Develop Reference

How to read header values with HttpClient in .net core

This is the code i'm using
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("bearer", HttpContext.Session.GetString("JwtToken"));
var url = $"...some url";
var requestUri = new Uri(url);
var responseTask = client.GetAsync(requestUri);
responseTask.Wait();
var result = responseTask.Result;
if (result.IsSuccessStatusCode)
{
var reportResults = Task.Run(async() => await result.Content.ReadAsAsync<JArray>()).Result;
return reportResults;
}
}
Here if i try to access header like this
string error = responseTask.Headers.TryGetValue("X-TotalResults").FirstOrDefault();
I'm getting error
Task<HttpResponseMessage> does not contain a
definition for Headers and no accessible extension method Headers
So How i can read the header .. thanks in advance

You have a Task<HttpResponseMessage> rather than a HttpResponseMessage.
Instead of using .Result, which is dangerous for many reasons, convert your code to use async properly.
static HttpClient client = new HttpClient();
private async JArray GetReportResults()
{
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("bearer", HttpContext.Session.GetString("JwtToken"));
var url = $"...some url";
using (var response = await client.GetAsync(url))
{
result.EnsureSuccessStatusCode()
var reportResults = await result.Content.ReadAsAsync<JArray>();
return reportResults;
}
}

ASP.NET Web API post to an external api

I would like to ask if it is possible for a created ASP.NET Web API (written in C#) to post to an external API?
If it is possible, please share sample code that can post to an url with adding headers and receive a callback from the external API.

A simple way to make HTTP-Request out of a .NET-Application is the System.Net.Http.HttpClient (MSDN). An example usage would look something like this:
// Should be a static readonly field/property, wich is only instanciated once
var client = new HttpClient();
var requestData = new Dictionary<string, string>
{
{ "field1", "Some data of the field" },
{ "field2", "Even more data" }
};
var request = new HttpRequestMessage() {
RequestUri = new Uri("https://domain.top/route"),
Method = HttpMethod.Post,
Content = new FormUrlEncodedContent(requestData)
};
request.Headers // Add or modify headers
var response = await client.SendAsync(request);
// To read the response as string
var responseString = await response.Content.ReadAsStringAsync();
// To read the response as json
var responseJson = await response.Content.ReadAsAsync<ResponseObject>();

Essentially you need use an instance of HttpClient to send an HttpRequestMessage to an endpoint.
Here is an example to post some jsonData to someEndPointUrl:
var client = new HttpClient();
var request = new HttpRequestMessage(HttpMethod.Post, someEndPointUrl);
request.Headers.Accept.Clear();
request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
request.Content = new StringContent(jsonData, Encoding.UTF8, "application/json");
var response = await client.SendAsync(request, CancellationToken.None);
var str = await response.Content.ReadAsStringAsync();
if (response.StatusCode == HttpStatusCode.OK)
{
// handle your response
}
else
{
// or failed response ?
}

How to pass request content with HttpClient GetAsync method in c#

How do I pass request content in the HttpClient.GetAsync method? I need to fetch data depending upon request content.
[HttpGet]
public async Task<HttpResponseMessage> QuickSearch()
{
try
{
using (HttpClient client = new HttpClient())
{
client.DefaultRequestHeaders.Accept.Clear();
HttpResponseMessage response =await client.GetAsync("http://localhost:8080/document/quicksearch");
if (response.IsSuccessStatusCode)
{
Console.Write("Success");
}

If you are using .NET Core, the standard HttpClient can do this out-of-the-box. For example, to send a GET request with a JSON body:
HttpClient client = ...
...
var request = new HttpRequestMessage
{
Method = HttpMethod.Get,
RequestUri = new Uri("some url"),
Content = new StringContent("some json", Encoding.UTF8, ContentType.Json),
};
var response = await client.SendAsync(request).ConfigureAwait(false);
response.EnsureSuccessStatusCode();
var responseBody = await response.Content.ReadAsStringAsync().ConfigureAwait(false);

If you want to send content, then you need to send it as query string (According to your API route)
HttpResponseMessage response =await client.GetAsync("http://localhost:8080/document/quicksearch/paramname=<dynamicName>&paramValue=<dynamicValue>");
And in API check for "paramName" and "paramValue"

this works for me:
using (var httpClient = new HttpClient())
{
var request = new HttpRequestMessage
{
Method = HttpMethod.Get,
RequestUri = new Uri("your url"),
Content = new StringContent("your json", Encoding.UTF8, ContentType.Json),
};
using (var response = await httpClient.SendAsync(request))
{
string apiResponse = await response.Content.ReadAsStringAsync();
}
}
EDITED:
This is minor different then #SonaliJain answer above:
MediaTypeNames.Application.Json instead of ContentType.Json

