Build request data through RequestData struct instead of fasthttp directly

Refactor request generators to populate a script.RequestData intermediate struct, then apply it to fasthttp.Request in one step. This eliminates the round-trip conversion (fasthttp → RequestData → fasthttp) when scripts are enabled. Remove the URL field from RequestData and the now-unused fasthttp conversion functions from chain.go.

internal/sarin/request.go

@@ -17,7 +17,7 @@ import (
 
 type RequestGenerator func(*fasthttp.Request) error
 
-type RequestGeneratorWithData func(*fasthttp.Request, any) error
+type requestDataGenerator func(*script.RequestData, any) error
 
 type valuesData struct {
 	Values map[string]string
@@ -59,13 +59,22 @@ func NewRequestGenerator(
 
 	hasScripts := scriptTransformer != nil && !scriptTransformer.IsEmpty()
 
+	host := requestURL.Host
+	scheme := requestURL.Scheme
+
+	reqData := &script.RequestData{
+		Headers: make(map[string][]string),
+		Params:  make(map[string][]string),
+		Cookies: make(map[string][]string),
+	}
+
 	var (
 		data valuesData
 		path string
 		err  error
 	)
 	return func(req *fasthttp.Request) error {
-			req.Header.SetHost(requestURL.Host)
+			resetRequestData(reqData)
 
 			data, err = valuesGenerator()
 			if err != nil {
@@ -76,44 +85,39 @@ func NewRequestGenerator(
 			if err != nil {
 				return err
 			}
-			req.SetRequestURI(path)
+			reqData.Path = path
 
-			if err = methodGenerator(req, data); err != nil {
+			if err = methodGenerator(reqData, data); err != nil {
 				return err
 			}
 
 			bodyTemplateFuncMapData.ClearFormDataContenType()
-			if err = bodyGenerator(req, data); err != nil {
+			if err = bodyGenerator(reqData, data); err != nil {
 				return err
 			}
 
-			if err = headersGenerator(req, data); err != nil {
+			if err = headersGenerator(reqData, data); err != nil {
 				return err
 			}
 			if bodyTemplateFuncMapData.GetFormDataContenType() != "" {
-				req.Header.Add("Content-Type", bodyTemplateFuncMapData.GetFormDataContenType())
+				reqData.Headers["Content-Type"] = append(reqData.Headers["Content-Type"], bodyTemplateFuncMapData.GetFormDataContenType())
 			}
 
-			if err = paramsGenerator(req, data); err != nil {
+			if err = paramsGenerator(reqData, data); err != nil {
 				return err
 			}
-			if err = cookiesGenerator(req, data); err != nil {
+			if err = cookiesGenerator(reqData, data); err != nil {
 				return err
 			}
 
-			if requestURL.Scheme == "https" {
-				req.URI().SetScheme("https")
-			}
-
-			// Apply script transformations if any
 			if hasScripts {
-				reqData := script.RequestDataFromFastHTTP(req)
 				if err = scriptTransformer.Transform(reqData); err != nil {
 					return err
 				}
-				script.ApplyToFastHTTP(reqData, req)
 			}
 
+			applyRequestDataToFastHTTP(reqData, req, host, scheme)
+
 			return nil
 		}, isPathGeneratorDynamic ||
 			isMethodGeneratorDynamic ||
@@ -124,50 +128,92 @@ func NewRequestGenerator(
 			hasScripts
 }
 
-func NewMethodGeneratorFunc(localRand *rand.Rand, methods []string, templateFunctions template.FuncMap) (RequestGeneratorWithData, bool) {
+func resetRequestData(reqData *script.RequestData) {
+	reqData.Method = ""
+	reqData.Path = ""
+	reqData.Body = ""
+	clear(reqData.Headers)
+	clear(reqData.Params)
+	clear(reqData.Cookies)
+}
+
+func applyRequestDataToFastHTTP(reqData *script.RequestData, req *fasthttp.Request, host, scheme string) {
+	req.Header.SetHost(host)
+	req.SetRequestURI(reqData.Path)
+	req.Header.SetMethod(reqData.Method)
+	req.SetBody([]byte(reqData.Body))
+
+	for k, values := range reqData.Headers {
+		for _, v := range values {
+			req.Header.Add(k, v)
+		}
+	}
+
+	for k, values := range reqData.Params {
+		for _, v := range values {
+			req.URI().QueryArgs().Add(k, v)
+		}
+	}
+
+	if len(reqData.Cookies) > 0 {
+		cookieStrings := make([]string, 0, len(reqData.Cookies))
+		for k, values := range reqData.Cookies {
+			for _, v := range values {
+				cookieStrings = append(cookieStrings, k+"="+v)
+			}
+		}
+		req.Header.Add("Cookie", strings.Join(cookieStrings, "; "))
+	}
+
+	if scheme == "https" {
+		req.URI().SetScheme("https")
+	}
+}
+
+func NewMethodGeneratorFunc(localRand *rand.Rand, methods []string, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
 	methodGenerator, isDynamic := buildStringSliceGenerator(localRand, methods, templateFunctions)
 
 	var (
 		method string
 		err    error
 	)
-	return func(req *fasthttp.Request, data any) error {
+	return func(reqData *script.RequestData, data any) error {
 		method, err = methodGenerator()(data)
 		if err != nil {
 			return err
 		}
 
