    if(last_progress != round(d/t*100))
    {
      nb_bar = 25;
      progress_bar_adv = round(d/t*nb_bar);

      cout<<"\r ";
      SetConsoleTextAttribute(hConsole, 160);
      cout<<" Progress : [ ";

      if(round(d/t*100) < 10)
      { cout<<"0"<<round(d/t*100)<<" %]"; }
      else
      { cout<<round(d/t*100)<<" %] "; }

      SetConsoleTextAttribute(hConsole, 15);
      cout<<" [";
      SetConsoleTextAttribute(hConsole, 10);
      for(int i = 0 ; i <= progress_bar_adv ; i++)
      { cout<<"#"; }
      SetConsoleTextAttribute(hConsole, 15);
      for(int i = 0 ; i < nb_bar - progress_bar_adv; i++)
      { cout<<"."; }

      cout<<"]";
      last_progress = round(d/t*100);
    }
  return 0;
}


int main()
{
  CURL *curl_download;
  FILE *fp;
  CURLcode res;
  string url = "http://www.gecif.net/articles/mathematiques/pi/pi_1_million.txt", output_file = "pi.txt";

  curl_download = curl_easy_init();

  if (curl_download)
  {
      //SetConsoleTextAttribute(hConsole, 11);
      fp = fopen(output_file.c_str(),"wb");

      curl_easy_setopt(curl_download, CURLOPT_URL, url.c_str());
      curl_easy_setopt(curl_download, CURLOPT_WRITEFUNCTION, NULL);
      curl_easy_setopt(curl_download, CURLOPT_WRITEDATA, fp);
      curl_easy_setopt(curl_download, CURLOPT_NOPROGRESS, FALSE);
      //progress_bar : the fonction for the progress bar
      curl_easy_setopt(curl_download, CURLOPT_PROGRESSFUNCTION, progress_bar);

      //Text color :   SetConsoleTextAttribute(hConsole, nb_color);
      SetConsoleTextAttribute(hConsole, 11);
      cout<<" Start download"<<endl<<endl;

      res = curl_easy_perform(curl_download);

      fclose(fp);
      if(res == CURLE_OK)
      {
        SetConsoleTextAttribute(hConsole, 10);
        cout<<endl<<endl<<" The file was download with succes"<<endl;
      }
      else
      {
        SetConsoleTextAttribute(hConsole, 4);
        cout<<endl<<endl<<" Error"<<endl;
      }
      curl_easy_cleanup(curl_download);
  }
  SetConsoleTextAttribute(hConsole, 11);
  return 0;
}