diff --git a/actionpack/lib/action_dispatch/middleware/params_parser.rb b/actionpack/lib/action_dispatch/middleware/params_parser.rb
index 58d527a6e717e..a42c6598e034a 100644
--- a/actionpack/lib/action_dispatch/middleware/params_parser.rb
+++ b/actionpack/lib/action_dispatch/middleware/params_parser.rb
@@ -32,16 +32,14 @@ def parse_formatted_parameters(env)
           when Proc
             strategy.call(request.raw_post)
           when :xml_simple, :xml_node
-            body = request.raw_post
-            body.blank? ? {} : Hash.from_xml(body).with_indifferent_access
+            request.body.size == 0 ? {} : Hash.from_xml(request.body).with_indifferent_access
           when :yaml
             YAML.load(request.raw_post)
           when :json
-            body = request.raw_post
-            if body.blank?
+            if request.body.size == 0
               {}
             else
-              data = ActiveSupport::JSON.decode(body)
+              data = ActiveSupport::JSON.decode(request.body)
               data = {:_json => data} unless data.is_a?(Hash)
               data.with_indifferent_access
             end
diff --git a/activesupport/lib/active_support/json/backends/jsongem.rb b/activesupport/lib/active_support/json/backends/jsongem.rb
index de847e30a31d6..d1a1cdd7d7fdd 100644
--- a/activesupport/lib/active_support/json/backends/jsongem.rb
+++ b/activesupport/lib/active_support/json/backends/jsongem.rb
@@ -6,8 +6,11 @@ module Backends
       module JSONGem
         extend self
 
-        # Converts a JSON string into a Ruby object.
+        # Parses a JSON string or IO and convert it into an object
         def decode(json)
+          if json.respond_to?(:read)
+            json = json.read
+          end
           data = ::JSON.parse(json)
           if ActiveSupport.parse_json_times
             convert_dates_from(data)
diff --git a/activesupport/lib/active_support/json/backends/yaml.rb b/activesupport/lib/active_support/json/backends/yaml.rb
index c7db508c2326c..1c18fc480166c 100644
--- a/activesupport/lib/active_support/json/backends/yaml.rb
+++ b/activesupport/lib/active_support/json/backends/yaml.rb
@@ -9,8 +9,11 @@ module Backends
       module Yaml
         extend self
 
-        # Converts a JSON string into a Ruby object.
+        # Parses a JSON string or IO and converts it into an object
         def decode(json)
+          if json.respond_to?(:read)
+            json = json.read
+          end
           YAML.load(convert_json_to_yaml(json))
         rescue ArgumentError => e
           raise ParseError, "Invalid JSON string"
diff --git a/activesupport/lib/active_support/xml_mini/jdom.rb b/activesupport/lib/active_support/xml_mini/jdom.rb
index d795d556909e6..1cd714d864e53 100644
--- a/activesupport/lib/active_support/xml_mini/jdom.rb
+++ b/activesupport/lib/active_support/xml_mini/jdom.rb
@@ -24,15 +24,19 @@ module XmlMini_JDOM #:nodoc:
     node_type_map = {}
     NODE_TYPE_NAMES.each { |type| node_type_map[Node.send(type)] = type }
 
-    # Parse an XML Document string into a simple hash using Java's jdom.
-    # string::
-    #   XML Document string to parse
-    def parse(string)
-      if string.blank?
+    # Parse an XML Document string or IO into a simple hash using Java's jdom.
+    # data::
+    #   XML Document string or IO to parse
+    def parse(data)
+      if data.respond_to?(:read)
+        data = data.read
+      end
+
+      if data.blank?
         {}
       else
         @dbf = DocumentBuilderFactory.new_instance
-        xml_string_reader = StringReader.new(string)
+        xml_string_reader = StringReader.new(data)
         xml_input_source = InputSource.new(xml_string_reader)
         doc = @dbf.new_document_builder.parse(xml_input_source)
         merge_element!({}, doc.document_element)
diff --git a/activesupport/lib/active_support/xml_mini/libxml.rb b/activesupport/lib/active_support/xml_mini/libxml.rb
index 370205409a92e..d4c4dc7be5a7f 100644
--- a/activesupport/lib/active_support/xml_mini/libxml.rb
+++ b/activesupport/lib/active_support/xml_mini/libxml.rb
@@ -5,16 +5,20 @@ module ActiveSupport
   module XmlMini_LibXML #:nodoc:
     extend self
 
