Foxnouns.NET/Foxnouns.Backend/Middleware/AuthorizationMiddleware.cs

95 lines
3.4 KiB
C#

// Copyright (C) 2023-present sam/u1f320 (vulpine.solutions)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
using Foxnouns.Backend.Database.Models;
using Foxnouns.Backend.Utils;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
namespace Foxnouns.Backend.Middleware;
public class AuthorizationMiddleware : IMiddleware
{
public async Task InvokeAsync(HttpContext ctx, RequestDelegate next)
{
Endpoint? endpoint = ctx.GetEndpoint();
AuthorizeAttribute? authorizeAttribute =
endpoint?.Metadata.GetMetadata<AuthorizeAttribute>();
LimitAttribute? limitAttribute = endpoint?.Metadata.GetMetadata<LimitAttribute>();
if (authorizeAttribute == null || authorizeAttribute.Scopes.Length == 0)
{
await next(ctx);
return;
}
Token? token = ctx.GetToken();
if (token == null)
{
throw new ApiError.Unauthorized(
"This endpoint requires an authenticated user.",
ErrorCode.AuthenticationRequired
);
}
// Users who got suspended by a moderator can still access *some* endpoints.
if (
token.User.Deleted
&& (limitAttribute?.UsableBySuspendedUsers != true || token.User.DeletedBy == null)
)
{
throw new ApiError.Forbidden("Deleted users cannot access this endpoint.");
}
if (
authorizeAttribute.Scopes.Length > 0
&& authorizeAttribute.Scopes.Except(token.Scopes.ExpandScopes()).Any()
)
{
throw new ApiError.Forbidden(
"This endpoint requires ungranted scopes.",
authorizeAttribute.Scopes.Except(token.Scopes.ExpandScopes()),
ErrorCode.MissingScopes
);
}
if (limitAttribute?.RequireAdmin == true && token.User.Role != UserRole.Admin)
{
throw new ApiError.Forbidden("This endpoint can only be used by admins.");
}
if (
limitAttribute?.RequireModerator == true
&& token.User.Role is not (UserRole.Admin or UserRole.Moderator)
)
{
throw new ApiError.Forbidden("This endpoint can only be used by moderators.");
}
await next(ctx);
}
}
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class AuthorizeAttribute(params string[] scopes) : Attribute
{
public readonly string[] Scopes = scopes.Except([":admin", ":moderator", ":deleted"]).ToArray();
}
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class LimitAttribute : Attribute
{
public bool UsableBySuspendedUsers { get; init; }
public bool RequireAdmin { get; init; }
public bool RequireModerator { get; init; }
}