diff --git a/README.md b/README.md
index 376f608..a1c0500 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,8 @@ A command-line tool for send the gcode file to Snapmaker Printers via WiFi conne
 ## Features:
 - Support Snapmaker 2 A150/250/350, J1, Artisan
 - Auto discover machines (UDP broadcast)
-- Simulated a OctoPrint server, so that it can be in any slicing software such as Cura/PrusaSlicer/SuperSlicer/ideaMaker send gcode to the printer
+- Simulated a OctoPrint server, so that it can be in any slicing software such as Cura/PrusaSlicer/SuperSlicer/OrcaSlicer send gcode to the printer
+- Smart pre-heat for switch tools, shutoff nozzles that are no longer in use, and other optimization features for multi-extruders.
 - No need to click Yes button on the touch screen every time for authorization connect
 - Support for multiple platforms including win/macOS/Linux/RaspberryPi
 
diff --git a/README.zh-cn.md b/README.zh-cn.md
index a3cfeab..1c375f5 100644
--- a/README.zh-cn.md
+++ b/README.zh-cn.md
@@ -7,7 +7,8 @@ Luban 和 Cura with SnapmakerPlugin 对于新手很友好，但是我的大部
 ## 功能
 - 支持 Snapmaker 2 A/J1/Artisan 全系列打印机
 - 自动发现局域网内所有的 Snapmaker 打印机（和 Luban 相同的协议，使用 UDP 广播）
-- 模拟 OctoPrint Server，这样就可以在各种切片软件，比如 Cura/PrusaSlicer/SuperSlicer/ideaMaker 中向 Snapmaker 打印机发送文件
+- 模拟 OctoPrint Server，这样就可以在各种切片软件，比如 Cura/PrusaSlicer/SuperSlicer/OrcaSlicer 中向 Snapmaker 打印机发送文件
+- 为多挤出机提供智能预热、关闭不再使用的喷头等优化功能
 - Snapmaker 2 A-Series 第一次连接时需要授权，之后可以直接一步上传
 - 支持 macOS/Windows/Linux/RaspberryPi 多个平台
 
diff --git a/connector.go b/connector.go
index c0add42..68e3602 100644
--- a/connector.go
+++ b/connector.go
@@ -4,6 +4,7 @@ import (
 	"errors"
 	"io"
 	"net"
+	"runtime"
 	"time"
 )
 
@@ -32,6 +33,7 @@ func (p *Payload) ReadableSize() string {
 }
 
 func (p *Payload) GetContent(fix bool) (cont []byte, err error) {
+	defer runtime.GC()
 	if fix {
 		cont, err = postProcess(p.File)
 		p.Size = int64(len(cont))
diff --git a/go.mod b/go.mod
index bceef0a..a85d89b 100644
--- a/go.mod
+++ b/go.mod
@@ -5,7 +5,7 @@ go 1.20
 require (
 	github.com/gosuri/uilive v0.0.4
 	github.com/imroc/req/v3 v3.11.0
-	github.com/macdylan/SMFix/fix v0.0.0-20230711071352-9db26cbcb3a3
+	github.com/macdylan/SMFix/fix v0.0.0-20230731072358-03b385d0df5a
 	github.com/manifoldco/promptui v0.9.0
 	gopkg.in/yaml.v3 v3.0.1
 )
diff --git a/go.sum b/go.sum
index 783132a..481a013 100644
--- a/go.sum
+++ b/go.sum
@@ -21,8 +21,8 @@ github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/macdylan/SMFix/fix v0.0.0-20230711071352-9db26cbcb3a3 h1:yHR5HciyfOoZyt5S3m3gBLYv+Q6L4iwXgGaJXRd+N04=
-github.com/macdylan/SMFix/fix v0.0.0-20230711071352-9db26cbcb3a3/go.mod h1:dnB1MevhW7tICqBpQ2aHpVClwLdmSBUNmfV7jpRmiWw=
+github.com/macdylan/SMFix/fix v0.0.0-20230731072358-03b385d0df5a h1:yy0uQ23OaihOPf88+TWqwFPJTdCsPQTfkQBRtYqug44=
+github.com/macdylan/SMFix/fix v0.0.0-20230731072358-03b385d0df5a/go.mod h1:dnB1MevhW7tICqBpQ2aHpVClwLdmSBUNmfV7jpRmiWw=
 github.com/manifoldco/promptui v0.9.0 h1:3V4HzJk1TtXW1MTZMP7mdlwbBpIinw3HztaIlYthEiA=
 github.com/manifoldco/promptui v0.9.0/go.mod h1:ka04sppxSGFAtxX0qhlYQjISsg9mR4GWtQEhdbn6Pgg=
 github.com/mattn/go-isatty v0.0.19 h1:JITubQf0MOLdlGRuRq+jtsDlekdYPia9ZFsB8h/APPA=
diff --git a/octoprint.go b/octoprint.go
index d71d54d..fd52420 100644
--- a/octoprint.go
+++ b/octoprint.go
@@ -4,6 +4,7 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"strings"
 	"time"
 )
 