-		req.Header.SetMethod(method)
+		reqData.Method = method
 		return nil
 	}, isDynamic
 }
 
-func NewBodyGeneratorFunc(localRand *rand.Rand, bodies []string, templateFunctions template.FuncMap) (RequestGeneratorWithData, bool) {
+func NewBodyGeneratorFunc(localRand *rand.Rand, bodies []string, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
 	bodyGenerator, isDynamic := buildStringSliceGenerator(localRand, bodies, templateFunctions)
 
 	var (
 		body string
 		err  error
 	)
-	return func(req *fasthttp.Request, data any) error {
+	return func(reqData *script.RequestData, data any) error {
 		body, err = bodyGenerator()(data)
 		if err != nil {
 			return err
 		}
 
-		req.SetBody([]byte(body))
+		reqData.Body = body
 		return nil
 	}, isDynamic
 }
 
-func NewParamsGeneratorFunc(localRand *rand.Rand, params types.Params, templateFunctions template.FuncMap) (RequestGeneratorWithData, bool) {
+func NewParamsGeneratorFunc(localRand *rand.Rand, params types.Params, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
 	generators, isDynamic := buildKeyValueGenerators(localRand, params, templateFunctions)
 
 	var (
 		key, value string
 		err        error
 	)
-	return func(req *fasthttp.Request, data any) error {
+	return func(reqData *script.RequestData, data any) error {
 		for _, gen := range generators {
 			key, err = gen.Key(data)
 			if err != nil {
@@ -179,20 +225,20 @@ func NewParamsGeneratorFunc(localRand *rand.Rand, params types.Params, templateF
 				return err
 			}
 
-			req.URI().QueryArgs().Add(key, value)
+			reqData.Params[key] = append(reqData.Params[key], value)
 		}
 		return nil
 	}, isDynamic
 }
 
-func NewHeadersGeneratorFunc(localRand *rand.Rand, headers types.Headers, templateFunctions template.FuncMap) (RequestGeneratorWithData, bool) {
+func NewHeadersGeneratorFunc(localRand *rand.Rand, headers types.Headers, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
 	generators, isDynamic := buildKeyValueGenerators(localRand, headers, templateFunctions)
 
 	var (
 		key, value string
 		err        error
 	)
-	return func(req *fasthttp.Request, data any) error {
+	return func(reqData *script.RequestData, data any) error {
 		for _, gen := range generators {
 			key, err = gen.Key(data)
 			if err != nil {
@@ -204,41 +250,33 @@ func NewHeadersGeneratorFunc(localRand *rand.Rand, headers types.Headers, templa
 				return err
 			}
 
-			req.Header.Add(key, value)
+			reqData.Headers[key] = append(reqData.Headers[key], value)
 		}
 		return nil
 	}, isDynamic
 }
 
-func NewCookiesGeneratorFunc(localRand *rand.Rand, cookies types.Cookies, templateFunctions template.FuncMap) (RequestGeneratorWithData, bool) {
+func NewCookiesGeneratorFunc(localRand *rand.Rand, cookies types.Cookies, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
 	generators, isDynamic := buildKeyValueGenerators(localRand, cookies, templateFunctions)
 
 	var (
 		key, value string
 		err        error
 	)
-	if len(generators) > 0 {
+	return func(reqData *script.RequestData, data any) error {
-		return func(req *fasthttp.Request, data any) error {
+		for _, gen := range generators {
-			cookieStrings := make([]string, 0, len(generators))
+			key, err = gen.Key(data)
-			for _, gen := range generators {
+			if err != nil {
-				key, err = gen.Key(data)
+				return err
-				if err != nil {
-					return err
-				}
-
-				value, err = gen.Value()(data)
-				if err != nil {
-					return err
-				}
-
-				cookieStrings = append(cookieStrings, key+"="+value)
 			}
-			req.Header.Add("Cookie", strings.Join(cookieStrings, "; "))
-			return nil
-		}, isDynamic
-	}
 
-	return func(req *fasthttp.Request, data any) error {
+			value, err = gen.Value()(data)
+			if err != nil {
+				return err
+			}
+
+			reqData.Cookies[key] = append(reqData.Cookies[key], value)
+		}
 		return nil
 	}, isDynamic
 }

internal/script/chain.go

@@ -1,7 +1,6 @@
 package script
 
 import (
-	"github.com/valyala/fasthttp"
 	"go.aykhans.me/sarin/internal/types"
 )
 
