I have created an API, which shall have the capability to connect to en external API via POST and with a request body in form of a string.
I am able to connect directly to the API from Postman without trouble.. But it does not work via my own API.
Any ideas?
This is the Pastebin.
private string EncodeExternalApiLink = "https://blabla.dk";
private string EncodeExternalApiLinkPostFilter = "searchstring/blabla/api/search";
[HttpPost("getdata/filtered")]
public async Task<IActionResult> GetDataFromExternalFiltered([FromBody] string filter)
{
var filterString = new StringContent(filter);
EncodeExternalToken token = GetExternalToken().Result;
using (var client = new HttpClient())
{
client.BaseAddress = new Uri(EncodeExternalApiLink);
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("text/plain"));
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token.access_token);
using (var response = await client.PostAsync(EncodeExternalApiLinkPostFilter, filterString))
{
return Json(response);
if (response.IsSuccessStatusCode)
{
string content = await response.Content.ReadAsStringAsync();
return Content(content, "application/json");
}
else
{
return NotFound();
}
}
}
}
Salutations. You might need to add a "/" to the end of your base address EncodeExternalApiLink or to the beginning of EncodeExternalApiLinkPostFilter.
I am using Microsoft Bot framework (SDK v3) to create a QnA bot. While calling the QnAMaker API, the execution gets stuck at HttpCleint.SendAsync.
I have tried calling ConfigureAwait(false) on all the async calls.
I have tried adding .Result at end of function calls.
Both doesn't seem to work.
[Serializable]
public class QnAMakerService
{
private string qnaServiceHostName;
private string knowledgeBaseId;
private string endpointKey;
public QnAMakerService()
{
qnaServiceHostName = "foo";
knowledgeBaseId = "bar";
endpointKey = "foo";
}
async Task<string> Post(string uri, string body)
{
using (var client = new HttpClient())
using (var request = new HttpRequestMessage())
{
request.Method = HttpMethod.Post;
request.RequestUri = new Uri(uri);
request.Content = new StringContent(body, Encoding.UTF8, "application/json");
request.Headers.Add("Authorization", "EndpointKey " + endpointKey);
var response = await client.SendAsync(request);
return await response.Content.ReadAsStringAsync();
}
}
public async Task<string> GetAnswer(string question)
{
string uri = qnaServiceHostName + "/qnamaker/knowledgebases/" + knowledgeBaseId + "/generateAnswer";
string questionJSON = #"{'question': '" + question + "'}";
var response = await Post(uri, questionJSON);
var answers = JsonConvert.DeserializeObject<QnAAnswer>(response);
if (answers.answers.Count > 0)
{
return answers.answers[0].answer;
}
else
{
return "No good match found.";
}
}
}
[BotAuthentication]
public class MessagesController : ApiController
{
/// <summary>
/// POST: api/Messages
/// Receive a message from a user and reply to it
/// </summary>
///
QnAMakerService qna = new QnAMakerService();
public async Task<HttpResponseMessage> Post([FromBody]Activity activity)
{
if (activity.Type == ActivityTypes.Message)
{
ConnectorClient connector = new ConnectorClient(new Uri(activity.ServiceUrl));
var q = await qna.GetAnswer(activity.Text);
// return our reply to the user
Activity reply = activity.CreateReply($"{q}");
connector.Conversations.ReplyToActivity(reply);
}
else
{
HandleSystemMessage(activity);
}
var response = Request.CreateResponse(HttpStatusCode.OK);
return response;
}
}
The execution stops after the SendAsync call with a 500 internal server error excception.
I think the asynchonous code is getting blocked somewhere, but I don't know where.
EDIT : The same block of code(to call the API) works if I try it in a console application.
I am trying to create a C# console application to download project details from a website which supports REST OAuth 2.0. How do I make a request/response call to the website using the Access Token?
Here is my code:
public string token = "4bjskfa2-b37d-6244-8413-3358b18c91b6";
public async Task GetProjectsAsync()
{
try
{
HttpClient client = new HttpClient();
var projects = "https://app.rakenapp.com/api/v2/projects?" + token;
client.CancelPendingRequests();
HttpResponseMessage output = await client.GetAsync(projects);
if (output.IsSuccessStatusCode)
{
string response = await output.Content.ReadAsStringAsync();
project proj = JsonConvert.DeserializeObject<project>(response);
if (proj != null)
{
Console.WriteLine(proj.name); // You will get the projects here.
