From ffb29dea7780bb2f12f1f85b00426aad8a09b337 Mon Sep 17 00:00:00 2001
From: Patrick <pk_hunter@sbcglobal.net>
Date: Thu, 9 Jan 2014 17:25:14 -0600
Subject: [PATCH] Refactor guardian as dissused in this topic
 https://meta.discourse.org/t/so-you-want-to-help-out-with-discourse/3823/41?u=hunter

Creates a mixin for the ensure_* functions and creates seperate mixins for functions dealing with posts, categories, and topics.
---
 lib/guardian.rb                   | 248 ++----------------------------
 lib/guardian/category_guardian.rb |  34 ++++
 lib/guardian/ensure_magic.rb      |  22 +++
 lib/guardian/post_guardian.rb     | 110 +++++++++++++
 lib/guardian/topic_guardian.rb    |  85 ++++++++++
 5 files changed, 261 insertions(+), 238 deletions(-)
 create mode 100644 lib/guardian/category_guardian.rb
 create mode 100644 lib/guardian/ensure_magic.rb
 create mode 100644 lib/guardian/post_guardian.rb
 create mode 100644 lib/guardian/topic_guardian.rb

diff --git a/lib/guardian.rb b/lib/guardian.rb
index 56083c457ca..089e20747ac 100644
--- a/lib/guardian.rb
+++ b/lib/guardian.rb
@@ -1,6 +1,14 @@
+require_dependency 'guardian/category_guardian'
+require_dependency 'guardian/ensure_magic'
+require_dependency 'guardian/post_guardian'
+require_dependency 'guardian/topic_guardian'
 # The guardian is responsible for confirming access to various site resources and operations
 class Guardian
-
+  include EnsureMagic
+  include CategoryGuardian
+  include PostGuardain
+  include TopicGuardian
+    
   class AnonymousUser
     def blank?; true; end
     def admin?; false; end
@@ -11,7 +19,6 @@ class Guardian
     def has_trust_level?(level); false; end
     def email; nil; end
   end
-
   def initialize(user=nil)
     @user = user.presence || AnonymousUser.new
   end
@@ -73,26 +80,7 @@ class Guardian
   alias :can_see_flags? :can_moderate?
   alias :can_send_activation_email? :can_moderate?
 
-  # Can the user create a topic in the forum
-  def can_create?(klass, parent=nil)
-    return false unless authenticated? && klass
-
-    # If no parent is provided, we look for a can_i_create_klass?
-    # custom method.
-    #
-    # If a parent is provided, we look for a method called
-    # can_i_create_klass_on_parent?
-    target = klass.name.underscore
-    if parent.present?
-      return false unless can_see?(parent)
-      target << "_on_#{parent.class.name.underscore}"
-    end
-    create_method = :"can_create_#{target}?"
-
-    return send(create_method, parent) if respond_to?(create_method)
-
-    true
-  end
+ 
 
   # Can we impersonate this user?
   def can_impersonate?(target)
@@ -120,10 +108,6 @@ class Guardian
   end
   alias :can_deactivate? :can_suspend?
 
-  def can_clear_flags?(post)
-    is_staff? && post
-  end
-
   def can_revoke_admin?(admin)
     can_administer_user?(admin) && admin.admin?
   end
@@ -160,22 +144,6 @@ class Guardian
     user && is_staff? && !user.admin? && user.created_at > SiteSetting.delete_user_max_age.to_i.days.ago
   end
 
-  # Can we see who acted on a post in a particular way?
-  def can_see_post_actors?(topic, post_action_type_id)
-    return false unless topic
-
-    type_symbol = PostActionType.types[post_action_type_id]
-    return false if type_symbol == :bookmark
-    return can_see_flags?(topic) if PostActionType.is_flag?(type_symbol)
-
-    if type_symbol == :vote
-      # We can see votes if the topic allows for public voting
-      return false if topic.has_meta_data_boolean?(:private_poll)
-    end
-
-    true
-  end
-
   # Support sites that have to approve users
   def can_access_forum?
     return true unless SiteSetting.must_approve_users?
@@ -203,90 +171,14 @@ class Guardian
     can_see?(object) && can_invite_to_forum?
   end
 
