Foxchat.NET/Foxchat.Chat/Controllers/HelloController.cs

using Foxchat.Chat.Database;
using Foxchat.Chat.Database.Models;
using Foxchat.Chat.Middleware;
using Foxchat.Core.Extensions;
using Foxchat.Core.Federation;
using Foxchat.Core.Models.Http;
using Microsoft.AspNetCore.Mvc;
using ApiError = Foxchat.Core.ApiError;

namespace Foxchat.Chat.Controllers;

[ApiController]
[ServerUnauthenticated]
[Route("/_fox/chat/hello")]
public class HelloController(
    ILogger logger,
    ChatContext db,
    InstanceConfig config,
    RequestSigningService requestSigningService)
    : ControllerBase
{
    [HttpPost]
    public async Task<IActionResult> Hello([FromBody] Hello.HelloRequest req)
    {
        var node = await requestSigningService.RequestAsync<Hello.NodeInfo>(HttpMethod.Get, req.Host,
            "/_fox/ident/node");

        if (!HttpContext.ExtractRequestData(out var signature, out var domain, out var signatureData))
            throw new ApiError.IncomingFederationError("This endpoint requires signed requests.");
        if (domain != req.Host)
            throw new ApiError.IncomingFederationError("Host is invalid.");

        if (!requestSigningService.VerifySignature(node.PublicKey, signature, signatureData))
            throw new ApiError.IncomingFederationError("Signature is not valid.");

        var instance = await db.GetInstanceAsync();
        db.IdentityInstances.Add(new IdentityInstance
        {
            Domain = req.Host,
            BaseUrl = $"https://{req.Host}",
            PublicKey = node.PublicKey
        });
        await db.SaveChangesAsync();

        return Ok(new Hello.HelloResponse(instance.PublicKey, config.Domain));
    }
}