}
}
}
catch (Exception ex)
{
//catching the exception
}
}
you need to add a header to your request:
string url = "https://app.rakenapp.com/api/v2/projects";
using (var httpClient = new HttpClient())
{
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", authorizationToken);
HttpResponseMessage response = await httpClient.GetAsync(url);
var contents = await response.Content.ReadAsStringAsync();
var model = JsonConvert.DeserializeObject<project>.contents);
return model;
}
We are building a web application that consist of an Angular2 frontend, a ASP.NET Core web api public backend, and a ASP.NET Core web api private backend.
Uploading files from Angular2 to the public backend works. But we would prefer to post them forward to the private backend.
Current working code
[HttpPost]
public StatusCodeResult Post(IFormFile file)
{
...
}
From there I can save the file to disk using file.CopyTo(fileStream);
However, I want to re-send that file, or those files, or, ideally, the whole request to my second web api core.
I am not sure how to achieve this with the HttpClient class of asp.net core.
I've tried all kinds of things such as
StreamContent ss = new StreamContent(HttpContext.Request.Body);
var result = client.PostAsync("api/Values", ss).Result;
But my second backend gets an empty IFormFile.
I have a feeling it is possible to send the file(s) as a stream and reconstruct them on the other side, but can't get it to work.
The solution must use two web api core.
Solution
Public backend in DMZ
[HttpPost]
public StatusCodeResult Post(IFormFile file)
{
try
{
if (file != null && file.Length > 0)
{
using (var client = new HttpClient())
{
try
{
client.BaseAddress = new Uri(currentPrivateBackendAddress);
byte[] data;
using (var br = new BinaryReader(file.OpenReadStream()))
data = br.ReadBytes((int)file.OpenReadStream().Length);
ByteArrayContent bytes = new ByteArrayContent(data);
MultipartFormDataContent multiContent = new MultipartFormDataContent();
multiContent.Add(bytes, "file", file.FileName);
var result = client.PostAsync("api/Values", multiContent).Result;
return StatusCode((int)result.StatusCode); //201 Created the request has been fulfilled, resulting in the creation of a new resource.
}
catch (Exception)
{
return StatusCode(500); // 500 is generic server error
}
}
}
return StatusCode(400); // 400 is bad request
}
catch (Exception)
{
return StatusCode(500); // 500 is generic server error
}
}
Private backend
[HttpPost]
public void Post()
{
//Stream bodyStream = HttpContext.Request.Body;
if (Request.HasFormContentType)
{
var form = Request.Form;
foreach (var formFile in form.Files)
{
var targetDirectory = Path.Combine(_appEnvironment.WebRootPath, "uploads");
var fileName = GetFileName(formFile);
var savePath = Path.Combine(targetDirectory, fileName);
using (var fileStream = new FileStream(savePath, FileMode.Create))
{
formFile.CopyTo(fileStream);
}
}
}
}
Hi i had the same issue and this is what worked for me :
My setup is netCore MVC netCoreApi.
My MVC Controller looks like :
[HttpPost("UploadFiles")]
public async Task<IActionResult> Post(List<IFormFile> files)
{
Sp4RestClient dataPovider = new Sp4RestClient("http://localhost:60077/");
long size = files.Sum(f => f.Length);
foreach (var file in files)
{
await dataPovider.ImportFile(file);
}
return Ok();
}
DataProvider Method :
public async Task ImportFile(IFormFile file)
{
RestClient restClient = new RestClient(_queryBulder.BuildImportFileRequest());
using (var content = new MultipartFormDataContent())
{
content.Add(new StreamContent(file.OpenReadStream())
{
Headers =
{
ContentLength = file.Length,
ContentType = new MediaTypeHeaderValue(file.ContentType)
}
}, "File", "FileImport");
var response = await restClient.Post<IFormFile>(content);
}
}
And least my WebApi Controller :
[HttpPost]
[Route("ImportData")]
public IActionResult Import(IFormFile file)
{
return Ok();
}
To see the complete code here is my RestClient Post method :
public async Task<RestResult<T>> Post<T>(HttpContent content)
{
using (HttpClient httpClient = new HttpClient())
{
HttpResponseMessage response = await httpClient.PostAsync(Endpoint, content);
if (response.StatusCode == HttpStatusCode.Created)
{
T result = JsonConvert.DeserializeObject<T>(await response.Content.ReadAsStringAsync());
return new RestResult<T> { Result = result, ResultCode = HttpStatusCode.OK };
}
RestResult<T> nonOkResult =
new RestResult<T> { Result = default(T), ResultCode = response.StatusCode, Message = await response.Content.ReadAsStringAsync() };
return nonOkResult;
