Creating a JSON object in ASP.Net

Question

I am trying to create a JSON object in a .Net 5 application. The default options I am presented with are Microsoft.AspNet.Mvc.Formatters.Json, Microsoft.Extensions.Configuration.Json, and Newtonsoft.Json when I use the Visual Studio 2015 Qucik Actions on Json. My understanding is that Configuration.Json is for reading form the appsettings.json so it probably is not what I would use to create a JSON object. I can't find any real information on Formatters.Json, how to use it, or what it's intended use it. Newtonsoft.Json is will documented but is it better over the Formatters.Json? Which of the two should I be using?

Answer 1

Taken directly from ASP.NET Core 1 tests

 var expected = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(new { foo = "abcd" })); 

Also taken from the tests and slightly modified, call it with HttpClient to see how to send your json string to the server.

 var response = await Client.PostAsync( "http://localhost/api/ActionUsingSpecificFormatters", new StringContent(yourJsonContent, Encoding.UTF8, "application/json")); 

As per Newtonsoft you can simply encode, then do whatever you want after that.

 Product product = new Product(); product.Name = "Apple"; product.ExpiryDate = new DateTime(2008, 12, 28); product.Price = 3.99M; product.Sizes = new string[] { "Small", "Medium", "Large" }; string output = JsonConvert.SerializeObject(product); //{ // "Name": "Apple", // "ExpiryDate": "2008-12-28T00:00:00", // "Price": 3.99, // "Sizes": [ // "Small", // "Medium", // "Large" // ] //} Product deserializedProduct = JsonConvert.DeserializeObject(output); 

Putting it all together - I just tested this. Keep in mind this is a real generic pass through test from MVC 6 (ASP.NET 5 ie ASP.NET Core 1) :)

 [HttpGet] public async Task<string> Get() { var client = new HttpClient(); var customer = new Customer() { Name = "Schmo", Address = "1999 Purple Rain St" }; var customerJson = JsonConvert.SerializeObject(customer); var response = await client.PostAsync( "http://localhost:4815/api/Customer", new StringContent(customerJson, Encoding.UTF8, "application/json")); //just some template output to test which I'm getting back. string resultJson = "{ 'Name':'adam'}"; if (response.StatusCode == HttpStatusCode.OK) { resultJson = await response.Content.ReadAsStringAsync(); var updatedCustomer = JsonConvert.DeserializeObject(resultJson); } return resultJson; } public class Customer { public string Name { get; set; } public string Address { get; set; } } 

Answer 2

I would use Json.Net to create the JSON payloads for sure (Afterall, Microsoft does for Web Api).

Nuget Package Source:

Install-Package Newtonsoft.Json 

Here is an example. If you want to call a REST api that returns a product when you make a GET call then you might do something like this.

public static class Main { string url = "https://TheDomainYouWantToContact.com/products/1"; HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url); request.Method = "GET"; request.ContentType = "application/json"; request.Accept = "application/json"; var httpResponse = (HttpWebResponse)request.GetResponse(); var dataStream = httpResponse.GetResponseStream(); var reader = new StreamReader(dataStream); var responseFromServer = reader.ReadToEnd(); reader.Close(); dataStream.Close(); // This is the code that turns the JSON string into the Product object. Product productFromServer = JsonConvert.Deserialize<Product>(responseFromServer); Console.Writeline(productFromServer.Id); } // This is the class that represents the JSON that you want to post to the service. public class Product { public string Id { get; set; } public decimal Cost { get; set; } public string Name { get; set; } public string Description { get; set; } } 

The exact same method can be used for POST and PUT as well.

You can use 3rd party assemblies to make this super easy too. We are the authors of DynamicApis.Api

Install-Package DynamicApis.Api 

The code to make the same request using this client would be:

public static class Main { RestClient client = new RestClient(); string url = "https://YourDomain.com/products/1"; var productFromServer = client.Get<Product>(url); Console.Writeline(productFromServer.Id); } 

Answer 3

you should use NewtonSoft.Json if you need to serialize objects as json

Answer 4

You shouldn't have to do anything special to send back Json data. The default output formatter is already Json, and if your Startup.cs file is somewhat normal, you should have a line similar to this:

services.AddMvc(); 

By default, this already contains the Json formatter, and your controller should autonegotiate the return type based on what the browser asked. So a controller like the following should work (taken from this Github issue, which contains some information on why/how this work):

public class ValuesController : ApiController { public SomeClass Get() { return new SomeClass(); } public SomeClass Post([FromBody] SomeClass x) { return x; } }