-    # Parse an XML Document string into a simple hash using libxml.
-    # string::
-    #   XML Document string to parse
-    def parse(string)
+    # Parse an XML Document string or IO into a simple hash using libxml.
+    # data::
+    #   XML Document string or IO to parse
+    def parse(data)
+      if data.respond_to?(:read)
+        data = data.read
+      end
+
       LibXML::XML.default_keep_blanks = false
 
-      if string.blank?
+      if data.blank?
         {}
       else
-        LibXML::XML::Parser.string(string.strip).parse.to_hash
+        LibXML::XML::Parser.string(data.strip).parse.to_hash
       end
     end
 
diff --git a/activesupport/lib/active_support/xml_mini/nokogiri.rb b/activesupport/lib/active_support/xml_mini/nokogiri.rb
index 8f9676e4f6269..7337c143c9089 100644
--- a/activesupport/lib/active_support/xml_mini/nokogiri.rb
+++ b/activesupport/lib/active_support/xml_mini/nokogiri.rb
@@ -5,14 +5,18 @@ module ActiveSupport
   module XmlMini_Nokogiri #:nodoc:
     extend self
 
-    # Parse an XML Document string into a simple hash using libxml / nokogiri.
-    # string::
-    #   XML Document string to parse
-    def parse(string)
-      if string.blank?
+    # Parse an XML Document string or IO into a simple hash using libxml / nokogiri.
+    # data::
+    #   XML Document string or IO to parse
+    def parse(data)
+      if data.respond_to?(:read)
+        data = data.read
+      end
+
+      if data.blank?
         {}
       else
-        doc = Nokogiri::XML(string)
+        doc = Nokogiri::XML(data)
         raise doc.errors.first if doc.errors.length > 0
         doc.to_hash
       end
diff --git a/activesupport/lib/active_support/xml_mini/rexml.rb b/activesupport/lib/active_support/xml_mini/rexml.rb
index 5033210aaeb74..1184d2d6c9682 100644
--- a/activesupport/lib/active_support/xml_mini/rexml.rb
+++ b/activesupport/lib/active_support/xml_mini/rexml.rb
@@ -7,16 +7,20 @@ module XmlMini_REXML #:nodoc:
 
     CONTENT_KEY = '__content__'.freeze
 
-    # Parse an XML Document string into a simple hash
+    # Parse an XML Document string or IO into a simple hash
     #
     # Same as XmlSimple::xml_in but doesn't shoot itself in the foot,
     # and uses the defaults from ActiveSupport
     #
-    # string::
-    #   XML Document string to parse
-    def parse(string)
+    # data::
+    #   XML Document string or IO to parse
+    def parse(data)
+      if data.respond_to?(:read)
+        data = data.read
+      end
+
       require 'rexml/document' unless defined?(REXML::Document)
-      doc = REXML::Document.new(string)
+      doc = REXML::Document.new(data)
       merge_element!({}, doc.root)
     end
 
diff --git a/activesupport/test/xml_mini/nokogiri_engine_test.rb b/activesupport/test/xml_mini/nokogiri_engine_test.rb
index 886a9d1aba38b..7c3a591e639ca 100644
--- a/activesupport/test/xml_mini/nokogiri_engine_test.rb
+++ b/activesupport/test/xml_mini/nokogiri_engine_test.rb
@@ -148,6 +148,19 @@ def test_children_with_non_adjacent_text
     eoxml
   end
 
+  def test_parse_from_io
+    io = StringIO.new(<<-eoxml)
+    <root>
+      good
+      <products>
+        hello everyone
+      </products>
+      morning
+    </root>
+    eoxml
+    XmlMini.parse(io)
+  end
+
   private
   def assert_equal_rexml(xml)
     hash = XmlMini.with_backend('REXML') { XmlMini.parse(xml) }
diff --git a/activesupport/test/xml_mini/rexml_engine_test.rb b/activesupport/test/xml_mini/rexml_engine_test.rb
index a412d8ca05690..57bb35254a83e 100644
--- a/activesupport/test/xml_mini/rexml_engine_test.rb
+++ b/activesupport/test/xml_mini/rexml_engine_test.rb
@@ -12,4 +12,18 @@ def test_set_rexml_as_backend
     XmlMini.backend = 'REXML'
     assert_equal XmlMini_REXML, XmlMini.backend
   end
+
+  def test_parse_from_io
+    XmlMini.backend = 'REXML'
+    io = StringIO.new(<<-eoxml)
+    <root>
+      good
+      <products>
+        hello everyone
+      </products>
+      morning
+    </root>
+    eoxml
+    XmlMini.parse(io)
+  end
 end