rest forum channel and remove message builder for 4.x

src/Discord.Net.Core/Entities/Channels/IForumChannel.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
@@ -39,15 +40,129 @@ namespace Discord
         /// </summary>
         /// <param name="title">The title of the post.</param>
         /// <param name="archiveDuration">The archive duration of the post.</param>
-        /// <param name="message">
-        ///     The starting message of the post. The content of the message supports full markdown.
+        /// <param name="slowmode">The slowmode for the posts thread.</param>
+        /// <param name="text">The message to be sent.</param>
+        /// <param name="embed">The <see cref="Discord.EmbedType.Rich"/> <see cref="Embed"/> to be sent.</param>
+        /// <param name="options">The options to be used when sending the request.</param>
+        /// <param name="allowedMentions">
+        ///     Specifies if notifications are sent for mentioned users and roles in the message <paramref name="text"/>.
+        ///     If <c>null</c>, all mentioned roles and users will be notified.
+        /// </param>
+        /// <param name="components">The message components to be included with this message. Used for interactions.</param>
+        /// <param name="stickers">A collection of stickers to send with the message.</param>
+        /// <param name="embeds">A array of <see cref="Embed"/>s to send with this response. Max 10.</param>
+        /// <param name="flags">A message flag to be applied to the sent message, only <see cref="MessageFlags.SuppressEmbeds"/> is permitted.</param>
+        /// <returns>
+        ///     A task that represents the asynchronous creation operation.
+        /// </returns>
+        Task<IThreadChannel> CreatePostAsync(string title, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay, int? slowmode = null,
+            string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null,
+            MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None);
+
+        /// <summary>
+        ///     Creates a new post (thread) within the forum.
+        /// </summary>
+        /// <param name="title">The title of the post.</param>
+        /// <param name="archiveDuration">The archive duration of the post.</param>
+        /// <param name="slowmode">The slowmode for the posts thread.</param>
+        /// <param name="filePath">The file path of the file.</param>
+        /// <param name="text">The message to be sent.</param>
+        /// <param name="embed">The <see cref="Discord.EmbedType.Rich" /> <see cref="Embed" /> to be sent.</param>
+        /// <param name="options">The options to be used when sending the request.</param>
+        /// <param name="isSpoiler">Whether the message attachment should be hidden as a spoiler.</param>
+        /// <param name="allowedMentions">
+        ///     Specifies if notifications are sent for mentioned users and roles in the message <paramref name="text"/>.
+        ///     If <c>null</c>, all mentioned roles and users will be notified.
+        /// </param>
+        /// <param name="components">The message components to be included with this message. Used for interactions.</param>
+        /// <param name="stickers">A collection of stickers to send with the file.</param>
+        /// <param name="embeds">A array of <see cref="Embed"/>s to send with this response. Max 10.</param>
+        /// <param name="flags">A message flag to be applied to the sent message, only <see cref="MessageFlags.SuppressEmbeds"/> is permitted.</param>
+        /// <returns>
+        ///     A task that represents the asynchronous creation operation.
+        /// </returns>
+        Task<IThreadChannel> CreatePostWithFileAsync(string title, string filePath, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, bool isSpoiler = false,
+            AllowedMentions allowedMentions = null, MessageComponent components = null,
+            ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None);
+
+        /// <summary>
+        ///     Creates a new post (thread) within the forum.
+        /// </summary>
+        /// <param name="title">The title of the post.</param>
+        /// <param name="stream">The <see cref="Stream" /> of the file to be sent.</param>
+        /// <param name="filename">The name of the attachment.</param>
+        /// <param name="archiveDuration">The archive duration of the post.</param>
+        /// <param name="slowmode">The slowmode for the posts thread.</param>
+        /// <param name="text">The message to be sent.</param>
+        /// <param name="embed">The <see cref="Discord.EmbedType.Rich"/> <see cref="Embed"/> to be sent.</param>
+        /// <param name="options">The options to be used when sending the request.</param>
+        /// <param name="isSpoiler">Whether the message attachment should be hidden as a spoiler.</param>
+        /// <param name="allowedMentions">
+        ///     Specifies if notifications are sent for mentioned users and roles in the message <paramref name="text"/>.
+        ///     If <c>null</c>, all mentioned roles and users will be notified.
+        /// </param>
+        /// <param name="components">The message components to be included with this message. Used for interactions.</param>
+        /// <param name="stickers">A collection of stickers to send with the file.</param>
+        /// <param name="embeds">A array of <see cref="Embed"/>s to send with this response. Max 10.</param>
+        /// <param name="flags">A message flag to be applied to the sent message, only <see cref="MessageFlags.SuppressEmbeds"/> is permitted.</param>
+        /// <returns>
+        ///     A task that represents the asynchronous creation operation.
+        /// </returns>
+        public Task<IThreadChannel> CreatePostWithFileAsync(string title, Stream stream, string filename, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, bool isSpoiler = false,
+            AllowedMentions allowedMentions = null, MessageComponent components = null,
+            ISticker[] stickers = null, Embed[] embeds = null,MessageFlags flags = MessageFlags.None);
+
+        /// <summary>
+        ///     Creates a new post (thread) within the forum.
+        /// </summary>
+        /// <param name="title">The title of the post.</param>
+        /// <param name="attachment">The attachment containing the file and description.</param>
+        /// <param name="archiveDuration">The archive duration of the post.</param>
+        /// <param name="slowmode">The slowmode for the posts thread.</param>
+        /// <param name="text">The message to be sent.</param>
+        /// <param name="embed">The <see cref="Discord.EmbedType.Rich"/> <see cref="Embed"/> to be sent.</param>
+        /// <param name="options">The options to be used when sending the request.</param>
+        /// <param name="allowedMentions">
+        ///     Specifies if notifications are sent for mentioned users and roles in the message <paramref name="text"/>.
+        ///     If <c>null</c>, all mentioned roles and users will be notified.
         /// </param>
+        /// <param name="components">The message components to be included with this message. Used for interactions.</param>
+        /// <param name="stickers">A collection of stickers to send with the file.</param>
+        /// <param name="embeds">A array of <see cref="Embed"/>s to send with this response. Max 10.</param>
+        /// <param name="flags">A message flag to be applied to the sent message, only <see cref="MessageFlags.SuppressEmbeds"/> is permitted.</param>
+        /// <returns>
+        ///     A task that represents the asynchronous creation operation.
+        /// </returns>
+        public Task<IThreadChannel> CreatePostWithFileAsync(string title, FileAttachment attachment, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null,
+            MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None);
+
+        /// <summary>
+        ///     Creates a new post (thread) within the forum.
+        /// </summary>
+        /// <param name="title">The title of the post.</param>
+        /// <param name="attachments">A collection of attachments to upload.</param>
+        /// <param name="archiveDuration">The archive duration of the post.</param>
         /// <param name="slowmode">The slowmode for the posts thread.</param>
+        /// <param name="text">The message to be sent.</param>
+        /// <param name="embed">The <see cref="Discord.EmbedType.Rich"/> <see cref="Embed"/> to be sent.</param>
         /// <param name="options">The options to be used when sending the request.</param>
+        /// <param name="allowedMentions">
+        ///     Specifies if notifications are sent for mentioned users and roles in the message <paramref name="text"/>.
+        ///     If <c>null</c>, all mentioned roles and users will be notified.
+        /// </param>
+        /// <param name="components">The message components to be included with this message. Used for interactions.</param>
+        /// <param name="stickers">A collection of stickers to send with the file.</param>
+        /// <param name="embeds">A array of <see cref="Embed"/>s to send with this response. Max 10.</param>
+        /// <param name="flags">A message flag to be applied to the sent message, only <see cref="MessageFlags.SuppressEmbeds"/> is permitted.</param>
         /// <returns>
         ///     A task that represents the asynchronous creation operation.
         /// </returns>
-        Task<IThreadChannel> CreatePostAsync(string title, ThreadArchiveDuration archiveDuration, Message message, int? slowmode = null, RequestOptions options = null);
+        public Task<IThreadChannel> CreatePostWithFilesAsync(string title, IEnumerable<FileAttachment> attachments, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null,
+            MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None);
 
