feat(bot): query updated signature parameters of expired discord attachments

Myriad/Rest/DiscordApiClient.cs

@@ -159,6 +159,9 @@ public class DiscordApiClient
     public Task<Channel> CreateDm(ulong recipientId) =>
         _client.Post<Channel>("/users/@me/channels", ("CreateDM", default), new CreateDmRequest(recipientId))!;
 
+    public Task<RefreshedUrlsResponse> RefreshUrls(string[] urls) =>
+        _client.Post<RefreshedUrlsResponse>("/attachments/refresh-urls", ("RefreshUrls", default), new RefreshUrlsRequest(urls));
+
     private static string EncodeEmoji(Emoji emoji) =>
         WebUtility.UrlEncode(emoji.Id != null ? $"{emoji.Name}:{emoji.Id}" : emoji.Name) ??
         throw new ArgumentException("Could not encode emoji");

Myriad/Rest/Types/Requests/RefreshUrlsRequest.cs

@@ -0,0 +1,3 @@
+namespace Myriad.Rest.Types.Requests;
+
+public record RefreshUrlsRequest(string[] AttachmentUrls);

Myriad/Types/RefreshedUrl.cs

@@ -0,0 +1,11 @@
+namespace Myriad.Types;
+
+public record RefreshedUrlsResponse
+{
+    public record RefreshedUrl
+    {
+        public string Original;
+        public string Refreshed;
+    }
+    public RefreshedUrl[] RefreshedUrls;
+}

PluralKit.Bot/Commands/ImportExport.cs

@@ -45,13 +45,20 @@ public class ImportExport
             try
             {
                 var response = await _client.GetAsync(url);
+                var content = await response.Content.ReadAsStringAsync();
+                if (content == "This content is no longer available.")
+                {
+                    var refreshed = await ctx.Rest.RefreshUrls(new[] { url.ToString() });
+                    response = await _client.GetAsync(new Uri(refreshed.RefreshedUrls[0].Refreshed));
+                    content = await response.Content.ReadAsStringAsync();
+                }
                 if (!response.IsSuccessStatusCode)
                     throw Errors.InvalidImportFile;
                 // hacky fix for discord api returning nonsense charsets sometimes
                 response.Content.Headers.Remove("content-type");
                 response.Content.Headers.Add("content-type", "application/json; charset=UTF-8");
                 data = JsonConvert.DeserializeObject<JObject>(
-                    await response.Content.ReadAsStringAsync(),
+                    content,
                     _settings
                 );
                 if (data == null)