从网上下载之前获取的图像文件大小 [英] Get Size of Image File before downloading from web

问题描述

我从网上使用下面的code在我的控制台应用程序下载的图像文件。

I am downloading image files from web using the following code in my Console Application.

WebClient client = new WebClient();
client.DownloadFile(string address_of_image_file,string filename);

在code上绝对没问题。

The code is running absolutely fine.

我想知道是否有一种方法，我可以得到这个图像文件的大小之前，我下载了。

PS-其实我已经写了code键使履带其周围的网站下载图像文件移动。所以，我不知道它的大小提前。我想说明的是文件的已提取网页的源代码的完整路径。

PS- Actually I have written code to make a crawler which moves around the site downloading image files. So I doesn't know its size beforehand. All I have is the complete path of file which has been extracted from the source of webpage.

推荐答案

如果网络服务为您提供了一个的内容长度的HTTP标头那么这将是该图像文件的大小。但是，如果Web服务要流的数据给你（使用块编码），那么你就不会知道，直到整个文件下载。

If the web-service gives you a Content-Length HTTP header then it will be the image file size. However, if the web-service wants to "stream" data to you (using Chunk encoding), then you won't know until the whole file is downloaded.

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