         /// <summary>
         ///     Gets a collection of active threads within this forum channel.

src/Discord.Net.Core/Entities/Messages/Message.cs

@@ -1,74 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace Discord
-{
-    /// <summary>
-    ///     Represents a message created by a <see cref="MessageBuilder"/> that can be sent to a channel. 
-    /// </summary>
-    public sealed class Message
-    {
-        /// <summary>
-        ///     Gets the content of the message.
-        /// </summary>
-        public string Content { get; }
-
-        /// <summary>
-        ///     Gets whether or not this message should be read by a text-to-speech engine.
-        /// </summary>
-        public bool IsTTS { get; }
-
-        /// <summary>
-        ///     Gets a collection of embeds sent along with this message.
-        /// </summary>
-        public IReadOnlyCollection<Embed> Embeds { get; }
-
-        /// <summary>
-        ///     Gets the allowed mentions for this message.
-        /// </summary>
-        public AllowedMentions AllowedMentions { get; }
-
-        /// <summary>
-        ///     Gets the message reference (reply to) for this message.
-        /// </summary>
-        public MessageReference MessageReference { get; }
-
-        /// <summary>
-        ///     Gets the components of this message.
-        /// </summary>
-        public MessageComponent Components { get; }
-
-        /// <summary>
-        ///     Gets a collection of sticker ids that will be sent with this message.
-        /// </summary>
-        public IReadOnlyCollection<ulong> StickerIds { get; }
-
-        /// <summary>
-        ///     Gets a collection of files sent with this message.
-        /// </summary>
-        public IReadOnlyCollection<FileAttachment> Attachments { get; }
-
-        /// <summary>
-        ///     Gets the message flags for this message.
-        /// </summary>
-        public MessageFlags Flags { get; }
-
-        internal Message(string content, bool istts, IReadOnlyCollection<Embed> embeds, AllowedMentions allowedMentions,
-            MessageReference messagereference, MessageComponent components, IReadOnlyCollection<ulong> stickerIds,
-            IReadOnlyCollection<FileAttachment> attachments, MessageFlags flags)
-        {
-            Content = content;
-            IsTTS = istts;
-            Embeds = embeds;
-            AllowedMentions = allowedMentions;
-            MessageReference = messagereference;
-            Components = components;
-            StickerIds = stickerIds;
-            Attachments = attachments;
-            Flags = flags;
-        }
-    }
-}

