Support Square Bracket Notation in Multipart Form data (#3268)

* Feature Request: Support Square Bracket Notation in Multipart Form Data #3224

* Feature Request: Support Square Bracket Notation in Multipart Form Data #3224

Author: ReneWerner87

ctx.go

@@ -406,28 +406,30 @@ func (c *Ctx) BodyParser(out interface{}) error {
 			k := c.app.getString(key)
 			v := c.app.getString(val)
 
-			if strings.Contains(k, "[") {
-				k, err = parseParamSquareBrackets(k)
-			}
-
-			if c.app.config.EnableSplittingOnParsers && strings.Contains(v, ",") && equalFieldType(out, reflect.Slice, k, bodyTag) {
-				values := strings.Split(v, ",")
-				for i := 0; i < len(values); i++ {
-					data[k] = append(data[k], values[i])
-				}
-			} else {
-				data[k] = append(data[k], v)
-			}
+			err = formatParserData(out, data, bodyTag, k, v, c.app.config.EnableSplittingOnParsers, true)
 		})
 
+		if err != nil {
+			return err
+		}
+
 		return c.parseToStruct(bodyTag, out, data)
 	}
 	if strings.HasPrefix(ctype, MIMEMultipartForm) {
-		data, err := c.fasthttp.MultipartForm()
+		multipartForm, err := c.fasthttp.MultipartForm()
 		if err != nil {
 			return err
 		}
-		return c.parseToStruct(bodyTag, out, data.Value)
+
+		data := make(map[string][]string)
+		for key, values := range multipartForm.Value {
+			err = formatParserData(out, data, bodyTag, key, values, c.app.config.EnableSplittingOnParsers, true)
+			if err != nil {
+				return err
+			}
+		}
+
+		return c.parseToStruct(bodyTag, out, data)
 	}
 	if strings.HasPrefix(ctype, MIMETextXML) || strings.HasPrefix(ctype, MIMEApplicationXML) {
 		if err := xml.Unmarshal(c.Body(), out); err != nil {
@@ -531,18 +533,7 @@ func (c *Ctx) CookieParser(out interface{}) error {
 		k := c.app.getString(key)
 		v := c.app.getString(val)
 
-		if strings.Contains(k, "[") {
-			k, err = parseParamSquareBrackets(k)
-		}
-
-		if c.app.config.EnableSplittingOnParsers && strings.Contains(v, ",") && equalFieldType(out, reflect.Slice, k, cookieTag) {
-			values := strings.Split(v, ",")
-			for i := 0; i < len(values); i++ {
-				data[k] = append(data[k], values[i])
-			}
-		} else {
-			data[k] = append(data[k], v)
-		}
+		err = formatParserData(out, data, cookieTag, k, v, c.app.config.EnableSplittingOnParsers, true)
 	})
 	if err != nil {
 		return err
@@ -1283,18 +1274,7 @@ func (c *Ctx) QueryParser(out interface{}) error {
 		k := c.app.getString(key)
 		v := c.app.getString(val)
 
-		if strings.Contains(k, "[") {
-			k, err = parseParamSquareBrackets(k)
-		}
-
-		if c.app.config.EnableSplittingOnParsers && strings.Contains(v, ",") && equalFieldType(out, reflect.Slice, k, queryTag) {
-			values := strings.Split(v, ",")
-			for i := 0; i < len(values); i++ {
-				data[k] = append(data[k], values[i])
-			}
-		} else {
-			data[k] = append(data[k], v)
-		}
+		err = formatParserData(out, data, queryTag, k, v, c.app.config.EnableSplittingOnParsers, true)
 	})
 
 	if err != nil {
@@ -1304,61 +1284,26 @@ func (c *Ctx) QueryParser(out interface{}) error {
 	return c.parseToStruct(queryTag, out, data)
 }
 
-func parseParamSquareBrackets(k string) (string, error) {
-	bb := bytebufferpool.Get()
-	defer bytebufferpool.Put(bb)
-
-	kbytes := []byte(k)
-	openBracketsCount := 0
-
-	for i, b := range kbytes {
-		if b == '[' {
-			openBracketsCount++
-			if i+1 < len(kbytes) && kbytes[i+1] != ']' {
-				if err := bb.WriteByte('.'); err != nil {
-					return "", fmt.Errorf("failed to write: %w", err)
-				}
-			}
-			continue
-		}
-
-		if b == ']' {
-			openBracketsCount--
-			if openBracketsCount < 0 {
-				return "", errors.New("unmatched brackets")
-			}
-			continue
-		}
-
-		if err := bb.WriteByte(b); err != nil {
-			return "", fmt.Errorf("failed to write: %w", err)
-		}
-	}
-
-	if openBracketsCount > 0 {
-		return "", errors.New("unmatched brackets")
-	}
-
-	return bb.String(), nil
-}
-
 // ReqHeaderParser binds the request header strings to a struct.
 func (c *Ctx) ReqHeaderParser(out interface{}) error {
 	data := make(map[string][]string)
+	var err error
+
 	c.fasthttp.Request.Header.VisitAll(func(key, val []byte) {
+		if err != nil {
+			return
+		}
+
 		k := c.app.getString(key)
 		v := c.app.getString(val)
 