-  def can_see_deleted_posts?
-    is_staff?
-  end
-
   def can_see_private_messages?(user_id)
     is_staff? || (authenticated? && @user.id == user_id)
   end
 
-  def can_delete_all_posts?(user)
-    is_staff? && user && !user.admin? && user.created_at >= SiteSetting.delete_user_max_age.days.ago && user.post_count <= SiteSetting.delete_all_posts_max.to_i
-  end
-
-  def can_remove_allowed_users?(topic)
-    is_staff?
-  end
-
-  # Support for ensure_{blah}! methods.
-  def method_missing(method, *args, &block)
-    if method.to_s =~ /^ensure_(.*)\!$/
-      can_method = :"#{Regexp.last_match[1]}?"
-
-      if respond_to?(can_method)
-        raise Discourse::InvalidAccess.new("#{can_method} failed") unless send(can_method, *args, &block)
-        return
-      end
-    end
-
-    super.method_missing(method, *args, &block)
-  end
-
-  # Make sure we can see the object. Will raise a NotFound if it's nil
-  def ensure_can_see!(obj)
-    raise Discourse::InvalidAccess.new("Can't see #{obj}") unless can_see?(obj)
-  end
-
-  # Creating Methods
-  def can_create_category?(parent)
-    is_staff?
-  end
-
-  def can_create_topic?(parent)
-    user && user.trust_level >= SiteSetting.min_trust_to_create_topic.to_i && can_create_post?(parent)
-  end
-
-  def can_create_topic_on_category?(category)
-    can_create_topic?(nil) && (
-      !category ||
-      Category.topic_create_allowed(self).where(:id => category.id).count == 1
-    )
-  end
-
-  def can_create_post?(parent)
-    !SpamRule::AutoBlock.block?(@user) && (
-      !parent ||
-      !parent.category ||
-      Category.post_create_allowed(self).where(:id => parent.category.id).count == 1
-    )
-  end
-
-  def can_create_post_on_topic?(topic)
-
-    # No users can create posts on deleted topics
-    return false if topic.trashed?
-
-    is_staff? || (not(topic.closed? || topic.archived? || topic.trashed?) && can_create_post?(topic))
-  end
-
-  # Editing Methods
-  def can_edit_category?(category)
-    is_staff?
-  end
-
-  def can_edit_post?(post)
-    is_staff? || (!post.topic.archived? && is_my_own?(post) && !post.user_deleted && !post.deleted_at && !post.edit_time_limit_expired?)
-  end
-
   def can_edit_user?(user)
     is_me?(user) || is_staff?
   end
 
-  def can_edit_topic?(topic)
-    !topic.archived && (is_staff? || is_my_own?(topic))
-  end
-
   def can_edit_username?(user)
     return true if is_staff?
     return false if SiteSetting.username_change_period <= 0
@@ -299,47 +191,6 @@ class Guardian
     can_edit?(user)
   end
 
-  # Deleting Methods
-  def can_delete_post?(post)
-    # Can't delete the first post
-    return false if post.post_number == 1
-
-    # Can't delete after post_edit_time_limit minutes have passed
-    return false if !is_staff? && post.edit_time_limit_expired?
-
-    # You can delete your own posts
-    return !post.user_deleted? if is_my_own?(post)
-
-    is_staff?
-  end
-
-  # Recovery Method
-  def can_recover_post?(post)
-    is_staff? || (is_my_own?(post) && post.user_deleted && !post.deleted_at)
-  end
-
-  def can_recover_topic?(topic)
-    is_staff?
-  end
-
-  def can_delete_category?(category)
-    is_staff? && category.topic_count == 0 && !category.uncatgorized?
-  end
-
-  def can_delete_topic?(topic)
-    !topic.trashed? &&
-    is_staff? &&
-    !(Category.exists?(topic_id: topic.id))
-  end
-
-  def can_delete_post_action?(post_action)
-    # You can only undo your own actions
-    is_my_own?(post_action) && not(post_action.is_private_message?) &&
-
-    # Make sure they want to delete it within the window
-    post_action.created_at > SiteSetting.post_undo_action_window_mins.minutes.ago
-  end
-
   def can_send_private_message?(target)
     (User === target || Group === target) &&
     authenticated? &&
@@ -353,85 +204,6 @@ class Guardian
     SiteSetting.enable_private_messages
   end
 
