How to return a "fail" request with ajax?

Question

I'm learning web api with jquery.

Here is my plugin to make a post request:

$.postAPI = function (url, data) {
    let defer = $.Deferred();

    let onSuccess = function (data) {
        defer.resolve(data);
    };

    let onError = function (error) {
        defer.reject(error);
    };

    $.ajax({
        url: url,
        method: 'POST',
        data: data || null
    }).done(onSuccess).fail(onError);

    return defer;
};

API controller:

[Route("api/user")]
public class UserApiController : Controller
{
    [HttpPost("{userid?}")]
    public IActionResult GetData(string userid)
    {
        if (!string.IsNullOrEmpty(userid))
        {
            return Ok(userid);
        }
        return new StatusCodeResult(401);

        // also try with
        // return BadRequest();
        // return Unauthorized();
    }
}

Testing:

$.postAPI('/api/user/getdata').done(function (data) {
    console.log('success:', data);
}).fail(function (e) { console.log('fail:', e); });

But I have always got this log:

success: getdata

I want to make the request becomes fail. So, the log may be:

fail: ...

My question: How can I do that?

UPDATE:

I've tried to add this line (based on the comment):

Response.StatusCode = 404;

to the method. But the problem wasn't solved.

Snapshot:

For your request to fail (or error out) the backend has to return an error code like 404 or 500, I'm not sure jQuery can simulate this. Try change your backend code instead. — silkfire, May 05 '17 at 12:53
You need to change the return HTTP Response Code other than 200 from the server — Agam Banga, May 05 '17 at 12:56
@AgamBanga I've tried to add `Response.StatusCode = 404;` but it still was not working. I still got the same log. — , May 05 '17 at 13:16
@foo can you check the network tab what status it shows in the tab ? — Agam Banga, May 05 '17 at 13:17
@silkfire I've searched with keywords `asp net set response code` but I can't find the solution. what can I do? — , May 05 '17 at 13:18
@AgamBanga I have made a snapshot based on your question. What can I check next? — , May 05 '17 at 13:22
@foo check this http://stackoverflow.com/questions/347281/asp-net-custom-404-returning-200-ok-instead-of-404-not-found — Agam Banga, May 05 '17 at 13:23
Can it simply be that your userid isn't NullOrEmpty? Try commenting `if (!string.IsNullOrEmpty(userid)) { return Ok(userid); }` and just return `return BadRequest();`. — Mike Bovenlander, May 05 '17 at 13:26
@Mike You can check again for my ajax. I didn't send any value for `userid` inside the request. — , May 05 '17 at 13:30

score 0 · Answer 1 · answered May 05 '17 at 13:33

0

Try this:

[HttpPost("{userid?}")]
public IActionResult GetData(string userid)
{
    if (!string.IsNullOrEmpty(userid))
    {
        return View(new ViewModel(userid));
    }

    return StatusCode(401);
}

answered May 05 '17 at 13:33

silkfire

24,585
15
82
105

Mike Bovenlander · Accepted Answer · 2017-05-05T13:49:52.160

0

If you call "api/user" this will directly call your function "GetData" because you have no route for the function defined.

The "getdata" part in the url api/user/getdata will be interpreted as your "userid" therefor if (!string.IsNullOrEmpty(userid)) will always return true.

If you call "api/user" without the "getdata" part it should fail.

If you want to keep using getdata as url you can add a route for the function like so:

[HttpPost("GetData/{userId?}")]
public IActionResult GetData(string userid)
{
    if (!string.IsNullOrEmpty(userid))
    {
        return Ok(userid);
    }
    return BadRequest();
}

See: https://learn.microsoft.com/en-us/aspnet/core/mvc/controllers/routing

edited May 05 '17 at 13:49

answered May 05 '17 at 13:33

Mike Bovenlander

5,236
5
28
47

Thank you! It's working. Can I have another question? After I change `BadRequest` to `Unauthorized`, why does the log still throw `404` error?. Image: http://i.imgur.com/o4DNsns.png – May 05 '17 at 13:42
I mean: the status code should be 401 instead of 404 – May 05 '17 at 13:43
Could be that routing is case sensitive: try `[HttpPost("getdata/{userId?}")]` – Mike Bovenlander May 05 '17 at 13:44

How to return a "fail" request with ajax?

2 Answers2