src/Discord.Net.Core/Entities/Messages/MessageBuilder.cs

@@ -1,220 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace Discord
-{
-    /// <summary>
-    ///     Represents a generic message builder that can build <see cref="Message"/>s.
-    /// </summary>
-    public class MessageBuilder
-    {
-        private string _content;
-        private List<ISticker> _stickers;
-        private List<EmbedBuilder> _embeds;
-
-        /// <summary>
-        ///     Gets or sets the content of this message
-        /// </summary>
-        /// <exception cref="ArgumentOutOfRangeException">The content is bigger than the <see cref="DiscordConfig.MaxMessageSize"/>.</exception>
-        public string Content
-        {
-            get => _content;
-            set
-            {
-                if (_content?.Length > DiscordConfig.MaxMessageSize)
-                    throw new ArgumentOutOfRangeException(nameof(value), $"Message size must be less than or equal to {DiscordConfig.MaxMessageSize} characters");
-
-                _content = value;
-            }
-        }
-
-        /// <summary>
-        ///     Gets or sets whether or not this message is TTS.
-        /// </summary>
-        public bool IsTTS { get; set; }
-
-        /// <summary>
-        ///     Gets or sets the embeds of this message.
-        /// </summary>
-        public List<EmbedBuilder> Embeds
-        {
-            get
-            {
-                if (_embeds == null)
-                    _embeds = new();
-                return _embeds;
-            }
-            set
-            {
-                if (value?.Count > DiscordConfig.MaxEmbedsPerMessage)
-                    throw new ArgumentOutOfRangeException(nameof(value), $"Embed count must be less than or equal to {DiscordConfig.MaxEmbedsPerMessage}");
-
-                _embeds = value;
-            }
-        }
-
-        /// <summary>
-        ///     Gets or sets the allowed mentions of this message.
-        /// </summary>
-        public AllowedMentions AllowedMentions { get; set; }
-
-        /// <summary>
-        ///     Gets or sets the message reference (reply to) of this message.
-        /// </summary>
-        public MessageReference MessageReference { get; set; }
-
-        /// <summary>
-        ///     Gets or sets the components of this message.
-        /// </summary>
-        public ComponentBuilder Components { get; set; } = new();
-
-        /// <summary>
-        ///     Gets or sets the stickers sent with this message.
-        /// </summary>
-        public List<ISticker> Stickers
-        {
-            get => _stickers;
-            set
-            {
-                if (value?.Count > DiscordConfig.MaxStickersPerMessage)
-                    throw new ArgumentOutOfRangeException(nameof(value), $"Sticker count must be less than or equal to {DiscordConfig.MaxStickersPerMessage}");
-
-                _stickers = value;
-            }
-        }
-
-        /// <summary>
-        ///     Gets or sets the files sent with this message.
-        /// </summary>
-        public List<FileAttachment> Files { get; set; } = new();
-
-        /// <summary>
-        ///     Gets or sets the message flags.
-        /// </summary>
-        public MessageFlags Flags { get; set; }
-
-        /// <summary>
-        ///     Sets the <see cref="Content"/> of this message.
-        /// </summary>
-        /// <param name="content">The content of the message.</param>
-        /// <returns>The current builder.</returns>
-        public MessageBuilder WithContent(string content)
-        {
-            Content = content;
-            return this;
-        }
-
-        /// <summary>
-        ///     Sets the <see cref="IsTTS"/> of this message.
-        /// </summary>
-        /// <param name="isTTS">whether or not this message is tts.</param>
-        /// <returns>The current builder.</returns>
-        public MessageBuilder WithTTS(bool isTTS)
-        {
-            IsTTS = isTTS;
-            return this;
-        }
-
-        public MessageBuilder WithEmbeds(params EmbedBuilder[] embeds)
-        {
-            Embeds = new(embeds);
-            return this;
-        }
-
-        public MessageBuilder AddEmbed(EmbedBuilder embed)
-        {
-            if (_embeds?.Count >= DiscordConfig.MaxEmbedsPerMessage)
-                throw new ArgumentOutOfRangeException(nameof(embed.Length), $"A message can only contain a maximum of {DiscordConfig.MaxEmbedsPerMessage} embeds");
-
-            _embeds ??= new();
-
-            _embeds.Add(embed);
-
-            return this;
-        }
-
-        public MessageBuilder WithAllowedMentions(AllowedMentions allowedMentions)
-        {
-            AllowedMentions = allowedMentions;
-            return this;
-        }
-
-        public MessageBuilder WithMessageReference(MessageReference reference)
-        {
-            MessageReference = reference;
-            return this;
-        }
-
-        public MessageBuilder WithMessageReference(IMessage message)
-        {
-            if (message != null)
-                MessageReference = new MessageReference(message.Id, message.Channel?.Id, ((IGuildChannel)message.Channel)?.GuildId);
-            return this;
-        }
-
-        public MessageBuilder WithComponentBuilder(ComponentBuilder builder)
-        {
-            Components = builder;
-            return this;
-        }
-
-        public MessageBuilder WithButton(ButtonBuilder button, int row = 0)
-        {
-            Components ??= new();
-            Components.WithButton(button, row);
-            return this;
-        }
-
-        public MessageBuilder WithButton(
-            string label = null,
-            string customId = null,
-            ButtonStyle style = ButtonStyle.Primary,
-            IEmote emote = null,
-            string url = null,
-            bool disabled = false,
-            int row = 0)
-        {
-            Components ??= new();
-            Components.WithButton(label, customId, style, emote, url, disabled, row);
-            return this;
-        }
-
-        public MessageBuilder WithSelectMenu(SelectMenuBuilder menu, int row = 0)
-        {
-            Components ??= new();
-            Components.WithSelectMenu(menu, row);
-            return this;
-        }
-
-        public MessageBuilder WithSelectMenu(string customId, List<SelectMenuOptionBuilder> options,
-            string placeholder = null, int minValues = 1, int maxValues = 1, bool disabled = false, int row = 0)
-        {
-            Components ??= new();
-            Components.WithSelectMenu(customId, options, placeholder, minValues, maxValues, disabled, row);
-            return this;
-        }
-
-        public Message Build()
-        {
-            var embeds = _embeds != null && _embeds.Count > 0
-                ? _embeds.Select(x => x.Build()).ToImmutableArray()
-                : ImmutableArray<Embed>.Empty;
-
-            return new Message(
-                _content,
-                IsTTS,
-                embeds,
-                AllowedMentions,
-                MessageReference,
-                Components?.Build(),
-                _stickers != null && _stickers.Any() ? _stickers.Select(x => x.Id).ToImmutableArray() : ImmutableArray<ulong>.Empty,
-                Files?.ToImmutableArray() ?? ImmutableArray<FileAttachment>.Empty,
-                Flags
-            );
-        }
-    }
-}

