How do you post a file with HttpClient?
It can't be that hard, can it?
I am posting a file from a Windows forms client to an ASP.Net Core 2.2 website API (not WebApi)
The file could be anything, word, pdf, image, video etc...
The file could be anything up to 500MB and my JSON methods won't send anything above 25MB
No matter what I do I keep getting
StatusCode: 415, ReasonPhrase: 'Unsupported Media Type'
I can't work out what's gong wrong I have no idea what's missing. I've narrowed it down to this
string filepath = file;
string filename = Path.GetFileName(file);
MultipartFormDataContent content = new MultipartFormDataContent();
var fileContent = new StreamContent(File.OpenRead(filepath));
fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data") { FileName = $"\"{filename}\"" };
content.Add(fileContent);
HttpResponseMessage response = await _httpClient.PostAsync(serviceMethod, content);
All the examples I've read (loads of them), most seem to be sensing JSON and I can do that in spades. The rest tell you what to read and look for but I'm still lost I just want to post a file. I have the server code ready to go.
[HttpPost]
public async Task<JsonResult> UploadFile([FromForm]IFormFile result)
I'll keep reading but any help would be much appreciated.
Ok, I got a bit closer. I've updated my code (see above) and now the controller on my API is getting invoked but now result is null
Try to change your code as shown:
public async Task<IActionResult> PostFile()
{
string filepath =file;
string filename = Path.GetFileName(file);
MultipartFormDataContent content = new MultipartFormDataContent();
var fileContent = new StreamContent(System.IO.File.OpenRead(filepath));
content.Add(fileContent, "result", filename);
HttpResponseMessage response = await _httpClient.PostAsync(serviceMethod, content);
}
[HttpPost]
public async Task<JsonResult> UploadFile(IFormFile result)
Result
Related
I am struggling with uploading an image from thew client-side to a folder on the server-side in .Net Core.I used Postman to check if the method on the server-side is working and it does without any problem,but when I try to upload an image from the client-side,I get an error on the server-side of type NullReferenceException:Object reference not set to an instance of an object.This is the Post method on the server-side:
[HttpPost]
public async Task Post(IFormFile file)
{
if (string.IsNullOrWhiteSpace(_environment.WebRootPath))
{
_environment.WebRootPath = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot");
}
var uploads = Path.Combine(_environment.WebRootPath, "uploads");
//var fileName = file.FileName.Split('\\').LastOrDefault().Split('/').LastOrDefault();
if (!Directory.Exists(uploads)) Directory.CreateDirectory(uploads);
if (file.Length > 0)
{
using (var fileStream = new FileStream(Path.Combine(uploads, file.FileName), FileMode.Create))
{
await file.CopyToAsync(fileStream);
}
}
}
Apparently the method is thrown where I check if the length of the file is bigger than 0.On the client-side I get error "500 internal server error" and I tried to check using the debugger where exactly the error is thrown but i can't find anything that could resemble an error of some sort.This is the API method for the client-side:
public async Task UploadPictureAsync(MediaFile image)
{
User user = new User();
string pictureUrl = "http://10.0.2.2:5000/api/UploadPicture";
HttpContent fileStreamContent = new StreamContent(image.GetStream());
// user.Picture=GetImageStreamAsBytes(image.GetStream());
fileStreamContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data") {FileName=Guid.NewGuid() + ".Png",Name="image"};
fileStreamContent.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
HttpClientHandler clientHandler = new HttpClientHandler();
clientHandler.ServerCertificateCustomValidationCallback = (sender, cert, chain, sslPolicyErrors) => { return true; };
using (var client = new HttpClient(clientHandler))
{
using (var formData = new MultipartFormDataContent())
{
formData.Add(fileStreamContent);
var response = await client.PostAsync(pictureUrl, formData);
if(response.IsSuccessStatusCode)
{
var result = response.Content.ReadAsStringAsync().Result;
}
}
}
}
The image is declared in the Model as byte array:
public byte[] Picture { get; set; }
Does someone understand why my POST method has this behavior since the server-side works perfectly but fails when I try to upload an image from the client-side?What I find weird though is that when i read the error and I look at the Content-Type it is "text/plain" instead of "form-data" and I have tried to set it at the MutipartFormDataContent like this:
formData.Headers.ContentType.MediaType = "multipart/form-data";
I also tried to set the MediaTypeHeaderValue on the client like this:
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/octet-stream"));
I still get the wrong content type.
