Can get a conversation ID from a POST request

src/helpers/conversations_helper.rs

@@ -77,7 +77,15 @@ pub fn get_list_members(conv_id: u64) -> ResultBoxError<Vec<UserID>> {
     database::QueryInfo::new(CONV_USERS_TABLE)
         .cond_u64("conv_id", conv_id)
         .add_field("user_id")
-        .exec(|res|res.get_user_id("user_id"))
+        .exec(|res| res.get_user_id("user_id"))
+}
+
+/// Check if a user belongs to a conversation or not
+pub fn does_user_belongs_to(user_id: UserID, conv_id: u64) -> ResultBoxError<bool> {
+    Ok(database::QueryInfo::new(CONV_USERS_TABLE)
+        .cond_u64("conv_id", conv_id)
+        .cond_user_id("user_id", user_id)
+        .exec_count()? > 0)
 }
 
 /// Turn a database entry into a ConversationInfo object