Make `env['rack.input']` optional. (#2018)

11 files changed, 79 insertions, 43 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f93d6b34..7fcc45a7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,12 @@
 
 All notable changes to this project will be documented in this file. For info on how to format all future additions to this file please reference [Keep A Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [Unreleased]
+
+### SPEC Changes
+
+- `rack.input` is now optional. ([#1997](https://github.com/rack/rack/pull/1997), [@ioquatix])
+
 ## [3.0.3] - 2022-12-07
 
 ### Fixed
diff --git a/SPEC.rdoc b/SPEC.rdoc
index ddf474ae..5c49cc7e 100644
--- a/SPEC.rdoc
+++ b/SPEC.rdoc
@@ -121,7 +121,7 @@ If the string values for CGI keys contain non-ASCII characters,
 they should use ASCII-8BIT encoding.
 There are the following restrictions:
 * <tt>rack.url_scheme</tt> must either be +http+ or +https+.
-* There must be a valid input stream in <tt>rack.input</tt>.
+* There may be a valid input stream in <tt>rack.input</tt>.
 * There must be a valid error stream in <tt>rack.errors</tt>.
 * There may be a valid hijack callback in <tt>rack.hijack</tt>
 * The <tt>REQUEST_METHOD</tt> must be a valid token.
diff --git a/lib/rack/lint.rb b/lib/rack/lint.rb
index ee3ec716..dc78b94d 100644
--- a/lib/rack/lint.rb
+++ b/lib/rack/lint.rb
@@ -56,9 +56,6 @@ module Rack
         raise LintError, "No env given" unless @env
         check_environment(@env)
 
-        @env[RACK_INPUT] = InputWrapper.new(@env[RACK_INPUT])
-        @env[RACK_ERRORS] = ErrorWrapper.new(@env[RACK_ERRORS])
-
         ## and returns a non-frozen Array of exactly three values:
         @response = @app.call(@env)
         raise LintError, "response is not an Array, but #{@response.class}" unless @response.kind_of? Array
@@ -265,11 +262,9 @@ module Rack
         ## is reserved for use with the Rack core distribution and other
         ## accepted specifications and must not be used otherwise.
         ##
-
-        %w[REQUEST_METHOD SERVER_NAME QUERY_STRING SERVER_PROTOCOL
-           rack.input rack.errors].each { |header|
+        %w[REQUEST_METHOD SERVER_NAME QUERY_STRING SERVER_PROTOCOL rack.errors].each do |header|
           raise LintError, "env missing required key #{header}" unless env.include? header
-        }
+        end
 
         ## The <tt>SERVER_PORT</tt> must be an Integer if set.
         server_port = env["SERVER_PORT"]
@@ -328,10 +323,17 @@ module Rack
           raise LintError, "rack.url_scheme unknown: #{env[RACK_URL_SCHEME].inspect}"
         end
 
-        ## * There must be a valid input stream in <tt>rack.input</tt>.
-        check_input env[RACK_INPUT]
+        ## * There may be a valid input stream in <tt>rack.input</tt>.
+        if rack_input = env[RACK_INPUT]
+          check_input_stream(rack_input)
+          @env[RACK_INPUT] = InputWrapper.new(rack_input)
+        end
+
         ## * There must be a valid error stream in <tt>rack.errors</tt>.
-        check_error env[RACK_ERRORS]
+        rack_errors = env[RACK_ERRORS]
+        check_error_stream(rack_errors)
+        @env[RACK_ERRORS] = ErrorWrapper.new(rack_errors)
+
         ## * There may be a valid hijack callback in <tt>rack.hijack</tt>
         check_hijack env
 
@@ -384,7 +386,7 @@ module Rack
       ##
       ## The input stream is an IO-like object which contains the raw HTTP
       ## POST data.
-      def check_input(input)
+      def check_input_stream(input)
         ## When applicable, its external encoding must be "ASCII-8BIT" and it
         ## must be opened in binary mode, for Ruby 1.9 compatibility.
         if input.respond_to?(:external_encoding) && input.external_encoding != Encoding::ASCII_8BIT
@@ -488,7 +490,7 @@ module Rack
       ##
       ## === The Error Stream
       ##
-      def check_error(error)
+      def check_error_stream(error)
         ## The error stream must respond to +puts+, +write+ and +flush+.
         [:puts, :write, :flush].each { |method|
           unless error.respond_to? method
diff --git a/lib/rack/mock_request.rb b/lib/rack/mock_request.rb
index b6d7ef4f..8e111653 100644
--- a/lib/rack/mock_request.rb
+++ b/lib/rack/mock_request.rb
@@ -41,11 +41,6 @@ module Rack
       end
     end
 
-    DEFAULT_ENV = {
-      RACK_INPUT        => StringIO.new,
-      RACK_ERRORS       => StringIO.new,
-    }.freeze
-
     def initialize(app)
       @app = app
     end
@@ -104,7 +99,7 @@ module Rack
       uri = parse_uri_rfc2396(uri)
       uri.path = "/#{uri.path}" unless uri.path[0] == ?/
 
