How can I use HttpPatch and JsonPatchDocument in a correct way

Question

After applying this request in Powershell, I encounter the error:

Invoke-RestMethod http://localhost:5000/api/suppliers/1 -Method PATCH -ContentType "application/json"
-Body '[{"op":"replace","path":"City","value":"Los Angeles"}]'

Error Message:

Invoke-RestMethod : {"errors":{"":["A non-empty request body is required."]},"type":"https://tools.ietf.org/html/rfc7231#section-6.5.1","title":"One or more validation errors occurred.","status":400,"traceId":"|c647c045-47f3a2d0bb2bc29c."} At line:1 char:1

• Invoke-RestMethod http://localhost:5000/api/suppliers/1 -Method PATCH ...

•   + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebExc
  

eption + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand -Body : The term '-Body' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. At line:2 char:1

• -Body '[{"op":"replace","path":"City","value":"Los Angeles"}]'

•   + CategoryInfo          : ObjectNotFound: (-Body:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException
  

How can I solve it?

Startup class:

public class Startup {

    public Startup(IConfiguration config) {
        Configuration = config;
    }

    public IConfiguration Configuration { get; set; }

    public void ConfigureServices(IServiceCollection services) {
        services.AddDbContext<DataContext>(opts => {
            opts.UseSqlServer(Configuration[
                "ConnectionStrings:ProductConnection"]);
            opts.EnableSensitiveDataLogging(true);
        });

        services.AddControllers().AddNewtonsoftJson();
        services.Configure<MvcNewtonsoftJsonOptions>(opts =>
        {
            opts.SerializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore;
        });
    }

    public void Configure(IApplicationBuilder app, DataContext context) {
        app.UseDeveloperExceptionPage();
        app.UseRouting();
        app.UseMiddleware<TestMiddleware>();
        app.UseEndpoints(endpoints => {
            endpoints.MapGet("/", async context => {
                await context.Response.WriteAsync("Hello World!");
            });
            endpoints.MapControllers();
        });
        SeedData.SeedDatabase(context);
    }
}

Supplier class:

public class Supplier {

    public long SupplierId { get; set; }
    public string Name { get; set; }
    public string City { get; set; }

    public IEnumerable<Product> Products { get; set; }
}

SuppliersController:

[ApiController]
[Route("api/[controller]")]
public class SuppliersController : ControllerBase
{
    private DataContext context;

    public SuppliersController(DataContext ctx)
    {
        context = ctx;
    }

    [HttpGet("{id}")]
    public async Task<Supplier> GetSupplier(long id)
    {
        Supplier supplier = await context.Suppliers
            .Include(s => s.Products)
            .FirstAsync(s => s.SupplierId == id);

        foreach (Product p in supplier.Products)
        {
            p.Supplier = null;
        }
        return supplier;
    }

    [HttpPatch("{id}")]
    public async Task<Supplier> PatchSupplier(long id, JsonPatchDocument<Supplier> patchDoc)
    {
        Supplier s = await context.Suppliers.FindAsync(id);
        if (s != null)
        {
            patchDoc.ApplyTo(s);
            await context.SaveChangesAsync();
        }
        return s;
    }
}

source code in github: https://github.com/Apress/pro-asp.net-core-3/tree/master/20%20-%20Advanced%20Web%20Services%20Features

Answer 1

$headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$headers.Add("Content-Type", "application/json")

$body = "[{`"op`":`"replace`",`"path`":`"City`",`"value`":`"Los Angeles`"}]"

$response = Invoke-RestMethod 'http://localhost:5000/api/suppliers/1' -Method 'PATCH' -Headers $headers -Body $body
$response | ConvertTo-Json

When call by Postman, it returns normally.

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