ASYNC error on WebApi Download - c#

I have the following code, used to download multiple files, create a zip file, and return the file to the user:
//In a WebAPI GET Handler
public async Task<HttpResponseMessage> Get(string id)
{
try
{
var urlList = CacheDictionary<String, List<String>>.Instance[id];
var helper = new Helper();
var zipFile = await helper.CreateZipFormUrls(urlList);
var response = new HttpResponseMessage(HttpStatusCode.OK);
var stream = new MemoryStream();
zipFile.Save(stream);
response.Content = new ByteArrayContent(stream.ToArray());
response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/zip");
response.Content.Headers.ContentLength = stream.Length;
response.Content.Headers.ContentDisposition.FileName = "download.zip";
return response;
}
catch (Exception)
{
return Request.CreateResponse(HttpStatusCode.BadRequest);
}
}
//In a Helper Class
public async Task<ZipFile> CreateZipFromUrls(List<string> urlList)
{
using (var zip = new ZipFile())
{
var files = await ReturnFileData(urlList);
foreach (var file in files)
{
var e = zip.AddEntry(GetFileNameFromUrlString(file.Key), file.Value);
}
return zip;
}
}
static Task<Dictionary<string, byte[]>> ReturnFileData(IEnumerable<string> urls)
{
Dictionary<Uri, Task<byte[]>> dictionary;
using (var client = new WebClient())
{
dictionary = urls.Select(url => new Uri(url)).ToDictionary(
uri => uri, uri => client.DownloadDataTaskAsync(uri));
await Task.WhenAll(dictionary.Values);
}
return dictionary.ToDictionary(pair => Path.GetFileName(pair.Key.ToString()),
pair => pair.Value.Result);
}
private string GetFileNameFromUrlString(string url)
{
var uri = new Uri(url);
return System.IO.Path.GetFileName(uri.LocalPath);
}
I always get:
An asynchronous module or handler completed while an asynchronous operation was still pending
And cannot reach any breakpoints after the download method is called. What am I doing wrong? Where do I look?

Try await on this
dictionary = urls.Select(url => new Uri(url)).ToDictionary(
uri => uri, uri => client.DownloadDataTaskAsync(uri));
The problem might be that
client.DownloadDataTaskAsync(uri));
is probably still running when the rest of your code is done.

Related

Can we send a memory stream object with web API?

I have one memory stream object in my server-side, this object should be accessible in another party, which I call it a client or a consumer for my API.
In server-side I have a method like this (parameters.Save is related to a third-party library)
public MemoryStream GetSerializedParameters()
{
var parameters = GetParameters();
MemoryStream memory = new MemoryStream();
parameters.Save(memory);
return memory;
}
I'm thinking about sending this memory stream to a client with web API, so my action is something like this:
[HttpGet("parameters")]
public HttpResponseMessage GetParameters()
{
var stream = _server.GetSerializedParameters();
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
result.Content = new StreamContent(stream);
result.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/octet-stream");
result.Content.Headers.ContentLength = stream.Length;
return result;
}
I'm not sure if it is the right way and this implementation is correct because I am in trouble to consume it:
I do not know which method of httpClient I have to use: ReadAsStreamAsync() or anything else, because I could not find anything to work
Sure you can:
[HttpGet]
public async Task Get()
{
var randomString = "thisIsCool";
var randomStringBytes = Encoding.UTF8.GetBytes(randomString);
using (var ms = new MemoryStream(randomStringBytes))
{
await ms.CopyToAsync(this.Response.Body);
}
Based on my under standing below code may help you:
WEB API:
[HttpGet]
public HttpResponseMessage ReadToStream(HttpRequestMessage requestMessage)
{
var streamObj = _server.GetSerializedParameters();
HttpResponseMessage response = new HttpResponseMessage();
response.Content = new StreamContent(streamObj);
requestMessage.RegisterForDispose(streamObj);
response.StatusCode = HttpStatusCode.OK;
return response;
}
Client Side
public async Task<string> DownloadFile(string guid)
{
var fileInfo = new FileInfo($"{guid}.txt");
var response = await _httpClient.GetAsync($"{url}/api/fileDownloadAPI?guid={guid}");
response.EnsureSuccessStatusCode();
await using var ms = await response.Content.ReadAsStreamAsync();
await using var fs = File.Create(fileInfo.FullName);
ms.Seek(0, SeekOrigin.Begin);
ms.CopyTo(fs);
return fileInfo.FullName;
}
I found the solution like this:
here is in server side:
[HttpGet("parameters")]
public IActionResult GetParameters()
{
var stream = _server.GetSerializedParameters();
stream.Seek(0, SeekOrigin.Begin);
return File(stream, MediaTypeNames.Text.Plain, "parameters.txt");
}
and here is in client-side:
public MemoryStream StoreParameters()
{
var request =new HttpRequestMessage
{
RequestUri = new Uri("https://localhost:44316/api/parameters"),
Method = HttpMethod.Get
};
request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var result = _httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead).Result;
var ms = new MemoryStream();
result.Content.CopyToAsync(ms).Wait();
return result.IsSuccessStatusCode ? ms: null;
}

