How do I fix unsupported media type error - .NET core web api

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i want to post json data to web api 2 but i’m receiving error 415- unsupported media type.

c# class.

C#

public class Person{

public int Id {get; set}

public string Name {get; set;}
}

... and below is the action of the webApi controller

C#

//


[httpPost]
public IActionResult PostAddPerson([FromBody] Person person)
{
 // processing here

}

... json from client

JavaScript

{
  "Id":1,
 "name":"Person1"
}

What I have tried:

I changed

C#

[FromBody]

which always returns null for 'person' to

C#

[FromForm]

, and when i check the parameter 'person' all properties are of default values only and not that from the client side.

i changed content-type to 'application/json' at client side and still nothing changed

Posted 4-Jun-19 11:07am

kwaku Emma

Updated 23-Oct-20 0:57am

v2

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ZurdoDev 5-Jun-19 15:11pm

That error is an http error usually indicating your content-type is incorrect.

Member 14740126 7-Aug-22 18:52pm

same problem
if any one knows tell me

2 solutions

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Thomas Daniels · Answer 1 · 2019-06-04T11:30:00

Solution 1

FromBody should work, but your JSON is invalid: valid JSON has double quotes around keys, and double quotes around strings. Try this JSON:

{
  "personId": 1,
  "name": "Person1"
}

I also don't know if it will work to have personId in your JSON but Id in your Person class?

Posted 4-Jun-19 11:30am

Thomas Daniels

Comments

kwaku Emma 5-Jun-19 10:45am

Thank you. the previous json was a mistake. I've tried your suggestion but still the same error is thrown.

Thomas Daniels 5-Jun-19 11:13am

I'm not sure then... you could try to have your JSON keys start with a capital letter like in your C# code (although I think it should be parsed case-insensitively, but it's worth a try).

Or check the Content-Encoding header that your client sends - that header may also cause a 415.

If the issue is neither of these two then I'm afraid I'm out of ideas.

kwaku Emma 5-Jun-19 19:51pm

thanks for your help so far. The problem was with the headers. Refer to this site for how to set Content-Type. What is on Mozilla's site on how to set 'Content-Type' header to 'application/json' was not working for me.

tobee · Answer 2 · 2020-10-23T00:58:00

Solution 2

You need to add this code in your Startup.cs inside ConfigureServices

services.AddControllers().AddNewtonsoftJson();

Posted 23-Oct-20 0:58am

tobee

Comments

Richard Deeming 27-Oct-20 11:59am

The question refers to WebAPI 2. Your answer applies to .NET Core, and doesn't explain why you think the built-in JSON library isn't up to the task of deserializing such basic JSON.