使用WebClient保存具有适当扩展名的图像 [英] Using a WebClient to save an image with the appropriate extension

问题描述

我需要检索并将图像从网站保存到我的本地文件夹。图像类型在.png，.jpg和.gif之间变化

I'm required to retrieve and save an image from a website to my local folder. The image type varies between .png, .jpg and .gif

我尝试过使用

string url = @"http://redsox.tcs.auckland.ac.nz/CSS/CSService.svc/";
string saveLoc = @"/project1/home_image";
using (var wc = new WebClient())
{
    wc.DownloadFile(url, saveLoc);
}

但这会将文件'home_image'保存在没有扩展名的文件夹中。我的问题是你如何确定扩展名？有一个简单的方法吗？可以使用HTTP请求的Content-Type吗？如果是这样，你怎么做？

but this saves the file 'home_image' in the folder without the extension. My question is how do you determine the extension? Is there a simple way to do this? Can one use the Content-Type of the HTTP request? If so, how do you do this?

推荐答案

如果你想使用 WebClient ，然后你必须从 WebClient.ResponseHeaders 中提取标题信息。您必须先将其存储为字节数组，然后在获取文件信息后保存文件。

If you want to use a WebClient, then you have to extract the header information from WebClient.ResponseHeaders. You'll have to store it as a byte array first, and then save the file after getting your file information.

string url = @"http://redsox.tcs.auckland.ac.nz/CSS/CSService.svc/";
string saveLoc = @"/project1/home_image";

using (WebClient wc = new WebClient())
{
    byte[] fileBytes = wc.DownloadData(url);

    string fileType = wc.ResponseHeaders[HttpResponseHeader.ContentType];

    if (fileType != null)
    {
        switch (fileType)
        {
            case "image/jpeg":
                saveloc += ".jpg";
                break;
            case "image/gif":
                saveloc += ".gif";
                break;
            case "image/png":
                saveloc += ".png";
                break;
            default:
                break;
        }

        System.IO.File.WriteAllBytes(saveloc, fileBytes);
    }
}

我喜欢我的扩展名为3个字母，如果他们可以....个人偏好。如果它不打扰你，你可以用以下代码替换整个开关语句：

I like my extensions to be 3 letters long if they can.... personal preference. If it doesn't bother you, you can replace the entire switch statement with:

saveloc += "." + fileType.Substring(fileType.IndexOf('/') + 1);

使代码更整洁。

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