A task was cancelled error - c#

I am using REST call, the code is like:
public bool restfunc(string id)
{
var result = Task.Factory.StartNew(() => RunAsync(id)).Result; //RunAsync(id).Wait();
return true;
}
public static Task RunAsync(string id)
{
try
{
dynamic result = null;
string pathValue = WebConfigurationManager.AppSettings["R2G2APIUrl"];
using (var client = new HttpClient())
{
client.BaseAddress = new Uri(pathValue);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
client.Timeout = TimeSpan.FromMinutes(5);
Task responsetask = null;
var jobid = id.Split('_')[1];
client.GetAsync("OnTranscriptionStarted/" + jobid).ContinueWith((requesttask) =>
{
responsetask = requesttask;
HttpResponseMessage resp = requesttask.Result; //HERE ERR OCCUR
resp.EnsureSuccessStatusCode();
resp.Content.ReadAsStringAsync().ContinueWith((readtask) =>
{
result = JsonConvert.DeserializeObject(readtask.Result);
});
});
}
return result;
Doubt:
I have API in pathvalue..I have to write pathvalue in
GetAsync() or function name and id which I want to call?
Help me out from this problem please..

You can use UriBuilder for that:
var builder = new UriBuilder(
"http", pathValue, 80, string.Format("OnTranscriptionStarted/{0}", jobId));
client.GetAsync(builder.Uri.ToString());

Related

Best way to make multiple calls to API endpoint

I have designed the following method to call api within the loop. I was wondering if there is any other better way (performance) of calling APIs multiple times?
private List<ClientInfo> populateDetails(List<ClientInfo> lstClientDetails)
{
using (var client = new HttpClient())
{
client.BaseAddress = EndpointAddress;
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
string Uri = "";
ClientInfo clientInfo;
foreach (var record in lstClientDetails)
{
Uri = string.Format("{0}", record.id);
var postResponse = client.GetAsync(Uri).Result;
if (postResponse.IsSuccessStatusCode)
{
string result = postResponse.Content.ReadAsStringAsync().Result;
clientInfo = JsonConvert.DeserializeObject<ClientInfo>(result);
if (clientInfo != null)
record.email = clientInfo.email;
}
}
return lstClientDetails;
}
}
Maybe you can change your code to use async/await pattern
private async Task populateDetails(List<ClientInfo> lstClientDetails)
{
using (var client = new HttpClient())
{
client.BaseAddress = EndpointAddress;
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
string Uri = "";
ClientInfo clientInfo;
foreach (var record in lstClientDetails)
{
Uri = string.Format("{0}", record.id);
var postResponse = await client.GetAsync(Uri);
if (postResponse.IsSuccessStatusCode)
{
string result = await postResponse.Content.ReadAsStringAsync();
clientInfo = JsonConvert.DeserializeObject<ClientInfo>(result);
if (clientInfo != null)
record.email = clientInfo.email;
}
}
}
}
And as you can see it doesn't make senso to return the same List which is passed as a paramters: the code will change the underlyne objects
Reference Microsoft Docs Parallel Library
sample code:
public class ParallelClient
{
private async Task ParallelRequest(List<string> requests)
{
var responses = new ConcurrentBag<HttpResponseMessage>();
using (var client = new HttpClient())
{
Parallel.ForEach(requests, new ParallelOptions { MaxDegreeOfParallelism = 10 }, async r =>
{
var requestMessage = new HttpRequestMessage();
requestMessage.Method = HttpMethod.Post;
requestMessage.Content = new StringContent(r, Encoding.UTF8, "application/json");
var response = await client.SendAsync(requestMessage);
responses.Add(response);
});
}
}
}