@@ -106,83 +105,3 @@ func (t *Transformer) Close() {
 func (t *Transformer) IsEmpty() bool {
 	return len(t.luaEngines) == 0 && len(t.jsEngines) == 0
 }
-
-// RequestDataFromFastHTTP extracts RequestData from a fasthttp.Request.
-func RequestDataFromFastHTTP(req *fasthttp.Request) *RequestData {
-	data := &RequestData{
-		Method:  string(req.Header.Method()),
-		URL:     string(req.URI().FullURI()),
-		Path:    string(req.URI().Path()),
-		Body:    string(req.Body()),
-		Headers: make(map[string][]string),
-		Params:  make(map[string][]string),
-		Cookies: make(map[string][]string),
-	}
-
-	// Extract headers (supports multiple values per key)
-	req.Header.All()(func(key, value []byte) bool {
-		k := string(key)
-		data.Headers[k] = append(data.Headers[k], string(value))
-		return true
-	})
-
-	// Extract query params (supports multiple values per key)
-	req.URI().QueryArgs().All()(func(key, value []byte) bool {
-		k := string(key)
-		data.Params[k] = append(data.Params[k], string(value))
-		return true
-	})
-
-	// Extract cookies (supports multiple values per key)
-	req.Header.Cookies()(func(key, value []byte) bool {
-		k := string(key)
-		data.Cookies[k] = append(data.Cookies[k], string(value))
-		return true
-	})
-
-	return data
-}
-
-// ApplyToFastHTTP applies the modified RequestData back to a fasthttp.Request.
-func ApplyToFastHTTP(data *RequestData, req *fasthttp.Request) {
-	// Method
-	req.Header.SetMethod(data.Method)
-
-	// Path (preserve scheme and host)
-	req.URI().SetPath(data.Path)
-
-	// Body
-	req.SetBody([]byte(data.Body))
-
-	// Clear and set headers (supports multiple values per key)
-	req.Header.All()(func(key, _ []byte) bool {
-		keyStr := string(key)
-		if keyStr != "Host" {
-			req.Header.Del(keyStr)
-		}
-		return true
-	})
-	for k, values := range data.Headers {
-		if k != "Host" { // Don't overwrite Host
-			for _, v := range values {
-				req.Header.Add(k, v)
-			}
-		}
-	}
-
-	// Clear and set query params (supports multiple values per key)
-	req.URI().QueryArgs().Reset()
-	for k, values := range data.Params {
-		for _, v := range values {
-			req.URI().QueryArgs().Add(k, v)
-		}
-	}
-
-	// Clear and set cookies (supports multiple values per key)
-	req.Header.DelAllCookies()
-	for k, values := range data.Cookies {
-		for _, v := range values {
-			req.Header.SetCookie(k, v)
-		}
-	}
-}

internal/script/js.go

@@ -86,7 +86,6 @@ func (e *JsEngine) requestDataToObject(req *RequestData) goja.Value {
 	obj := e.runtime.NewObject()
 
 	_ = obj.Set("method", req.Method)
-	_ = obj.Set("url", req.URL)
 	_ = obj.Set("path", req.Path)
 	_ = obj.Set("body", req.Body)
 
@@ -130,11 +129,6 @@ func (e *JsEngine) objectToRequestData(val goja.Value, req *RequestData) error {
 		req.Method = v.String()
 	}
 
-	// URL
-	if v := obj.Get("url"); v != nil && !goja.IsUndefined(v) {
-		req.URL = v.String()
-	}
-
 	// Path
 	if v := obj.Get("path"); v != nil && !goja.IsUndefined(v) {
 		req.Path = v.String()

internal/script/lua.go

@@ -90,7 +90,6 @@ func (e *LuaEngine) requestDataToTable(req *RequestData) *lua.LTable {
 	t := L.NewTable()
 
 	t.RawSetString("method", lua.LString(req.Method))
-	t.RawSetString("url", lua.LString(req.URL))
 	t.RawSetString("path", lua.LString(req.Path))
 	t.RawSetString("body", lua.LString(req.Body))
 
@@ -137,11 +136,6 @@ func (e *LuaEngine) tableToRequestData(t *lua.LTable, req *RequestData) {
 		req.Method = string(v.(lua.LString))
 	}
 
-	// URL
-	if v := t.RawGetString("url"); v.Type() == lua.LTString {
-		req.URL = string(v.(lua.LString))
-	}
-
 	// Path
 	if v := t.RawGetString("path"); v.Type() == lua.LTString {
 		req.Path = string(v.(lua.LString))

internal/script/script.go

@@ -17,7 +17,6 @@ import (
 // Headers, Params, and Cookies use []string values to support multiple values per key.
 type RequestData struct {
 	Method  string              `json:"method"`
-	URL     string              `json:"url"`
 	Path    string              `json:"path"`
 	Headers map[string][]string `json:"headers"`
 	Params  map[string][]string `json:"params"`