I'm assuming that your "request content" would be POST data, no?
If you're sending it using the standard form content way of doing it, you would first have to build the content:
var content = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("username", "theperplexedone"),
new KeyValuePair<string, string>("password", "mypassword123"),
});
And then submit it using PostAsync instead:
var response = await client.PostAsync("http://localhost:8080/document/quicksearch", content);

Hi all thank you for your comments, i got the solution
[HttpGet]
public async Task<HttpResponseMessage> QuickSearch(HttpRequestMessage Query)
{
Debugger.Launch();
try
{
using (HttpClient client = new HttpClient())
{
client.DefaultRequestHeaders.Accept.Clear();
Console.WriteLine(Query);
HttpResponseMessage response = await client.GetAsync("http://localhost:8080/document/quicksearch/"+ Query.RequestUri.Query);
if (response.IsSuccessStatusCode)
{
Console.Write("Success");
}
else
{
Console.Write("Failure");
}
return response;
}
}
catch (Exception e)
{
throw e;
}

Call REST Service from WebAPi and transfer HttpResponseMessage

I have to call a REST Service from Web API.
Call and retrieve data works well but the return method crash.
I have tried several method that return an async HttpResponseMessage, but I can return this object as well (error socket on chrome ERR_SPDY_PROTOCOL_ERROR).
I've tried too with just a plain json as string, but no more success.
Here some tries :
[Route("{id}")]
public async Task<JObject> Get(string id)
{
dynamic client = new RestClient($"https://...../accounts/{id}/summary",
new Dictionary<string, string> {
//some KVP for access Rest API
});
//await client.Get() returns HttpResponseMessage 200 and Content is well populated
JObject result = JObject.FromObject(await client.Get());
return result;
//Request.CreateResponse(HttpStatusCode.OK, await result.Content.ReadAsAsync<string>());
//HttpResponseMessage result = await client.Get(); => HttpResponseMessage is well filled
//Request.CreateResponse(HttpStatusCode.OK, await result.Content.ReadAsAsync<string>()); => test with wrapping inside a new HttpResponseMessage but no more success
//using (var client = new HttpClient())
//{
// client.BaseAddress = new Uri($"https://....../v1/accounts/{id}/summary");
// client.DefaultRequestHeaders.Accept.Clear();
// client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
// HttpResponseMessage response = await client.GetAsync("");
// return Request.CreateResponse(HttpStatusCode.OK, response.Content.ReadAsAsync());
//}
}
Is there a simple method to retrieve json from Rest Service and transfer this as it is ?

If these calls are being performed in a Web API, and there is no logic being applied to the JSON Object, then there is little need to parse it before returning it as it will get serialized again when being returned, you can instead parse it on the front-end application and perform your logic there.
HttpClient has a method which returns the response body as a string, this is GetStringAsync. With the body returned as string, you can return that directly in your HttpResponseMessage
Here's an example using your HttpClient commented code.
[Route("{id}")]
public async Task<HttpResponseMessage> Get(string id)
{
using (var client = new HttpClient())
{
client.BaseAddress = new Uri($"https://....../v1/accounts/");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
// Fetch the response body as a string
// Resource URI added below
string responseContent = await client.GetStringAsync($"{id}/summary");
// Create our response object and set the content to its StringContent
var response =
new HttpResponseMessage(HttpStatusCode.OK) {Content = new StringContent(responseContent)};
// Return our HttpResponseMessage containing our json text
return response;
}
}

If you just want to transfer the json response from another API, you can use code like the following in Web API:
[HttpGet]
[Route("v1/test", Name = "test")]
public HttpResponseMessage GetTest()
{
UriBuilder uriBuilder = new UriBuilder($"https://...../...");
var webRequest = (HttpWebRequest)WebRequest.Create(uriBuilder.Uri);
webRequest.Method = "GET";
webRequest.ContentType = "application/json; charset=utf-8";
webRequest.Accept = "application/json, text/javascript, */*";
using (var jsonResponse = (HttpWebResponse) webRequest.GetResponse())
{
var jsonStream = jsonResponse.GetResponseStream();
MemoryStream ms = new MemoryStream();
jsonStream.CopyTo(ms);
ms.Position = 0;
HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
response.Content = new StreamContent(ms);
response.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/json");
return response;
}
}
When the only thing needed is to support authentication or authorization features, i would prefer to use an API manager and not maintain this kind of code myself.