-      env = DEFAULT_ENV.dup
+      env = {}
 
       env[REQUEST_METHOD]  = (opts[:method] ? opts[:method].to_s.upcase : GET).b
       env[SERVER_NAME]     = (uri.host || "example.org").b
@@ -144,20 +139,21 @@ module Rack
         end
       end
 
-      opts[:input] ||= String.new
       if String === opts[:input]
         rack_input = StringIO.new(opts[:input])
       else
         rack_input = opts[:input]
       end
 
-      rack_input.set_encoding(Encoding::BINARY)
-      env[RACK_INPUT] = rack_input
+      if rack_input
+        rack_input.set_encoding(Encoding::BINARY)
+        env[RACK_INPUT] = rack_input
 
-      env["CONTENT_LENGTH"] ||= env[RACK_INPUT].size.to_s if env[RACK_INPUT].respond_to?(:size)
+        env["CONTENT_LENGTH"] ||= env[RACK_INPUT].size.to_s if env[RACK_INPUT].respond_to?(:size)
+      end
 
       opts.each { |field, value|
-        env[field] = value  if String === field
+        env[field] = value if String === field
       }
 
       env
diff --git a/lib/rack/multipart.rb b/lib/rack/multipart.rb
index 3347662a..76b25a51 100644
--- a/lib/rack/multipart.rb
+++ b/lib/rack/multipart.rb
@@ -13,9 +13,14 @@ module Rack
   module Multipart
     MULTIPART_BOUNDARY = "AaB03x"
 
+    class MissingInputError < StandardError
+    end
+
     class << self
       def parse_multipart(env, params = Rack::Utils.default_query_parser)
-        io = env[RACK_INPUT]
+        unless io = env[RACK_INPUT]
+          raise MissingInputError, "Missing input stream!"
+        end
 
         if content_length = env['CONTENT_LENGTH']
           content_length = content_length.to_i
diff --git a/lib/rack/request.rb b/lib/rack/request.rb
index 40922a21..a3eb9926 100644
--- a/lib/rack/request.rb
+++ b/lib/rack/request.rb
@@ -501,10 +501,20 @@ module Rack
         end
 
         begin
-          if get_header(RACK_INPUT).nil?
-            raise "Missing rack.input"
-          elsif get_header(RACK_REQUEST_FORM_INPUT) == get_header(RACK_INPUT)
-            get_header(RACK_REQUEST_FORM_HASH)
+          rack_input = get_header(RACK_INPUT)
+
+          # If the form hash was already memoized:
+          if form_hash = get_header(RACK_REQUEST_FORM_HASH)
+            # And it was memoized from the same input:
+            if get_header(RACK_REQUEST_FORM_INPUT).equal?(rack_input)
+              return form_hash
+            end
+          end
+
+          # Otherwise, figure out how to parse the input:
+          if rack_input.nil?
+            set_header RACK_REQUEST_FORM_INPUT, nil
+            set_header(RACK_REQUEST_FORM_HASH, {})
           elsif form_data? || parseable_data?
             unless set_header(RACK_REQUEST_FORM_HASH, parse_multipart)
               form_vars = get_header(RACK_INPUT).read
@@ -516,6 +526,7 @@ module Rack
               set_header RACK_REQUEST_FORM_VARS, form_vars
               set_header RACK_REQUEST_FORM_HASH, parse_query(form_vars, '&')
             end
+
             set_header RACK_REQUEST_FORM_INPUT, get_header(RACK_INPUT)
             get_header RACK_REQUEST_FORM_HASH
           else
diff --git a/test/spec_lint.rb b/test/spec_lint.rb
index 081ff367..f7e5852a 100644
--- a/test/spec_lint.rb
+++ b/test/spec_lint.rb
@@ -13,8 +13,12 @@ describe Rack::Lint do
     [200, { "content-type" => "test/plain", "content-length" => "3" }, ["foo"]]
   end
 
-  def env(*args)
-    Rack::MockRequest.env_for("/", *args)
+  def env(options = {})
+    unless options.key?(:input)
+      options[:input] = String.new
+    end
+
+    Rack::MockRequest.env_for("/", options)
   end
 
   it "pass valid request" do
diff --git a/test/spec_mock_request.rb b/test/spec_mock_request.rb
index b2a16fde..b702cea5 100644
--- a/test/spec_mock_request.rb
+++ b/test/spec_mock_request.rb
@@ -14,7 +14,10 @@ end
 app = Rack::Lint.new(lambda { |env|
   req = Rack::Request.new(env)
 
