FEATURE: optional regex to be applied against first posts

for spam prevention you can add a regex to auto_block_first_post_regex
this will be applied against all first posts, if it matches post will go
into the approval queue and user will be blocked

config/locales/server.en.yml

@@ -1080,6 +1080,7 @@ en:
     min_first_post_typing_time: "Minimum amount of time in milliseconds a user must type during first post, if threshold is not met post will automatically enter the needs approval queue. Set to 0 to disable (not recommended)"
     auto_block_fast_typers_on_first_post: "Automatically block users that do not meet min_first_post_typing_time"
     auto_block_fast_typers_max_trust_level: "Maximum trust level to auto block fast typers"
+    auto_block_first_post_regex: "Case insensitive regex that if passed will cause first post by user to be blocked and sent to approval queue. Example: raging|a[bc]a , will cause all posts containing raging or aba or aca to be blocked on first. Only applies to first post."
 
     reply_by_email_enabled: "Enable replying to topics via email."
     reply_by_email_address: "Template for reply by email incoming email address, for example: %{reply_key}@reply.example.com or replies+%{reply_key}@example.com"

config/site_settings.yml

@@ -683,6 +683,7 @@ spam:
   min_first_post_typing_time: 3000
   auto_block_fast_typers_on_first_post: true
   auto_block_fast_typers_max_trust_level: 0
+  auto_block_first_post_regex: ""
 
 rate_limits:
   unique_posts_mins:

lib/new_post_manager.rb

@@ -28,15 +28,40 @@ class NewPostManager
     @sorted_handlers.sort_by! {|h| -h[:priority]}
   end
 
-  def self.is_fast_typer?(manager)
+  def self.is_first_post?(manager)
     user = manager.user
     args = manager.args
 
     args[:first_post_checks] &&
-    user.post_count == 0 &&
+    user.post_count == 0
+  end
+
+  def self.is_fast_typer?(manager)
+    args = manager.args
+
+    is_first_post?(manager) &&
     args[:typing_duration_msecs].to_i < SiteSetting.min_first_post_typing_time
   end
 
+  def self.matches_auto_block_regex?(manager)
+    args = manager.args
+
+    pattern = SiteSetting.auto_block_first_post_regex
+
+    return false unless pattern.present?
+    return false unless is_first_post?(manager)
+
+    begin
+      regex = Regexp.new(pattern, Regexp::IGNORECASE)
+    rescue => e
+      Rails.logger.warn "Invalid regex in auto_block_first_post_regex #{e}"
+      return false
+    end
+
+    "#{args[:title]} #{args[:raw]}" =~ regex
+
+  end
+
   def self.user_needs_approval?(manager)
     user = manager.user
 
@@ -44,7 +69,8 @@ class NewPostManager
 
     (user.post_count < SiteSetting.approve_post_count) ||
     (user.trust_level < SiteSetting.approve_unless_trust_level.to_i) ||
-    is_fast_typer?(manager)
+    is_fast_typer?(manager) ||
+    matches_auto_block_regex?(manager)
   end
 
   def self.default_handler(manager)
@@ -52,13 +78,13 @@ class NewPostManager
 
       result = manager.enqueue('default')
 
-      if  is_fast_typer?(manager) &&
-          SiteSetting.auto_block_fast_typers_on_first_post &&
-          SiteSetting.auto_block_fast_typers_max_trust_level <= manager.user.trust_level
+      block = is_fast_typer?(manager) &&
+              SiteSetting.auto_block_fast_typers_on_first_post &&
+              SiteSetting.auto_block_fast_typers_max_trust_level <= manager.user.trust_level
 
-        manager.user.update_columns(blocked: true)
+      block ||= matches_auto_block_regex?(manager)
 
-      end
+      manager.user.update_columns(blocked: true) if block
 
       result
 

spec/controllers/posts_controller_spec.rb

@@ -505,6 +505,20 @@ describe PostsController do
 
       end
 
+      it 'blocks correctly based on auto_block_first_post_regex' do
+        SiteSetting.auto_block_first_post_regex = "I love candy|i eat s[1-5]"
+
+        xhr :post, :create, {raw: 'this is the test content', title: 'when I eat s3 sometimes when not looking'}
+
+        expect(response).to be_success
+        parsed = ::JSON.parse(response.body)
+
+        expect(parsed["action"]).to eq("enqueued")
+
+        user.reload
+        expect(user.blocked).to eq(true)
+      end
+
       it 'creates the post' do
         xhr :post, :create, {raw: 'this is the test content', title: 'this is the test title for the topic'}