feat: Add slowmode functionality to text channels (#680)

* feat: Add slowmode functionality to text channels

Signed-off-by: arsabutispik <ispik@ispik.dev>

* fix: use atomic check-and-set to prevent spamming with scripts

Signed-off-by: arsabutispik <ispik@ispik.dev>

* feat: Add BypassSlowmode permission to channel permissions

Signed-off-by: arsabutispik <ispik@ispik.dev>

* refactor: Use set_options instead of manually building the command

Signed-off-by: arsabutispik <ispik@ispik.dev>

---------

Signed-off-by: arsabutispik <ispik@ispik.dev>

crates/core/database/src/models/channels/model.rs

@@ -110,6 +110,10 @@ auto_derived!(
             /// Voice Information for when this channel is also a voice channel
             #[serde(skip_serializing_if = "Option::is_none")]
             voice: Option<VoiceInformation>,
+
+            /// The channel's slowmode delay in seconds
+            #[serde(skip_serializing_if = "Option::is_none")]
+            slowmode: Option<u64>,
         },
     }
 
@@ -146,6 +150,8 @@ auto_derived!(
         pub last_message_id: Option<String>,
         #[serde(skip_serializing_if = "Option::is_none")]
         pub voice: Option<VoiceInformation>,
+        #[serde(skip_serializing_if = "Option::is_none")]
+        pub slowmode: Option<u64>,
     }
 
     /// Optional fields on channel object
@@ -206,6 +212,7 @@ impl Channel {
                 role_permissions: HashMap::new(),
                 nsfw: data.nsfw.unwrap_or(false),
                 voice: data.voice.map(|voice| voice.into()),
+                slowmode: None
             },
             v0::LegacyServerChannelType::Voice => Channel::TextChannel {
                 id: id.clone(),
@@ -218,6 +225,7 @@ impl Channel {
                 role_permissions: HashMap::new(),
                 nsfw: data.nsfw.unwrap_or(false),
                 voice: Some(data.voice.unwrap_or_default().into()),
+                slowmode: None
             },
         };
 

crates/core/database/src/util/bridge/v0.rs

@@ -190,6 +190,7 @@ impl From<crate::Channel> for Channel {
                 role_permissions,
                 nsfw,
                 voice,
+                slowmode
             } => Channel::TextChannel {
                 id,
                 server,
@@ -201,6 +202,7 @@ impl From<crate::Channel> for Channel {
                 role_permissions,
                 nsfw,
                 voice: voice.map(|voice| voice.into()),
+                slowmode
             },
         }
     }
@@ -254,6 +256,7 @@ impl From<Channel> for crate::Channel {
                 role_permissions,
                 nsfw,
                 voice,
+                slowmode
             } => crate::Channel::TextChannel {
                 id,
                 server,
@@ -265,6 +268,7 @@ impl From<Channel> for crate::Channel {
                 role_permissions,
                 nsfw,
                 voice: voice.map(|voice| voice.into()),
+                slowmode
             },
         }
     }
@@ -283,7 +287,8 @@ impl From<crate::PartialChannel> for PartialChannel {
             role_permissions: value.role_permissions,
             default_permissions: value.default_permissions,
             last_message_id: value.last_message_id,
-            voice: value.voice.map(|voice| voice.into())
+            voice: value.voice.map(|voice| voice.into()),
+            slowmode: value.slowmode,
         }
     }
 }
@@ -301,7 +306,8 @@ impl From<PartialChannel> for crate::PartialChannel {
             role_permissions: value.role_permissions,
             default_permissions: value.default_permissions,
             last_message_id: value.last_message_id,
-            voice: value.voice.map(|voice| voice.into())
+            voice: value.voice.map(|voice| voice.into()),
+            slowmode: value.slowmode
         }
     }
 }

crates/core/models/src/v0/channels.rs

@@ -112,6 +112,10 @@ auto_derived!(
             /// Voice Information for when this channel is also a voice channel
             #[cfg_attr(feature = "serde", serde(skip_serializing_if = "Option::is_none"))]
             voice: Option<VoiceInformation>,
+
+            /// The channel's slowmode delay in seconds
+            #[serde(skip_serializing_if = "Option::is_none")]
+            slowmode: Option<u64>,
         },
     }
 
@@ -150,6 +154,8 @@ auto_derived!(
         pub last_message_id: Option<String>,
         #[cfg_attr(feature = "serde", serde(skip_serializing_if = "Option::is_none"))]
         pub voice: Option<VoiceInformation>,
+        #[cfg_attr(feature = "serde", serde(skip_serializing_if = "Option::is_none"))]
+        pub slowmode: Option<u64>,
     }
 
     /// Optional fields on channel object
@@ -189,6 +195,10 @@ auto_derived!(
         /// Voice Information for voice channels
         pub voice: Option<VoiceInformation>,
 
+        /// The channel's slow mode delay in seconds, up to 6 hours
+        #[cfg_attr(feature = "validator", validate(range(min = 0, max = 21600)))]
+        pub slowmode: Option<u64>,
+
         /// Fields to remove from channel
         #[cfg_attr(feature = "serde", serde(default))]
         pub remove: Vec<FieldsChannel>,

crates/core/permissions/src/models/channel.rs

@@ -75,6 +75,8 @@ pub enum ChannelPermission {
     Masquerade = 1 << 28,
     /// React to messages with emojis
     React = 1 << 29,
+    /// Bypass slowmode
+    BypassSlowmode = 1 << 39,
 