HttpClient PostAsycn Always returns 404 Not Found but controller works with Postman and Javascript application

I have a Post Web Api Method in a controller and it's already working, I've been testing the method sending file from postman and a my own web application and it works but now I'm trying to send file from console application using Httpclient but always get 404.
Controller Method
public async Task<IHttpActionResult> Post()
{
FileServerConfig config = FileServerConfiguration.ObtenerConfiguracion(ConfigurationManager.AppSettings);
var path = string.Empty;
try
{
if (!Request.Content.IsMimeMultipartContent())
{
return StatusCode(HttpStatusCode.UnsupportedMediaType);
}
var filesReadToProvider = await Request.Content.ReadAsMultipartAsync();
foreach (var stream in filesReadToProvider.Contents)
{
IFileServerWrapper _cliente = FileServerConfiguration.CrearCliente(config);
var name = stream.Headers.ContentDisposition.FileName.Replace("\"", "").Replace("\\", "");
var fileUploaded = await _cliente.FileUpload(path, await stream.ReadAsStreamAsync(), name, false);
}
return Ok();
}
catch (HttpException httpex)
{
if (httpex.GetHttpCode() == (int)HttpStatusCode.Conflict)
{
return Conflict();
}
else
{
return InternalServerError(httpex);
}
}
catch (Exception ex)
{
return InternalServerError(ex);
}
}
Console application
static void Main(string[] args)
{
string filePath = #"C:\Software\itextTifftoPDF.rar";
using (var client = new HttpClient())
using (var content = new MultipartFormDataContent())
{
// Make sure to change API address
//client.BaseAddress = new Uri("http://localhost:80/FileServerAPI/");
client.DefaultRequestHeaders.Add("Accept-Language", "en-GB,en-US;q=0.8,en;q=0.6,ru;q=0.4");
client.DefaultRequestHeaders.CacheControl = CacheControlHeaderValue.Parse("no-cache");
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
// Add first file content
var fileContent1 = new ByteArrayContent(File.ReadAllBytes(filePath));
fileContent1.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")
{
FileName = "itextTifftoPDF.rar"
};
content.Add(fileContent1);
// Make a call to Web API
var result = client.PostAsync("http://localhost/FileServerAPI/api/File", content).Result;
Console.WriteLine(result.StatusCode);
Console.ReadLine();
}
}
Finally I found a solution. the code is ugly because it was made just to be sure it works but I'll hope it may help others with the same problem.
string filePath = #"C:\temp\webdavtest.txt";
using (HttpClient httpClient = new HttpClient())
{
using (MultipartFormDataContent content =
new MultipartFormDataContent())
{
using (FileStream stream = File.Open(
filePath, FileMode.Open, FileAccess.Read))
{
using (StreamContent streamConent =
new StreamContent(stream))
{
content.Add(
streamConent, "webdavtest.txt", "webdavtest.txt");
var result = await httpClient.PostAsync("http://localhost:3983/api/File?path=/nivel5/", content);
return result.StatusCode.ToString();
}
}
}
}

