Develop Reference

Uploading a file like form-data in postman

I have found some answers here that give examples but none seems to work for me..
this is how my postman looks:
In the code I download the picture from a URL, save it as jpeg inside a folder and then I try to upload that image with a POST request, here is how it looks:
var fileName = image.PhotoId + ".jpeg";
await Task.WhenAll(client.DownloadFileTaskAsync(new Uri(image.ImageUrl), #"wwwroot\images\"+fileName));
var files = Directory.GetFiles(#"wwwroot\images\", "*.jpeg");
var filePath = Path.Combine(#"wwwroot\images\", fileName);
using var stream = File.OpenRead(filePath);
var file_content = new ByteArrayContent(new StreamContent(stream).ReadAsByteArrayAsync().Result);
var formData = new MultipartFormDataContent();
formData.Add(file_content, "file", fileName);
var res = await clientAsync.PostAsync(url, formData);
problem is the response that I get in the code is an error..:
{"error_code":6,"error_message":"Sorry, please try a different picture"}
this type of response is the same one I get when trying to upload a pdf instead of a jpeg on postman so I guess the file is getting corrupted in the code somewhere.
would love to get any ideas to where the problem is!

Downloading File in C# with DownloadUrl [duplicate]

I have a web service, like this example for downloading a zip file from the server. When i open the URL through web browsers,I can download the zip file correctly. The problem is when I try to download the zip file through my desktop application. I use the following code to download:
WebClient webClient = new WebClient();
webClient.DownloadFileCompleted += new AsyncCompletedEventHandler(Completed);
webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(ProgressChanged);
webClient.DownloadFileAsync(new Uri(#"http://localhost:9000/api/file/GetFile?filename=myPackage.zip"), #"myPackage.zip");
After testing this, I get the myPackage.zip downloaded, but it is empty, 0kb. Any help about this or any other server code + client code example?

You can try to use HttpClient instead. Usually, it is more convenient.
var client = new HttpClient();
var response = await client.GetAsync(#"http://localhost:9000/api/file/GetFile?filename=myPackage.zip");
using (var stream = await response.Content.ReadAsStreamAsync())
{
var fileInfo = new FileInfo("myPackage.zip");
using (var fileStream = fileInfo.OpenWrite())
{
await stream.CopyToAsync(fileStream);
}
}

how to download a file using sync webclient request in c# with out showing popup

I am using "webclient" to download and save a file by url in windows application.
here is my code:
WebClient wc = new WebClient();
wc.Headers.Add(HttpRequestHeader.Cookie, cc);
wc.DownloadFile(new Uri(e.Url.ToString()), targetPath);
this is working fine local system.(downloading the file and saved to target path automatically with out showing any popup).
But when i am trying to execute the .exe in server its showing save/open popup.
Is there any modifications require to download a file in server settings.
Please help me to download the file with out showing popup in server too.
thanks in advance..

Finally i got the solution for this issue..
herw the code:
WebClient wc = new WebClient();
wc.Headers.Add(HttpRequestHeader.Cookie, cc);
using (Stream data = wc.OpenRead(new Uri(e.Url.ToString())))
{
using (Stream targetfile = File.Create(targetPath))
{
data.CopyTo(targetfile);
}
}
here i just replaced the code
wc.DownloadFile(new Uri(e.Url.ToString()), targetPath);
with the blow lines:
using (Stream data = wc.OpenRead(new Uri(e.Url.ToString())))
{
using (Stream targetfile = File.Create(targetPath))
{
data.CopyTo(targetfile);
}
}
Now its working fine..
Thanks all for ur response..

