Fix http client header duplicates

CHANGELOG.md

@@ -5,6 +5,8 @@ All notable changes to this project will be documented in this file.
 
 ## Unreleased
 
+## 4.8.0 - 2022-09-30
+
 ### Added
 
 - All `sql` components now support Oracle DB.
@@ -13,6 +15,7 @@ All notable changes to this project will be documented in this file.
 
 - All SQL components now accept an empty or unspecified `args_mapping` as an alias for no arguments.
 - Field `unsafe_dynamic_query` added to the `sql_raw` output.
+- Fixed a regression in 4.7.0 where HTTP client components were sending duplicate request headers.
 
 ## 4.7.0 - 2022-09-27
 

internal/httpclient/request.go

@@ -224,28 +224,6 @@ func (r *RequestCreator) Create(refBatch message.Batch) (req *http.Request, err
 		req.Header.Add("Content-Type", overrideContentType)
 	}
 
-	if err = r.reqSigner(req); err != nil {
-		return
-	}
-
-	for k, v := range r.headers {
-		req.Header.Add(k, v.String(0, refBatch))
-	}
-	if len(refBatch) > 0 {
-		_ = r.metaInsertFilter.Iter(refBatch[0], func(k, v string) error {
-			req.Header.Add(k, v)
-			return nil
-		})
-	}
-
-	if r.host != nil {
-		req.Host = r.host.String(0, refBatch)
-	}
-	if overrideContentType != "" {
-		req.Header.Del("Content-Type")
-		req.Header.Add("Content-Type", overrideContentType)
-	}
-
 	err = r.reqSigner(req)
 	return
 }

internal/httpclient/request_test.go

@@ -0,0 +1,34 @@
+package httpclient
+
+import (
+	"testing"
+
+	"github.com/benthosdev/benthos/v4/internal/httpclient/oldconfig"
+	"github.com/benthosdev/benthos/v4/internal/manager/mock"
+	"github.com/benthosdev/benthos/v4/internal/message"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSingleMessageHeaders(t *testing.T) {
+	oldConf := oldconfig.NewOldConfig()
+	oldConf.Headers["Content-Type"] = "foo"
+	oldConf.Metadata.IncludePrefixes = []string{"more_"}
+
+	reqCreator, err := RequestCreatorFromOldConfig(oldConf, mock.NewManager())
+	require.NoError(t, err)
+
+	part := message.NewPart([]byte("hello world"))
+	part.MetaSet("more_bar", "barvalue")
+	part.MetaSet("ignore_baz", "bazvalue")
+
+	b := message.Batch{part}
+
+	req, err := reqCreator.Create(b)
+	require.NoError(t, err)
+
+	assert.Equal(t, []string{"foo"}, req.Header.Values("Content-Type"))
+	assert.Equal(t, []string{"barvalue"}, req.Header.Values("more_bar"))
+	assert.Equal(t, []string(nil), req.Header.Values("ignore_baz"))
+}