Client code to upload file via ASP.NET MVC WebApi

I am trying to write code to upload file(s) by WinForm app to WebApi.
The WebApi code is like:
[HttpPost]
[Route("UploadEnvelope")]
[HostAuthentication(DefaultAuthenticationTypes.ExternalBearer)]
public Task<HttpResponseMessage> PostUploadEnvelope()
{
HttpRequestMessage request = this.Request;
if (!request.Content.IsMimeMultipartContent())
{
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}
string root = System.Web.HttpContext.Current.Server.MapPath("~/App_Data/uploads");
var provider = new MultipartFormDataStreamProvider(root);
var task = request.Content.ReadAsMultipartAsync(provider).ContinueWith<HttpResponseMessage>(o =>
{
foreach (MultipartFileData fileData in provider.FileData)
{
if (string.IsNullOrEmpty(fileData.Headers.ContentDisposition.FileName))
{
return Request.CreateResponse(HttpStatusCode.NotAcceptable, "This request is not properly formatted");
}
string fileName = fileData.Headers.ContentDisposition.FileName;
if (fileName.StartsWith("\"") && fileName.EndsWith("\""))
{
fileName = fileName.Trim('"');
}
if (fileName.Contains(#"/") || fileName.Contains(#"\"))
{
fileName = Path.GetFileName(fileName);
}
File.Move(fileData.LocalFileName, Path.Combine(root, fileName));
}
return new HttpResponseMessage()
{
Content = new StringContent("Files uploaded.")
};
}
);
return task;
}
But I am not sure how to call it and pass file in a client app.
static string UploadEnvelope(string filePath, string token, string url)
{
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
// How to pass file here ???
var response = client.GetAsync(url + "/api/Envelope/UploadEnvelope").Result;
return response.Content.ReadAsStringAsync().Result;
}
}
Any help or suggestion is welcome. Thanks in advance!
First you are using Get method which is used for reading. You have to use Post instead.
Try the following:
public static string UploadEnvelope(string filePath,string token, string url)
{
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
using (var content = new MultipartFormDataContent("Envelope" + DateTime.Now.ToString(CultureInfo.InvariantCulture)))
{
content.Add(new StreamContent(new MemoryStream(File.ReadAllBytes(filePath))), "filename", "filename.ext");
using (var message = await client.PostAsync(url + "/api/Envelope/UploadEnvelope", content))
{
var input = await message.Content.ReadAsStringAsync();
return "success";
}
}
}
}
Note: For a large file you have to change configuration on IIS web.config.

