415 when passing string parameter to Web Api Post method

Question

When I POST this request to http://localhost:61679/api/Login:

Headers =>  Content-Type: text/plain
Body =>     grant_type=password&username=doug&password=12345

I get 415 Unsupported Media Type:

HTTP/1.1 415 Unsupported Media Type
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/json; charset=utf-8
Expires: -1
Server: Microsoft-IIS/10.0
X-AspNet-Version: 4.0.30319
X-SourceFiles: =?UTF-8?B?QzpcZGV2ZWxvcG1lbnRcYml0Y29pblxwYXltZW50cy1zZXJ2aWNlLW5vLWNoZWNrc3VtLW5vLXVzZXJcUGF5bWVudHNTZXJ2aWNlXGFwaVxBdXRoZW50aWNhdGU=?=
X-Powered-By: ASP.NET
Date: Mon, 28 Dec 2015 16:58:36 GMT
Content-Length: 900

{"Message":"The request entity's media type 'text/plain' is not supported for this resource.","ExceptionMessage":"No MediaTypeFormatter is available to read an object of type 'String' from content with media type 'text/plain'.","ExceptionType":"System.Net.Http.UnsupportedMediaTypeException","StackTrace":"   at System.Net.Http.HttpContentExtensions.ReadAsAsync[T](HttpContent content, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)\r\n   at System.Net.Http.HttpContentExtensions.ReadAsAsync(HttpContent content, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)\r\n   at System.Web.Http.ModelBinding.FormatterParameterBinding.ReadContentAsync(HttpRequestMessage request, Type type, IEnumerable`1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)"}

The controller:

    // POST api/Login
    public HttpResponseMessage Post([FromBody]string loginDetails)
    {
       // process loginDetails here
    }

Just curious - why would you accept a string in your controller but it looks like you're passing a complex object? — Mark C., Dec 28 '15 at 18:03
String in body should be quoted. Content-Type should be application/json. http://stackoverflow.com/a/41114909/4854931 — Alex78191, Jan 07 '17 at 06:40

Anik Saha · Accepted Answer · 2015-12-28T18:08:56.133

You have to set your Content-Type:application/json; charset=utf-8 instead of text/plain

have to create a viewmodel

public class LoginDetails{
public string grant_type{get;set;}
public string username{get;set;}
public string password{get;set;}
}

your action result be like

public HttpResponseMessage Post(LoginDetails loginDetails)

in request time your body be like

 {
    "grant_type":"...",
    "username":".....",
    "password":"....."
 }

415 when passing string parameter to Web Api Post method

1 Answers1