refactoring query.conditions

lib/cancan/ability.rb

@@ -183,8 +183,10 @@ module CanCan
     end
 
     # Returns a CanCan::Query instance to help generate database queries based on the ability.
+    # If any relevant can definitions use a block then an exception will be raised because an
+    # SQL query cannot be generated from blocks of code.
     def query(action, subject)
-      Query.new(subject, relevant_can_definitions_without_block(action, subject))
+      Query.new(subject, relevant_can_definitions_for_query(action, subject))
     end
     
     private
@@ -211,7 +213,7 @@ module CanCan
       end
     end
 
-    def relevant_can_definitions_without_block(action, subject)
+    def relevant_can_definitions_for_query(action, subject)
       relevant_can_definitions(action, subject).each do |can_definition|
         if can_definition.only_block?
           raise Error, "Cannot determine SQL conditions or joins from block for #{action.inspect} #{subject.inspect}"

lib/cancan/active_record_additions.rb

@@ -21,11 +21,10 @@ module CanCan
       # internally uses Ability#conditions method, see that for more information.
       def accessible_by(ability, action = :read)
         query = ability.query(action, self)
-        conditions = query.sql_conditions || {:id => nil}
         if respond_to? :where
-          where(conditions).joins(query.association_joins)
+          where(query.conditions).joins(query.joins)
         else
-          scoped(:conditions => conditions, :joins => query.association_joins)
+          scoped(:conditions => query.conditions, :joins => query.joins)
         end
       end
     end

lib/cancan/query.rb

@@ -7,82 +7,61 @@ module CanCan
       @sanitizer = sanitizer
       @can_definitions = can_definitions
     end
-
-    # Returns an array of arrays composing from desired action and hash of conditions which match the given ability.
-    # This is useful if you need to generate a database query based on the current ability.
-    # 
-    #   can :read, Article, :visible => true
-    #   conditions :read, Article # returns [ [ true, { :visible => true } ] ]
-    #
-    #   can :read, Article, :visible => true
-    #   cannot :read, Article, :blocked => true
-    #   conditions :read, Article # returns [ [ false, { :blocked => true } ], [ true, { :visible => true } ] ]
-    # 
-    # Normally you will not call this method directly, but instead go through ActiveRecordAdditions#accessible_by method.
-    #
-    # If the ability is not defined then false is returned so be sure to take that into consideration.
-    # If the ability is defined using a block then this will raise an exception since a hash of conditions cannot be
-    # determined from that.
-    def conditions
-      unless @can_definitions.empty?
-        @can_definitions.map do |can_definition|
-          [can_definition.base_behavior, can_definition.tableized_conditions]
-        end
-      else
-        false
-      end
-    end
     
-    # Returns sql conditions for object, which responds to :sanitize_sql .
-    # This is useful if you need to generate a database query based on the current ability.
+    # Returns a string of SQL conditions which match the ability query.
     # 
     #   can :manage, User, :id => 1
     #   can :manage, User, :manager_id => 1
     #   cannot :manage, User, :self_managed => true
-    #   sql_conditions :manage, User # returns not (self_managed = 't') AND ((manager_id = 1) OR (id = 1))
+    #   query(:manage, User).conditions # => "not (self_managed = 't') AND ((manager_id = 1) OR (id = 1))"
     #
-    # Normally you will not call this method directly, but instead go through ActiveRecordAdditions#accessible_by method.
+    # Normally you will not call this method directly, but instead go through ActiveRecordAdditions#accessible_by.
     # 
-    # If the ability is not defined then false is returned so be sure to take that into consideration.
     # If there is just one :can ability, it conditions returned untouched.
-    # If the ability is defined using a block then this will raise an exception since a hash of conditions cannot be
-    # determined from that.
-    def sql_conditions
-      conds = conditions
-      return false if conds == false
-      return (conds[0][1] || {}) if conds.size==1 && conds[0][0] == true # to match previous spec
-      
-      true_cond = sanitize_sql(['?=?', true, true])
-      false_cond = sanitize_sql(['?=?', true, false])
-      conds.reverse.inject(false_cond) do |sql, action|
-        behavior, condition = action
-        if condition && condition != {}
-          condition = sanitize_sql(condition)
-          case sql
-            when true_cond
-              behavior ? true_cond : "not (#{condition})"
-            when false_cond
-              behavior ? condition : false_cond
-            else
-              behavior ? "(#{condition}) OR (#{sql})" : "not (#{condition}) AND (#{sql})"
-          end
-        else
-          behavior ? true_cond : false_cond
+    def conditions
+      if @can_definitions.size == 1 && @can_definitions.first.base_behavior
+        # Return the conditions directly if there's just one definition
+        @can_definitions.first.tableized_conditions
+      else
+        @can_definitions.reverse.inject(false_sql) do |sql, can_definition|
+          merge_conditions(sql, can_definition.tableized_conditions, can_definition.base_behavior)
         end
       end
     end
     
