I have an ASP.Net Web API that generally works fine. I have a Winforms client application that does GET requests. The client application runs on our corporate network (the API is hosted as an Azure Website). Occasionally, and inconsistently, the HttpClient calls I make add what seem to be corporate URLs in front of my GET call.
Example: I try to call send an HttpClient request to the following URL: 'http://xyzxyz.azurewebsites.net/api/user/1'
but the actual request made is:
'http://usgaabc1iru01/B0000D0000N0001F0000S0000R0004/http://xyzxyz.azurewebsites.net/api/user/1'
This obviously causes an error.
I've asked our IT department what may be happening and they are at a loss. Hoping someone could point me in the right direction.
Edit:
Here's the code I use. First I have a static method I call everything I make a call to the API to get the HttpClient (is this awkward/bad perhaps):
public static HttpClient GetHttpClient()
{
var credentials = new NetworkCredential(GlobalVariables.CurrentUser.UserName, GlobalVariables.CurrentUser.Password);
HttpClientHandler handler = new HttpClientHandler();
handler.UseDefaultCredentials = false;
handler.Credentials = credentials;
HttpClient client = new HttpClient(handler);
client.BaseAddress = new Uri(PublicClasses.GlobalVariables.BaseUriString);
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
GlobalVariables.CredentialedHttpClient = client;
}
return GlobalVariables.CredentialedHttpClient;
}
}
Here's a simple GET call I use:
public static List<Project> GetAllProjects()
{
try
{
HttpClient client = GetHttpClient();
HttpResponseMessage response = client.GetAsync("api/project").Result; // Blocking call!
if (response.IsSuccessStatusCode)
{
var projects = response.Content.ReadAsAsync<IEnumerable<Project>>().Result;
return (List<Project>)projects;
}
else
{
Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
return null;
}
}
catch (Exception)
{
throw;
}
}
I don't have an answer for why is this happening but I came across similar issue in a web form (not a win forms client). That is solved by using base meta tag.I am not sure if that solves your problem, but you can give a try.
You can use base address with HttpClient like this (if you are not already doing this):
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("http://xyzxyz.azurewebsites.net/");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = await client.GetAsync("api/user/1");
if (response.IsSuccessStatusCode)
{
//add your code
}
}
Related
I have a web server on which I'm hosting my own api for one of my projects.
This is the php-code of the api-website:
$user = $_POST['username'];
$password = $_POST['password'];
if(strcmp($user, "username") == 0 && strcmp($password, "password") == 0) {
...
} else {
die("No Permissions");
}
I want to send the two variables username and password with a HttpClient and the postAsync-method to this website and if the right log in data is detected, it returns the data I want.
For this I have the following code in C#:
Task<HttpResponseMessage> response;
var url = "www.url.de"; //not the url I'm actually calling!
var vars = "[{\"username\":\"username\", \"password\":\"password\"}]";
using (var client = new HttpClient())
{
client.BaseAddress = new Uri(url);
client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
response = client.PostAsync(url, new StringContent(vars, Encoding.UTF8));
Console.WriteLine(response.Result.Content.ReadAsStringAsync().Result);
if (response.IsCompleted)
{
Console.WriteLine(response.Result.Content.ReadAsStringAsync().Result);
}
}
But the problem is that no matter what I have tried the output from this code is, that i have no permissions. And I have changed the php-code, so that I can see which data is stored in $username and $password, but they are empty and I don't know why. I hope somebody can help me with this.
Your PHP code is expecting the data sent as application/x-www-form-urlencoded, but your C# code is sending it as JSON.
As mentioned in the comment by M. Eriksson, you either need to change your PHP to accept JSON, or change your C# to send as form data.
This answer shows how to use HTTPClient to send data like that.
Here's my modification of your code based on the above code (I did test it):
public static async Task DoSomething()
{
string url = "http://httpbin.org/post"; //not the url I'm actually calling!
Dictionary<string, string> postData = new();
postData["username"] = "username";
postData["password"] = "password";
using HttpClient client = new();
client.DefaultRequestHeaders.Accept.Add(new("application/json"));
HttpRequestMessage request = new(HttpMethod.Post, url);
request.Content = new FormUrlEncodedContent(postData);
HttpResponseMessage response = await client.SendAsync(request);
Console.WriteLine(response.Content.ReadAsStringAsync().Result);
}
I am creating an application in .Net Core 2.1 and I am using http client for web requests. The issue is I have to send parallel calls to save time and for that I am using Task.WhenAll() method but when I hit this method I get the error "This instance has already started one or more requests. Properties can only be modified before sending the first request" Previously I was using RestSharp and everything was fine but I want to use httpclient. Here is the code:
public async Task<User> AddUser(string email)
{
var url = "user/";
_client.BaseAddress = new Uri("https://myWeb.com/");
_client.DefaultRequestHeaders.Accept.Clear();
_client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(Constants."application/json"));
_client.DefaultRequestHeaders.Add("Authorization", "Bearer " + token);
var json = new {email = email }
var response = await _client.PostAsJsonAsync(url,json);
if (response .IsSuccessStatusCode)
{ ....
