How to add and get Header values in WebApi

I need to create a POST method in WebApi so I can send data from application to WebApi method. I'm not able to get header value.

Here I have added header values in the application:

 using (var client = new WebClient())
{
// Set the header so it knows we are sending JSON.
client.Headers[HttpRequestHeader.ContentType] = "application/json";


client.Headers.Add("Custom", "sample");
// Make the request
var response = client.UploadString(url, jsonObj);
}

Following the WebApi post method:

 public string Postsam([FromBody]object jsonData)
{
HttpRequestMessage re = new HttpRequestMessage();
var headers = re.Headers;


if (headers.Contains("Custom"))
{
string token = headers.GetValues("Custom").First();
}
}

What is the correct method for getting header values?

Thanks.

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小开

You need to get the HttpRequestMessage from the current OperationContext. Using OperationContext you can do it like so

OperationContext context = OperationContext.Current;
MessageProperties messageProperties = context.IncomingMessageProperties;


HttpRequestMessageProperty requestProperty = messageProperties[HttpRequestMessageProperty.Name] as HttpRequestMessageProperty;


string customHeaderValue = requestProperty.Headers["Custom"];
小开
最佳答案

On the Web API side, simply use Request object instead of creating new HttpRequestMessage

     var re = Request;
var headers = re.Headers;


if (headers.Contains("Custom"))
{
string token = headers.GetValues("Custom").First();
}


return null;

Output -

enter image description here

小开

Another way using a the TryGetValues method.

public string Postsam([FromBody]object jsonData)
{
IEnumerable<string> headerValues;


if (Request.Headers.TryGetValues("Custom", out headerValues))
{
string token = headerValues.First();
}
}
小开

Suppose we have a API Controller ProductsController : ApiController

There is a Get function which returns some value and expects some input header (for eg. UserName & Password)

[HttpGet]
public IHttpActionResult GetProduct(int id)
{
System.Net.Http.Headers.HttpRequestHeaders headers = this.Request.Headers;
string token = string.Empty;
string pwd = string.Empty;
if (headers.Contains("username"))
{
token = headers.GetValues("username").First();
}
if (headers.Contains("password"))
{
pwd = headers.GetValues("password").First();
}
//code to authenticate and return some thing
if (!Authenticated(token, pwd)
return Unauthorized();
var product = products.FirstOrDefault((p) => p.Id == id);
if (product == null)
{
return NotFound();
}
return Ok(product);
}

Now we can send the request from page using JQuery:

$.ajax({
url: 'api/products/10',
type: 'GET',
headers: { 'username': 'test','password':'123' },
success: function (data) {
alert(data);
},
failure: function (result) {
alert('Error: ' + result);
}
});

Hope this helps someone ...

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try these line of codes working in my case:

IEnumerable<string> values = new List<string>();
this.Request.Headers.TryGetValues("Authorization", out values);
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In case someone is using ASP.NET Core for model binding,

https://learn.microsoft.com/en-us/aspnet/core/mvc/models/model-binding

There's is built in support for retrieving values from the header using the [FromHeader] attribute

public string Test([FromHeader]string Host, [FromHeader]string Content-Type )
{
return $"Host: {Host} Content-Type: {Content-Type}";
}
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For .NET Core:

string Token = Request.Headers["Custom"];

Or

var re = Request;
var headers = re.Headers;
string token = string.Empty;
StringValues x = default(StringValues);
if (headers.ContainsKey("Custom"))
{
var m = headers.TryGetValue("Custom", out x);
}
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As someone already pointed out how to do this with .Net Core, if your header contains a "-" or some other character .Net disallows, you can do something like:

public string Test([FromHeader]string host, [FromHeader(Name = "Content-Type")] string contentType)
{
}
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For .net Core in GET method, you can do like this:

 StringValues value1;
string DeviceId = string.Empty;


if (Request.Headers.TryGetValue("param1", out value1))
{
DeviceId = value1.FirstOrDefault();
}
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For WEB API 2.0:

I had to use Request.Content.Headers instead of Request.Headers

and then i declared an extestion as below

  /// <summary>
/// Returns an individual HTTP Header value
/// </summary>
/// <param name="headers"></param>
/// <param name="key"></param>
/// <returns></returns>
public static string GetHeader(this HttpContentHeaders headers, string key, string defaultValue)
{
IEnumerable<string> keys = null;
if (!headers.TryGetValues(key, out keys))
return defaultValue;


return keys.First();
}

And then i invoked it by this way.

  var headerValue = Request.Content.Headers.GetHeader("custom-header-key", "default-value");

I hope it might be helpful

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app.MapGet("/", ([FromHeader(Name = "User-Agent")] string data) =>
{
return $"User agent header is: {data}";
});
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A simple function to get a header value, with a "one-liner" variant using TryGetValue:

private string GetHeaderValue(string key) =>
Request.Headers.TryGetValue(key, out var value)
? value.First()
: null;


var headerValue = GetHeaderValue("Custom");

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