fix: Decompress request body when multi Content-Encoding sent on request headers

ctx.go

@@ -260,31 +260,92 @@ func (c *Ctx) BaseURL() string {
 	return c.baseURI
 }
 
-// Body contains the raw body submitted in a POST request.
+// BodyRaw contains the raw body submitted in a POST request.
 // Returned value is only valid within the handler. Do not store any references.
 // Make copies or use the Immutable setting instead.
+func (c *Ctx) BodyRaw() []byte {
+	return c.fasthttp.Request.Body()
+}
+
+func (c *Ctx) tryDecodeBodyInOrder(
+	originalBody *[]byte,
+	encodings []string,
+) ([]byte, uint8, error) {
+	var (
+		err             error
+		body            []byte
+		decodesRealized uint8
+	)
+
+	for index, encoding := range encodings {
+		decodesRealized++
+		switch encoding {
+		case StrGzip:
+			body, err = c.fasthttp.Request.BodyGunzip()
+		case StrBr, StrBrotli:
+			body, err = c.fasthttp.Request.BodyUnbrotli()
+		case StrDeflate:
+			body, err = c.fasthttp.Request.BodyInflate()
+		default:
+			decodesRealized--
+			if len(encodings) == 1 {
+				body = c.fasthttp.Request.Body()
+			}
+			return body, decodesRealized, nil
+		}
+
+		if err != nil {
+			return nil, decodesRealized, err
+		}
+
+		// Only execute body raw update if it has a next iteration to try to decode
+		if index < len(encodings)-1 && decodesRealized > 0 {
+			if index == 0 {
+				tempBody := c.fasthttp.Request.Body()
+				*originalBody = make([]byte, len(tempBody))
+				copy(*originalBody, tempBody)
+			}
+			c.fasthttp.Request.SetBodyRaw(body)
+		}
+	}
+
+	return body, decodesRealized, nil
+}
+
+// Body contains the raw body submitted in a POST request.
+// This method will decompress the body if the 'Content-Encoding' header is provided.
+// It returns the original (or decompressed) body data which is valid only within the handler.
+// Don't store direct references to the returned data.
+// If you need to keep the body's data later, make a copy or use the Immutable option.
 func (c *Ctx) Body() []byte {
-	var err error
-	var encoding string
-	var body []byte
+	var (
+		err                error
+		body, originalBody []byte
+		headerEncoding     string
+		encodingOrder      = []string{"", "", ""}
+	)
+
 	// faster than peek
 	c.Request().Header.VisitAll(func(key, value []byte) {
 		if c.app.getString(key) == HeaderContentEncoding {
-			encoding = c.app.getString(value)
+			headerEncoding = c.app.getString(value)
 		}
 	})
 
-	switch encoding {
-	case StrGzip:
-		body, err = c.fasthttp.Request.BodyGunzip()
-	case StrBr, StrBrotli:
-		body, err = c.fasthttp.Request.BodyUnbrotli()
-	case StrDeflate:
-		body, err = c.fasthttp.Request.BodyInflate()
-	default:
-		body = c.fasthttp.Request.Body()
+	// Split and get the encodings list, in order to attend the
+	// rule defined at: https://www.rfc-editor.org/rfc/rfc9110#section-8.4-5
+	encodingOrder = getSplicedStrList(headerEncoding, encodingOrder)
+	if len(encodingOrder) == 0 {
+		return c.fasthttp.Request.Body()
 	}
 
+	var decodesRealized uint8
+	body, decodesRealized, err = c.tryDecodeBodyInOrder(&originalBody, encodingOrder)
+
+	// Ensure that the body will be the original
+	if originalBody != nil && decodesRealized > 0 {
+		c.fasthttp.Request.SetBodyRaw(originalBody)
+	}
 	if err != nil {
 		return []byte(err.Error())
 	}

ctx_test.go

@@ -9,6 +9,7 @@ import (
 	"bufio"
 	"bytes"
 	"compress/gzip"
+	"compress/zlib"
 	"context"
 	"crypto/tls"
 	"encoding/xml"
@@ -323,47 +324,211 @@ func Test_Ctx_Body(t *testing.T) {
 	utils.AssertEqual(t, []byte("john=doe"), c.Body())
 }
 
