I want to send dynamic object like
new { x = 1, y = 2 };
as body of HTTP POST message. So I try to write
var client = new HttpClient();
but I can't find method
client.PostAsJsonAsync()
So I tried to add Microsoft.AspNetCore.Http.Extensions package to project.json and add
using Microsoft.AspNetCore.Http.Extensions;
to uses clause. However It didn't help me.
So what is the easiest way to send POST request with JSON body in ASP.NET Core?
This question is related to
c#
asp.net-core
.net-core
You are right that this has long since been implemented in .NET Core.
At the time of writing (September 2019), the project.json
file of NuGet 3.x+ has been superseded by PackageReference
(as explained at https://docs.microsoft.com/en-us/nuget/archive/project-json).
To get access to the *Async
methods of the HttpClient
class, your .csproj
file must be correctly configured.
Open your .csproj
file in a plain text editor, and make sure the first line is
<Project Sdk="Microsoft.NET.Sdk.Web">
(as pointed out at https://docs.microsoft.com/en-us/dotnet/core/tools/project-json-to-csproj#the-csproj-format).
To get access to the *Async
methods of the HttpClient
class, you also need to have the correct package reference in your .csproj
file, like so:
<ItemGroup>
<!-- ... -->
<PackageReference Include="Microsoft.AspNetCore.App" />
<!-- ... -->
</ItemGroup>
(See https://docs.microsoft.com/en-us/nuget/consume-packages/package-references-in-project-files#adding-a-packagereference. Also: We recommend applications targeting ASP.NET Core 2.1 and later use the Microsoft.AspNetCore.App metapackage, https://docs.microsoft.com/en-us/aspnet/core/fundamentals/metapackage)
Methods such as PostAsJsonAsync
, ReadAsAsync
, PutAsJsonAsync
and DeleteAsync
should now work out of the box. (No using directive needed.)
Update: The PackageReference tag is no longer needed in .NET Core 3.0.
I use this class:
public class JsonContent : StringContent
{
public JsonContent(object obj) :
base(JsonConvert.SerializeObject(obj), Encoding.UTF8, "application/json")
{ }
}
Sample of usage:
new HttpClient().PostAsync("http://...", new JsonContent(new { x = 1, y = 2 }));
I would add to the accepted answer that you would also want to add the Accept
header to the httpClient
:
httpClient.DefaultRequestHeaders.Accept.Clear();
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
Microsoft now recommends using an IHttpClientFactory
with the following benefits:
HttpClient
instances. For example, a client named github could be
registered and configured to access GitHub. A default client can be
registered for general access.HttpClient
. Provides extensions for Polly-based middleware to take
advantage of delegating handlers in HttpClient
.HttpClientMessageHandler
instances. Automatic management avoids
common DNS (Domain Name System) problems that occur when manually
managing HttpClient
lifetimes.ILogger
) for all requests
sent through clients created by the factory.https://docs.microsoft.com/en-us/aspnet/core/fundamentals/http-requests?view=aspnetcore-3.1
Setup:
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
public void ConfigureServices(IServiceCollection services)
{
services.AddHttpClient();
// Remaining code deleted for brevity.
POST example:
public class BasicUsageModel : PageModel
{
private readonly IHttpClientFactory _clientFactory;
public BasicUsageModel(IHttpClientFactory clientFactory)
{
_clientFactory = clientFactory;
}
public async Task CreateItemAsync(TodoItem todoItem)
{
var todoItemJson = new StringContent(
JsonSerializer.Serialize(todoItem, _jsonSerializerOptions),
Encoding.UTF8,
"application/json");
var httpClient = _clientFactory.CreateClient();
using var httpResponse =
await httpClient.PostAsync("/api/TodoItems", todoItemJson);
httpResponse.EnsureSuccessStatusCode();
}
Source: Stackoverflow.com