src/Discord.Net.Rest/API/Common/ForumThreadMessage.cs

@@ -0,0 +1,33 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Discord.API
+{
+    internal class ForumThreadMessage
+    {
+        [JsonProperty("content")]
+        public Optional<string> Content { get; set; }
+
+        [JsonProperty("nonce")]
+        public Optional<string> Nonce { get; set; }
+
+        [JsonProperty("embeds")]
+        public Optional<Embed[]> Embeds { get; set; }
+
+        [JsonProperty("allowed_mentions")]
+        public Optional<AllowedMentions> AllowedMentions { get; set; }
+
+        [JsonProperty("components")]
+        public Optional<API.ActionRowComponent[]> Components { get; set; }
+
+        [JsonProperty("sticker_ids")]
+        public Optional<ulong[]> Stickers { get; set; }
+
+        [JsonProperty("flags")]
+        public Optional<MessageFlags> Flags { get; set; }
+    }
+}

src/Discord.Net.Rest/API/Rest/CreateMultipartPostAsync.cs

@@ -22,7 +22,6 @@ namespace Discord.API.Rest
 
 
         public Optional<string> Content { get; set; }
-        public Optional<bool> IsTTS { get; set; }
         public Optional<Embed[]> Embeds { get; set; }
         public Optional<AllowedMentions> AllowedMentions { get; set; }
         public Optional<ActionRowComponent[]> MessageComponent { get; set; }
@@ -39,26 +38,27 @@ namespace Discord.API.Rest
             var d = new Dictionary<string, object>();
 
             var payload = new Dictionary<string, object>();
+            var message = new Dictionary<string, object>();
 
-            payload["title"] = Title;
+            payload["name"] = Title;
             payload["auto_archive_duration"] = ArchiveDuration;
 
             if (Slowmode.IsSpecified)
                 payload["rate_limit_per_user"] = Slowmode.Value;
+
+            // message
             if (Content.IsSpecified)
-                payload["content"] = Content.Value;
-            if (IsTTS.IsSpecified)
-                payload["tts"] = IsTTS.Value;
+                message["content"] = Content.Value;
             if (Embeds.IsSpecified)
-                payload["embeds"] = Embeds.Value;
+                message["embeds"] = Embeds.Value;
             if (AllowedMentions.IsSpecified)
-                payload["allowed_mentions"] = AllowedMentions.Value;
+                message["allowed_mentions"] = AllowedMentions.Value;
             if (MessageComponent.IsSpecified)
-                payload["components"] = MessageComponent.Value;
+                message["components"] = MessageComponent.Value;
             if (Stickers.IsSpecified)
-                payload["sticker_ids"] = Stickers.Value;
+                message["sticker_ids"] = Stickers.Value;
             if (Flags.IsSpecified)
-                payload["flags"] = Flags.Value;
+                message["flags"] = Flags.Value;
 
             List<object> attachments = new();
 
@@ -79,7 +79,9 @@ namespace Discord.API.Rest
                 });
             }
 
-            payload["attachments"] = attachments;
+            message["attachments"] = attachments;
+
+            payload["message"] = message;
 
             var json = new StringBuilder();
             using (var text = new StringWriter(json))

src/Discord.Net.Rest/API/Rest/CreatePostParams.cs

@@ -19,26 +19,7 @@ namespace Discord.API.Rest
         [JsonProperty("rate_limit_per_user")]
         public Optional<int?> Slowmode { get; set; }
 
-        // message
-        [JsonProperty("content")]
-        public string Content { get; set; }
-
-        [JsonProperty("tts")]
-        public Optional<bool> IsTTS { get; set; }
-
-        [JsonProperty("embeds")]
-        public Optional<Embed[]> Embeds { get; set; }
-
-        [JsonProperty("allowed_mentions")]
-        public Optional<AllowedMentions> AllowedMentions { get; set; }
-
-        [JsonProperty("components")]
-        public Optional<API.ActionRowComponent[]> Components { get; set; }
-
-        [JsonProperty("sticker_ids")]
-        public Optional<ulong[]> Stickers { get; set; }
-
-        [JsonProperty("flags")]
-        public Optional<MessageFlags> Flags { get; set; }
+        [JsonProperty("message")]
+        public ForumThreadMessage Message { get; set; }
     }
 }