}
}
// Yeah i know im not getting HttpStatusCode.Created back ;)
happy coding ;)
API Code
[Route("api/upload/{id}")]
[HttpPost]
public async Task<IActionResult> Post(string id)
{
var filePath = #"D:\" + id; //+ Guid.NewGuid() + ".png";
if (Request.HasFormContentType)
{
var form = Request.Form;
foreach (var formFile in form.Files)
{
if (formFile.Length > 0)
{
using (var stream = new FileStream(filePath, FileMode.Create))
{
await formFile.CopyToAsync(stream);
}
}
}
}
return Ok(new { Path = filePath });
}
Back End
[Route("home/UploadFile")]
[HttpPost]
public IActionResult UploadFile(IFormFile file)
{
if (file == null || file.Length == 0)
return Content("file not selected");
var client = new HttpClient();
byte[] data;
using (var br = new BinaryReader(file.OpenReadStream()))
data = br.ReadBytes((int)file.OpenReadStream().Length);
ByteArrayContent bytes = new ByteArrayContent(data);
MultipartFormDataContent multiContent = new MultipartFormDataContent
{
{ bytes, "file", file.FileName }
};
var result = client.PostAsync("http://localhost:2821/api/upload/" + file.FileName, multiContent).Result;
return RedirectToAction("file");
}
Download Source
I was in a similar situation - I needed a proxy method for forwarding not only files but also JSON data and whatnot. I did not want to do any analysis of the data in my proxy to let the final receiver deal with it.
So with some help from #Anton Tykhyy I came to the following working solution:
byte[] arr = null;
using (var mems = new MemoryStream())
{
// read entire body into memory first because it might be chunked with unknown length
await request.Body.CopyToAsync(mems);
await mems.FlushAsync(); // not sure if needed after CopyToAsync - better safe then sorry
arr = mems.ToArray();
}
msg.Content = new ByteArrayContent(arr);
msg.Content.Headers.ContentLength = arr.Length;
// keep content-type header "as is" to preserve multipart boundaries etc.
msg.Content.Headers.TryAddWithoutValidation("Content-Type", request.ContentType);
var response = await _httpClient.SendAsync(msg);
I tested it with complex request that contained multipart form data with JSON field and multiple attached files, and all the data reached my backend server without any issues.
Ignoring the HttpClient when you call the private backend API, can you reference the private Core API project from the public Core API project and call the controller directly from the Core API project? See the request is still null/empty. If the request comes out with a value then the issue is with the use of the HttpClient.
Ideally, you want to create a package library(kind of SDK) for your private Core API that you want to distribute to consuming clients. This acts like a wrapper/proxy. This way you can isolate the private backend system and you can troubleshoot it in isolation. So you public Core API project(which is the private backend client) can reference it as nuget package.
i have the following problem, i try to wait for for an Async Web Response.
But it never finished.
public string getTermine(string trmId)
{
System.Threading.Tasks.Task<string> lisi = LoadTermine((HttpWebRequest)WebRequest.Create("http://" + curent.usrCH + apiKey + curent.phrase + apiTrmIDIS + trmId));//Request get String result like http://ajax.googleapis.com/ajax/services/search/web?v=1.0&start="+i+"&q=
lisi.Wait();
return lisi.Result;
}
private async System.Threading.Tasks.Taskstring>LoadTermine(HttpWebRequest myRequest)
{
//List<Termine> terminListe = new List<Termine>();
List<Appointment> Resu = null;
using (WebResponse response = await myRequest.GetResponseAsync())
{
using (System.IO.StreamReader reader = new System.IO.StreamReader(response.GetResponseStream()))
{
Resu = reader.ReadToEnd();
}
}
return Resu;
}
P.S. I cant use and synchronous request because this methods are an part of the Base code which is used by iOS, WinPhone and Android and i dont know why i cant get an synchronous WebResponse.
You are creating a deadlock by calling .Result on the task.
You could do something like this where the remoteUrl variabled is the url of your web service
private async System.Threading.Tasks.Task<string> LoadTermineAsync(HttpWebRequest myRequest)
{
using (var client = new HttpClient()) {
using (var request = new HttpRequestMessage(HttpMethod.Get, myRemoteUrl)) {
var response = await client.SendAsync(request).ConfigureAwait(false);
var result = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
return result;
}
}
}
For more info on Async/Await
And this evolve video is a little bit more advanced.