-// go test -run Test_Ctx_Body_With_Compression
-func Test_Ctx_Body_With_Compression(t *testing.T) {
-	t.Parallel()
+func Benchmark_Ctx_Body(b *testing.B) {
+	const input = "john=doe"
+
 	app := New()
 	c := app.AcquireCtx(&fasthttp.RequestCtx{})
 	defer app.ReleaseCtx(c)
-	c.Request().Header.Set("Content-Encoding", "gzip")
-	var b bytes.Buffer
-	gz := gzip.NewWriter(&b)
-	_, err := gz.Write([]byte("john=doe"))
-	utils.AssertEqual(t, nil, err)
-	err = gz.Flush()
-	utils.AssertEqual(t, nil, err)
-	err = gz.Close()
-	utils.AssertEqual(t, nil, err)
-	c.Request().SetBody(b.Bytes())
-	utils.AssertEqual(t, []byte("john=doe"), c.Body())
+
+	c.Request().SetBody([]byte(input))
+	for i := 0; i < b.N; i++ {
+		_ = c.Body()
+	}
+
+	utils.AssertEqual(b, []byte(input), c.Body())
+}
+
+// go test -run Test_Ctx_Body_With_Compression
+func Test_Ctx_Body_With_Compression(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name            string
+		contentEncoding string
+		body            []byte
+		expectedBody    []byte
+	}{
+		{
+			name:            "gzip",
+			contentEncoding: "gzip",
+			body:            []byte("john=doe"),
+			expectedBody:    []byte("john=doe"),
+		},
+		{
+			name:            "unsupported_encoding",
+			contentEncoding: "undefined",
+			body:            []byte("keeps_ORIGINAL"),
+			expectedBody:    []byte("keeps_ORIGINAL"),
+		},
+		{
+			name:            "gzip then unsupported",
+			contentEncoding: "gzip, undefined",
+			body:            []byte("Go, be gzipped"),
+			expectedBody:    []byte("Go, be gzipped"),
+		},
+		{
+			name:            "invalid_deflate",
+			contentEncoding: "gzip,deflate",
+			body:            []byte("I'm not correctly compressed"),
+			expectedBody:    []byte(zlib.ErrHeader.Error()),
+		},
+	}
+
+	for _, testObject := range tests {
+		tCase := testObject // Duplicate object to ensure it will be unique across all runs
+		t.Run(tCase.name, func(t *testing.T) {
+			app := New()
+			c := app.AcquireCtx(&fasthttp.RequestCtx{})
+			defer app.ReleaseCtx(c)
+			c.Request().Header.Set("Content-Encoding", tCase.contentEncoding)
+
+			if strings.Contains(tCase.contentEncoding, "gzip") {
+				var b bytes.Buffer
+				gz := gzip.NewWriter(&b)
+				_, err := gz.Write(tCase.body)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if err = gz.Flush(); err != nil {
+					t.Fatal(err)
+				}
+				if err = gz.Close(); err != nil {
+					t.Fatal(err)
+				}
+				tCase.body = b.Bytes()
+			}
+
+			c.Request().SetBody(tCase.body)
+			body := c.Body()
+			utils.AssertEqual(t, tCase.expectedBody, body)
+
+			// Check if body raw is the same as previous before decompression
+			utils.AssertEqual(
+				t, tCase.body, c.Request().Body(),
+				"Body raw must be the same as set before",
+			)
+		})
+	}
 }
 