src/Discord.Net.Rest/Entities/Channels/RestForumChannel.cs

@@ -0,0 +1,131 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Model = Discord.API.Channel;
+
+namespace Discord.Rest
+{
+    /// <summary>
+    ///     Represents a REST-based forum channel in a guild.
+    /// </summary>
+    public class RestForumChannel : RestGuildChannel, IForumChannel
+    {
+        /// <inheritdoc/>
+        public bool IsNsfw { get; private set; }
+
+        /// <inheritdoc/>
+        public string Topic { get; private set; }
+
+        /// <inheritdoc/>
+        public ThreadArchiveDuration DefaultAutoArchiveDuration { get; private set; }
+
+        /// <inheritdoc/>
+        public IReadOnlyCollection<ForumTag> Tags { get; private set; }
+
+        /// <inheritdoc/>
+        public string Mention => MentionUtils.MentionChannel(Id);
+
+        internal RestForumChannel(BaseDiscordClient client, IGuild guild, ulong id)
+            : base(client, guild, id)
+        {
+
+        }
+
+        internal new static RestStageChannel Create(BaseDiscordClient discord, IGuild guild, Model model)
+        {
+            var entity = new RestStageChannel(discord, guild, model.Id);
+            entity.Update(model);
+            return entity;
+        }
+
+        internal override void Update(Model model)
+        {
+            base.Update(model);
+            IsNsfw = model.Nsfw.GetValueOrDefault(false);
+            Topic = model.Topic.GetValueOrDefault();
+            DefaultAutoArchiveDuration = model.AutoArchiveDuration.GetValueOrDefault(ThreadArchiveDuration.OneDay);
+
+            Tags = model.ForumTags.GetValueOrDefault(Array.Empty<API.ForumTags>()).Select(
+                x => new ForumTag(x.Id, x.Name, x.EmojiId.GetValueOrDefault(null), x.EmojiName.GetValueOrDefault())
+            ).ToImmutableArray();
+        }
+
+        /// <inheritdoc cref="IForumChannel.CreatePostAsync(string, ThreadArchiveDuration, int?, string, Embed, RequestOptions, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public Task<RestThreadChannel> CreatePostAsync(string title, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay, int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null, MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+            => ThreadHelper.CreatePostAsync(this, Discord, title, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags);
+
+        /// <inheritdoc cref="IForumChannel.CreatePostWithFileAsync(string, string, ThreadArchiveDuration, int?, string, Embed, RequestOptions, bool, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public async Task<RestThreadChannel> CreatePostWithFileAsync(string title, string filePath, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, bool isSpoiler = false,
+            AllowedMentions allowedMentions = null, MessageComponent components = null,
+            ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+        {
+            using var file = new FileAttachment(filePath, isSpoiler: isSpoiler);
+            return await ThreadHelper.CreatePostAsync(this, Discord, title, new FileAttachment[] { file }, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        }
+
+        /// <inheritdoc cref="IForumChannel.CreatePostWithFileAsync(string, Stream, string, ThreadArchiveDuration, int?, string, Embed, RequestOptions, bool, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public async Task<RestThreadChannel> CreatePostWithFileAsync(string title, Stream stream, string filename, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, bool isSpoiler = false,
+            AllowedMentions allowedMentions = null, MessageComponent components = null,
+            ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+        {
+            using var file = new FileAttachment(stream, filename, isSpoiler: isSpoiler);
+            return await ThreadHelper.CreatePostAsync(this, Discord, title, new FileAttachment[] { file }, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        }
+
+        /// <inheritdoc cref="IForumChannel.CreatePostWithFileAsync(string, FileAttachment, ThreadArchiveDuration, int?, string, Embed, RequestOptions, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public Task<RestThreadChannel> CreatePostWithFileAsync(string title, FileAttachment attachment, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null,
+            MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+            => ThreadHelper.CreatePostAsync(this, Discord, title, new FileAttachment[] { attachment }, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags);
+
+        /// <inheritdoc cref="IForumChannel.CreatePostWithFilesAsync(string, IEnumerable{FileAttachment}, ThreadArchiveDuration, int?, string, Embed, RequestOptions, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public Task<RestThreadChannel> CreatePostWithFilesAsync(string title, IEnumerable<FileAttachment> attachments, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null,
+            MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+            => ThreadHelper.CreatePostAsync(this, Discord, title, attachments, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags);
+
+        /// <inheritdoc cref="IForumChannel.GetActiveThreadsAsync(RequestOptions)"/>
+        public Task<IReadOnlyCollection<RestThreadChannel>> GetActiveThreadsAsync(RequestOptions options = null)
+            => ThreadHelper.GetActiveThreadsAsync(Guild, Discord, options);
+
+        /// <inheritdoc cref="IForumChannel.GetJoinedPrivateArchivedThreadsAsync(int?, DateTimeOffset?, RequestOptions)"/>
+        public Task<IReadOnlyCollection<RestThreadChannel>> GetJoinedPrivateArchivedThreadsAsync(int? limit = null, DateTimeOffset? before = null, RequestOptions options = null)
+            => ThreadHelper.GetJoinedPrivateArchivedThreadsAsync(this, Discord, limit, before, options);
+
+        /// <inheritdoc cref="IForumChannel.GetPrivateArchivedThreadsAsync(int?, DateTimeOffset?, RequestOptions)"/>
+        public Task<IReadOnlyCollection<RestThreadChannel>> GetPrivateArchivedThreadsAsync(int? limit = null, DateTimeOffset? before = null, RequestOptions options = null)
+            => ThreadHelper.GetPrivateArchivedThreadsAsync(this, Discord, limit, before, options);
+
+        /// <inheritdoc cref="IForumChannel.GetPublicArchivedThreadsAsync(int?, DateTimeOffset?, RequestOptions)"/>
+        public Task<IReadOnlyCollection<RestThreadChannel>> GetPublicArchivedThreadsAsync(int? limit = null, DateTimeOffset? before = null, RequestOptions options = null)
+            => ThreadHelper.GetPublicArchivedThreadsAsync(this, Discord, limit, before, options);
+
+        #region IForumChannel
+        async Task<IReadOnlyCollection<IThreadChannel>> IForumChannel.GetActiveThreadsAsync(RequestOptions options)
+            => await GetActiveThreadsAsync(options).ConfigureAwait(false);
+        async Task<IReadOnlyCollection<IThreadChannel>> IForumChannel.GetPublicArchivedThreadsAsync(int? limit, DateTimeOffset? before, RequestOptions options)
+            => await GetPublicArchivedThreadsAsync(limit, before, options).ConfigureAwait(false);
+        async Task<IReadOnlyCollection<IThreadChannel>> IForumChannel.GetPrivateArchivedThreadsAsync(int? limit, DateTimeOffset? before, RequestOptions options)
+            => await GetPrivateArchivedThreadsAsync(limit, before, options).ConfigureAwait(false);
+        async Task<IReadOnlyCollection<IThreadChannel>> IForumChannel.GetJoinedPrivateArchivedThreadsAsync(int? limit, DateTimeOffset? before, RequestOptions options)
+            => await GetJoinedPrivateArchivedThreadsAsync(limit, before, options).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostAsync(string title, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostAsync(title, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostWithFileAsync(string title, string filePath, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, bool isSpoiler, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostWithFileAsync(title, filePath, archiveDuration, slowmode, text, embed, options, isSpoiler, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostWithFileAsync(string title, Stream stream, string filename, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, bool isSpoiler, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostWithFileAsync(title, stream, filename, archiveDuration, slowmode, text, embed, options, isSpoiler, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostWithFileAsync(string title, FileAttachment attachment, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostWithFileAsync(title, attachment, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostWithFilesAsync(string title, IEnumerable<FileAttachment> attachments, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostWithFilesAsync(title, attachments, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags);
+
+        #endregion
+    }
+}