Set Authorization/Content-Type headers when call HTTPClient.PostAsync

Where can I set headers to REST service call when using simple HTTPClient?
I do :
HttpClient client = new HttpClient();
var values = new Dictionary<string, string>
{
{"id", "111"},
{"amount", "22"}
};
var content = new FormUrlEncodedContent(values);
var uri = new Uri(#"https://some.ns.restlet.uri");
var response = await client.PostAsync(uri, content);
var responseString = await response.Content.ReadAsStringAsync();
UPD
Headers I want to add:
{
"Authorization": "NLAuth nlauth_account=5731597_SB1, nlauth_email=xxx#xx.com, nlauth_signature=Pswd1234567, nlauth_role=3",
"Content-Type": "application/json"
}
Should I do the following?
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Authorization", "NLAuth nlauth_account=5731597_SB1, nlauth_email=xxx#xx.com, nlauth_signature=Pswd1234567, nlauth_role=3","Content-Type":"application/json");

The way to add headers is as follows:
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", "Your Oauth token");
Or if you want some custom header:
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Add("HEADERNAME", "HEADERVALUE");
This answer has SO responses already, see below:
Adding headers when using httpClient.GetAsync
Setting Authorization Header of HttpClient
UPDATE
Seems you are adding two headerrs; authorization and content type.
string authValue = "NLAuth nlauth_account=5731597_SB1,nlauth_email=xxx#xx.com, nlauth_signature=Pswd1234567, nlauth_role=3";
string contentTypeValue = "application/json";
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(authValue);
client.DefaultRequestHeaders.Add("Content-Type", contentTypeValue);

I know this was asked a while ago, but Juan's solution didn't work for me.
(Also, pretty sure this question is duplicated here.)
The method that finally worked was to use HttpClient with HttpRequestMessage and HttpResponseMessage.
Also note that this is using Json.NET from Newtonsoft.
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using System.Net.Http.Headers;
using Newtonsoft.Json;
namespace NetsuiteConnector
{
class Netsuite
{
public void RunHttpTest()
{
Task t = new Task(TryConnect);
t.Start();
Console.WriteLine("Connecting to NS...");
Console.ReadLine();
}
private static async void TryConnect()
{
// dummy payload
String jsonString = JsonConvert.SerializeObject(
new NewObj() {
Name = "aname",
Email = "someone#somewhere.com"
}
);
string auth = "NLAuth nlauth_account=123456,nlauth_email=youremail#somewhere.com,nlauth_signature=yourpassword,nlauth_role=3";
string url = "https://somerestleturl";
var uri = new Uri(#url);
HttpClient c = new HttpClient();
c.BaseAddress = uri;
c.DefaultRequestHeaders.TryAddWithoutValidation("Authorization", auth);
c.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Post, url);
req.Content = new StringContent(jsonString, Encoding.UTF8, "application/json");
HttpResponseMessage httpResponseMessage = await c.SendAsync(req);
httpResponseMessage.EnsureSuccessStatusCode();
HttpContent httpContent = httpResponseMessage.Content;
string responseString = await httpContent.ReadAsStringAsync();
Console.WriteLine(responseString);
}
}
class NewObj
{
public string Name { get; set; }
public string Email { get; set; }
}
}

The other answers do not work if you are using an HttpClientFactory, and here's some reasons why you should. With an HttpClientFactory the HttpMessages are reused from a pool, so setting default headers should be reserved for headers that will be used in every request.
If you just want to add a content-type header you can use the alternate PostAsJsonAsync or PostAsXmlAsync.
var response = await _httpClient.PostAsJsonAsync("account/update", model);
Unfortunately I don't have a better solution for adding authorization headers than this.
_httpClient.DefaultRequestHeaders.Add(HttpRequestHeader.Authorization.ToString(), $"Bearer {bearer}");

On dotnet core 3.1 trying to run the top answer:
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Add("Content-Type", "application/x-msdownload");
threw an exception: System.InvalidOperationException: Misused header name. Make sure request headers are used with HttpRequestMessage, response headers with HttpResponseMessage, and content headers with HttpContent objects.
What worked for me was to instead set HttpContent.Headers -> HttpContentHeaders.ContentType property with a MediaTypeHeaderValue value:
HttpClient client = new HttpClient();
var content = new StreamContent(File.OpenRead(path));
content.Headers.ContentType = new MediaTypeHeaderValue("application/x-msdownload");
var post = client.PostAsync(myUrl, content);

I prefer to cache the httpClient so I avoid setting headers which could affect other requests and use SendAsync
var postRequest = new System.Net.Http.HttpRequestMessage(System.Net.Http.HttpMethod.Get, url);
postRequest.Headers.Add("Content-Type", "application/x-msdownload");
var response = await httpClient.SendAsync(postRequest);
var content = await response.Content.ReadAsStringAsync();