-  def can_reply_as_new_topic?(topic)
-    authenticated? && topic && not(topic.private_message?) && @user.has_trust_level?(:basic)
-  end
-
-  def can_see_topic?(topic)
-    if topic
-      is_staff? ||
-
-      topic.deleted_at.nil? &&
-
-      # not secure, or I can see it
-      (not(topic.read_restricted_category?) || can_see_category?(topic.category)) &&
-
-      # NOTE
-      # At the moment staff can see PMs, there is some talk of restricting this, however
-      # we still need to allow staff to join PMs for the case of flagging ones
-
-      # not private, or I am allowed (or is staff)
-      (not(topic.private_message?) || authenticated? && (topic.all_allowed_users.where(id: @user.id).exists? || is_staff?))
-    end
-  end
-
-  def can_see_post?(post)
-    post.present? && (is_staff? || (!post.deleted_at.present? && can_see_topic?(post.topic)))
-  end
-
-  def can_see_post_revision?(post_revision)
-    post_revision.present? && (is_staff? || can_see_post?(post_revision.post))
-  end
-
-  def can_see_category?(category)
-    not(category.read_restricted) || secure_category_ids.include?(category.id)
-  end
-
-  def can_vote?(post, opts={})
-    post_can_act?(post,:vote, opts)
-  end
-
-  # Can the user act on the post in a particular way.
-  #  taken_actions = the list of actions the user has already taken
-  def post_can_act?(post, action_key, opts={})
-
-    taken = opts[:taken_actions].try(:keys).to_a
-    is_flag = PostActionType.is_flag?(action_key)
-    already_taken_this_action = taken.any? && taken.include?(PostActionType.types[action_key])
-    already_did_flagging      = taken.any? && (taken & PostActionType.flag_types.values).any?
-
-    if  authenticated? && post
-      # we always allow flagging - NOTE: this does not seem true, see specs. (MVH)
-      (is_flag && @user.has_trust_level?(:basic) && not(already_did_flagging)) ||
-
-      # not a flagging action, and haven't done it already
-      not(is_flag || already_taken_this_action) &&
-
-      # nothing except flagging on archived posts
-      not(post.topic.archived?) &&
-
-      # don't like your own stuff
-      not(action_key == :like && is_my_own?(post)) &&
-
-      # no voting more than once on single vote topics
-      not(action_key == :vote && opts[:voted_in_topic] && post.topic.has_meta_data_boolean?(:single_vote))
-    end
-  end
-
-  def secure_category_ids
-    @secure_category_ids ||= @user.secure_category_ids
-  end
-
-  # all allowed category ids
-  def allowed_category_ids
-    unrestricted = Category.where(read_restricted: false).pluck(:id)
-    unrestricted.concat(secure_category_ids)
-  end
-
-  def topic_create_allowed_category_ids
-    @topic_create_allowed_category_ids ||= @user.topic_create_allowed_category_ids
-  end
-
   private
 
