# C#

Start with the [gRPC guide](../grpc.md) to create a Platform API token and download `platform.proto`. Run the commands below from the directory containing that file.

Create a .NET console project:

```bash
dotnet new console -n ReconstructExample
```

Enter the project directory:

```bash
cd ReconstructExample
```

Add the gRPC client packages:

```bash
dotnet add package Grpc.Net.Client
```

```bash
dotnet add package Grpc.Tools
```

```bash
dotnet add package Google.Protobuf
```

Copy the downloaded `platform.proto` into the `ReconstructExample` directory.

Add this item to the project's `.csproj` file. `Grpc.Tools` generates the client when you build:

```xml
<ItemGroup>
  <Protobuf Include="platform.proto" GrpcServices="Client" />
</ItemGroup>
```

Use the generated types in `Program.cs`:

```csharp
using Cr.Reconstruct.External.Grpc;
using Grpc.Core;
using Grpc.Net.Client;

var token = Environment.GetEnvironmentVariable("CR_RECONSTRUCT_API_TOKEN")
    ?? throw new InvalidOperationException("Set CR_RECONSTRUCT_API_TOKEN.");
var address = Environment.GetEnvironmentVariable("CR_RECONSTRUCT_GRPC_URL")
    ?? "https://reconstruct.dev";

using var channel = GrpcChannel.ForAddress(address);
var client = new PlatformService.PlatformServiceClient(channel);
var headers = new Metadata { { "authorization", $"Bearer {token}" } };
var page = await client.ListCatalogsAsync(
    new ListCatalogsRequest { PageSize = 10 }, headers, deadline: DateTime.UtcNow.AddSeconds(10));

foreach (var catalog in page.Catalogs)
{
    var detail = await client.GetCatalogAsync(
        new GetCatalogRequest { CatalogId = catalog.CatalogId }, headers);
    Console.WriteLine($"{detail.CatalogId}: {detail.Description}");
}
```

Run `dotnet run`. The native gRPC channel uses the HTTPS authority; it does not include the REST `/api/v1/platform` path.