SocialPub/PrivaPub/Api/Mastodon/Controllers/MediaController.cs

using PrivaPub.Infrastructure.Statistics;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

using MongoDB.Entities;

using PrivaPub.Api.Mastodon.Infrastructure;
using PrivaPub.Domain.Media;
using PrivaPub.Models.Media;

using System.Globalization;

namespace PrivaPub.Api.Mastodon.Controllers
{
	public class MediaController : MastodonController
	{
		const long UploadLimit = 100L * 1024 * 1024;

		readonly IMediaService _media;
		readonly IMediaProxy _proxy;

		readonly IInteractionLedger _ledger;

		public MediaController(IMediaService media, IMediaProxy proxy, IInteractionLedger ledger = default)
		{
			_media = media;
			_proxy = proxy;
			_ledger = ledger;
		}

		[HttpPost("/api/v1/media"), HttpPost("/api/v2/media"), Scope("write:media"), RequestSizeLimit(UploadLimit),
			RequestFormLimits(MultipartBodyLengthLimit = UploadLimit)]
		public async Task<IActionResult> Upload(CancellationToken token)
		{
			if (!Request.HasFormContentType)
				return Error(StatusCodes.Status422UnprocessableEntity, "Validation failed: File can't be blank");
			var form = await Request.ReadFormAsync(token);
			var outcome = await _media.Upload(Me, form.Files["file"], form["description"], form["focus"], token);
			return outcome.Ok ? Json(View(outcome.Attachment)) : Error(outcome.Status, outcome.Error);
		}

		[HttpGet("/api/v1/media/{id}"), Scope("write:media")]
		public async Task<IActionResult> Get(string id, CancellationToken token)
		{
			var attachment = await DB.Default.Find<MediaAttachment>().Match(m => m.ID == id && m.OwnerAvatarId == MyId).ExecuteFirstAsync(token);
			return attachment == default ? NotFoundError() : Json(View(attachment));
		}

		[HttpPut("/api/v1/media/{id}"), Scope("write:media")]
		public async Task<IActionResult> Update(string id, CancellationToken token)
		{
			var attachment = await DB.Default.Find<MediaAttachment>().Match(m => m.ID == id && m.OwnerAvatarId == MyId).ExecuteFirstAsync(token);
			if (attachment == default)
				return NotFoundError();
			if (Params.Has("description"))
				attachment.Description = Params.Get("description")?.Trim() is { Length: > 0 } description ? description[..Math.Min(description.Length, 1500)] : default;
			if (Params.Get("focus")?.Split(',') is [var x, var y]
				&& float.TryParse(x, NumberStyles.Float, CultureInfo.InvariantCulture, out var fx) && float.TryParse(y, NumberStyles.Float, CultureInfo.InvariantCulture, out var fy))
				attachment.Focus = new[] { Math.Clamp(fx, -1, 1), Math.Clamp(fy, -1, 1) };
			await DB.Default.SaveAsync(attachment, token);
			return Json(View(attachment));
		}

		[HttpGet("/media/proxy/{signature}/{encoded}"), AllowAnonymous, ApiExplorerSettings(IgnoreApi = true)]
		public async Task<IActionResult> Proxy(string signature, string encoded, CancellationToken token)
		{
			var url = _proxy.Verified(signature, encoded);
			if (url == default)
				return NotFound();
			Response.Headers["X-Content-Type-Options"] = "nosniff";
			Response.Headers["Content-Security-Policy"] = "default-src 'none'; sandbox";
			Response.Headers["Cache-Control"] = "public, max-age=604800";
			if (_proxy.Cached(url) is { Path: not null } cached)
			{
				_ledger?.Count(Interactions.HostOf(url), "media:hit");
				return PhysicalFile(cached.Path, cached.ContentType, enableRangeProcessing: true);
			}
			if (Request.Headers.Range.Count == 0)
			{
				var (path, contentType) = await _proxy.Fetch(signature, encoded, token);
				if (path != default)
					return PhysicalFile(path, contentType, enableRangeProcessing: true);
			}
			return await Stream(url, token);
		}

		async Task<IActionResult> Stream(string url, CancellationToken token)
		{
			var range = System.Net.Http.Headers.RangeHeaderValue.TryParse(Request.Headers.Range.ToString(), out var asked) ? asked : default;
			using var upstream = await _proxy.Open(url, range, token);
			if (upstream == default)
				return NotFound();
			Response.StatusCode = (int)upstream.StatusCode;
			Response.ContentType = upstream.Content.Headers.ContentType?.ToString() ?? "application/octet-stream";
			if (upstream.Content.Headers.ContentLength is { } length)
				Response.ContentLength = length;
			if (upstream.Content.Headers.ContentRange is { } contentRange)
				Response.Headers.ContentRange = contentRange.ToString();
			Response.Headers.AcceptRanges = "bytes";
			await upstream.Content.CopyToAsync(Response.Body, token);
			return new EmptyResult();
		}

		object View(MediaAttachment attachment) => new
		{
			id = attachment.ID,
			type = attachment.Kind,
			url = _media.Url(attachment.FilePath),
			preview_url = _media.Url(attachment.PreviewPath ?? attachment.FilePath),
			remote_url = default(string),
			text_url = default(string),
			meta = new
			{
				original = attachment.Width.HasValue && attachment.Height > 0
					? new { width = attachment.Width, height = attachment.Height, size = $"{attachment.Width}x{attachment.Height}", aspect = (double)attachment.Width / attachment.Height.Value }
					: default,
				focus = attachment.Focus is { Length: 2 } ? new { x = attachment.Focus[0], y = attachment.Focus[1] } : default
			},
			description = attachment.Description,
			blurhash = attachment.Blurhash
		};
	}
}