   def is_my_own?(obj)
diff --git a/lib/guardian/category_guardian.rb b/lib/guardian/category_guardian.rb
new file mode 100644
index 00000000000..7c91bbb9a62
--- /dev/null
+++ b/lib/guardian/category_guardian.rb
@@ -0,0 +1,34 @@
+#mixin for all guardian methods dealing with category permisions
+module CategoryGuardian
+  # Creating Method
+  def can_create_category?(parent)
+    is_staff?
+  end
+
+  # Editing Method
+  def can_edit_category?(category)
+    is_staff?
+  end
+
+  def can_delete_category?(category)
+    is_staff? && category.topic_count == 0 && !category.uncatgorized?
+  end
+
+  def can_see_category?(category)
+    not(category.read_restricted) || secure_category_ids.include?(category.id)
+  end
+
+  def secure_category_ids
+    @secure_category_ids ||= @user.secure_category_ids
+  end
+
+  # all allowed category ids
+  def allowed_category_ids
+    unrestricted = Category.where(read_restricted: false).pluck(:id)
+    unrestricted.concat(secure_category_ids)
+  end
+
+  def topic_create_allowed_category_ids
+    @topic_create_allowed_category_ids ||= @user.topic_create_allowed_category_ids
+  end
+end
\ No newline at end of file
diff --git a/lib/guardian/ensure_magic.rb b/lib/guardian/ensure_magic.rb
new file mode 100644
index 00000000000..9ccfbd1168c
--- /dev/null
+++ b/lib/guardian/ensure_magic.rb
@@ -0,0 +1,22 @@
+# Support for ensure_{blah}! methods.
+module EnsureMagic
+    
+  def method_missing(method, *args, &block)
+    if method.to_s =~ /^ensure_(.*)\!$/
+      can_method = :"#{Regexp.last_match[1]}?"
+
+      if respond_to?(can_method)
+        raise Discourse::InvalidAccess.new("#{can_method} failed") unless send(can_method, *args, &block)
+        return
+      end
+    end
+
+    super.method_missing(method, *args, &block)
+  end
+
+  # Make sure we can see the object. Will raise a NotFound if it's nil
+  def ensure_can_see!(obj)
+    raise Discourse::InvalidAccess.new("Can't see #{obj}") unless can_see?(obj)
+  end
+ 
+end
\ No newline at end of file
diff --git a/lib/guardian/post_guardian.rb b/lib/guardian/post_guardian.rb
new file mode 100644
index 00000000000..8aab476b3dd
--- /dev/null
+++ b/lib/guardian/post_guardian.rb
@@ -0,0 +1,110 @@
+#mixin for all guardian methods dealing with post permisions
+module PostGuardain
+  # Can the user act on the post in a particular way.
+  #  taken_actions = the list of actions the user has already taken
+  def post_can_act?(post, action_key, opts={})
+
+    taken = opts[:taken_actions].try(:keys).to_a
+    is_flag = PostActionType.is_flag?(action_key)
+    already_taken_this_action = taken.any? && taken.include?(PostActionType.types[action_key])
+    already_did_flagging      = taken.any? && (taken & PostActionType.flag_types.values).any?
+
+    if  authenticated? && post
+      # we always allow flagging - NOTE: this does not seem true, see specs. (MVH)
+      (is_flag && @user.has_trust_level?(:basic) && not(already_did_flagging)) ||
+
+      # not a flagging action, and haven't done it already
+      not(is_flag || already_taken_this_action) &&
+
+      # nothing except flagging on archived posts
+      not(post.topic.archived?) &&
+
+      # don't like your own stuff
+      not(action_key == :like && is_my_own?(post)) &&
+
+      # no voting more than once on single vote topics
+      not(action_key == :vote && opts[:voted_in_topic] && post.topic.has_meta_data_boolean?(:single_vote))
+    end
+  end
+
+  def can_clear_flags?(post)
+    is_staff? && post
+  end
+
+  # Can we see who acted on a post in a particular way?
+  def can_see_post_actors?(topic, post_action_type_id)
+    return false unless topic
+
+    type_symbol = PostActionType.types[post_action_type_id]
+    return false if type_symbol == :bookmark
+    return can_see_flags?(topic) if PostActionType.is_flag?(type_symbol)
+
+    if type_symbol == :vote
+      # We can see votes if the topic allows for public voting
+      return false if topic.has_meta_data_boolean?(:private_poll)
+    end
+
+    true
+  end
+
+  def can_see_deleted_posts?
+    is_staff?
+  end
+
+  def can_delete_all_posts?(user)
+    is_staff? && user && !user.admin? && user.created_at >= SiteSetting.delete_user_max_age.days.ago && user.post_count <= SiteSetting.delete_all_posts_max.to_i
+  end
+
+  # Creating Method