I have also tried a different approach with Stream instead of MediaFile but without any luck as it did not even hit the break point in debugger mode for the response.Any help would be appreciated! :)
I have managed to find the answer finalllyyyyy!!!The problem was on the client-side as I suspected and guess what,it was all about the correct name.It turns out that since on the server side I have IFormFile file I had to change the client side to take the parameter name "file" instead of image as well so that it could work.Thank you #Jason for the suggestions as I didn't understand the error from the first place and did some debugging on the server-side to help me figure it out.
I have a .net core 2.1 api application that will download a file from a remote location based on the file name. Here is the code:
static public class FileDownloadAsync
{
static public async Task DownloadFile(string filename)
{
//File name is 1GB.zip for testing
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
using (HttpClient client = new HttpClient())
{
string url = #"http://speedtest.tele2.net/" + filename;
using (HttpResponseMessage response = await client.GetAsync(url, HttpCompletionOption.ResponseHeadersRead))
using (Stream readFrom = await response.Content.ReadAsStreamAsync())
{
string tempFile = $"D:\\Test\\{filename}";
using (Stream writeTo = File.Open(tempFile, FileMode.Create))
{
await readFrom.CopyToAsync(writeTo);
}
}
stopwatch.Stop();
Debug.Print(stopwatch.Elapsed.ToString());
}
}
}
This is working great, it will pull a 1 gig file down in about 50 seconds. Well within the required download time. I have hard coded a test file to download in this code for testing as well as storage location--these values will ultimately come from a config file when moved into production. Here is the API endpoint that calls this function:
[HttpGet("{fileName}")]
public async Task<string> GetFile(string fileName)
{
await FileDownloadAsync.DownloadFile(fileName);
return "Done";
}
So getting the file from a remote location down to the local server is not a problem. I need some help/guidance on re-posting this file to another API. Once the file is downloaded, there is some work done on the file to prepare it for upload (the files are all MP4 files), and once that work is done, I need to post it to another API for more proprietary processing. Here is the API end point data I have:
POST: /batch/requests Allocates resources to start new batch transcription. Use this method to request[work] on the input
audio data. Upon the accepted request, the response provides
information about the associated request ID and processing status.
Headers: Authorization: Authorization token
Accept: application/json
Content-Type: Indicates the audio format. The value must be:
audio/x-wav;codec=pcm;bit=16;rate=8000;channels=1
audio/x-wav;codec=pcm;bit=16;rate=16000;channels=1
audio/x-raw;codec=pcm;bit=16;rate=8000;channels=1
audio/x-raw;codec=pcm;bit=16;rate=16000;channels=1
video/mp4
Content-Length (optional): The size of the input voice file. Not
required if a chunked transfer is used.
Query string parameters (required):
profileId: one of supported (see GET profiles) customerId: the id of
the customer. A string of minimum 1 and up to 250 alphanumeric, dot
(.) and dash (-) characters.
So I will set the Content-Type to video/MP4 for processing. Note that if the input size is not used if a chunked transfer is used.
Right now, I am more concerned with just posting (streaming) the file in a non-chunked format while we await for more information on what they consider "chunking" a file.
So I am looking for help on steaming the file from disk to the endpoint. Everything I am running across for .net core API is creating the API to download the file from a POST like a Razor page or Angular page--I already have that. I just need some help on "re-posting" to another API.
Thanks
Using the HttpClient you open a stream to the file, create a content stream, set the necessary headers and post to the endpoint
Stream file = File.Open(filepath, FileMode.Open);
var content = new StreamContent(file);
content.Headers.ContentType = new MediaTypeHeaderValue("video/MP4");
client.DefaultRequestHeaders.Add("Authorization", "token here");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json");
using (HttpResponseMessage response = await client.PostAsync(url, content)) {
//...
}
I am trying to download a 1GB file from blob storage into the client. I used before Memory Stream and I get OutOfMemory exception.
now I am trying to open a read stream from the blob and send it directly to the client.