HttpClient usage in polly

Wanted to verify if HttpCLient instance should be created outside method passed to polly for ExecuteAsync, or in?
My current usage varies between the two options and I am not sure which is the correct one?
Also, if it incurs some drawbacks, or possible memory leaks, etc. ?
Get:
var client = new HttpClient(new NativeMessageHandler()) { Timeout = new TimeSpan(0, 0, TimeOutSec) };
var httpResponse = await AuthenticationOnUnauthorizePolicy.ExecuteAsync(async () =>
{
UpdateClientHeader(client, correlationId);
return await client.GetAsync(url, token);
});
Post:
var httpResponse = await AuthenticationOnUnauthorizePolicy.ExecuteAsync(async () =>
{
using (var client = new HttpClient(new NativeMessageHandler()) { Timeout = new TimeSpan(0, 0, TimeOutSec) })
{
UpdateClientHeader(client, correlationId);
WriteNetworkAccessStatusToLog();
return await client.PostAsync(url, content);
}
});
The policy used here:
AuthenticationOnUnauthorizePolicy = Policy
.HandleResult<HttpResponseMessage>(reposnse => reposnse.StatusCode == HttpStatusCode.Unauthorized)
.RetryAsync(1, onRetryAsync:
async (response, count, context) =>
{
_logger.Info("Unauthorized Response! Retrying Authentication...");
await Authenticate();
});
Appreciates any comments on the code above.
Is there a correct way?
Do I need to use the Context to get the client again, or is my usage okay?
Update:
Authenticate method:
public virtual async Task Authenticate()
{
// lock it - only one request can request token
if (Interlocked.CompareExchange(ref _isAuthenticated, 1, 0) == 0)
{
var result = new WebResult();
var loginModel = new LoginModel
{
email = _settingService.Email,
password = _settingService.Password
};
var url = ......
var correlationId = Guid.NewGuid().ToString();
try
{
var stringObj = JsonHelper.SerializeObject(loginModel);
HttpContent content = new StringContent(stringObj, Encoding.UTF8, HttpConsts.JsonMediaType);
using (var client = new HttpClient(new NativeMessageHandler()) { Timeout = new TimeSpan(0, 0, TimeOutSec) }
)
{
UpdateClientHeader(client, correlationId, useToken: false); // not token, we need new one
using (var httpResponse = await client.PostAsync(url, content))
{
var sReader = await httpResponse.Content.ReadAsStringAsync();
await HandleRequest(result, sReader, httpResponse, correlationId, url, "result");
}
}
if (result != null && !result.HasError)
{
_loginToken = result.Token;
}
}
catch (Exception ex)
{
// Log error
}
finally
{
_isAuthenticated = 0;
}
}
}
Update client headr method:
if (_loginToken != null &&
!client.DefaultRequestHeaders.Contains("Token"))
{
client.DefaultRequestHeaders.Add("Token", _loginToken );
}
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(HttpConsts.JsonMediaType));

C# HttpClient return Status WaitingForActivation

I have only one method for Api Request as follow
private async Task<Site> getSiteAsync(string siteId)
{
Site site = null;
var response = await httpClient.SendAsync(
new HttpRequestMessage(HttpMethod.Get, httpClient.BaseAddress + $"api/sites/{siteId}"));
if (response.IsSuccessStatusCode)
{
var stream = await response.Content.ReadAsStreamAsync();
site = await JsonSerializer.DeserializeAsync<Site>(stream, serializerOptions);
}
return site;
}
When I try to call it from my MainClass the first call (a) works fine, but the b,c and d they all return me the Status = WaitingForActivation.
private readonly HttpClient httpClient = new HttpClient();
private readonly JsonSerializerOptions serializerOptions = new JsonSerializerOptions();
public MainWindow()
{
httpClient.BaseAddress = new Uri($"http://localhost:5000/MyApi/");
httpClient.DefaultRequestHeaders.Accept.Clear();
httpClient.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
serializerOptions.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
var a = getSiteAsync("0001"); << I only get the value of this call.
var b = getSiteAsync("0002");
var c = getSiteAsync("0003");
var d = getSiteAsync("0004");
InitializeComponent();
}
How can I get the Result of b,c and d ?
You should await the calls and since you can only do this in an async method and not in a constructor, you should move your code to a method or an event handler:
public MainWindow()
{
httpClient.BaseAddress = new Uri($"http://localhost:5000/MyApi/");
httpClient.DefaultRequestHeaders.Accept.Clear();
httpClient.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
serializerOptions.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
Loaded += async (s, e) =>
{
var a = await getSiteAsync("0001");
var b = await getSiteAsync("0002");
var c = await getSiteAsync("0003");
var d = await getSiteAsync("0004");
};
InitializeComponent();
}