src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs

@@ -39,6 +39,7 @@ namespace Discord.Rest
                 ChannelType.Text => RestTextChannel.Create(discord, guild, model),
                 ChannelType.Voice => RestVoiceChannel.Create(discord, guild, model),
                 ChannelType.Stage => RestStageChannel.Create(discord, guild, model),
+                ChannelType.Forum => RestForumChannel.Create(discord, guild, model),
                 ChannelType.Category => RestCategoryChannel.Create(discord, guild, model),
                 ChannelType.PublicThread or ChannelType.PrivateThread or ChannelType.NewsThread => RestThreadChannel.Create(discord, guild, model),
                 _ => new RestGuildChannel(discord, guild, model.Id),

src/Discord.Net.Rest/Entities/Channels/ThreadHelper.cs

@@ -103,47 +103,112 @@ namespace Discord.Rest
             return RestThreadUser.Create(client, channel.Guild, model, channel);
         }
 
-        public static async Task<RestThreadChannel> CreatePostAsync(IForumChannel channel, BaseDiscordClient client, string title, ThreadArchiveDuration archiveDuration, Message message, int? slowmode = null, RequestOptions options = null)
+        public static async Task<RestThreadChannel> CreatePostAsync(IForumChannel channel, BaseDiscordClient client, string title, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay, int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null, MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
         {
-            Model model;
+            embeds ??= Array.Empty<Embed>();
+            if (embed != null)
+                embeds = new[] { embed }.Concat(embeds).ToArray();
+
+            Preconditions.AtMost(allowedMentions?.RoleIds?.Count ?? 0, 100, nameof(allowedMentions.RoleIds), "A max of 100 role Ids are allowed.");
+            Preconditions.AtMost(allowedMentions?.UserIds?.Count ?? 0, 100, nameof(allowedMentions.UserIds), "A max of 100 user Ids are allowed.");
+            Preconditions.AtMost(embeds.Length, 10, nameof(embeds), "A max of 10 embeds are allowed.");
 
-            if (message.Attachments?.Any() ?? false)
+            // check that user flag and user Id list are exclusive, same with role flag and role Id list
+            if (allowedMentions != null && allowedMentions.AllowedTypes.HasValue)
             {
-                var args = new CreateMultipartPostAsync(message.Attachments.ToArray())
+                if (allowedMentions.AllowedTypes.Value.HasFlag(AllowedMentionTypes.Users) &&
+                    allowedMentions.UserIds != null && allowedMentions.UserIds.Count > 0)
                 {
-                    AllowedMentions = message.AllowedMentions.ToModel(),
-                    ArchiveDuration = archiveDuration,
-                    Content = message.Content,
-                    Embeds = message.Embeds.Any() ? message.Embeds.Select(x => x.ToModel()).ToArray() : Optional<API.Embed[]>.Unspecified,
-                    Flags = message.Flags,
-                    IsTTS = message.IsTTS,
-                    MessageComponent = message.Components?.Components?.Any() ?? false ? message.Components.Components.Select(x => new API.ActionRowComponent(x)).ToArray() : Optional<API.ActionRowComponent[]>.Unspecified,
-                    Slowmode = slowmode,
-                    Stickers = message.StickerIds?.Any() ?? false ? message.StickerIds.ToArray() : Optional<ulong[]>.Unspecified,
-                    Title = title
-                };
-
-                model = await client.ApiClient.CreatePostAsync(channel.Id, args, options).ConfigureAwait(false);
+                    throw new ArgumentException("The Users flag is mutually exclusive with the list of User Ids.", nameof(allowedMentions));
+                }
+
+                if (allowedMentions.AllowedTypes.Value.HasFlag(AllowedMentionTypes.Roles) &&
+                    allowedMentions.RoleIds != null && allowedMentions.RoleIds.Count > 0)
+                {
+                    throw new ArgumentException("The Roles flag is mutually exclusive with the list of Role Ids.", nameof(allowedMentions));
+                }
             }
-            else
+
+            if (stickers != null)
             {
-                var args = new CreatePostParams()
+                Preconditions.AtMost(stickers.Length, 3, nameof(stickers), "A max of 3 stickers are allowed.");
+            }
+
+
+            if (flags is not MessageFlags.None and not MessageFlags.SuppressEmbeds)
+                throw new ArgumentException("The only valid MessageFlags are SuppressEmbeds and none.", nameof(flags));
+
+            var args = new CreatePostParams()
+            {
+                Title = title,
+                ArchiveDuration = archiveDuration,
+                Slowmode = slowmode,
+                Message = new()
                 {
-                    AllowedMentions = message.AllowedMentions.ToModel(),
-                    ArchiveDuration = archiveDuration,
-                    Content = message.Content,
-                    Embeds = message.Embeds.Any() ? message.Embeds.Select(x => x.ToModel()).ToArray() : Optional<API.Embed[]>.Unspecified,
-                    Flags = message.Flags,
-                    IsTTS = message.IsTTS,
-                    Components = message.Components?.Components?.Any() ?? false ? message.Components.Components.Select(x => new API.ActionRowComponent(x)).ToArray() : Optional<API.ActionRowComponent[]>.Unspecified,
-                    Slowmode = slowmode,
-                    Stickers = message.StickerIds?.Any() ?? false ? message.StickerIds.ToArray() : Optional<ulong[]>.Unspecified,
-                    Title = title
-                };
-
-                model = await client.ApiClient.CreatePostAsync(channel.Id, args, options);
+                    AllowedMentions = allowedMentions.ToModel(),
+                    Content = text,
+                    Embeds = embeds.Any() ? embeds.Select(x => x.ToModel()).ToArray() : Optional<API.Embed[]>.Unspecified,
+                    Flags = flags,
+                    Components = components?.Components?.Any() ?? false ? components.Components.Select(x => new API.ActionRowComponent(x)).ToArray() : Optional<API.ActionRowComponent[]>.Unspecified,
+                    Stickers = stickers?.Any() ?? false ? stickers.Select(x => x.Id).ToArray() : Optional<ulong[]>.Unspecified,
+                }
+            };
+
+            var model = await client.ApiClient.CreatePostAsync(channel.Id, args, options).ConfigureAwait(false);
+
+            return RestThreadChannel.Create(client, channel.Guild, model);
+        }
+
+        public static async Task<RestThreadChannel> CreatePostAsync(IForumChannel channel, BaseDiscordClient client, string title, IEnumerable<FileAttachment> attachments, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+        {
+            embeds ??= Array.Empty<Embed>();
+            if (embed != null)
+                embeds = new[] { embed }.Concat(embeds).ToArray();
+
+            Preconditions.AtMost(allowedMentions?.RoleIds?.Count ?? 0, 100, nameof(allowedMentions.RoleIds), "A max of 100 role Ids are allowed.");
+            Preconditions.AtMost(allowedMentions?.UserIds?.Count ?? 0, 100, nameof(allowedMentions.UserIds), "A max of 100 user Ids are allowed.");
+            Preconditions.AtMost(embeds.Length, 10, nameof(embeds), "A max of 10 embeds are allowed.");
+
+            // check that user flag and user Id list are exclusive, same with role flag and role Id list
+            if (allowedMentions != null && allowedMentions.AllowedTypes.HasValue)
+            {
+                if (allowedMentions.AllowedTypes.Value.HasFlag(AllowedMentionTypes.Users) &&
+                    allowedMentions.UserIds != null && allowedMentions.UserIds.Count > 0)
+                {
+                    throw new ArgumentException("The Users flag is mutually exclusive with the list of User Ids.", nameof(allowedMentions));
+                }
+
+                if (allowedMentions.AllowedTypes.Value.HasFlag(AllowedMentionTypes.Roles) &&
+                    allowedMentions.RoleIds != null && allowedMentions.RoleIds.Count > 0)
+                {
+                    throw new ArgumentException("The Roles flag is mutually exclusive with the list of Role Ids.", nameof(allowedMentions));
+                }
+            }
+
+            if (stickers != null)
+            {
+                Preconditions.AtMost(stickers.Length, 3, nameof(stickers), "A max of 3 stickers are allowed.");
             }
 