-    # Returns the associations used in conditions. This is usually used in the :joins option for a search.
+    # Returns the associations used in conditions for the :joins option of a search
     # See ActiveRecordAdditions#accessible_by for use in Active Record.
-    def association_joins
+    def joins
       unless @can_definitions.empty?
         collect_association_joins(@can_definitions)
-      else
-        nil
       end
     end
     
     private
+    
+    def merge_conditions(sql, conditions_hash, behavior)
+      if conditions_hash.blank?
+        behavior ? true_sql : false_sql
+      else
+        conditions = sanitize_sql(conditions_hash)
+        case sql
+        when true_sql
+          behavior ? true_sql : "not (#{conditions})"
+        when false_sql
+          behavior ? conditions : false_sql
+        else
+          behavior ? "(#{conditions}) OR (#{sql})" : "not (#{conditions}) AND (#{sql})"
+        end
+      end
+    end
+
+    def false_sql
+      sanitize_sql(['?=?', true, false])
+    end
+
+    def true_sql
+      sanitize_sql(['?=?', true, true])
+    end
 
     def sanitize_sql(conditions)
       @sanitizer.sanitize_sql(conditions)

spec/cancan/active_record_additions_spec.rb

@@ -9,9 +9,9 @@ describe CanCan::ActiveRecordAdditions do
     @ability.extend(CanCan::Ability)
   end
 
-  it "should call where(:id => nil) when no ability is defined so no records are found" do
-    stub(@model_class).where(:id => nil).stub!.joins(nil) { :no_where }
-    @model_class.accessible_by(@ability, :read).should == :no_where
+  it "should call where('true=false') when no ability is defined so no records are found" do
+    stub(@model_class).where('true=false').stub!.joins(nil) { :no_match }
+    @model_class.accessible_by(@ability, :read).should == :no_match
   end
 
   it "should call where with matching ability conditions" do
@@ -44,7 +44,7 @@ describe CanCan::ActiveRecordAdditions do
         stub(@model_class).scoped( :conditions => condition, :joins => joins ) { :found_records }
       end
     end
-    # @ability.sql_conditions(:read, @model_class).should == '(too.car=1 AND too.far.bar=1) OR (foo.bar=1)'
+    # @ability.conditions(:read, @model_class).should == '(too.car=1 AND too.far.bar=1) OR (foo.bar=1)'
     # @ability.association_joins(:read, @model_class).should == [{:too => [:far]}, :foo]
     @model_class.accessible_by(@ability).should == :found_records
   end

spec/cancan/query_spec.rb

@@ -6,72 +6,70 @@ describe CanCan::Query do
     @ability.extend(CanCan::Ability)
   end
   
-  it "should return array of behavior and conditions for a given ability" do
-    @ability.can :read, Person, :first => 1, :last => 3
-    @ability.query(:show, Person).conditions.should == [[true, {:first => 1, :last => 3}]]
+  it "should have false conditions if no abilities match" do
+    @ability.query(:destroy, Person).conditions.should == "true=false"
   end
   
-  it "should raise an exception when a block is used on condition, and no hash" do
-    @ability.can :read, Person do |a|
-      true
-    end
-    lambda { @ability.query(:show, Person).conditions }.should raise_error(CanCan::Error, "Cannot determine SQL conditions or joins from block for :show Person")
+  it "should return hash for single `can` definition" do
+    @ability.can :read, Person, :blocked => false, :user_id => 1
+    @ability.query(:read, Person).conditions.should == { :blocked => false, :user_id => 1 }
   end
   
-  it "should return an array with just behavior for conditions when there are no conditions" do
-    @ability.can :read, Person
-    @ability.query(:show, Person).conditions.should == [ [true, {}] ]
+  it "should merge multiple can definitions into single SQL string joining with OR" do
+    @ability.can :read, Person, :blocked => false
+    @ability.can :read, Person, :admin => true
+    @ability.query(:read, Person).conditions.should == "(admin=true) OR (blocked=false)"
   end
-
-  it "should return false when performed on an action which isn't defined" do
-    @ability.query(:foo, Person).conditions.should == false
+  
+  it "should merge multiple can definitions into single SQL string joining with OR and AND" do
+    @ability.can :read, Person, :blocked => false, :active => true
+    @ability.can :read, Person, :admin => true
+    @ability.query(:read, Person).conditions.should orderlessly_match("(blocked=false AND active=true) OR (admin=true)")
   end
   
