expect plugin

this plugin sets all body requests to send the expect-100 header before
sending any payload, a la curl. It recovers from 417 as well.

lib/httpx/plugins/expect.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module HTTPX
+  module Plugins
+    #
+    # This plugin makes all HTTP/1.1 requests with a body send the "Expect: 100-continue".
+    #
+    # https://gitlab.com/honeyryderchuck/httpx/wikis/Expect#expect
+    #
+    module Expect
+      module RequestBodyMethods
+        def initialize(*)
+          super
+          return if @body.nil?
+
+          @headers["expect"] = "100-continue"
+        end
+      end
+
+      module InstanceMethods
+        def fetch_response(request, connections, options)
+          response = @responses.delete(request)
+          return unless response
+
+          if response.status == 417 && request.headers.key?("expect")
+            request.headers.delete("expect")
+            request.transition(:idle)
+            connection = find_connection(request, connections, options)
+            connection.send(request)
+            return
+          end
+
+          response
+        end
+      end
+    end
+    register_plugin :expect, Expect
+  end
+end

lib/httpx/session.rb

@@ -54,6 +54,7 @@ module HTTPX
     def fetch_response(request, connections, options)
       response = @responses.delete(request)
       return unless response
+
       if response.status == 417 && request.headers.key?("expect")
         request.headers.delete("expect")
         request.transition(:idle)

test/http_test.rb

@@ -24,6 +24,7 @@ class HTTPTest < Minitest::Test
   include Plugins::H2C
   include Plugins::Retries
   include Plugins::Multipart
+  include Plugins::Expect
 
   def test_verbose_log
     log = StringIO.new

test/https_test.rb

@@ -24,6 +24,7 @@ class HTTPSTest < Minitest::Test
   include Plugins::PushPromise if OpenSSL::SSL::SSLContext.instance_methods.include?(:alpn_protocols)
   include Plugins::Retries
   include Plugins::Multipart
+  include Plugins::Expect
 
   def test_connection_coalescing
     coalesced_origin = "https://#{ENV["HTTPBIN_COALESCING_HOST"]}"

test/support/requests/plugins/expect.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module Requests
+  module Plugins
+    module Expect
+      def test_plugin_expect_100_form_params
+        uri = build_uri("/post")
+        response = HTTPX.plugin(:expect).post(uri, form: { "foo" => "bar" })
+        verify_status(response, 200)
+        body = json_body(response)
+        verify_header(body["headers"], "Content-Type", "application/x-www-form-urlencoded")
+        verify_header(body["headers"], "Expect", "100-continue")
+        verify_uploaded(body, "form", "foo" => "bar")
+      end
+
+      # def test_plugin_expect_100_send_body_after_delay
+      #   uri = build_uri("/delay/3")
+      #   response = HTTPX.plugin(:expect).post(uri, form: { "foo" => "bar" })
+      #   verify_status(response, 200)
+      #   body = json_body(response)
+      #   verify_header(body["headers"], "Content-Type", "application/x-www-form-urlencoded")
+      #   verify_header(body["headers"], "Expect", "100-continue")
+      #   verify_uploaded(body, "form", "foo" => "bar")
+
+      #   verify_no_header(response.instance_variable_get(:@request).headers, "expect")
+      # end
+
+      def test_plugin_expect_100_form_params_417
+        uri = build_uri("/status/417")
+        response = HTTPX.plugin(:expect).post(uri, form: { "foo" => "bar" })
+
+        # we can't really test that the request would be successful without it, however we can
+        # test whether the header has been removed from the request.
+        verify_status(response, 417)
+        verify_no_header(response.instance_variable_get(:@request).headers, "expect")
+      end
+    end
+  end
+end

test/support/requests/with_body.rb

@@ -32,17 +32,6 @@ module Requests
         verify_uploaded(body, "form", "foo" => "bar")
       end
 
-       define_method :"test_#{meth}_expect_100_form_params_417" do
-        uri = build_uri("/status/417")
-        response = HTTPX.headers("expect" => "100-continue")
-                        .send(meth, uri, form: { "foo" => "bar" })
-
-        # we can't really test that the request would be successful without it, however we can
-        # test whether the header has been removed from the request.
-        verify_status(response, 417)
-        verify_no_header(response.instance_variable_get(:@request).headers, "expect")
-      end
-
       define_method :"test_#{meth}_json_params" do
         uri = build_uri("/#{meth}")
         response = HTTPX.send(meth, uri, json: { "foo" => "bar" })