+
+            if (flags is not MessageFlags.None and not MessageFlags.SuppressEmbeds)
+                throw new ArgumentException("The only valid MessageFlags are SuppressEmbeds and none.", nameof(flags));
+
+            var args = new CreateMultipartPostAsync(attachments.ToArray())
+            {
+                AllowedMentions = allowedMentions.ToModel(),
+                ArchiveDuration = archiveDuration,
+                Content = text,
+                Embeds = embeds.Any() ? embeds.Select(x => x.ToModel()).ToArray() : Optional<API.Embed[]>.Unspecified,
+                Flags = flags,
+                MessageComponent = components?.Components?.Any() ?? false ? components.Components.Select(x => new API.ActionRowComponent(x)).ToArray() : Optional<API.ActionRowComponent[]>.Unspecified,
+                Slowmode = slowmode,
+                Stickers = stickers?.Any() ?? false ? stickers.Select(x => x.Id).ToArray() : Optional<ulong[]>.Unspecified,
+                Title = title
+            };
+
+            var model = await client.ApiClient.CreatePostAsync(channel.Id, args, options);
+
             return RestThreadChannel.Create(client, channel.Guild, model);
         }
     }

src/Discord.Net.WebSocket/Entities/Channels/SocketForumChannel.cs

@@ -2,6 +2,7 @@ using Discord.Rest;
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.IO;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
@@ -45,14 +46,46 @@ namespace Discord.WebSocket
             Topic = model.Topic.GetValueOrDefault();
             DefaultAutoArchiveDuration = model.AutoArchiveDuration.GetValueOrDefault(ThreadArchiveDuration.OneDay);
 
-            Tags = model.ForumTags.GetValueOrDefault(new API.ForumTags[0]).Select(
+            Tags = model.ForumTags.GetValueOrDefault(Array.Empty<API.ForumTags>()).Select(
                 x => new ForumTag(x.Id, x.Name, x.EmojiId.GetValueOrDefault(null), x.EmojiName.GetValueOrDefault())
             ).ToImmutableArray();
         }
 