Here is the constructor:
private readonly HttpClient _httpClient;
public UserRepository(HttpClient httpClient)
{
_httpClient = httpClient;
}
Method calling:
var user1 = AddUser("user#user.com");
var user2 = AddUser("test#test.com");
await Task.WhenAll(user1, user2);
and here is the startup configuation:
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
So what am I doing wrong? Do I need to change AddSingleton with AddTransient() or is there any other issue. One more question do I need to use _client.Dispose() after the response because the tutorial which I followed didn't use dispose method so I am little confused in that.
HttpClient.DefaultRequestHeaders (and BaseAddress) should only be set once, before you make any requests. HttpClient is only safe to use as a singleton if you don't modify it once it's in use.
Rather than setting DefaultRequestHeaders, set the headers on each HttpRequestMessage you are sending.
var request = new HttpRequestMessage(HttpMethod.Post, url);
request.Headers.Accept.Clear();
request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
request.Content = new StringContent("{...}", Encoding.UTF8, "application/json");
var response = await _client.SendAsync(request, CancellationToken.None);
Replace "{...}" with your JSON.
Maybe my two cents will help someone.
I ran into this issue when refreshing the page when debugging the application.
I was using a singleton, but each refresh, it was trying to set the base address. So I just wrapped it in a check to see if the base address had already been set.
The issue for me was, it was trying to set the baseAddress, even though it was already set. You can't do this with a httpClient.
if (_httpClient.BaseAddress == null)
{
_httpClient.BaseAddress = new Uri(baseAddress);
}
The issue is caused by resetting BaseAddress and headers for the same instance of the httpclient.
I tried
if (_httpClient.BaseAddress == null)
but I am not keen on this.
In my opinion, a better soloution is to use the httpclientFactory. This will terminate and garbage collect the instance of the httpclient after its use.
private readonly IHttpClientFactory _httpClientFactory;
public Foo (IHttpClientFactory httpClientFactory)
{
_httpClientFactory = httpClientFactory;
}
public httpresponse Bar ()
{
_httpClient = _httpClientFactory.CreateClient(command.ClientId);
using var response = await _httpclient.PostAsync(uri,content);
return response;
// here as there is no more reference to the _httpclient, the garbage collector will clean
// up the _httpclient and release that instance. Next time the method is called a new
// instance of the _httpclient is created
}
It Works well when you add the request url and the headers at the message, rather than at the client. So better not to assign to BaseAddress Or the header DefaultRequestHeaders if you will use them for many requests.
HttpRequestMessage msg = new HttpRequestMessage {
Method = HttpMethod.Put,
RequestUri = new Uri(url),
Headers = httpRequestHeaders;
};
httpClient.SendAsync(msg);
There is a POST rest api which used to work from code before. But recently it is broken and is not returning any response. However if I try to call the api from the Postman, then it works fine.
In what way can I debug this to find the root cause of the issue ?
Following is the C# code which I am using to call this post rest api
public async Task SaveToServerAsync()
{
string filePath = #"<filePath>";
ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
// tried this line of code from another SO answer, but this didn't work either
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("https://<server name>/");
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", "d2ebf9aefbaa416adcd0");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Add("Accept", "*/*");
client.DefaultRequestHeaders.Add("Connection", "keep-alive");
using (var fileStream = new FileStream(filePath, FileMode.Open))
{
var content = new MultipartFormDataContent();
content.Add(new StreamContent(fileStream), "file", filePath);
content.Add(new StringContent("e8d002f9-f381-44c2-bce0-13416929f14d"), "Id");
try
{
var response = await client.PostAsync("<rest api end point>", content).ConfigureAwait(false);
if (response.IsSuccessStatusCode)
{
Debug.Write("Response received");
}
}
catch (Exception ex)
{
Debug.Write("Exception occured");
Debug.Write(ex.Message);
}
finally
{
}
}
}
}
It always goes to the exception block with exception as "The task was cancelled"
Not sure how can I debug it when it anyway works from the Postman.
So the problem was related to ExpectContinue header which goes as true by default. Somehow server was not handling it properly and client was waiting for continue (100) message for indefinite time.
For the time being manually setting this header to be false worked for us:
httpClient.DefaultRequestHeaders.ExpectContinue = false;
I configured a Concur Sandbox and played around with the api. Since the User api is not supported by the .Net SDK I wrote following code.
Issue is that code for Expenses work (returns 200 with valida result), but code for users returns 401 Unauthorized.
