Files
PluralKit/PluralKit.Bot/Services/WebhookExecutorService.cs

106 lines
4.4 KiB
C#

using System;
using System.Net.Http;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using App.Metrics;
using Discord;
using Humanizer;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using Serilog;
namespace PluralKit.Bot
{
public class WebhookExecutorService: IDisposable
{
private WebhookCacheService _webhookCache;
private ILogger _logger;
private IMetrics _metrics;
private HttpClient _client;
public WebhookExecutorService(IMetrics metrics, WebhookCacheService webhookCache, ILogger logger)
{
_metrics = metrics;
_webhookCache = webhookCache;
_logger = logger.ForContext<WebhookExecutorService>();
_client = new HttpClient();
}
public async Task<ulong> ExecuteWebhook(ITextChannel channel, string name, string avatarUrl, string content, IAttachment attachment)
{
_logger.Verbose("Invoking webhook in channel {Channel}", channel.Id);
// Get a webhook, execute it
var webhook = await _webhookCache.GetWebhook(channel);
var id = await ExecuteWebhookInner(webhook, name, avatarUrl, content, attachment);
// Log the relevant metrics
_metrics.Measure.Meter.Mark(BotMetrics.MessagesProxied);
_logger.Information("Invoked webhook {Webhook} in channel {Channel}", webhook.Id,
channel.Id);
return id;
}
private async Task<ulong> ExecuteWebhookInner(IWebhook webhook, string name, string avatarUrl, string content,
IAttachment attachment, bool hasRetried = false)
{
var mfd = new MultipartFormDataContent();
mfd.Add(new StringContent(content.Truncate(2000)), "content");
mfd.Add(new StringContent(FixClyde(name).Truncate(80)), "username");
if (avatarUrl != null) mfd.Add(new StringContent(avatarUrl), "avatar_url");
if (attachment != null)
{
var attachmentResponse = await _client.GetAsync(attachment.Url);
var attachmentStream = await attachmentResponse.Content.ReadAsStreamAsync();
mfd.Add(new StreamContent(attachmentStream), "file", attachment.Filename);
}
HttpResponseMessage response;
using (_metrics.Measure.Timer.Time(BotMetrics.WebhookResponseTime))
response = await _client.PostAsync($"{DiscordConfig.APIUrl}webhooks/{webhook.Id}/{webhook.Token}?wait=true", mfd);
// TODO: are there cases where an error won't also return a parseable JSON object?
var responseJson = JsonConvert.DeserializeObject<JObject>(await response.Content.ReadAsStringAsync());
if (responseJson.ContainsKey("code"))
{
if (responseJson["code"].Value<int>() == 10015 && !hasRetried)
{
// Error 10015 = "Unknown Webhook" - this likely means the webhook was deleted
// but is still in our cache. Invalidate, refresh, try again
_logger.Warning("Error invoking webhook {Webhook} in channel {Channel}", webhook.Id, webhook.ChannelId);
return await ExecuteWebhookInner(await _webhookCache.InvalidateAndRefreshWebhook(webhook), name, avatarUrl, content, attachment, hasRetried: true);
}
// TODO: look into what this actually throws, and if this is the correct handling
response.EnsureSuccessStatusCode();
}
// At this point we're sure we have a 2xx status code, so just assume success
// TODO: can we do this without a round-trip to a string?
return responseJson["id"].Value<ulong>();
}
private string FixClyde(string name)
{
// Check if the name contains "Clyde" - if not, do nothing
var match = Regex.Match(name, "clyde", RegexOptions.IgnoreCase);
if (!match.Success) return name;
// Put a hair space (\u200A) between the "c" and the "lyde" in the match to avoid Discord matching it
// since Discord blocks webhooks containing the word "Clyde"... for some reason. /shrug
return name.Substring(0, match.Index + 1) + '\u200A' + name.Substring(match.Index + 1);
}
public void Dispose()
{
_client.Dispose();
}
}
}