I use HTTP GET that downloads a zip file in a browser, something like https://example.com/up/DBID/a/rRID/eFID/vVID (not the exact url)
Now, when I try to do the same download in C# code(same GET method as above) for a desktop applicat开发者_开发百科ion, the zip file downloaded is not a valid archive file. When I opened this file in notepad, it was some HTML page.
I think I'm not setting some header correctly. I looked around for examples. I'd found several wrt uploads, but did not see anything for downloads.
Code:
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Method = "GET";
request.ContentType = "application/zip";
try
{
HttpWebResponse res = (HttpWebResponse)request.GetResponse();
using (StreamReader sr = new StreamReader(res.GetResponseStream(), System.Text.Encoding.Default))
{
StreamWriter oWriter = new StreamWriter(@"D:\Downloads\1.zip");
oWriter.Write(sr.ReadToEnd());
oWriter.Close();
}
res.Close();
}
catch (Exception ex)
{
}
It's mainly because you use a StreamWriter : TextWriter
to handle a binary Zip file. A StreamWriter expects text and will apply an Encoding. And even the simple ASCII Encoder might try to 'fix' what it thinks are invalid line-endings.
You can replace all your code with:
using (var client = new WebClient())
{
client.DownloadFile("http://something", @"D:\Downloads\1.zip");
}
Note that for new code you should look at HttpClient instead of WebClient.
And then don't use using( ) { }
You could just use WebClient
for a 2-liner:
using(WebClient wc = new WebClient())
{
wc.DownloadFile(url, @"D:\Downloads\1.zip");
}
You can also use System.Net.Http.HttpClient
using (HttpClient client = new HttpClient())
{
using (HttpResponseMessage response = await client.GetAsync(downloadURL))
{
using(var stream = await response.Content.ReadAsStreamAsync())
{
using(Stream zip = FileManager.OpenWrite(ZIP_PATH))
{
stream.CopyTo(zip);
}
}
}
}
Expanding on Ruben's answer which uses HttpClient instead of WebClient, you can add as an extension method like this:
using System.IO;
using System.Net.Http;
using System.Threading.Tasks;
public static class Extensions
{
public static async Task DownloadFile (this HttpClient client, string address, string fileName) {
using (var response = await client.GetAsync(address))
using (var stream = await response.Content.ReadAsStreamAsync())
using (var file = File.OpenWrite(fileName)) {
stream.CopyTo(file);
}
}
}
And then use like this:
var archivePath = "https://api.github.com/repos/microsoft/winget-pkgs/zipball/";
using (var httpClient = new HttpClient())
{
await httpClient.DownloadFile(archivePath, "./repo.zip");
}
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