# C#

Start with the [REST guide](../rest.md) to create a Platform API token. This example uses `HttpClient` and the built-in JSON APIs; no generated gRPC client is required.

Create a console project:

```bash
dotnet new console -n ReconstructRestExample
```

Enter the project directory:

```bash
cd ReconstructRestExample
```

Use this `Program.cs`:

```csharp
using System.Net.Http.Headers;
using System.Net.Http.Json;
using System.Text.Json;

var token = Environment.GetEnvironmentVariable("CR_RECONSTRUCT_API_TOKEN")
    ?? throw new InvalidOperationException("Set CR_RECONSTRUCT_API_TOKEN.");
var baseUrl = Environment.GetEnvironmentVariable("CR_RECONSTRUCT_REST_URL")
    ?? "https://reconstruct.dev/api/v1/platform";

using var client = new HttpClient { BaseAddress = new Uri(baseUrl.TrimEnd('/') + "/") };
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);

using var page = await client.GetFromJsonAsync<JsonDocument>("catalogs?pageSize=10")
    ?? throw new InvalidOperationException("The catalog response was empty.");

if (page.RootElement.TryGetProperty("catalogs", out var catalogs))
{
    foreach (var catalog in catalogs.EnumerateArray())
    {
        var id = catalog.GetProperty("catalogId").GetString()!;
        using var detail = await client.GetFromJsonAsync<JsonDocument>(
            "catalogs/" + Uri.EscapeDataString(id))
            ?? throw new InvalidOperationException("The catalog detail was empty.");
        Console.WriteLine($"{id}: {detail.RootElement.GetProperty("description").GetString()}");
    }
}
```

Run `dotnet run`. If `nextPageToken` is present in the list response, send it as the URL-encoded `pageToken` query parameter to continue.