-		if c.app.config.EnableSplittingOnParsers && strings.Contains(v, ",") && equalFieldType(out, reflect.Slice, k, reqHeaderTag) {
-			values := strings.Split(v, ",")
-			for i := 0; i < len(values); i++ {
-				data[k] = append(data[k], values[i])
-			}
-		} else {
-			data[k] = append(data[k], v)
-		}
+		err = formatParserData(out, data, reqHeaderTag, k, v, c.app.config.EnableSplittingOnParsers, false)
 	})
 
+	if err != nil {
+		return err
+	}
+
 	return c.parseToStruct(reqHeaderTag, out, data)
 }
 

ctx_test.go

@@ -610,6 +610,48 @@ func Test_Ctx_BodyParser(t *testing.T) {
 	utils.AssertEqual(t, 2, len(cq.Data))
 	utils.AssertEqual(t, "john", cq.Data[0].Name)
 	utils.AssertEqual(t, "doe", cq.Data[1].Name)
+
+	t.Run("MultipartCollectionQueryDotNotation", func(t *testing.T) {
+		c := app.AcquireCtx(&fasthttp.RequestCtx{})
+		c.Request().Reset()
+
+		buf := &bytes.Buffer{}
+		writer := multipart.NewWriter(buf)
+		utils.AssertEqual(t, nil, writer.WriteField("data.0.name", "john"))
+		utils.AssertEqual(t, nil, writer.WriteField("data.1.name", "doe"))
+		utils.AssertEqual(t, nil, writer.Close())
+
+		c.Request().Header.SetContentType(writer.FormDataContentType())
+		c.Request().SetBody(buf.Bytes())
+		c.Request().Header.SetContentLength(len(c.Body()))
+
+		cq := new(CollectionQuery)
+		utils.AssertEqual(t, nil, c.BodyParser(cq))
+		utils.AssertEqual(t, len(cq.Data), 2)
+		utils.AssertEqual(t, "john", cq.Data[0].Name)
+		utils.AssertEqual(t, "doe", cq.Data[1].Name)
+	})
+
+	t.Run("MultipartCollectionQuerySquareBrackets", func(t *testing.T) {
+		c := app.AcquireCtx(&fasthttp.RequestCtx{})
+		c.Request().Reset()
+
+		buf := &bytes.Buffer{}
+		writer := multipart.NewWriter(buf)
+		utils.AssertEqual(t, nil, writer.WriteField("data[0][name]", "john"))
+		utils.AssertEqual(t, nil, writer.WriteField("data[1][name]", "doe"))
+		utils.AssertEqual(t, nil, writer.Close())
+
+		c.Request().Header.SetContentType(writer.FormDataContentType())
+		c.Request().SetBody(buf.Bytes())
+		c.Request().Header.SetContentLength(len(c.Body()))
+
+		cq := new(CollectionQuery)
+		utils.AssertEqual(t, nil, c.BodyParser(cq))
+		utils.AssertEqual(t, len(cq.Data), 2)
+		utils.AssertEqual(t, "john", cq.Data[0].Name)
+		utils.AssertEqual(t, "doe", cq.Data[1].Name)
+	})
 }
 
 func Test_Ctx_ParamParser(t *testing.T) {

go.mod

@@ -19,6 +19,4 @@ require (
 	github.com/philhofer/fwd v1.1.3-0.20240916144458-20a13a1f6b7c // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/valyala/tcplisten v1.0.0 // indirect
-	golang.org/x/mod v0.18.0 // indirect
-	golang.org/x/tools v0.22.0 // indirect
 )

