CODEWITHSUNDEEP
c#asp.net-core-mvcrest-client
developer7788
developer7788

Reputation: 409

post json to mvc .net core

I launch an asp.netcore mvc project with a controller accepting post with json object as parameter

then I used Insomnia rest client to test this action by posting json object to the action

however I get bad request error

when I do the post via webpage, it works fine

what is wrong with my test from the rest client

* Preparing request to http://localhost:51840/Books/Create
* Using libcurl/7.51.0-DEV OpenSSL/1.0.2j zlib/1.2.8 libssh2/1.6.1_DEV
* Enable automatic URL encoding
* Enable SSL validation
* Enable cookie sending with jar of 0 cookies
* Found bundle for host localhost: 0x1df804a67a0 [can pipeline]
* Re-using existing connection! (#6) with host localhost
* Connected to localhost (::1) port 51840 (#6)
> POST /Books/Create HTTP/1.1
> Host: localhost:51840
> User-Agent: insomnia/5.14.9
> Content-Type: application/json
> Accept: */*
> Content-Length: 32
| {
|   "Id" : 5,
|   "Name": "Book 3"
| }
* upload completely sent off: 32 out of 32 bytes
< HTTP/1.1 400 Bad Request
< Server: Kestrel
< X-SourceFiles: =?UTF-8?B?QzpcVXNlcnNcbWljcm9cRG9jdW1lbnRzXFZpc3VhbCBTdHVkaW8gMjAxN1xQcm9qZWN0c1xRdWlya3lCb29rTGlzdFxCb29rTGlzdFxCb29rTGlzdFxCb29rc1xDcmVhdGU=?=
< X-Powered-By: ASP.NET
< Date: Fri, 16 Mar 2018 08:03:48 GMT
< Content-Length: 0

* Curl_http_done: called premature == 0
* Connection #6 to host localhost left intact

Upvotes: 0

Views: 1876

Answers (1)

Chris Pratt
Chris Pratt

Reputation: 239430

There's really not enough here to accurately answer your question, but one thing you said has me guessing a potential problem:

when I do the post via webpage, it works fine

A form submission via a web page is usually going to be encoded as x-www-form-urlencoded or multipart/form-data. ASP.NET Core will happily accept either encoding with no additional configuration. However, to accept JSON, the parameter you're binding to on your action method needs to be decorated with [FromBody]:

public IActionResult Foo([FromBody]Bar bar)

Once you do that, though, the action will no longer accept anything but JSON/XML/etc. If you try to post as x-www-form-urlencoded or multipart/form-data, it will fail.

So two things:

  1. If you need to accept something like JSON add the FromBody attribute to your action param.

  2. If you need to accept both something like JSON and a regular form post, you need two action methods. Yep, you read that right: two. One with FromBody and one without. Internally, you can factor out the actual code for the action method into a private or protected method on your controller and then have both actions use that, so at least you do not have to duplicate code.

Upvotes: 1

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