+  def can_create_post?(parent)
+    !SpamRule::AutoBlock.block?(@user) && (
+    !parent ||
+    !parent.category ||
+    Category.post_create_allowed(self).where(:id => parent.category.id).count == 1
+    )
+  end
+
+  # Editing Method
+  def can_edit_post?(post)
+    is_staff? || (!post.topic.archived? && is_my_own?(post) && !post.user_deleted && !post.deleted_at && !post.edit_time_limit_expired?)
+  end
+
+  # Deleting Methods
+  def can_delete_post?(post)
+    # Can't delete the first post
+    return false if post.post_number == 1
+
+    # Can't delete after post_edit_time_limit minutes have passed
+    return false if !is_staff? && post.edit_time_limit_expired?
+
+    # You can delete your own posts
+    return !post.user_deleted? if is_my_own?(post)
+
+    is_staff?
+  end
+
+  # Recovery Method
+  def can_recover_post?(post)
+    is_staff? || (is_my_own?(post) && post.user_deleted && !post.deleted_at)
+  end
+
+  def can_delete_post_action?(post_action)
+    # You can only undo your own actions
+    is_my_own?(post_action) && not(post_action.is_private_message?) &&
+
+    # Make sure they want to delete it within the window
+    post_action.created_at > SiteSetting.post_undo_action_window_mins.minutes.ago
+  end
+
+  def can_see_post?(post)
+    post.present? && (is_staff? || (!post.deleted_at.present? && can_see_topic?(post.topic)))
+  end
+
+  def can_see_post_revision?(post_revision)
+    post_revision.present? && (is_staff? || can_see_post?(post_revision.post))
+  end
+
+  def can_vote?(post, opts={})
+    post_can_act?(post,:vote, opts)
+  end
+end
\ No newline at end of file
diff --git a/lib/guardian/topic_guardian.rb b/lib/guardian/topic_guardian.rb
new file mode 100644
index 00000000000..69445489f77
--- /dev/null
+++ b/lib/guardian/topic_guardian.rb
@@ -0,0 +1,85 @@
+#mixin for all guardian methods dealing with topic permisions
+module TopicGuardian
+  # Can the user create a topic in the forum
+  def can_create?(klass, parent=nil)
+    return false unless authenticated? && klass
+
+    # If no parent is provided, we look for a can_i_create_klass?
+    # custom method.
+    #
+    # If a parent is provided, we look for a method called
+    # can_i_create_klass_on_parent?
+    target = klass.name.underscore
+    if parent.present?
+      return false unless can_see?(parent)
+      target << "_on_#{parent.class.name.underscore}"
+    end
+    create_method = :"can_create_#{target}?"
+
+    return send(create_method, parent) if respond_to?(create_method)
+
+    true
+  end
+
+  def can_remove_allowed_users?(topic)
+    is_staff?
+  end
+
+  # Creating Methods
+  def can_create_topic?(parent)
+    user && user.trust_level >= SiteSetting.min_trust_to_create_topic.to_i && can_create_post?(parent)
+  end
+
+  def can_create_topic_on_category?(category)
+    can_create_topic?(nil) && (
+    !category ||
+    Category.topic_create_allowed(self).where(:id => category.id).count == 1
+    )
+  end
+
+  def can_create_post_on_topic?(topic)
+
+    # No users can create posts on deleted topics
+    return false if topic.trashed?
+
+    is_staff? || (not(topic.closed? || topic.archived? || topic.trashed?) && can_create_post?(topic))
+  end
+
+  # Editing Method
+  def can_edit_topic?(topic)
+    !topic.archived && (is_staff? || is_my_own?(topic))
+  end
+
+  # Recovery Method
+  def can_recover_topic?(topic)
+    is_staff?
+  end
+
+  def can_delete_topic?(topic)
+    !topic.trashed? &&
+    is_staff? &&
+    !(Category.exists?(topic_id: topic.id))
+  end
+
+  def can_reply_as_new_topic?(topic)
+    authenticated? && topic && not(topic.private_message?) && @user.has_trust_level?(:basic)
+  end
+
+  def can_see_topic?(topic)
+    if topic
+      is_staff? ||
+
+      topic.deleted_at.nil? &&
+
+      # not secure, or I can see it
+      (not(topic.read_restricted_category?) || can_see_category?(topic.category)) &&
+
+      # NOTE
+      # At the moment staff can see PMs, there is some talk of restricting this, however
+      # we still need to allow staff to join PMs for the case of flagging ones
+
+      # not private, or I am allowed (or is staff)
+      (not(topic.private_message?) || authenticated? && (topic.all_allowed_users.where(id: @user.id).exists? || is_staff?))
+    end
+  end
+end
\ No newline at end of file