BodyDecoded() for request and responses (#1308)

* header.go ContentEncoding() getter and setters

For Response the CE header is stored into a separate field because compressed responses are often used.
But for the Request let's just peek and store it from headers map

* http.go: New BodyUncompressed() method for request and responses

The new method returns a body and uncompress if it's gzipped

header.go

@@ -371,6 +371,21 @@ func (h *RequestHeader) SetContentTypeBytes(contentType []byte) {
 	h.contentType = append(h.contentType[:0], contentType...)
 }
 
+// ContentEncoding returns Content-Encoding header value.
+func (h *RequestHeader) ContentEncoding() []byte {
+	return peekArgBytes(h.h, strContentEncoding)
+}
+
+// SetContentEncoding sets Content-Encoding header value.
+func (h *RequestHeader) SetContentEncoding(contentEncoding string) {
+	h.SetBytesK(strContentEncoding, contentEncoding)
+}
+
+// SetContentEncodingBytes sets Content-Encoding header value.
+func (h *RequestHeader) SetContentEncodingBytes(contentEncoding []byte) {
+	h.setNonSpecial(strContentEncoding, contentEncoding)
+}
+
 // SetMultipartFormBoundary sets the following Content-Type:
 // 'multipart/form-data; boundary=...'
 // where ... is substituted by the given boundary.

http.go

@@ -486,6 +486,48 @@ func inflateData(p []byte) ([]byte, error) {
 	return bb.B, nil
 }
 
+var ErrContentEncodingUnsupported = errors.New("unsupported Content-Encoding")
+
+// BodyUncompressed returns body data and if needed decompress it from gzip, deflate or Brotli.
+//
+// This method may be used if the response header contains
+// 'Content-Encoding' for reading uncompressed request body.
+// Use Body for reading the raw request body.
+func (req *Request) BodyUncompressed() ([]byte, error) {
+	switch string(req.Header.ContentEncoding()) {
+	case "":
+		return req.Body(), nil
+	case "deflate":
+		return req.BodyInflate()
+	case "gzip":
+		return req.BodyGunzip()
+	case "br":
+		return req.BodyUnbrotli()
+	default:
+		return nil, ErrContentEncodingUnsupported
+	}
+}
+
+// BodyUncompressed returns body data and if needed decompress it from gzip, deflate or Brotli.
+//
+// This method may be used if the response header contains
+// 'Content-Encoding' for reading uncompressed response body.
+// Use Body for reading the raw response body.
+func (resp *Response) BodyUncompressed() ([]byte, error) {
+	switch string(resp.Header.ContentEncoding()) {
+	case "":
+		return resp.Body(), nil
+	case "deflate":
+		return resp.BodyInflate()
+	case "gzip":
+		return resp.BodyGunzip()
+	case "br":
+		return resp.BodyUnbrotli()
+	default:
+		return nil, ErrContentEncodingUnsupported
+	}
+}
+
 // BodyWriteTo writes request body to w.
 func (req *Request) BodyWriteTo(w io.Writer) error {
 	if req.bodyStream != nil {

http_test.go

@@ -347,6 +347,12 @@ func testResponseBodyStreamDeflate(t *testing.T, body []byte, bodySize int) {
 	if !bytes.Equal(respBody, body) {
 		t.Fatalf("unexpected body: %q. Expecting %q", respBody, body)
 	}
+	// check for invalid
+	resp.SetBodyRaw([]byte("invalid"))
+	_, errDeflate := resp.BodyInflate()
+	if errDeflate == nil || errDeflate.Error() != "zlib: invalid header" {
+		t.Fatalf("expected error: 'zlib: invalid header' but was %v", errDeflate)
+	}
 }
 
 func testResponseBodyStreamGzip(t *testing.T, body []byte, bodySize int) {
@@ -375,6 +381,12 @@ func testResponseBodyStreamGzip(t *testing.T, body []byte, bodySize int) {
 	if !bytes.Equal(respBody, body) {
 		t.Fatalf("unexpected body: %q. Expecting %q", respBody, body)
 	}
+	// check for invalid
+	resp.SetBodyRaw([]byte("invalid"))
+	_, errUnzip := resp.BodyGunzip()
+	if errUnzip == nil || errUnzip.Error() != "unexpected EOF" {
+		t.Fatalf("expected error: 'unexpected EOF' but was %v", errUnzip)
+	}
 }
 
 func TestResponseWriteGzipNilBody(t *testing.T) {
@@ -405,6 +417,46 @@ func TestResponseWriteDeflateNilBody(t *testing.T) {
 	}
 }
 
+func TestResponseBodyUncompressed(t *testing.T) {
+	body := "body"
+	var r Response
+	r.SetBodyStream(bytes.NewReader([]byte(body)), len(body))
+
+	w := &bytes.Buffer{}
+	bw := bufio.NewWriter(w)
+	if err := r.WriteDeflate(bw); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if err := bw.Flush(); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	var resp Response
+	br := bufio.NewReader(w)
+	if err := resp.Read(br); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	ce := resp.Header.ContentEncoding()
+	if string(ce) != "deflate" {
+		t.Fatalf("unexpected Content-Encoding: %s", ce)
+	}
+	respBody, err := resp.BodyUncompressed()
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if string(respBody) != body {
+		t.Fatalf("unexpected body: %q. Expecting %q", respBody, body)
+	}
+
+	// check for invalid encoding
+	resp.Header.SetContentEncoding("invalid")
+	_, decodeErr := resp.BodyUncompressed()
+	if decodeErr != ErrContentEncodingUnsupported {
+		t.Fatalf("unexpected error: %v", decodeErr)
+	}
+}
+
 func TestResponseSwapBodySerial(t *testing.T) {
 	t.Parallel()
 
@@ -1145,8 +1197,8 @@ func TestRequestReadGzippedBody(t *testing.T) {
 		t.Fatalf("unexpected error: %v", err)
 	}
 
-	if string(r.Header.Peek(HeaderContentEncoding)) != "gzip" {
-		t.Fatalf("unexpected content-encoding: %q. Expecting %q", r.Header.Peek(HeaderContentEncoding), "gzip")
+	if string(r.Header.ContentEncoding()) != "gzip" {
+		t.Fatalf("unexpected content-encoding: %q. Expecting %q", r.Header.ContentEncoding(), "gzip")
 	}
 	if r.Header.ContentLength() != len(body) {
 		t.Fatalf("unexpected content-length: %d. Expecting %d", r.Header.ContentLength(), len(body))