Implement multi-file upload to webhooks (#1942)

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

@@ -11,9 +11,8 @@ namespace Discord.API.Rest
     {
         private static JsonSerializer _serializer = new JsonSerializer { ContractResolver = new DiscordContractResolver() };
 
-        public Stream File { get; }
+        public FileAttachment[] Files { get; }
 
-        public Optional<string> Filename { get; set; }
         public Optional<string> Content { get; set; }
         public Optional<string> Nonce { get; set; }
         public Optional<bool> IsTTS { get; set; }
@@ -21,22 +20,16 @@ namespace Discord.API.Rest
         public Optional<string> AvatarUrl { get; set; }
         public Optional<Embed[]> Embeds { get; set; }
         public Optional<AllowedMentions> AllowedMentions { get; set; }
+        public Optional<ActionRowComponent[]> MessageComponents { get; set; }
 
-        public bool IsSpoiler { get; set; } = false;
+        public UploadWebhookFileParams(params FileAttachment[] files)
-
-        public UploadWebhookFileParams(Stream file)
         {
-            File = file;
+            Files = files;
         }
 
         public IReadOnlyDictionary<string, object> ToDictionary()
         {
             var d = new Dictionary<string, object>();
-            var filename = Filename.GetValueOrDefault("unknown.dat");
-            if (IsSpoiler && !filename.StartsWith(AttachmentExtensions.SpoilerPrefix))
-                filename = filename.Insert(0, AttachmentExtensions.SpoilerPrefix);
-
-            d["file"] = new MultipartFile(File, filename);
 
             var payload = new Dictionary<string, object>();
             if (Content.IsSpecified)
@@ -49,11 +42,34 @@ namespace Discord.API.Rest
                 payload["username"] = Username.Value;
             if (AvatarUrl.IsSpecified)
                 payload["avatar_url"] = AvatarUrl.Value;
+            if (MessageComponents.IsSpecified)
+                payload["components"] = MessageComponents.Value;
             if (Embeds.IsSpecified)
                 payload["embeds"] = Embeds.Value;
             if (AllowedMentions.IsSpecified)
                 payload["allowed_mentions"] = AllowedMentions.Value;
 
+            List<object> attachments = new();
+
+            for (int n = 0; n != Files.Length; n++)
+            {
+                var attachment = Files[n];
+
+                var filename = attachment.FileName ?? "unknown.dat";
+                if (attachment.IsSpoiler && !filename.StartsWith(AttachmentExtensions.SpoilerPrefix))
+                    filename = filename.Insert(0, AttachmentExtensions.SpoilerPrefix);
+                d[$"files[{n}]"] = new MultipartFile(attachment.Stream, filename);
+
+                attachments.Add(new
+                {
+                    id = (ulong)n,
+                    filename = filename,
+                    description = attachment.Description ?? Optional<string>.Unspecified
+                });
+            }
+
+            payload["attachments"] = attachments;
+
             var json = new StringBuilder();
             using (var text = new StringWriter(json))
             using (var writer = new JsonTextWriter(text))

src/Discord.Net.Webhook/DiscordWebhookClient.cs

@@ -123,14 +123,35 @@ namespace Discord.Webhook
         /// <returns> Returns the ID of the created message. </returns>
         public Task<ulong> SendFileAsync(string filePath, string text, bool isTTS = false,
             IEnumerable<Embed> embeds = null, string username = null, string avatarUrl = null,
-            RequestOptions options = null, bool isSpoiler = false, AllowedMentions allowedMentions = null)
+            RequestOptions options = null, bool isSpoiler = false, AllowedMentions allowedMentions = null,
-            => WebhookClientHelper.SendFileAsync(this, filePath, text, isTTS, embeds, username, avatarUrl, allowedMentions, options, isSpoiler);
+            MessageComponent components = null)
+            => WebhookClientHelper.SendFileAsync(this, filePath, text, isTTS, embeds, username, avatarUrl,
+                allowedMentions, options, isSpoiler, components);
         /// <summary> Sends a message to the channel for this webhook with an attachment. </summary>
         /// <returns> Returns the ID of the created message. </returns>
         public Task<ulong> SendFileAsync(Stream stream, string filename, string text, bool isTTS = false,
             IEnumerable<Embed> embeds = null, string username = null, string avatarUrl = null,
-            RequestOptions options = null, bool isSpoiler = false, AllowedMentions allowedMentions = null)
+            RequestOptions options = null, bool isSpoiler = false, AllowedMentions allowedMentions = null,
-            => WebhookClientHelper.SendFileAsync(this, stream, filename, text, isTTS, embeds, username, avatarUrl, allowedMentions, options, isSpoiler);
+            MessageComponent components = null)
+            => WebhookClientHelper.SendFileAsync(this, stream, filename, text, isTTS, embeds, username,
+                avatarUrl, allowedMentions, options, isSpoiler, components);
+
+        /// <summary> Sends a message to the channel for this webhook with an attachment. </summary>
+        /// <returns> Returns the ID of the created message. </returns>
+        public Task<ulong> SendFileAsync(FileAttachment attachment, string text, bool isTTS = false,
+            IEnumerable<Embed> embeds = null, string username = null, string avatarUrl = null,
+            RequestOptions options = null, AllowedMentions allowedMentions = null, MessageComponent components = null)
+            => WebhookClientHelper.SendFileAsync(this, attachment, text, isTTS, embeds, username,
+                avatarUrl, allowedMentions, components, options);
+
+        /// <summary> Sends a message to the channel for this webhook with an attachment. </summary>
+        /// <returns> Returns the ID of the created message. </returns>
+        public Task<ulong> SendFilesAsync(IEnumerable<FileAttachment> attachments, string text, bool isTTS = false,
+            IEnumerable<Embed> embeds = null, string username = null, string avatarUrl = null,
+            RequestOptions options = null, AllowedMentions allowedMentions = null, MessageComponent components = null)
+            => WebhookClientHelper.SendFilesAsync(this, attachments, text, isTTS, embeds, username, avatarUrl,
+                allowedMentions, components, options);
+
 