Expenses
using (var httpClient = new HttpClient())
{
httpClient.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("OAuth", oauthAccessToken);
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/xml"));
var requestUri = "https://www.concursolutions.com/api/v3.0/expense/receiptimages";
var respone = await httpClient.GetAsync(requestUri);
if (respone.IsSuccessStatusCode)
{
var result = respone.Content.ReadAsStringAsync();
//throw new InvalidUriException(string.Format("Invalid uri: {0}", requestUri));
}
}
Ideally this should also work as the previous code works,
Users
using (var httpClient = new HttpClient())
{
httpClient.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("OAuth", oauthAccessToken);
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/xml"));
var requestUri = "http://www.concursolutions.com/api/v3.0/common/users?user=user1%40company.net";
var respone = await httpClient.GetAsync(requestUri);
if (!respone.IsSuccessStatusCode)
{
//throw new InvalidUriException(string.Format("Invalid uri: {0}", requestUri));
}
}
}
I thought it's a permission issue, but I given allowed enough permission.
Here is the Administration->Webservice app configuration,
Issue is that the User Api call needs to be https.
I have a application that uses the SharePoint 2010 REST API.
In the process of creating an Item there are multiple request done after each other:
1 Call: Getting Items from List: Succes
2 Call: Create Item: 401 Unauthorized
This is the same if I do it like this:
1 Call: Create Item: Succes
2 Call: Delete Item: 401 Unauthorized
What I know is that my functions work separately they DON'T work when they are called after each other.
When I close the application (Windows Phone 8.1 app) after creating a item and when restarted try to delete the item it works.
First I thought it had to do with the way I handle my fields so I changed them to NULL in a finally statement but that didn't work.
public async Task<bool> CreateNewItem(NewItem myNewItem)
{
try
{
StatusBar statusBar = await MyStatusBar.ShowStatusBar("Creating new List Item.");
//Retrieving Settings from Saved file
mySettings = await MyCredentials.GetMySettings();
myCred = new NetworkCredential(mySettings.UserName, mySettings.Password, mySettings.Domain);
using (var handler = new HttpClientHandler { Credentials = myCred })
{
HttpClient client = new HttpClient(handler);
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
NewItem newItem = myNewItem;
var jsonObject = JsonConvert.SerializeObject(newItem);
HttpResponseMessage response = await client.PostAsync(new Uri(baseUrl + listNameHourRegistration), new StringContent(jsonObject.ToString(), Encoding.Unicode, "application/json"));
response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
response.EnsureSuccessStatusCode();
string responseMessage = await response.Content.ReadAsStringAsync();
client.Dispose();
if (responseMessage.Length > 0)
return true;
}
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
return false;
}
finally
{
request = null;
response = null;
myCred = null;
mySettings = null;
}
return false;
}
Just run into the same problem.
Anyway, the 2nd request does not follow the same authentication procedure. Even if you initialize a new HttpClient object. I sniffed the HTTP traffic.
After the 1st request I am doing another with different credentials. This is also ending in a 401. I am really confused...
Seems the NTLM Handshake stucks at the 2nd of 6 steps
http://www.innovation.ch/personal/ronald/ntlm.html
Edit:
You may want to use the CSOM.
http://social.msdn.microsoft.com/Forums/office/en-US/efd12f11-cdb3-4b28-a9e0-32bfab71a419/windows-phone-81-sdk-for-sharepoint-csom?forum=sharepointdevelopment
While I still don't know what the actual problem is, at least I found a workaround: Use the WebRequest class instead of HttpClient.
I was running into this same error when I realized I was adding the headers each time I was calling the endpoint. Hopefully this will help someone.
Instead I initialized the HttpClient instance in my class constructor and set the headers there. Also I learned it is better practice to only use 1 instance instead of recreating with "using" (See this article https://www.aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/)
I'm invoking CallApiAsync from another class in a loop.
Here's my final solution:
class ApiShared
{
private HttpClient client;
public ApiShared() {
client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", ConfigurationManager.AppSettings["ApiKey"]);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
}
public async Task<ApiResponse_Root> CallApiAsync(string endpoint)
{
// Make API call
Uri endpointUri = new Uri(endpoint);
var stringTask = client.GetStringAsync(endpointUri);
var data = JsonConvert.DeserializeObject<ApiResponse_Root>(await stringTask);
return data;
}
}
On a windows machine you can resolve this with this registry setting change:
Go to the following Registry entry:
Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
Now add a new DWORD to the Lsa folder called: DisableLoopBackCheck and set this to 1
I see that this question has been posted long back. But I don't see a correctly working solution posted yet to this thread.
I faced exactly the same issue where the next requests kept on failing returning me 401 UnAuthorized.
I figured out using fiddler that from SECOND request onwards, there was a Cookie added to the request which was possibly a result of Set-Cookie response sent by the server along with first response.
So here's how I tackled the situation - Make UseCookies false:
new HttpClientHandler { Credentials = myCred, UseCookies = false }
This should resolve your issue. Hope this helps someone who's looking for a solution to a similar issue.