 // go test -v -run=^$ -bench=Benchmark_Ctx_Body_With_Compression -benchmem -count=4
 func Benchmark_Ctx_Body_With_Compression(b *testing.B) {
-	app := New()
-	c := app.AcquireCtx(&fasthttp.RequestCtx{})
-	defer app.ReleaseCtx(c)
-	c.Request().Header.Set("Content-Encoding", "gzip")
-	var buf bytes.Buffer
-	gz := gzip.NewWriter(&buf)
-	_, err := gz.Write([]byte("john=doe"))
-	utils.AssertEqual(b, nil, err)
-	err = gz.Flush()
-	utils.AssertEqual(b, nil, err)
-	err = gz.Close()
-	utils.AssertEqual(b, nil, err)
+	encodingErr := errors.New("failed to encoding data")
+
+	var (
+		compressGzip = func(data []byte) ([]byte, error) {
+			var buf bytes.Buffer
+			writer := gzip.NewWriter(&buf)
+			if _, err := writer.Write(data); err != nil {
+				return nil, encodingErr
+			}
+			if err := writer.Flush(); err != nil {
+				return nil, encodingErr
+			}
+			if err := writer.Close(); err != nil {
+				return nil, encodingErr
+			}
+			return buf.Bytes(), nil
+		}
+		compressDeflate = func(data []byte) ([]byte, error) {
+			var buf bytes.Buffer
+			writer := zlib.NewWriter(&buf)
+			if _, err := writer.Write(data); err != nil {
+				return nil, encodingErr
+			}
+			if err := writer.Flush(); err != nil {
+				return nil, encodingErr
+			}
+			if err := writer.Close(); err != nil {
+				return nil, encodingErr
+			}
+			return buf.Bytes(), nil
+		}
+	)
+	compressionTests := []struct {
+		contentEncoding string
+		compressWriter  func([]byte) ([]byte, error)
+	}{
+		{
+			contentEncoding: "gzip",
+			compressWriter:  compressGzip,
+		},
+		{
+			contentEncoding: "gzip,invalid",
+			compressWriter:  compressGzip,
+		},
+		{
+			contentEncoding: "deflate",
+			compressWriter:  compressDeflate,
+		},
+		{
+			contentEncoding: "gzip,deflate",
+			compressWriter: func(data []byte) ([]byte, error) {
+				var (
+					buf    bytes.Buffer
+					writer interface {
+						io.WriteCloser
+						Flush() error
+					}
+					err error
+				)
+
+				// deflate
+				{
+					writer = zlib.NewWriter(&buf)
+					if _, err = writer.Write(data); err != nil {
+						return nil, encodingErr
+					}
+					if err = writer.Flush(); err != nil {
+						return nil, encodingErr
+					}
+					if err = writer.Close(); err != nil {
+						return nil, encodingErr
+					}
+				}
 
-	c.Request().SetBody(buf.Bytes())
+				data = make([]byte, buf.Len())
+				copy(data, buf.Bytes())
+				buf.Reset()
+
+				// gzip
+				{
+					writer = gzip.NewWriter(&buf)
+					if _, err = writer.Write(data); err != nil {
+						return nil, encodingErr
+					}
+					if err = writer.Flush(); err != nil {
+						return nil, encodingErr
+					}
+					if err = writer.Close(); err != nil {
+						return nil, encodingErr
+					}
+				}
 
-	for i := 0; i < b.N; i++ {
-		_ = c.Body()
+				return buf.Bytes(), nil
+			},
+		},
 	}
 
-	utils.AssertEqual(b, []byte("john=doe"), c.Body())
+	for _, ct := range compressionTests {
+		b.Run(ct.contentEncoding, func(b *testing.B) {
+			app := New()
+			const input = "john=doe"
+			c := app.AcquireCtx(&fasthttp.RequestCtx{})
+			defer app.ReleaseCtx(c)
+
+			c.Request().Header.Set("Content-Encoding", ct.contentEncoding)
+			compressedBody, err := ct.compressWriter([]byte(input))
+			utils.AssertEqual(b, nil, err)
+
+			c.Request().SetBody(compressedBody)
+			for i := 0; i < b.N; i++ {
+				_ = c.Body()
+			}
+
+			utils.AssertEqual(b, []byte(input), c.Body())
+		})
+	}
 }
 
 // go test -run Test_Ctx_BodyParser