-  it "should return hash for single `can` definition" do
-    @ability.can :read, Person, :blocked => false, :user_id => 1
-    
-    @ability.query(:read, Person).sql_conditions.should == { :blocked => false, :user_id => 1 }    
+  it "should merge multiple can definitions into single SQL string joining with OR and AND" do
+    @ability.can :read, Person, :blocked => false, :active => true
+    @ability.can :read, Person, :admin => true
+    @ability.query(:read, Person).conditions.should orderlessly_match("(blocked=false AND active=true) OR (admin=true)")
   end
   
-  it "should return `sql` for single `can` definition in front of default `cannot` condition" do
+  it "should return false conditions for cannot clause" do
+    @ability.cannot :read, Person
+    @ability.query(:read, Person).conditions.should == "true=false"
+  end
+  
+  it "should return SQL for single `can` definition in front of default `cannot` condition" do
     @ability.cannot :read, Person
     @ability.can :read, Person, :blocked => false, :user_id => 1
     
-    result = @ability.query(:read, Person).sql_conditions
-    result.should include("blocked=false")
-    result.should include(" AND ")
-    result.should include("user_id=1")
-  end 
-
-  it "should return `true condition` for single `can` definition in front of default `can` condition" do
+    result = @ability.query(:read, Person).conditions.should orderlessly_match("blocked=false AND user_id=1")
+  end
+  
+  it "should return true condition for single `can` definition in front of default `can` condition" do
     @ability.can :read, Person
     @ability.can :read, Person, :blocked => false, :user_id => 1
     
-    @ability.query(:read, Person).sql_conditions.should == 'true=true'
+    @ability.query(:read, Person).conditions.should == 'true=true'
   end 
-
-  it "should return `false condition` for single `cannot` definition" do
+  
+  it "should return false condition for single `cannot` definition" do
     @ability.cannot :read, Person, :blocked => true, :user_id => 1
     
-    @ability.query(:read, Person).sql_conditions.should == 'true=false'
+    @ability.query(:read, Person).conditions.should == 'true=false'
   end
   
   it "should return `false condition` for single `cannot` definition in front of default `cannot` condition" do
     @ability.cannot :read, Person
     @ability.cannot :read, Person, :blocked => true, :user_id => 1
     
-    @ability.query(:read, Person).sql_conditions.should == 'true=false'
+    @ability.query(:read, Person).conditions.should == 'true=false'
   end
   
   it "should return `not (sql)` for single `cannot` definition in front of default `can` condition" do
     @ability.can :read, Person
     @ability.cannot :read, Person, :blocked => true, :user_id => 1
     
-    result = @ability.query(:read, Person).sql_conditions
-    result.should include("not ")
-    result.should include("blocked=true")
-    result.should include(" AND ")
-    result.should include("user_id=1")
+    result = @ability.query(:read, Person).conditions.should orderlessly_match("not (blocked=true AND user_id=1)")
   end
   
   it "should return appropriate sql conditions in complex case" do
@@ -80,8 +78,8 @@ describe CanCan::Query do
     @ability.can :update, Person, :manager_id => 1
     @ability.cannot :update, Person, :self_managed => true
     
-    @ability.query(:update, Person).sql_conditions.should == 'not (self_managed=true) AND ((manager_id=1) OR (id=1))'
-    @ability.query(:manage, Person).sql_conditions.should == {:id=>1}
-    @ability.query(:read, Person).sql_conditions.should == 'true=true'
+    @ability.query(:update, Person).conditions.should == 'not (self_managed=true) AND ((manager_id=1) OR (id=1))'
+    @ability.query(:manage, Person).conditions.should == {:id=>1}
+    @ability.query(:read, Person).conditions.should == 'true=true'
   end
 end

spec/matchers.rb

+Spec::Matchers.define :orderlessly_match do |original_string|
+  match do |given_string|
+    original_string.bytes.sum == given_string.bytes.sum
+  end
+
+  failure_message_for_should do |given_string|
+    "expected \"#{given_string}\" to have the same characters as \"#{original_string}\""
+  end
+
+  failure_message_for_should_not do |given_string|
+    "expected \"#{given_string}\" not to have the same characters as \"#{original_string}\""
+  end
+end

spec/spec_helper.rb

@@ -4,6 +4,7 @@ require 'active_support'
 require 'active_record'
 require 'action_controller'
 require 'action_view'
+require 'matchers'
 require 'cancan'
 require 'cancan/matchers'