Unsupported Media Type when consuming text/plain

Question

I receive the following response when trying to consume text/plain:

{
    "type": "https://tools.ietf.org/html/rfc7231#section-6.5.13",
    "title": "Unsupported Media Type",
    "status": 415,
    "traceId": "|b28d0526-4ca38d2ff7036964."
}

Controller definition:

[HttpPost]
[Consumes("text/plain")]
public async Task<IActionResult> PostTrace([FromBody]string body)
{ ... }

HTTP message:

POST /api/traces HTTP/1.1
Content-Type: text/plain
User-Agent: PostmanRuntime/7.19.0
Accept: */*
Cache-Control: no-cache
Postman-Token: 37d27eb6-92a0-4a6a-8b39-adf2c93955ee
Host: 0.0.0.0:6677
Accept-Encoding: gzip, deflate
Content-Length: 3
Connection: keep-alive

I am able to consume JSON or XML just fine. What am I missing?

Answer 1

Reference: Accepting Raw Request Body Content in ASP.NET Core API Controllers:

Unfortunately ASP.NET Core doesn't let you just capture 'raw' data in any meaningful way just by way of method parameters. One way or another you need to do some custom processing of the Request.Body to get the raw data out and then deserialize it.

You can capture the raw Request.Body and read the raw buffer out of that which is pretty straight forward.

The easiest and least intrusive, but not so obvious way to do this is to have a method that accepts POST or PUT data without parameters and then read the raw data from Request.Body:

[HttpPost]
[Route("api/BodyTypes/ReadStringDataManual")]
public async Task<string> ReadStringDataManual()
{
    using (StreamReader reader = new StreamReader(Request.Body, Encoding.UTF8))
    {  
        return await reader.ReadToEndAsync();
    }
}

Request:

POST http://localhost:5000/api/BodyTypes/ReadStringDataManual HTTP/1.1
Accept-Encoding: gzip,deflate
Content-Type: text/plain
Host: localhost:5000
Content-Length: 37
Expect: 100-continue
Connection: Keep-Alive

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