c#
using Backend.Common;
using Backend.Common.Api.Extensions;
using Backend.Data;
using Backend.Data.Types;
using FluentValidation;
using Microsoft.AspNetCore.Http.HttpResults;
using Microsoft.EntityFrameworkCore;

namespace Backend.Posts.Endpoints;

public class UpdatePost : IEndpoint
{
    public static void Map(IEndpointRouteBuilder app)
    {
        app
            .MapPut("{id:guid}", Handle)
            .RequireAuthorization()
            .WithSummary("Updates an existing post")
            .WithRequestValidation<Request>()
            .WithEnsureUserOwnsEntity<Post, Request>(x => x.Id);
    }
    
    public record Request(
        Guid Id,
        string Title, 
        string Body, 
        Uri? CoverImageUrl);

    public record Response(Guid Id, string Title, DateTime UpdatedAtUtc);

    public class RequestValidator : AbstractValidator<Request>
    {
        public RequestValidator()
        {
            RuleFor(x => x.Id)
                .NotEmpty()
                .Must(x => Guid.TryParse(x.ToString(), out _))
                .WithMessage("Invalid GUID format");
                
            RuleFor(x => x.Title)
                .NotEmpty()
                .MaximumLength(200);

            RuleFor(x => x.Body)
                .NotEmpty();
        }
    }
    
    private static async Task<Ok<Response>> Handle(
        [AsParameters] Request request,
        BlogDbContext dbContext,
        CancellationToken cancellationToken)
    {

        var post = await dbContext.Posts
            .FirstAsync(p => p.Id == request.Id, cancellationToken);

        post.Title = request.Title;
        post.Body = request.Body;
        post.CoverImageUrl = request.CoverImageUrl;
        post.UpdatedAtUtc = DateTime.UtcNow;

        await dbContext.SaveChangesAsync(cancellationToken);

        var response = new Response(post.Id, post.Title, post.UpdatedAtUtc ?? DateTime.UtcNow);
        return TypedResults.Ok(response);
    }
}

c#
using Backend.Common;
using Backend.Common.Api.Extensions;
using Backend.Data;
using Backend.Data.Types;
using FluentValidation;
using Microsoft.AspNetCore.Http.HttpResults;
using Microsoft.EntityFrameworkCore;

namespace Backend.Posts.Endpoints;

public class UpdatePost : IEndpoint
{
    public static void Map(IEndpointRouteBuilder app)
    {
        app
            .MapPut("{id:guid}", Handle)
            .RequireAuthorization()
            .WithSummary("Updates an existing post")
            .WithRequestValidation<Request>()
            .WithEnsureUserOwnsEntity<Post, Request>(x => x.Id);
    }
    
    public record Request(
        Guid Id,
        string Title, 
        string Body, 
        Uri? CoverImageUrl);

    public record Response(Guid Id, string Title, DateTime UpdatedAtUtc);

    public class RequestValidator : AbstractValidator<Request>
    {
        public RequestValidator()
        {
            RuleFor(x => x.Id)
                .NotEmpty()
                .Must(x => Guid.TryParse(x.ToString(), out _))
                .WithMessage("Invalid GUID format");
                
            RuleFor(x => x.Title)
                .NotEmpty()
                .MaximumLength(200);

            RuleFor(x => x.Body)
                .NotEmpty();
        }
    }
    
    private static async Task<Ok<Response>> Handle(
        [AsParameters] Request request,
        BlogDbContext dbContext,
        CancellationToken cancellationToken)
    {

        var post = await dbContext.Posts
            .FirstAsync(p => p.Id == request.Id, cancellationToken);

        post.Title = request.Title;
        post.Body = request.Body;
        post.CoverImageUrl = request.CoverImageUrl;
        post.UpdatedAtUtc = DateTime.UtcNow;

        await dbContext.SaveChangesAsync(cancellationToken);

        var response = new Response(post.Id, post.Title, post.UpdatedAtUtc ?? DateTime.UtcNow);
        return TypedResults.Ok(response);
    }
}