feat(core): add a limit to no. of outgoing pending friend requests

crates/core/config/Revolt.toml

@@ -47,6 +47,8 @@ webhooks_enabled = false
 [features.limits]
 
 [features.limits.default]
+outgoing_friend_requests = 10
+
 group_size = 100
 bots = 5
 message_length = 2000

crates/core/config/src/lib.rs

@@ -106,6 +106,8 @@ pub struct Api {
 
 #[derive(Deserialize, Debug, Clone)]
 pub struct FeaturesLimits {
+    pub outgoing_friend_requests: usize,
+
     pub group_size: usize,
     pub bots: usize,
     pub message_length: usize,

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

@@ -470,6 +470,24 @@ impl User {
 
     /// Add another user as a friend
     pub async fn add_friend(&mut self, db: &Database, target: &mut User) -> Result<()> {
+        let count = self
+            .relations
+            .as_ref()
+            .map(|relations| {
+                relations
+                    .iter()
+                    .filter(|r| matches!(r.status, RelationshipStatus::Outgoing))
+                    .count()
+            })
+            .unwrap_or_default();
+
+        let config = config().await;
+        if count >= config.features.limits.default.outgoing_friend_requests {
+            return Err(create_error!(TooManyPendingFriendRequests {
+                max: config.features.limits.default.outgoing_friend_requests
+            }));
+        }
+
         match self.relationship_with(&target.id) {
             RelationshipStatus::User => Err(create_error!(NoEffect)),
             RelationshipStatus::Friend => Err(create_error!(AlreadyFriends)),

crates/core/result/src/lib.rs

@@ -60,6 +60,9 @@ pub enum ErrorType {
     Blocked,
     BlockedByOther,
     NotFriends,
+    TooManyPendingFriendRequests {
+        max: usize,
+    },
 
     // ? Channel related errors
     UnknownChannel,

crates/core/result/src/rocket.rs

@@ -25,6 +25,7 @@ impl<'r> Responder<'r, 'static> for Error {
             ErrorType::Blocked => Status::Conflict,
             ErrorType::BlockedByOther => Status::Forbidden,
             ErrorType::NotFriends => Status::Forbidden,
+            ErrorType::TooManyPendingFriendRequests { .. } => Status::BadRequest,
 
             ErrorType::UnknownChannel => Status::NotFound,
             ErrorType::UnknownMessage => Status::NotFound,