basic web app
This commit is contained in:
Matthew Frost
parent
4da54d788e
commit
8721646b29
2 changed files with 111 additions and 87 deletions
147
main.go
147
main.go
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@ -1,60 +1,125 @@
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package main
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import (
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"encoding/json"
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"fmt"
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"github.com/kenshaw/escpos"
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"math"
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"net/http"
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"time"
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"log"
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"os"
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"time"
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)
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// RequestData represents the JSON request body structure
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type RequestData struct {
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Date string `json:"date"`
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Nickname string `json:"nickname"`
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const ESC = byte(27)
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func pageWidth(widht int) []byte {
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return []byte{escpos.GS, 87, byte(widht), 0}
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}
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func pageMargin(margin int) []byte {
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return []byte{escpos.GS, 76, byte(margin), 0}
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}
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func pageMode() []byte {
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return []byte{ESC, 'L'}
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}
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func pageDirection(direction uint8) []byte {
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// https://www.epson-biz.com/modules/ref_escpos/index.php?content_id=55
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return []byte{ESC, 'T', direction}
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}
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func pagePrintArea(x, y, width, height int) []byte {
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return []byte{ESC, 'W',
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byte(x & 255), byte(x >> 8 & 255),
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byte(y & 255), byte(y >> 8 & 255),
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byte(width & 255), byte(width >> 8 & 255),
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byte(height & 255), byte(height >> 8 & 255)}
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}
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func offsetY(offset int) []byte {
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// A positive number specifies movement downward, and a negative number specifies movement upward.
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// The horizontal or vertical motion unit is used for the print direction set by ESC T.
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// When the starting position is set to the upper left or lower right of the print area using ESC T, the vertical motion unit is used.
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// When the starting position is set to the upper right or lower left of the print area using ESC T, the horizontal motion unit is used.
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return []byte{escpos.GS, '\\', byte(offset & 255), byte(offset >> 8 & 255)}
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}
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func offsetX(offset int) []byte {
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// A positive number specifies movement to the right, and a negative number specifies movement to the left.
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// When Standard mode is selected, the horizontal motion unit is used.
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// when Page mode is selected, the horizontal or vertical motion unit is used for the print direction set by ESC T.
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// When the starting position is set to the upper left or lower right of the print area using ESC T, the horizontal motion unit is used.
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// When the starting position is set to the upper right or lower left of the print area using ESC T, the vertical motion unit is used.
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return []byte{ESC, '\\', byte(offset & 255), byte(offset >> 8 & 255)}
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}
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func invert(n int) []byte {
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//When the LSB of n is 0, white/black reverse print mode is turned off.
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//n = 0 – 255
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return []byte{escpos.GS, byte('B'), byte(n)}
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}
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func disableSensors() []byte {
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return []byte{ESC, 'c', '3', 0}
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}
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func printSpeed(m int) []byte {
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// m = 0 – 9, 48 – 57 : slowest - fastest
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// [Default] 0 = Setting value of GS ( E <Function 5> customize value (a = 6)
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// m = 0
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//Slower print speed seems to retain a bit more quality in dithered images. pure B/W images do not have a noticable difference
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return []byte{escpos.GS, '(', 'K', 2, 0, 50, byte(m & 255), byte(m >> 8 & 255)}
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}
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func main() {
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// Set the output to unbuffered
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log.SetOutput(os.Stdout)
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http.HandleFunc("/print/dnh-label", func(w http.ResponseWriter, r *http.Request) {
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// Only handle POST requests
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if r.Method != http.MethodPost {
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http.Error(w, "Invalid request method", http.StatusMethodNotAllowed)
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return
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}
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// Parse JSON request body
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var requestData RequestData
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decoder := json.NewDecoder(r.Body)
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if err := decoder.Decode(&requestData); err != nil {
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http.Error(w, "Invalid JSON request body", http.StatusBadRequest)
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return
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}
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// Validate the date format
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_, err := time.Parse("2006-01-02", requestData.Date)
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f, err := os.OpenFile("/dev/usb/lp0", os.O_WRONLY|os.O_CREATE, 0)
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if err != nil {
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http.Error(w, "Invalid date format. Please use yyyy-mm-dd", http.StatusBadRequest)
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return
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panic(err)
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}
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defer f.Close()
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// Process the request
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response := fmt.Sprintf("Received Date: %s, Nickname: %s", requestData.Date, requestData.Nickname)
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ep := escpos.New(f)
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ep.Init()
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// Send a JSON response
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w.Header().Set("Content-Type", "application/json")
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w.WriteHeader(http.StatusOK)
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json.NewEncoder(w).Encode(map[string]string{"message": response})
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// Force immediate output to the console
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log.Println(response)
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http.HandleFunc("/create_label", func(w http.ResponseWriter, r *http.Request) {
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createDnhLabelHandler(w, r, ep)
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})
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// Start the server
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fmt.Println("Server is running on :8080")
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http.ListenAndServe(":8080", nil)
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fmt.Println("Server starting on port 8080")
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if err := http.ListenAndServe(":8080", nil); err != nil {
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panic(err)
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}
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}
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func createDnhLabelHandler(w http.ResponseWriter, r *http.Request, ep *escpos.Escpos) {
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if r.Method != http.MethodPost {
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http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
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return
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}
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name := r.FormValue("name")
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date := r.FormValue("date")
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// Check if name is blank
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if name == "" {
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http.Error(w, "Name cannot be blank", http.StatusBadRequest)
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return
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}
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// Set date to today if not defined
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if date == "" {
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date = time.Now().Format("2006-01-02")
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}
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// Here you can add the logic for creating a label using the POST data
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text := fmt.Sprintf("%s - %s \n", name, date)
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ep.Init()
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ep.WriteRaw(pageMode())
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ep.WriteRaw(pageDirection(1))
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ep.WriteRaw(pagePrintArea(0, 0, int(math.Round((29.0/80.0)*512)), 850))
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ep.WriteRaw(offsetY(30))
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ep.SetFontSize(1, 1)
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ep.Write("Technologia Incognita\n")
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ep.WriteRaw(offsetY(35))
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ep.SetFontSize(3, 2)
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ep.SetEmphasize(1)
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ep.Write("Do Not Hack\n")
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ep.SetEmphasize(0)
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ep.WriteRaw(offsetY(15))
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ep.SetFontSize(1, 1)
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ep.Write(text)
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ep.WriteRaw([]byte{12}) // FF: in Page mode, prints all the data in the print buffer collectively and switches from Page mode to Standard mode.
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ep.Cut()
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ep.End()
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}
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41
server.go
41
server.go
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@ -1,41 +0,0 @@
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package main
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import (
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"fmt"
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"net/http"
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"time"
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)
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func main() {
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http.HandleFunc("/create_label", createLabelHandler)
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fmt.Println("Server starting on port 8080")
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if err := http.ListenAndServe(":8080", nil); err != nil {
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panic(err)
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}
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}
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func createLabelHandler(w http.ResponseWriter, r *http.Request) {
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if r.Method != http.MethodPost {
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http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
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return
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}
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name := r.FormValue("name")
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date := r.FormValue("date")
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// Check if name is blank
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if name == "" {
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http.Error(w, "Name cannot be blank", http.StatusBadRequest)
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return
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}
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// Set date to today if not defined
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if date == "" {
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date = time.Now().Format("2006-01-02")
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}
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// Here you can add the logic for creating a label using the POST data
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fmt.Fprintf(w, "Label created! Name: %s, Date: %s", name, date)
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}
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