How to PATCH data using System.Net.Http

I have uploaded a file to SharePoint and found out what id it has. Now I need to update some of the other columns on that listitem. The problem is that System.Net.Http.HttpMethod.Patch doesn't exist.
public static async Task<string> UpdateFileData()
{
var (authResult, message) = await Authentication.AquireTokenAsync();
string updateurl = MainPage.rooturl + "lists/edd49389-7edb-41db-80bd-c8493234eafa/items/" + fileID + "/";
var httpClient = new HttpClient();
HttpResponseMessage response;
try
{
var root = new
{
fields = new Dictionary<string, string>
{
{ "IBX", App.IBX }, //column to update
{ "Year", App.Year}, //column to update
{ "Month", App.Month} //column to update
}
};
var s = new JsonSerializerSettings { DateFormatHandling = DateFormatHandling.MicrosoftDateFormat };
var content = JsonConvert.SerializeObject(root, s);
var request = new HttpRequestMessage(HttpMethod.Put, updateurl);
request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", authResult.AccessToken);
request.Content = new StringContent(content, Encoding.UTF8, "application/json");
response = await httpClient.SendAsync(request);
var responseString = await response.Content.ReadAsStringAsync();
return responseString;
}
catch (Exception ex)
{
return ex.ToString();
}
}
Modify the code as below.
public static async Task<string> UpdateFileData()
{
var (authResult, message) = await Authentication.AquireTokenAsync();
string updateurl = MainPage.rooturl + "lists/edd49389-7edb-41db-80bd-c8493234eafa/items/" + fileID + "/";
var httpClient = new HttpClient();
HttpResponseMessage response;
try
{
var root = new
{
fields = new Dictionary<string, string>
{
{ "IBX", App.IBX }, //column to update
{ "Year", App.Year}, //column to update
{ "Month", App.Month} //column to update
}
};
var s = new JsonSerializerSettings { DateFormatHandling = DateFormatHandling.MicrosoftDateFormat };
var content = JsonConvert.SerializeObject(root, s);
var request = new HttpRequestMessage(new HttpMethod("PATCH"), updateurl);
request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", authResult.AccessToken);
request.Content = new StringContent(content, System.Text.Encoding.UTF8, "application/json;odata=verbose");
response = await httpClient.SendAsync(request);
var responseString = await response.Content.ReadAsStringAsync();
return responseString;
}
catch (Exception ex)
{
return ex.ToString();
}
}
Or we can also use REST API to update list item by ID.
Refer to: SharePoint 2013 REST Services using C# and the HttpClient
It dependents whether .NET Core or .NET Framework is utilized, in case of `.NET Core HttpClient.PatchAsync Method could be utilized.
In case of .NET Framework ListItem could be updated like this:
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
client.BaseAddress = new Uri("https://graph.microsoft.com");
var listItemPayload = new Dictionary<string, object>
{
{"Color", "Fuchsia"},
{"Quantity", 934}
};
var requestContent = new StringContent(JsonConvert.SerializeObject(listItemPayload));
requestContent.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json");
var response = await client.PatchAsync(new Uri($"https://graph.microsoft.com/v1.0/sites/{siteId}/lists/{listId}/items/{itemId}/fields"), requestContent);
var data = response.Content.ReadAsStringAsync().Result.ToString();
}
where PatchAsync is the extension method for HttpClient class:
public static class HttpClientExtensions
{
public static async Task<HttpResponseMessage> PatchAsync(this HttpClient client, Uri requestUri, HttpContent iContent)
{
var method = new HttpMethod("PATCH");
var request = new HttpRequestMessage(method, requestUri)
{
Content = iContent
};
HttpResponseMessage response = new HttpResponseMessage();
try
{
response = await client.SendAsync(request);
}
catch (TaskCanceledException e)
{
Debug.WriteLine("ERROR: " + e.ToString());
}
return response;
}
}
All the credits for extension method go to the author of this answer
Can't you just use the HttpMethod class constructor?
new HttpMethod("PATCH");
Source: https://learn.microsoft.com/en-us/dotnet/api/system.net.http.httpmethod.-ctor?view=netframework-4.7.2#System_Net_Http_HttpMethod__ctor_System_String_

How to reconstruct return type object in web api

Given that I have the following web api method in my controller
public HttpResponseMessage PostGrantAccess(GrantAccessRequest grantAccessRequest)
{
var deviceId = grantAccessRequest.DeviceId;
var grantAccessResponse = new GrantAccessResponse()
{
Status = "OK"
};
var response = Request.CreateResponse<GrantAccessResponse>(HttpStatusCode.OK, grantAccessResponse);
return response;
}
Client calling code:
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("http://localhost:55208/");
var request = new GrantAccessRequest { DeviceId = "bla" };
var response = client.PostAsJsonAsync("api/accesspanel", request).Result;
if (response.IsSuccessStatusCode)
{
var uri = response.Headers.Location;
}
}
How do I get back GrantAccessResponse at the client?
response.Content.ReadAsAsync<GrantAccessResponse>()

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