CODEWITHSUNDEEP
c#asp.net-mvc-4asp.net-web-api
Kai CriticallyAcclaimed Cooper
Kai CriticallyAcclaimed Cooper

Reputation: 978

Get response from PostAsJsonAsync

I have this line of code 

var response = new HttpClient().PostAsJsonAsync(posturi, model).Result;

The Called WebAPI controller returns a bool to make sure the object was saved, but how do I return that bool response?

Upvotes: 40

Views: 124349

Answers (6)

cheny
cheny

Reputation: 2735

It's July 2021 and I'm using .net 5 (namely the .net core 5).

I did not see any generic methods above in System.Net.Http. Now the code looks like this (tested):

using (var client = new HttpClient())
{
    client.BaseAddress = new Uri("https://localhost:44330/api/Book/Add");
    var response = client.PostAsJsonAsync(client.BaseAddress,
        JsonSerializer.Serialize(_teamSummaries));
    MessageBox.Show(@"Result is " + JsonSerializer.Serialize(response));
    var returnValue = response.Result.Content.ReadAsStringAsync();
    MessageBox.Show(@"Return value is " + returnValue.Result);
}

There are also ReadAsStringAsync, ReadAsByteArrayAsync, ReadAsStream, ReadFromJsonAsync, ReadFromJsonAsync<T> (this method returns Task<T>).

But from the text meaning "ReadFromJsonAsync", I think the T is not the bool mentioned above, but a class that contains the bool member. If you want to return something like book, give it a try.

On the other hands, since code on the server looks like this(.net 5):

[HttpPost]
[Route("Add")]
public async Task<ActionResult<IEnumerable<Book>>> Add(string value)
{
    var all = await _dbCollection.FindAsync(Builders<Book>.Filter.Empty);
    return Ok("Everything is ok.");
}

So, if we want to return true by bool, we should return Ok(...). If we want to return false by bool, we should return something else. There are more than 20 other types of results, which contains much more information rather than just "false".

Upvotes: 1

Stephen Lautier
Stephen Lautier

Reputation: 3365

Since its an Async operation don't immediately do .Result as its wrong

Instead you need to do it async by doing this:

    var httpClient = new HttpClient()

    var task = httpClient.PostAsJsonAsync(posturi, model)
                         .ContinueWith( x => x.Result.Content.ReadAsAsync<bool>().Result);

    // 1. GETTING RESPONSE - NOT ASYNC WAY
    task.Wait(); //THIS WILL HOLD THE THREAD AND IT WON'T BE ASYNC ANYMORE!
    bool response = task.Result

    // 2. GETTING RESPONSE - TASK ASYNC WAY (usually used in < .NET 4.5 
    task.ContinueWith( x => {
                              bool response = x.Result
                          });

    // 3. GETTING RESPONSE - TASK ASYNC WAY (usually used in >= .NET 4.5 
    bool response = await task;

NOTE: I just wrote them in here, so I didnt actually test them but more or less that's what you want.

I hope it helps!

Upvotes: 13

cuongle
cuongle

Reputation: 75316

Continue to get from content:

var httpClient = new HttpClient();
var response = httpClient.PostAsJsonAsync(posturi, model).Result;
bool returnValue = response.Content.ReadAsAsync<bool>().Result;

But, this is really naive approach for quick way to get result. PostAsJsonAsync and ReadAsAsync is not designed to do like this, they are designed to support async await programming, so your code should be:

var httpClient = new HttpClient();
var response = await httpClient.PostAsJsonAsync(posturi, model);
bool returnValue = await response.Content.ReadAsAsync<bool>();

Also, instead of using a flag to check whether an object is saved or not, you should make use of HTTP codes by returning 200 OK to determine that saving is successfully.

Upvotes: 86

Todd Menier
Todd Menier

Reputation: 39349

The accepted answer is technically correct but blocks the current thread on calls to .Result. If you are using .NET 4.5 or higher, you should avoid that in almost all situations. Instead, use the equivalent asynchronous (non-blocking) version:

var httpClient = new HttpClient();
var response = await httpClient.PostAsJsonAsync(posturi, model);
bool returnValue = await response.Content.ReadAsAsync<bool>();

Note that the method containing the above code needs to be marked async, and should itself be awaited.

Upvotes: 43

Xaris Fytrakis
Xaris Fytrakis

Reputation: 497

I used HttpStatusCode to check the result.

    public HttpStatusCode PostStaffPositions(Foo foo)
    {
        string uri = myapiuri;

        using (HttpClient httpClient = new HttpClient())
        {
            var response = httpClient.PostAsJsonAsync(uri, foo).Result;
            return response.StatusCode;
        }
    }

And then in Controller check it like this:

   HttpStatusCode update = staffrest.PostStaffPositions(foo);
            if (update == HttpStatusCode.OK)
            {
               //Update Succeed
            }
            else
            {
                //Update Failed
            }

Upvotes: 3

Davin Tryon
Davin Tryon

Reputation: 67316

If you call the generic version, it should give you back the bool:

var response = new HttpClient().PostAsJsonAsync<bool>(posturi, model).Result;

At least according to the docs.

Upvotes: 1

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