-        /// <inheritdoc cref="IForumChannel.CreatePostAsync(string, ThreadArchiveDuration, Message, int?, RequestOptions)"/>
-        public Task<RestThreadChannel> CreatePostAsync(string title, ThreadArchiveDuration archiveDuration, Message message, int? slowmode = null, RequestOptions options = null)
-            => ThreadHelper.CreatePostAsync(this, Discord, title, archiveDuration, message, slowmode, options);
+        /// <inheritdoc cref="IForumChannel.CreatePostAsync(string, ThreadArchiveDuration, int?, string, Embed, RequestOptions, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public Task<RestThreadChannel> CreatePostAsync(string title, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay, int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null, MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+            => ThreadHelper.CreatePostAsync(this, Discord, title, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags);
+
+        /// <inheritdoc cref="IForumChannel.CreatePostWithFileAsync(string, string, ThreadArchiveDuration, int?, string, Embed, RequestOptions, bool, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public async Task<RestThreadChannel> CreatePostWithFileAsync(string title, string filePath, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, bool isSpoiler = false,
+            AllowedMentions allowedMentions = null, MessageComponent components = null,
+            ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+        {
+            using var file = new FileAttachment(filePath, isSpoiler: isSpoiler);
+            return await ThreadHelper.CreatePostAsync(this, Discord, title, new FileAttachment[] { file }, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        }
+
+        /// <inheritdoc cref="IForumChannel.CreatePostWithFileAsync(string, Stream, string, ThreadArchiveDuration, int?, string, Embed, RequestOptions, bool, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public async Task<RestThreadChannel> CreatePostWithFileAsync(string title, Stream stream, string filename, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, bool isSpoiler = false,
+            AllowedMentions allowedMentions = null, MessageComponent components = null,
+            ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+        {
+            using var file = new FileAttachment(stream, filename, isSpoiler: isSpoiler);
+            return await ThreadHelper.CreatePostAsync(this, Discord, title, new FileAttachment[] { file }, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        }
+
+        /// <inheritdoc cref="IForumChannel.CreatePostWithFileAsync(string, FileAttachment, ThreadArchiveDuration, int?, string, Embed, RequestOptions, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public Task<RestThreadChannel> CreatePostWithFileAsync(string title, FileAttachment attachment, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null,
+            MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+            => ThreadHelper.CreatePostAsync(this, Discord, title, new FileAttachment[] { attachment }, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags);
+
+        /// <inheritdoc cref="IForumChannel.CreatePostWithFilesAsync(string, IEnumerable{FileAttachment}, ThreadArchiveDuration, int?, string, Embed, RequestOptions, AllowedMentions, MessageComponent, ISticker[], Embed[], MessageFlags)"/>
+        public Task<RestThreadChannel> CreatePostWithFilesAsync(string title, IEnumerable<FileAttachment> attachments, ThreadArchiveDuration archiveDuration = ThreadArchiveDuration.OneDay,
+            int? slowmode = null, string text = null, Embed embed = null, RequestOptions options = null, AllowedMentions allowedMentions = null,
+            MessageComponent components = null, ISticker[] stickers = null, Embed[] embeds = null, MessageFlags flags = MessageFlags.None)
+            => ThreadHelper.CreatePostAsync(this, Discord, title, attachments, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags);
 
         /// <inheritdoc cref="IForumChannel.GetActiveThreadsAsync(RequestOptions)"/>
         public Task<IReadOnlyCollection<RestThreadChannel>> GetActiveThreadsAsync(RequestOptions options = null)
@@ -71,8 +104,6 @@ namespace Discord.WebSocket
             => ThreadHelper.GetPublicArchivedThreadsAsync(this, Discord, limit, before, options);
 
         #region IForumChannel
-        async Task<IThreadChannel> IForumChannel.CreatePostAsync(string title, ThreadArchiveDuration archiveDuration, Message message, int? slowmode, RequestOptions options)
-            => await CreatePostAsync(title, archiveDuration, message, slowmode, options).ConfigureAwait(false);
         async Task<IReadOnlyCollection<IThreadChannel>> IForumChannel.GetActiveThreadsAsync(RequestOptions options)
             => await GetActiveThreadsAsync(options).ConfigureAwait(false);
         async Task<IReadOnlyCollection<IThreadChannel>> IForumChannel.GetPublicArchivedThreadsAsync(int? limit, DateTimeOffset? before, RequestOptions options)
@@ -81,6 +112,17 @@ namespace Discord.WebSocket
             => await GetPrivateArchivedThreadsAsync(limit, before, options).ConfigureAwait(false);
         async Task<IReadOnlyCollection<IThreadChannel>> IForumChannel.GetJoinedPrivateArchivedThreadsAsync(int? limit, DateTimeOffset? before, RequestOptions options)
             => await GetJoinedPrivateArchivedThreadsAsync(limit, before, options).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostAsync(string title, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostAsync(title, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostWithFileAsync(string title, string filePath, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, bool isSpoiler, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostWithFileAsync(title, filePath, archiveDuration, slowmode, text, embed, options, isSpoiler, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostWithFileAsync(string title, Stream stream, string filename, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, bool isSpoiler, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostWithFileAsync(title, stream, filename, archiveDuration, slowmode, text, embed, options, isSpoiler, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostWithFileAsync(string title, FileAttachment attachment, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostWithFileAsync(title, attachment, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags).ConfigureAwait(false);
+        async Task<IThreadChannel> IForumChannel.CreatePostWithFilesAsync(string title, IEnumerable<FileAttachment> attachments, ThreadArchiveDuration archiveDuration, int? slowmode, string text, Embed embed, RequestOptions options, AllowedMentions allowedMentions, MessageComponent components, ISticker[] stickers, Embed[] embeds, MessageFlags flags)
+            => await CreatePostWithFilesAsync(title, attachments, archiveDuration, slowmode, text, embed, options, allowedMentions, components, stickers, embeds, flags);
+
         #endregion
     }
 }

src/Discord.Net.WebSocket/Entities/Guilds/SocketGuild.cs

@@ -705,7 +705,15 @@ namespace Discord.WebSocket
         /// </returns>
         public SocketThreadChannel GetThreadChannel(ulong id)
             => GetChannel(id) as SocketThreadChannel;
-
+        /// <summary>
+        ///     Gets a forum channel in this guild.
+        /// </summary>
+        /// <param name="id">The snowflake identifier for the forum channel.</param>
+        /// <returns>
+        ///     A forum channel associated with the specified <paramref name="id" />; <see langword="null"/> if none is found.
+        /// </returns>
+        public SocketForumChannel GetForumChannel(ulong id)
+            => GetChannel(id) as SocketForumChannel;
         /// <summary>
         ///     Gets a voice channel in this guild.
         /// </summary>