Support attachments in forum posts

examples/testing/src/main.rs

@@ -209,6 +209,31 @@ async fn message(ctx: &Context, msg: Message) -> Result<(), serenity::Error> {
             &*guild.member(ctx, msg.author.id).await?,
         );
         channel_id.say(ctx, format!("{:?}", perms)).await?;
+    } else if let Some(forum_channel_id) = msg.content.strip_prefix("createforumpostin ") {
+        forum_channel_id
+            .parse::<ChannelId>()
+            .unwrap()
+            .create_forum_post(
+                ctx,
+                CreateForumPost::new(
+                    "a",
+                    CreateMessage::new()
+                        .add_file(CreateAttachment::bytes(b"Hallo welt!", "lul.txt")),
+                ),
+                // CreateForumPost::new(
+                //     "a",
+                //     CreateMessage::new()
+                //         .content("test, i hope that forum posts without attachments still
+                // work?")         .embed(CreateEmbed::new().title("hmmm").
+                // description("do they?")), ),
+            )
+            .await?;
+    } else if let Some(forum_post_url) = msg.content.strip_prefix("deleteforumpost ") {
+        let (_guild_id, channel_id, _message_id) =
+            serenity::utils::parse_message_url(forum_post_url).unwrap();
+        msg.channel_id.say(ctx, format!("Deleting <#{}> in 10 seconds...", channel_id)).await?;
+        tokio::time::sleep(std::time::Duration::from_secs(10)).await;
+        channel_id.delete(ctx).await?;
     } else {
         return Ok(());
     }

src/builder/create_forum_post.rs

@@ -106,10 +106,14 @@ impl<'a> Builder for CreateForumPost<'a> {
     ///
     /// Returns [`Error::Http`] if the current user lacks permission, or if invalid data is given.
     async fn execute(
-        self,
+        mut self,
         cache_http: impl CacheHttp,
         ctx: Self::Context<'_>,
     ) -> Result<Self::Built> {
-        cache_http.http().create_forum_post(ctx, &self, self.audit_log_reason).await
+        let files = self.message.attachments.take_files();
+        cache_http
+            .http()
+            .create_forum_post_with_attachments(ctx, &self, files, self.audit_log_reason)
+            .await
     }
 }

src/builder/create_message.rs

@@ -67,7 +67,7 @@ pub struct CreateMessage {
     sticker_ids: Vec<StickerId>,
     #[serde(skip_serializing_if = "Option::is_none")]
     flags: Option<MessageFlags>,
-    attachments: EditAttachments,
+    pub(crate) attachments: EditAttachments,
 
     // The following fields are handled separately.
     #[serde(skip)]

src/http/client.rs

@@ -416,18 +416,31 @@ impl Http {
         .await
     }
 
-    /// Creates a forum post channel in the [`GuildChannel`] given its Id.
+    /// Shortcut for [`Self::create_forum_post_with_attachments`]
     pub async fn create_forum_post(
         &self,
         channel_id: ChannelId,
         map: &impl serde::Serialize,
         audit_log_reason: Option<&str>,
     ) -> Result<GuildChannel> {
-        let body = to_vec(map)?;
+        self.create_forum_post_with_attachments(channel_id, map, vec![], audit_log_reason).await
+    }
 
+    /// Creates a forum post channel in the [`GuildChannel`] given its Id.
+    pub async fn create_forum_post_with_attachments(
+        &self,
+        channel_id: ChannelId,
+        map: &impl serde::Serialize,
+        files: Vec<CreateAttachment>,
+        audit_log_reason: Option<&str>,
+    ) -> Result<GuildChannel> {
         self.fire(Request {
-            body: Some(body),
-            multipart: None,
+            body: None,
+            multipart: Some(Multipart {
+                upload: MultipartUpload::Attachments(files.into_iter().collect()),
+                payload_json: Some(to_string(map)?),
+                fields: vec![],
+            }),
             headers: audit_log_reason.map(reason_into_header),
             method: LightMethod::Post,
             route: Route::ChannelForumPosts {