Add check for message content intent

DiscordChatExporter.Core/Discord/Data/Application.cs

@@ -0,0 +1,28 @@
+using System.Text.Json;
+using DiscordChatExporter.Core.Utils.Extensions;
+using JsonExtensions.Reading;
+
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/application#application-object
+public partial record Application(Snowflake Id, string Name, ApplicationFlags Flags)
+{
+    public bool IsMessageContentIntentEnabled =>
+        Flags.HasFlag(ApplicationFlags.GatewayMessageContent)
+        || Flags.HasFlag(ApplicationFlags.GatewayMessageContentLimited);
+}
+
+public partial record Application
+{
+    public static Application Parse(JsonElement json)
+    {
+        var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
+        var name = json.GetProperty("name").GetNonWhiteSpaceString();
+
+        var flags =
+            json.GetPropertyOrNull("flags")?.GetInt32OrNull()?.Pipe(x => (ApplicationFlags)x)
+            ?? ApplicationFlags.None;
+
+        return new Application(id, name, flags);
+    }
+}

DiscordChatExporter.Core/Discord/Data/ApplicationFlags.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace DiscordChatExporter.Core.Discord.Data;
+
+// https://discord.com/developers/docs/resources/application#application-object-application-flags
+[Flags]
+public enum ApplicationFlags
+{
+    None = 0,
+    ApplicationAutoModerationRuleCreateBadge = 64,
+    GatewayPresence = 4096,
+    GatewayPresenceLimited = 8192,
+    GatewayGuildMembers = 16384,
+    GatewayGuildMembersLimited = 32768,
+    VerificationPendingGuildLimit = 65536,
+    Embedded = 131072,
+    GatewayMessageContent = 262144,
+    GatewayMessageContentLimited = 524288,
+    ApplicationCommandBadge = 8388608
+}

DiscordChatExporter.Core/Discord/Data/Channel.cs

@@ -62,7 +62,7 @@ public partial record Channel
     public static Channel Parse(JsonElement json, Channel? parent = null, int? positionHint = null)
     {
         var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
-        var kind = (ChannelKind)json.GetProperty("type").GetInt32();
+        var kind = json.GetProperty("type").GetInt32().Pipe(t => (ChannelKind)t);
 
         var guildId =
             json.GetPropertyOrNull("guild_id")

DiscordChatExporter.Core/Discord/Data/Message.cs

@@ -118,14 +118,15 @@ public partial record Message
     public static Message Parse(JsonElement json)
     {
         var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
-        var kind = (MessageKind)json.GetProperty("type").GetInt32();
+        var kind = json.GetProperty("type").GetInt32().Pipe(t => (MessageKind)t);
+
         var flags =
-            (MessageFlags?)json.GetPropertyOrNull("flags")?.GetInt32OrNull() ?? MessageFlags.None;
-        var author = json.GetProperty("author").Pipe(User.Parse);
+            json.GetPropertyOrNull("flags")?.GetInt32OrNull()?.Pipe(f => (MessageFlags)f)
+            ?? MessageFlags.None;
 
+        var author = json.GetProperty("author").Pipe(User.Parse);
         var timestamp = json.GetProperty("timestamp").GetDateTimeOffset();
         var editedTimestamp = json.GetPropertyOrNull("edited_timestamp")?.GetDateTimeOffsetOrNull();
-
         var callEndedTimestamp = json.GetPropertyOrNull("call")
             ?.GetPropertyOrNull("ended_timestamp")
             ?.GetDateTimeOffsetOrNull();