[HttpGet]
[ResponseType(typeof(HttpResponseMessage))]
public async Task<HttpResponseMessage> DownloadAsync(string file)
{
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
var stream = await blob.OpenReadAsync("container", file);
result.Content = new StreamContent(stream);
return result;
}
The file is downloaded correctly, but the problem is: The code download the complete stream in the client, then the client sees the downloaded file.
I wanted the client to see the file as being downloaded, so the user knows that he is downloading something. Not just blocking the request and wait till it finished.
I am using FileSaver in Angular2:
this.controller.download('data.zip').subscribe(
data => {
FileSaver.saveAs(data, 'data.zip');
});
Has anybody an idea how to fix it?
Thank you!
To fix it you'd need to use the following javascript code instead:
var fileUri = "http://localhost:56676/api/blobfile"; //replace with your web api endpoint
var link = document.createElement('a');
document.body.appendChild(link);
link.href = fileUri;
link.click();
And then in your backend, make it like so:
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
var stream = await blob.OpenReadAsync("container", file);
result.Content = new StreamContent(stream);
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
{
FileName = "data.zip"
};
result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
return result;
I had the same problem.
The Solution I sorted out was -
First thing, the expected behaviour can occur only when client tries to download the file from blob and usually I prefer downloading the file from the client itself.
As in your case, try to get file blob uri and do some operations as below to open file in browser using Angular Router or simply window.location.href.
window.location.href = “https://*/filename.xlsx”
This worked for me.
I am using loopback Storage component REST API in Xamarin to finish a file uploading job. However, it does not work and does not return any exceptions to me.
Here is my code:
library using: RestSharp.portable
public async Task addFiles(string name, byte[] file)
{
try
{
var client = new RestClient(App.StrongLoopAPI);
var request = new RestRequest("containers/container1/upload", HttpMethod.Post);
request.AddHeader("cache-control", "no-cache");
request.AddHeader("content-type", "multipart/form-data");
request.AddFile("file", file, name + ".jpg", System.Net.Http.Headers.MediaTypeHeaderValue.Parse("multipart/form-data"));
var res = await client.Execute(request);
}
catch (Exception ex)
{
//return null;
}
}
Does my function have any problems?
You're setting the Content Type (Mime Type) wrong.
AddFile accepts as the last parameter the Content Type (for example image/jpeg for a JPG image), where you're using multipart/form-data.
There are different ways to figure out the Content Type of a file, see here:
Get MIME type from filename extension
This should fix your issue.
I have an endpoint that needs to accept a file upload and also some other information from the client request. With the following code I can upload the file successfully but can't seem to figure out how to read the other info.
I make a test request from Postman with the following form data:
image -- myimage.jpg -- of type File
email -- a#b.com -- of type Text
The backend code looks like this:
[HttpPost]
public async Task<HttpResponseMessage> SharePhoto()
{
try
{
var provider = new MultipartMemoryStreamProvider();
var data = await Request.Content.ReadAsMultipartAsync(provider);
// this is how I get the image which I am succesfully passing to EmailService
var item = (StreamContent)provider.Contents[0];
using (var stream = new MemoryStream())
{
await item.CopyToAsync(stream);
String emailAddress;
EmailService.SendSharedPhoto(emailAddress, stream);
return Request.CreateResponse();
}
}
catch
{
// do stuff
}
}
In this example I am able to access provider.Contents[1] but can't seem to be able to get the value from it into emailAddress. I'm thinking it may be possible to use the same trick as the await item.CopyToASync(stream) from the image upload, but I'm hoping I can get a simpler solution to that. Any ideas?
I just barely answered a very similar question to this yesterday. See my answer here complete with sample controller code.
The method I ended up using is:
If the form elements are strings (and it worked for me since the mobiel frontend took responsability for input data) you can do this:
var streamContent = (StreamContent)provider.Contents[1];
var memStream = new MemoryStream();
await streamContent.CopyToAsync(memStream);
var actualString = Encoding.UTF8.GetString(x.ToArray());
If however the field needs to represent a collection of items, like for example the email list: ["a#b.com", "x#c.com"], etc a JavaScriptSerializer can be user, like so:
var streamContent = (StreamContent)provider.Contents[1];
var emailAddresses = await str.ReadAsStringAsync();
var jsSerializer = new JavaScriptSerializer();
var deserializedData = jsSerializer.Deserialize<string[]>(emailAddresses);
Note that this is nowhere near safe, though it is few lines of code and happens to work.