Upload file to Pushbullet in Windows 10 app c#

I'm currently using Pushbullet API and need to upload a file.
I can successfully get an upload url as specified in the docs using this method:
public static async Task<Uploads> GetUploadUrl(string file_name, string file_type)
{
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.Add("Access-Token", AccessToken);
var json = new JObject
{
["file_name"] = file_name,
["file_type"] = file_type
};
var result = await client.PostAsync(new Uri(_uploadUrl, UriKind.RelativeOrAbsolute), new HttpStringContent(json.ToString(), UnicodeEncoding.Utf8, "application/json"));
if (result.IsSuccessStatusCode)
{
var textresult = await result.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<Uploads>(textresult);
}
}
return null;
}
The problem is when I try to upload the file. I'm currently using this method:
public static async Task<bool> UploadFile(StorageFile file, string upload_url)
{
try
{
System.Net.Http.HttpClient client = new System.Net.Http.HttpClient();
var content = new MultipartFormDataContent();
if (file != null)
{
var streamData = await file.OpenReadAsync();
var bytes = new byte[streamData.Size];
using (var dataReader = new DataReader(streamData))
{
await dataReader.LoadAsync((uint)streamData.Size);
dataReader.ReadBytes(bytes);
}
var streamContent = new ByteArrayContent(bytes);
content.Add(streamContent);
}
client.DefaultRequestHeaders.Add("Access-Token", AccessToken);
var response = await client.PostAsync(new Uri(upload_url, UriKind.Absolute), content);
if (response.IsSuccessStatusCode)
return true;
}
catch { return false; }
return false;
}
but I get a Http 400 error. What's the right way to upload a file using multipart/form-data in a UWP app?
HTTP 400 error indicates Bad Request, it means the request could not be understood by the server due to malformed syntax. In the other word, the request sent by the client doesn't follow server's rules.
Let's look at the document, and we can find in the example request it uses following parameter:
-F file=#cat.jpg
So in the request, we need to set the name for the uploaded file and the name should be "file". Besides, in this request, there is no need to use access token. So you can change your code like following:
public static async Task<bool> UploadFile(StorageFile file, string upload_url)
{
try
{
System.Net.Http.HttpClient client = new System.Net.Http.HttpClient();
var content = new MultipartFormDataContent();
if (file != null)
{
var streamData = await file.OpenReadAsync();
var bytes = new byte[streamData.Size];
using (var dataReader = new DataReader(streamData))
{
await dataReader.LoadAsync((uint)streamData.Size);
dataReader.ReadBytes(bytes);
}
var streamContent = new ByteArrayContent(bytes);
content.Add(streamContent, "file");
}
//client.DefaultRequestHeaders.Add("Access-Token", AccessToken);
var response = await client.PostAsync(new Uri(upload_url, UriKind.Absolute), content);
if (response.IsSuccessStatusCode)
return true;
}
catch { return false; }
return false;
}
Then your code should be able to work. You will get a 204 No Content response and UploadFile method will return true.

How to upload file mvc6?

I want implement api that upload zip files.
My function working for text files but not for zip file.
Zip file is saved but can not be open.
Do you know whet is good aproach for this?
At client I call api in next action:
[HttpPost]
public async Task<IActionResult> Upload(ICollection<IFormFile> files)
{
using (var client = new HttpClient())
{
foreach (var file in files)
{
if (file.Length > 0)
{
var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
var fileContent = new StreamContent(file.OpenReadStream());
fileContent.Headers.Add("X-FileName", fileName);
fileContent.Headers.Add("X-ContentType", file.ContentType);
var response = await client.PostAsync(url2, fileContent);
}
}
}
return View(nameof(this.Index));
}
This is my api:
[HttpPost]
public async Task<IActionResult> Post()
{
var input = new StreamReader(Request.Body).ReadToEnd();
var fileName = Request.Headers["X-FileName"];
var fileType = Request.Headers["X-ContentType"];
using (var sw = new StreamWriter(#"C:\" + fileName))
{
sw.Write(input);
}
await Task.FromResult(0);
return new ObjectResult(true);
}
This is my solutin:
On client API
[HttpPost("{lastModified}")]
public async Task<string> Upload(long lastModified)
{
using (var client = new HttpClient())
{
foreach (var file in Request.Form.Files)
{
if (file.Length > 0)
{
var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
var fileContent = new StreamContent(file.OpenReadStream());
var archiveUrl = "path to api with 2 parameters {fileName}/{lastModified}";
var datasetResponse = await client.PostAsync(archiveUrl, fileContent);
var dataset = await datasetResponse.Content.ReadAsStringAsync();
return dataset;
}
}
throw new ApplicationException("Cannot updated dataset to archive");
}
}
On server API
[HttpPost("{fileName}/{lastModified}")]
public async Task<IActionResult> Post(string fileName, long lastModified)
{
var dataSet = getDataSet();
return new ObjectResult(dataSet);
}

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