DiscordChatExporter.Core/Discord/Data/Sticker.cs

@@ -13,7 +13,7 @@ public record Sticker(Snowflake Id, string Name, StickerFormat Format, string So
     {
         var id = json.GetProperty("id").GetNonWhiteSpaceString().Pipe(Snowflake.Parse);
         var name = json.GetProperty("name").GetNonNullString();
-        var format = (StickerFormat)json.GetProperty("format_type").GetInt32();
+        var format = json.GetProperty("format_type").GetInt32().Pipe(t => (StickerFormat)t);
 
         var sourceUrl = ImageCdn.GetStickerUrl(
             id,

DiscordChatExporter.Core/Discord/DiscordClient.cs

@@ -86,10 +86,13 @@ public class DiscordClient
         );
     }
 
-    private async ValueTask<TokenKind> GetTokenKindAsync(
+    private async ValueTask<TokenKind> ResolveTokenKindAsync(
         CancellationToken cancellationToken = default
     )
     {
+        if (_resolvedTokenKind is not null)
+            return _resolvedTokenKind.Value;
+
         // Try authenticating as a user
         using var userResponse = await GetResponseAsync(
             "users/@me",
@@ -98,7 +101,7 @@ public class DiscordClient
         );
 
         if (userResponse.StatusCode != HttpStatusCode.Unauthorized)
-            return TokenKind.User;
+            return (_resolvedTokenKind = TokenKind.User).Value;
 
         // Try authenticating as a bot
         using var botResponse = await GetResponseAsync(
@@ -108,7 +111,7 @@ public class DiscordClient
         );
 
         if (botResponse.StatusCode != HttpStatusCode.Unauthorized)
-            return TokenKind.Bot;
+            return (_resolvedTokenKind = TokenKind.Bot).Value;
 
         throw new DiscordChatExporterException("Authentication token is invalid.", true);
     }
@@ -116,11 +119,12 @@ public class DiscordClient
     private async ValueTask<HttpResponseMessage> GetResponseAsync(
         string url,
         CancellationToken cancellationToken = default
-    )
-    {
-        var tokenKind = _resolvedTokenKind ??= await GetTokenKindAsync(cancellationToken);
-        return await GetResponseAsync(url, tokenKind, cancellationToken);
-    }
+    ) =>
+        await GetResponseAsync(
+            url,
+            await ResolveTokenKindAsync(cancellationToken),
+            cancellationToken
+        );
 
     private async ValueTask<JsonElement> GetJsonResponseAsync(
         string url,
@@ -174,6 +178,14 @@ public class DiscordClient
             : null;
     }
 
+    public async ValueTask<Application> GetApplicationAsync(
+        CancellationToken cancellationToken = default
+    )
+    {
+        var response = await GetJsonResponseAsync("applications/@me", cancellationToken);
+        return Application.Parse(response);
+    }
+
     public async ValueTask<User?> TryGetUserAsync(
         Snowflake userId,
         CancellationToken cancellationToken = default
@@ -285,7 +297,7 @@ public class DiscordClient
         if (guildId == Guild.DirectMessages.Id)
             yield break;
 
-        var tokenKind = _resolvedTokenKind ??= await GetTokenKindAsync(cancellationToken);
+        var tokenKind = await ResolveTokenKindAsync(cancellationToken);
 
         var channels = (await GetGuildChannelsAsync(guildId, cancellationToken))
             // Categories cannot have threads
@@ -559,6 +571,22 @@ public class DiscordClient
         [EnumeratorCancellation] CancellationToken cancellationToken = default
     )
     {
+        // If authenticating as a bot, ensure that we have the correct permissions to
+        // retrieve message content.
+        // https://github.com/Tyrrrz/DiscordChatExporter/issues/1106#issuecomment-1741548959
+        var tokenKind = await ResolveTokenKindAsync(cancellationToken);
+        if (tokenKind == TokenKind.Bot)
+        {
+            var application = await GetApplicationAsync(cancellationToken);
+            if (!application.IsMessageContentIntentEnabled)
+            {
+                throw new DiscordChatExporterException(
+                    "Bot account does not have the Message Content Intent enabled.",
+                    true
+                );
+            }
+        }
+
         // Get the last message in the specified range, so we can later calculate the
         // progress based on the difference between message timestamps.
         // This also snapshots the boundaries, which means that messages posted after