Send HTTP POST message in ASP NET Core using HttpClient PostAsJsonAsync

Question

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

User · Answer

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At the time of writing (September 2019), the project.json file of NuGet 3.x+ has been superseded by PackageReference (as explained at https://docs.microsoft.com/en-us/nuget/archive/project-json).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.

User · Answer

Microsoft now recommends using an IHttpClientFactory with the following benefits   Provides a central location for naming and configuring logical 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  Codifies the concept of outgoing middleware via delegating handlers in HttpClient  Provides extensions for Polly-based middleware to take advantage of delegating handlers in HttpClient  Manages the pooling and lifetime of underlying HttpClientMessageHandler instances  Automatic management avoids common DNS  Domain Name System  problems that occur when manually managing HttpClient lifetimes  Adds a configurable logging experience  via 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               quot application json quot                         var httpClient    clientFactory CreateClient                     using var httpResponse               await httpClient PostAsync  quot  api TodoItems quot   todoItemJson                httpResponse EnsureSuccessStatusCode           https   docs microsoft com en-us aspnet core fundamentals http-requests view aspnetcore-3 1 make-post-put-and-delete-requests

User · Answer

You should add reference to  Microsoft AspNet WebApi Client  package  read this article for samples     Without any additional extension  you may use standard PostAsync method   client PostAsync uri  new StringContent jsonInString  Encoding UTF8   application json       where jsonInString value you can get by calling JsonConvert SerializeObject  lt your object gt

User · Answer

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

User · Answer

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

[c#] Send HTTP POST message in ASP.NET Core using HttpClient PostAsJsonAsync

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