如何从C中的URL下载文件作为浏览器？ [英] How to download a file from a URL in C, as a browser would?

问题描述

我想从一个URL下载一个文件，一个： http://download.finance.yahoo/d/quotes.csv?s=YHOO+GOOG+MSFT&f=sl1d1t1c1hgvbap2
当我浏览我的浏览器并输入此URL在浏览器中，文件会自动下载。
我想要的是下载这个文件，而不用我的浏览器使用C语言的程序，我需要这种类型的财务项目的信息。
我尝试使用libcurl下载文件，但libcurl下载与此URL相对应的HTML页面，这是空的，因为这个URL唯一的作用是开始下载。
我想这个URL是一种HTTP服务器的方式，但是我完全失去了如何获取这个文件。

I want to download a file from a URL, this one : http://download.finance.yahoo/d/quotes.csv?s=YHOO+GOOG+MSFT&f=sl1d1t1c1hgvbap2 When i go on my browser and input this URL in my browser, the file is automatically downloaded as it should. What I want is to download this file without going on my browser using a program in C language, I need this type of information for a financial project. I tried to download the file using libcurl but libcurl downloads the HTML page corresponding to this URL which is empty of course because the only thing this URL does is start a download. I suppose this URL is the way int a HTTP server of some kind but I am completely lost as to how to get this file.

谢谢大家提前为您的时间和帮助，请如果您可以通过解释或甚至更好的C代码随意提供帮助，并且不要害怕太精确。

Thank you all in advance for your time and help, please if you can help by explaining or even better with C code feel free to do so and don't be afraid to be too precise.

推荐答案

使用 libcurl ，并查看此示例页面。

如果要使其正常工作，请使用命令行 curl ，并使用 - libcurl 选项。我怀疑这个问题可能更多的是与javascript，cookies，登录等等。所有这些都是可溶的，但是与命令行一起使其工作。我的诊断是，您的网址在 yahoo 之后缺少 .com 。

If you want to get it to work, make it work with the command line curl too, and use the --libcurl option. I suspect the problem might be more to do with javascript, cookies, a login or whatever. All these are soluble, but play with the command line to get it to work. My diagnosis here is that your URL is missing .com after yahoo.

例如：

curl --silent --libcurl /tmp/test.c 'http://download.finance.yahoo.com/d/quotes.csv?s=YHOO+GOOG+MSFT&f=sl1d1t1c1hgvbap2'

生成要显示的输出：

"YHOO",51.04,"11/21/2014","4:00pm",-0.21,52.25,50.99,22226984,N/A,52.49,"-0.41%"
"GOOG",537.50,"11/21/2014","4:00pm",+2.67,542.14,536.56,2218249,N/A,575.00,"+0.50%"
"MSFT",47.98,"11/21/2014","4:00pm",-0.72,49.05,47.57,42884796,N/A,49.05,"-1.48%"

并生成代码：

/********* Sample code generated by the curl command line tool **********
 * All curl_easy_setopt() options are documented at:
 * http://curl.haxx.se/libcurl/c/curl_easy_setopt.html
 ************************************************************************/
#include <curl/curl.h>

int
main (int argc, char *argv[])
{
  CURLcode ret;
  CURL *hnd;

  hnd = curl_easy_init ();
  curl_easy_setopt (hnd, CURLOPT_URL,
                    "http://download.finance.yahoo.com/d/quotes.csv?s=YHOO+GOOG+MSFT&f=sl1d1t1c1hgvbap2");
  curl_easy_setopt (hnd, CURLOPT_NOPROGRESS, 1L);
  curl_easy_setopt (hnd, CURLOPT_USERAGENT, "curl/7.35.0");
  curl_easy_setopt (hnd, CURLOPT_MAXREDIRS, 50L);
  curl_easy_setopt (hnd, CURLOPT_TCP_KEEPALIVE, 1L);

  /* Here is a list of options the curl code used that cannot get generated
     as source easily. You may select to either not use them or implement
     them yourself.

     CURLOPT_WRITEDATA set to a objectpointer
     CURLOPT_WRITEFUNCTION set to a functionpointer
     CURLOPT_READDATA set to a objectpointer
     CURLOPT_READFUNCTION set to a functionpointer
     CURLOPT_SEEKDATA set to a objectpointer
     CURLOPT_SEEKFUNCTION set to a functionpointer
     CURLOPT_ERRORBUFFER set to a objectpointer
     CURLOPT_STDERR set to a objectpointer
     CURLOPT_HEADERFUNCTION set to a functionpointer
     CURLOPT_HEADERDATA set to a objectpointer

   */

  ret = curl_easy_perform (hnd);

  curl_easy_cleanup (hnd);
  hnd = NULL;

  return (int) ret;
}

/**** End of sample code ****/

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