         /// <summary> Modifies the properties of this webhook. </summary>
         public Task ModifyWebhookAsync(Action<WebhookProperties> func, RequestOptions options = null)

src/Discord.Net.Webhook/WebhookClientHelper.cs

@@ -97,24 +97,51 @@ namespace Discord.Webhook
             await client.ApiClient.DeleteWebhookMessageAsync(client.Webhook.Id, messageId, options).ConfigureAwait(false);
         }
         public static async Task<ulong> SendFileAsync(DiscordWebhookClient client, string filePath, string text, bool isTTS,
-            IEnumerable<Embed> embeds, string username, string avatarUrl, AllowedMentions allowedMentions, RequestOptions options, bool isSpoiler)
+            IEnumerable<Embed> embeds, string username, string avatarUrl, AllowedMentions allowedMentions, RequestOptions options, bool isSpoiler, MessageComponent components)
         {
             string filename = Path.GetFileName(filePath);
             using (var file = File.OpenRead(filePath))
-                return await SendFileAsync(client, file, filename, text, isTTS, embeds, username, avatarUrl, allowedMentions, options, isSpoiler).ConfigureAwait(false);
+                return await SendFileAsync(client, file, filename, text, isTTS, embeds, username, avatarUrl, allowedMentions, options, isSpoiler, components).ConfigureAwait(false);
         }
-        public static async Task<ulong> SendFileAsync(DiscordWebhookClient client, Stream stream, string filename, string text, bool isTTS,
+        public static Task<ulong> SendFileAsync(DiscordWebhookClient client, Stream stream, string filename, string text, bool isTTS,
-            IEnumerable<Embed> embeds, string username, string avatarUrl, AllowedMentions allowedMentions, RequestOptions options, bool isSpoiler)
+            IEnumerable<Embed> embeds, string username, string avatarUrl, AllowedMentions allowedMentions, RequestOptions options, bool isSpoiler,
+            MessageComponent components)
+            => SendFileAsync(client, new FileAttachment(stream, filename, isSpoiler: isSpoiler), text, isTTS, embeds, username, avatarUrl, allowedMentions, components, options);
+
+        public static Task<ulong> SendFileAsync(DiscordWebhookClient client, FileAttachment attachment, string text, bool isTTS, IEnumerable<Embed> embeds, string username, string avatarUrl, AllowedMentions allowedMentions, MessageComponent components, RequestOptions options)
+            => SendFilesAsync(client, new FileAttachment[] { attachment }, text, isTTS, embeds, username, avatarUrl, allowedMentions, components, options);
+
+        public static async Task<ulong> SendFilesAsync(DiscordWebhookClient client,
+            IEnumerable<FileAttachment> attachments, string text, bool isTTS, IEnumerable<Embed> embeds, string username, string avatarUrl, AllowedMentions allowedMentions, MessageComponent components, RequestOptions options)
         {
-            var args = new UploadWebhookFileParams(stream) { Filename = filename, Content = text, IsTTS = isTTS, IsSpoiler = isSpoiler };
+            embeds ??= Array.Empty<Embed>();
-            if (username != null)
+           
-                args.Username = username;
+            Preconditions.AtMost(allowedMentions?.RoleIds?.Count ?? 0, 100, nameof(allowedMentions.RoleIds), "A max of 100 role Ids are allowed.");
-            if (avatarUrl != null)
+            Preconditions.AtMost(allowedMentions?.UserIds?.Count ?? 0, 100, nameof(allowedMentions.UserIds), "A max of 100 user Ids are allowed.");
-                args.AvatarUrl = avatarUrl;
+            Preconditions.AtMost(embeds.Count(), 10, nameof(embeds), "A max of 10 embeds are allowed.");
-            if (embeds != null)
+
-                args.Embeds = embeds.Select(x => x.ToModel()).ToArray();
+            foreach (var attachment in attachments)
-            if(allowedMentions != null)
+            {
-                args.AllowedMentions = allowedMentions.ToModel();
+                Preconditions.NotNullOrEmpty(attachment.FileName, nameof(attachment.FileName), "File Name must not be empty or null");
+            }
+
+            // 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));
+                }
+            }
+
+            var args = new UploadWebhookFileParams(attachments.ToArray()) {AvatarUrl = avatarUrl, Username = username, Content = text, IsTTS = isTTS, Embeds = embeds.Any() ? embeds.Select(x => x.ToModel()).ToArray() : Optional<API.Embed[]>.Unspecified, AllowedMentions = allowedMentions?.ToModel() ?? Optional<API.AllowedMentions>.Unspecified, MessageComponents = components?.Components.Select(x => new API.ActionRowComponent(x)).ToArray() ?? Optional<API.ActionRowComponent[]>.Unspecified };
             var msg = await client.ApiClient.UploadWebhookFileAsync(client.Webhook.Id, args, options).ConfigureAwait(false);
             return msg.Id;
         }