URL Formats are not supported

I am reading File with File.OpenRead method, I am giving this path
http://localhost:10001/MyFiles/folder/abc.png
I have tried this as well but no luck
http://localhost:10001//MyFiles//abc.png
but its giving
URL Formats are not supported
When I give physical path of my Drive like this,It works fine
d:\MyFolder\MyProject\MyFiles\folder\abc.png
How can I give file path to an Http path?
this is my code
public FileStream GetFile(string filename)
{
FileStream file = File.OpenRead(filename);
return file;
}

Have a look at WebClient (MSDN docs), it has many utility methods for downloading data from the web.
If you want the resource as a Stream, try:
using(WebClient webClient = new WebClient())
{
using(Stream stream = webClient.OpenRead(uriString))
{
using( StreamReader sr = new StreamReader(stream) )
{
Console.WriteLine(sr.ReadToEnd());
}
}
}

You could either use a WebClient as suggested in other answers or fetch the relative path like this:
var url = "http://localhost:10001/MyFiles/folder/abc.png";
var uri = new Uri(url);
var path = Path.GetFileName(uri.AbsolutePath);
var file = GetFile(path);
// ...
In general you should get rid of the absolute URLs.

The best way to download the HTML is by using the WebClient class. You do this like:
private string GetWebsiteHtml(string url)
{
WebRequest request = WebRequest.Create(url);
WebResponse response = request.GetResponse();
Stream stream = response.GetResponseStream();
StreamReader reader = new StreamReader(stream);
string result = reader.ReadToEnd();
stream.Dispose();
reader.Dispose();
return result;
}
Then, If you want to further process the HTML to ex. extract images or links, you will want to use technique known as HTML scrapping.
It's currently best achieved by using the HTML Agility Pack.
Also, documentation on WebClient class: MSDN

Here I found this snippet. Might do exactly what you need:
using(WebClient client = new WebClient()) {
string s = client.DownloadFile(new Uri("http://.../abc.png"), filename);
}
It uses the WebClient class.

To convert a file:// URL to a UNC file name, you should use the Uri.LocalPath property, as documented.
In other words, you can do this:
public FileStream GetFile(string url)
{
var filename = new Uri(url).LocalPath;
FileStream file = File.OpenRead(filename);
return file;
}

Downloading image from url doesn't always save the entire image (Winrt)

I'm using the following code to download an image from a url
HttpClient client = new HttpClient();
var stream = await client.GetStreamAsync(new Uri("<your url>"));
var file = await KnownFolders.PictureLibrary.CreateFileAsync("myfile.png");
using (var targetStream = await file.OpenAsync(FileAccessMode.ReadWrite))
{
using (stream)
await stream.CopyToAsync(targetStream.AsStreamForWrite());
}
several users have reported that it doesn't always download the entire image. That they sometimes get partial images and the rest is just garbage.
Is there any reason for this?
Thanks!

I would suggest trying the WebClient class with the DownloadData or DownloadDataAsync method.
File.WriteAllBytes("myfile.png",
new WebClient().DownloadData("<your url>"));
edit If the stream is giving you trouble you could use the byte array response instead. Your "using" statement with async code inside may be causing it to dispose early, perhaps?
var httpClient = new HttpClient();
var data = await httpClient.GetByteArrayAsync(new Uri("<Your URI>"));
var file = await KnownFolders.PictureLibrary.CreateFileAsync("myfile.png");
var targetStream = await file.OpenAsync(FileAccessMode.ReadWrite)
await targetStream.AsStreamForWrite().WriteAsync(data, 0, data.Length);
targetStream.FlushAsync().Wait();
targetStream.Close();

BackgroundDownloader is the easiest way to download a file.
using Windows.Storage;
public async Task DownloadPhoto(Uri uri)
{
var folder = ApplicationData.Current.LocalFolder;
var photoFile = await folder.CreateFileAsync("photo.jpg", CreationCollisionOption.ReplaceExisting);
var downloader = new Windows.Networking.BackgroundTransfer.BackgroundDownloader();
var dl = downloader.CreateDownload(uri, photoFile);
await dl.StartAsync();
}

If your using HttpClient then if your image is larger than 64K it will error out. You will have to set the httpClient.MaxResponseContentBufferSize to something larger.
See the MSDN Quick Start where they set the max-buffer-size to 256K.
http://msdn.microsoft.com/en-us/library/windows/apps/xaml/JJ152726(v=win.10).aspx
Personally though, I use the BackgroundDownloader.