go.sum

@@ -15,8 +15,6 @@ github.com/philhofer/fwd v1.1.3-0.20240916144458-20a13a1f6b7c h1:dAMKvw0MlJT1Gsh
 github.com/philhofer/fwd v1.1.3-0.20240916144458-20a13a1f6b7c/go.mod h1:RqIHx9QI14HlwKwm98g9Re5prTQ6LdeRQn+gXJFxsJM=
 github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
-github.com/tinylib/msgp v1.1.3 h1:3giwAkmtaEDLSV0MdO1lDLuPgklgPzmk8H9+So2BVfA=
-github.com/tinylib/msgp v1.1.3/go.mod h1:+d+yLhGm8mzTaHzB+wgMYrodPfmZrzkirds8fDWklFE=
 github.com/tinylib/msgp v1.2.5 h1:WeQg1whrXRFiZusidTQqzETkRpGjFjcIhW6uqWH09po=
 github.com/tinylib/msgp v1.2.5/go.mod h1:ykjzy2wzgrlvpDCRc4LA8UXy6D8bzMSuAF3WD57Gok0=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
@@ -25,11 +23,7 @@ github.com/valyala/fasthttp v1.51.0 h1:8b30A5JlZ6C7AS81RsWjYMQmrZG6feChmgAolCl1S
 github.com/valyala/fasthttp v1.51.0/go.mod h1:oI2XroL+lI7vdXyYoQk03bXBThfFl2cVdIA3Xl7cH8g=
 github.com/valyala/tcplisten v1.0.0 h1:rBHj/Xf+E1tRGZyWIWwJDiRY0zc1Js+CV5DqwacVSA8=
 github.com/valyala/tcplisten v1.0.0/go.mod h1:T0xQ8SeCZGxckz9qRXTfG43PvQ/mcWh7FwZEA7Ioqkc=
-golang.org/x/mod v0.18.0 h1:5+9lSbEzPSdWkH32vYPBwEpX8KwDbM52Ud9xBUvNlb0=
-golang.org/x/mod v0.18.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
 golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/tools v0.22.0 h1:gqSGLZqv+AI9lIQzniJ0nZDRG5GBPsSi+DRNHWNz6yA=
-golang.org/x/tools v0.22.0/go.mod h1:aCwcsjqvq7Yqt6TNyX7QMU2enbQ/Gt0bo6krSeEri+c=

helpers.go

@@ -7,6 +7,7 @@ package fiber
 import (
 	"bytes"
 	"crypto/tls"
+	"errors"
 	"fmt"
 	"hash/crc32"
 	"io"
@@ -1151,3 +1152,75 @@ func IndexRune(str string, needle int32) bool {
 	}
 	return false
 }
+
+func parseParamSquareBrackets(k string) (string, error) {
+	bb := bytebufferpool.Get()
+	defer bytebufferpool.Put(bb)
+
+	kbytes := []byte(k)
+	openBracketsCount := 0
+
+	for i, b := range kbytes {
+		if b == '[' {
+			openBracketsCount++
+			if i+1 < len(kbytes) && kbytes[i+1] != ']' {
+				if err := bb.WriteByte('.'); err != nil {
+					return "", fmt.Errorf("failed to write: %w", err)
+				}
+			}
+			continue
+		}
+
+		if b == ']' {
+			openBracketsCount--
+			if openBracketsCount < 0 {
+				return "", errors.New("unmatched brackets")
+			}
+			continue
+		}
+
+		if err := bb.WriteByte(b); err != nil {
+			return "", fmt.Errorf("failed to write: %w", err)
+		}
+	}
+
+	if openBracketsCount > 0 {
+		return "", errors.New("unmatched brackets")
+	}
+
+	return bb.String(), nil
+}
+
+func formatParserData(out interface{}, data map[string][]string, aliasTag, key string, value interface{}, enableSplitting, supportBracketNotation bool) error { //nolint:revive // it's okay
+	var err error
+	if supportBracketNotation && strings.Contains(key, "[") {
+		key, err = parseParamSquareBrackets(key)
+		if err != nil {
+			return err
+		}
+	}
+
+	switch v := value.(type) {
+	case string:
+		assignBindData(out, data, aliasTag, key, v, enableSplitting)
+	case []string:
+		for _, val := range v {
+			assignBindData(out, data, aliasTag, key, val, enableSplitting)
+		}
+	default:
+		return fmt.Errorf("unsupported value type: %T", value)
+	}
+
+	return err
+}
+
+func assignBindData(out interface{}, data map[string][]string, aliasTag, key, value string, enableSplitting bool) { //nolint:revive // it's okay
+	if enableSplitting && strings.Contains(value, ",") && equalFieldType(out, reflect.Slice, key, aliasTag) {
+		values := strings.Split(value, ",")
+		for i := 0; i < len(values); i++ {
+			data[key] = append(data[key], values[i])
+		}
+	} else {
+		data[key] = append(data[key], value)
+	}
+}