@@ -11,6 +12,12 @@ const (
 	maxMemory = 64 << 20 // 64MB
 )
 
+var (
+	noTrim    = false
+	noShutoff = false
+	noPreheat = false
+)
+
 func LoggingMiddleware(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		start := time.Now()
@@ -51,6 +58,27 @@ func startOctoPrintServer(listenAddr string, printer *Printer) error {
 		}
 		defer file.Close()
 
+		// read X-Api-Key header
+		apiKey := r.Header.Get("X-Api-Key")
+		if len(apiKey) > 5 {
+			noTrim = strings.Contains(apiKey, "notrim")
+			noPreheat = strings.Contains(apiKey, "nopreheat")
+			noShutoff = strings.Contains(apiKey, "noshutoff")
+			msg := make([]string, 0, 3)
+			if noTrim {
+				msg = append(msg, "-notrim")
+			}
+			if noPreheat {
+				msg = append(msg, "-nopreheat")
+			}
+			if noShutoff {
+				msg = append(msg, "-noshutoff")
+			}
+			if len(msg) > 0 {
+				log.Printf("SMFix with args: %s", strings.Join(msg, " "))
+			}
+		}
+
 		// Send the stream to the printer
 		payload := NewPayload(file, fd.Filename, fd.Size)
 		if err := Connector.Upload(printer, payload); err != nil {
diff --git a/utils.go b/utils.go
index 5c9347c..a74cd56 100644
--- a/utils.go
+++ b/utils.go
@@ -1,11 +1,13 @@
 package main
 
 import (
+	"bufio"
 	"bytes"
 	"fmt"
 	"io"
 	"os"
 	"regexp"
+	"strings"
 
 	"github.com/macdylan/SMFix/fix"
 )
@@ -43,20 +45,32 @@ func postProcessFile(file_path string) (out []byte, err error) {
 func postProcess(r io.Reader) (out []byte, err error) {
 	header, errfix := fix.ExtractHeader(r)
 
-	out, err = io.ReadAll(r)
-	if err != nil {
-		return
+	if h, ok := r.(io.ReadSeeker); ok {
+		h.Seek(0, 0)
 	}
 
-	/*
-		if err == fix.ErrIsFixed || err == fix.ErrInvalidGcode {
-			return out, nil
-		}
+	gcodes := make([]string, 0, fix.Params.TotalLines+len(header)+128)
+	sc := bufio.NewScanner(r)
+	for sc.Scan() {
+		gcodes = append(gcodes, sc.Text())
+	}
+	if err = sc.Err(); err != nil {
+		return nil, err
+	}
 
-		if err != nil {
-			return out, err
+	if errfix == nil {
+		if !noTrim {
+			gcodes = fix.GcodeTrimLines(gcodes)
 		}
-	*/
+		if !noShutoff {
+			gcodes = fix.GcodeFixShutoff(gcodes)
+		}
+		if !noPreheat {
+			gcodes = fix.GcodeFixPreheat(gcodes)
+		}
+	}
+
+	out = []byte(strings.Join(gcodes, "\n"))
 
 	if len(header) > 25 {
 		return append(bytes.Join(header, []byte("\n")), out...), nil