-  env["mock.postdata"] = env["rack.input"].read
+  if input = env["rack.input"]
+    env["mock.postdata"] = input.read
+  end
+
   if req.GET["error"]
     env["rack.errors"].puts req.GET["error"]
     env["rack.errors"].flush
@@ -46,7 +49,7 @@ describe Rack::MockRequest do
   end
 
   it "should handle a non-GET request with both :input and :params" do
-    env = Rack::MockRequest.env_for("/", method: :post, input: nil, params: {})
+    env = Rack::MockRequest.env_for("/", method: :post, input: "", params: {})
     env["PATH_INFO"].must_equal "/"
     env.must_be_kind_of Hash
     env['rack.input'].read.must_equal ''
@@ -71,7 +74,7 @@ describe Rack::MockRequest do
     env["PATH_INFO"].must_equal "/"
     env["SCRIPT_NAME"].must_equal ""
     env["rack.url_scheme"].must_equal "http"
-    env["mock.postdata"].must_be :empty?
+    env["mock.postdata"].must_be_nil
   end
 
   it "allow GET/POST/PUT/DELETE/HEAD" do
@@ -194,7 +197,7 @@ describe Rack::MockRequest do
     env["QUERY_STRING"].must_include "baz=2"
     env["QUERY_STRING"].must_include "foo%5Bbar%5D=1"
     env["PATH_INFO"].must_equal "/foo"
-    env["mock.postdata"].must_equal ""
+    env["mock.postdata"].must_be_nil
   end
 
   it "accept raw input in params for GET requests" do
@@ -204,7 +207,7 @@ describe Rack::MockRequest do
     env["QUERY_STRING"].must_include "baz=2"
     env["QUERY_STRING"].must_include "foo%5Bbar%5D=1"
     env["PATH_INFO"].must_equal "/foo"
-    env["mock.postdata"].must_equal ""
+    env["mock.postdata"].must_be_nil
   end
 
   it "accept params and build url encoded params for POST requests" do
diff --git a/test/spec_mock_response.rb b/test/spec_mock_response.rb
index 5cc4fe76..0704ef95 100644
--- a/test/spec_mock_response.rb
+++ b/test/spec_mock_response.rb
@@ -14,7 +14,10 @@ end
 app = Rack::Lint.new(lambda { |env|
   req = Rack::Request.new(env)
 
-  env["mock.postdata"] = env["rack.input"].read
+  if input = env["rack.input"]
+    env["mock.postdata"] = input.read
+  end
+
   if req.GET["error"]
     env["rack.errors"].puts req.GET["error"]
     env["rack.errors"].flush
diff --git a/test/spec_multipart.rb b/test/spec_multipart.rb
index 43bb90b2..7097528a 100644
--- a/test/spec_multipart.rb
+++ b/test/spec_multipart.rb
@@ -30,8 +30,7 @@ describe Rack::Multipart do
   end
 
   it "return nil if content type is not multipart" do
-    env = Rack::MockRequest.env_for("/",
-            "CONTENT_TYPE" => 'application/x-www-form-urlencoded')
+    env = Rack::MockRequest.env_for("/", "CONTENT_TYPE" => 'application/x-www-form-urlencoded', :input => "")
     Rack::Multipart.parse_multipart(env).must_be_nil
   end
 
@@ -42,6 +41,13 @@ describe Rack::Multipart do
     }.must_raise Rack::Multipart::Error
   end
 
+  it "raises a bad request exception if no body is given but content type indicates a multipart body" do
+    env = Rack::MockRequest.env_for("/", "CONTENT_TYPE" => 'multipart/form-data; boundary=BurgerBurger', :input => nil)
+    lambda {
+      Rack::Multipart.parse_multipart(env)
+    }.must_raise Rack::Multipart::MissingInputError
+  end
+
   it "parse multipart content when content type present but disposition is not" do
     env = Rack::MockRequest.env_for("/", multipart_fixture(:content_type_and_no_disposition))
     params = Rack::Multipart.parse_multipart(env)
diff --git a/test/spec_request.rb b/test/spec_request.rb
index 68782625..295abf95 100644
--- a/test/spec_request.rb
+++ b/test/spec_request.rb
@@ -113,7 +113,7 @@ class RackRequestTest < Minitest::Spec
   it "wrap the rack variables" do
     req = make_request(Rack::MockRequest.env_for("http://example.com:8080/"))
 
-    req.body.must_respond_to :gets
+    req.body.must_be_nil
     req.scheme.must_equal "http"
     req.request_method.must_equal "GET"
 
@@ -131,7 +131,7 @@ class RackRequestTest < Minitest::Spec
     req.host.must_equal "example.com"
     req.port.must_equal 8080
 
-    req.content_length.must_equal "0"
+    req.content_length.must_be_nil
     req.content_type.must_be_nil
   end
 
@@ -712,9 +712,9 @@ class RackRequestTest < Minitest::Spec
       message.must_equal "invalid %-encoding (a%)"
   end
 
-  it "raise if rack.input is missing" do
+  it "return empty POST data if rack.input is missing" do
     req = make_request({})
-    lambda { req.POST }.must_raise RuntimeError
+    req.POST.must_be_empty
   end
 
   it "parse POST data when method is POST and no content-type given" do