     // * Voice permissions
     /// Connect to a voice channel
@@ -99,7 +101,7 @@ pub enum ChannelPermission {
     MentionRoles = 1 << 38,
 
     // * Misc. permissions
-    // % Bits 38 to 52: free area
+    // % Bits 39 to 52: free area
     // % Bits 53 to 64: do not use
 
     // * Grant all permissions

crates/core/result/src/axum.rs

@@ -36,6 +36,9 @@ impl IntoResponse for Error {
             ErrorType::NotInGroup => StatusCode::NOT_FOUND,
             ErrorType::AlreadyPinned => StatusCode::BAD_REQUEST,
             ErrorType::NotPinned => StatusCode::BAD_REQUEST,
+            ErrorType::InSlowmode {
+                retry_after: _,
+            } => StatusCode::TOO_MANY_REQUESTS,
 
             ErrorType::CantCreateServers => StatusCode::FORBIDDEN,
             ErrorType::UnknownServer => StatusCode::NOT_FOUND,

crates/core/result/src/lib.rs

@@ -102,6 +102,9 @@ pub enum ErrorType {
     NotInGroup,
     AlreadyPinned,
     NotPinned,
+    InSlowmode {
+        retry_after: u64,
+    },
 
     // ? Server related errors
     CantCreateServers,

crates/core/result/src/rocket.rs

@@ -42,6 +42,9 @@ impl<'r> Responder<'r, 'static> for Error {
             ErrorType::NotInGroup => Status::NotFound,
             ErrorType::AlreadyPinned => Status::BadRequest,
             ErrorType::NotPinned => Status::BadRequest,
+            ErrorType::InSlowmode {
+                retry_after: _,
+            } => Status::TooManyRequests,
             ErrorType::InvalidFlagValue => Status::BadRequest,
 
             ErrorType::CantCreateServers => Status::Forbidden,

crates/delta/src/routes/channels/channel_edit.rs

@@ -41,6 +41,7 @@ pub async fn edit(
         && data.nsfw.is_none()
         && data.owner.is_none()
         && data.voice.is_none()
+        && data.slowmode.is_none()
         && data.remove.is_empty()
     {
         return Ok(Json(channel.into()));
@@ -200,6 +201,7 @@ pub async fn edit(
             icon,
             nsfw,
             voice,
+            slowmode,
             ..
         } => {
             if data.remove.contains(&v0::FieldsChannel::Icon) {
@@ -247,6 +249,11 @@ pub async fn edit(
                 *voice = Some(new_voice.clone().into());
                 partial.voice = Some(new_voice.into());
             }
+
+            if let Some(new_slowmode) = data.slowmode {
+                *slowmode = Some(new_slowmode);
+                partial.slowmode = Some(new_slowmode);
+            }
         }
         _ => return Err(create_error!(InvalidOperation)),
     };

crates/delta/src/routes/channels/message_send.rs

@@ -1,9 +1,10 @@
 use chrono::{Duration, Utc};
+use redis_kiss::{get_connection, redis, AsyncCommands};
 use revolt_database::util::permissions::DatabasePermissionQuery;
 use revolt_database::{
     util::idempotency::IdempotencyKey, util::reference::Reference, Database, User,
 };
-use revolt_database::{Interactions, Message, AMQP};
+use revolt_database::{Channel, Interactions, Message, AMQP};
 use revolt_models::v0;
 use revolt_permissions::PermissionQuery;
 use revolt_permissions::{calculate_channel_permissions, ChannelPermission};
@@ -57,6 +58,50 @@ pub async fn message_send(
         permissions.throw_if_lacking_channel_permission(ChannelPermission::UploadFiles)?;
     }
 
+    if !permissions.has_channel_permission(ChannelPermission::BypassSlowmode) {
+        if let Channel::TextChannel {
+            slowmode: Some(channel_slowmode),
+            id: channel_id,
+            ..
+        } = &channel
+        {
+            if *channel_slowmode > 0 {
+                if let Ok(conn) = get_connection().await {
+                    let mut conn = conn.into_inner();
+
+                    let slowmode_key = format!("slowmode:{}:{}", user.id, channel_id);
+
+                    // Atomic check-and-set: only set if absent and apply expiry in one command.
+                    let set_result: Option<String> = conn
+                        .set_options(
+                            &slowmode_key,
+                            "1", // The value doesn't matter, only the key's existence
+                            redis::SetOptions::default()
+                                .conditional_set(redis::ExistenceCheck::NX)
+                                .with_expiration(redis::SetExpiry::EX(*channel_slowmode as usize)),
+                        )
+                        .await
+                        .unwrap_or(None);
+
+                    // If `set_result` is None, the `NX` condition failed because the key already exists.
+                    // This means the user is currently in slowmode.
+                    if set_result.is_none() {
+                        // Fetch the remaining TTL to accurately populate the retry_after field
+                        let ttl: i64 = conn.ttl(&slowmode_key).await.unwrap_or(0);
+
+                        // Redis returns positive integers for valid TTLs
+                        if ttl > 0 {
+                            return Err(create_error!(InSlowmode {
+                                retry_after: ttl as u64
+                            }));
+                        }
+                    }
+                }
+                // If Redis connection fails, just skip the slowmode check
+            }
+        }
+    }
+
     // Ensure interactions information is correct
     if let Some(interactions) = &data.interactions {
         let interactions: Interactions = interactions.clone().into();
@@ -186,6 +231,7 @@ mod test {
             }),
             last_message_id: None,
             voice: None,
+            slowmode: None,
         };
         locked_channel
             .update(&harness.db, partial, vec![])