Question

我想将文件http://img1.ak.crunchyroll.com/i/croll_manga/e/257692e8c297b8907e2607964454b941_1438752352_main下载到字符串。

在C ++中我写了函数

string opener(string url)
{
  CURL *curl;
  CURLcode res;
  std::string readBuffer;

  curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &readBuffer);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
  return readBuffer;
}

这项工作正常。

在C＃中我写了这个课程

namespace Crmrip
{
    class opener
    {
        public static string open(string url)
        {

            using (WebClient page = new WebClient())
            {
                try
                {
                    page.Encoding = Encoding.UTF8;
                    page.Headers["User-Agent"] = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0";
                    string result = page.DownloadString(url);
                    return result;
                }

                catch (WebException er)
                {
                    MessageBox.Show(er.ToString());
                    return null;
                }
            }

        }
    }
}

这个班级工作不正常。下载的文件太大了。用C ++下载的文件有487 778字节，没问题。用C＃下载的文件有879 910，太大了。

为什么用C＃下载的文件太大了？

Answer 1

使用DownloadData将响应作为字节数组获取。执行XOR并将结果写入文件

所以稍微改变你的代码：

using (WebClient page = new WebClient())
{
    try
    {
        byte[] result = page.DownloadData(url);
        for(int i=0;i<result.Length;i++)
        {
            result[i] ^= 0x42;
        }
        File.WriteAllBytes(filename, result);
    }

    catch (WebException er)
    {
        MessageBox.Show(er.ToString());

    }
}

Answer 2

似乎工作：

void Main()
{
    string url = "http://img1.ak.crunchyroll.com/i/croll_manga/e/257692e8c297b8907e2607964454b941_1438752352_main";
    Console.WriteLine(open(url));
}


 public static async Task<string> open(string url)
    {

        using (HttpClient page = new HttpClient())
        {
            try
            {
                //page.Encoding = Encoding.UTF8;
                //page.Headers["User-Agent"] = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0";
                page.DefaultRequestHeaders.TryAddWithoutValidation("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0");
                return await page.GetStringAsync(url);
            }

            catch (Exception er)
            {
                //MessageBox.Show(er.ToString());
                return null;
            }
        }

    }

我不确定编码是否会成为问题 - 这里是reference

为什么下载文件太大了？

2 个答案: