218 lines
7.3 KiB
Go
218 lines
7.3 KiB
Go
// This file is part of https://github.com/racingmars/go3270/
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// Copyright 2020 by Matthew R. Wilson, licensed under the MIT license. See
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// LICENSE in the project root for license information.
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package main
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import (
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"fmt"
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"net"
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"strings"
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"time"
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"github.com/racingmars/go3270"
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)
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func init() {
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// put the go3270 library in debug mode:
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// go3270.Debug = os.Stderr
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}
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// A Screen is an array of go3270.Field structs. We will build two screens,
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// a query screen and a result screen:
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var screen1 = go3270.Screen{
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{Row: 0, Col: 27, Intense: true, Content: "3270 Example Application"},
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{Row: 2, Col: 0, Content: "Welcome to the go3270 example application. Please enter your name."},
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{Row: 4, Col: 0, Content: "First Name . . ."},
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{Row: 4, Col: 19, Name: "fname", Write: true, Highlighting: go3270.Underscore},
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{Row: 4, Col: 40, Autoskip: true}, // field "stop" character
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{Row: 5, Col: 0, Content: "Last Name . . . ."},
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{Row: 5, Col: 19, Name: "lname", Write: true, Highlighting: go3270.Underscore},
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{Row: 5, Col: 40, Autoskip: true}, // field "stop" character
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{Row: 6, Col: 0, Content: "Password . . . ."},
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{Row: 6, Col: 19, Name: "password", Write: true, Hidden: true},
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{Row: 6, Col: 40}, // field "stop" character
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{Row: 7, Col: 0, Content: "Employee ID . . ."},
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{Row: 7, Col: 19, Name: "employeeID", Write: true, Highlighting: go3270.Underscore, NumericOnly: true},
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{Row: 7, Col: 40}, // field "stop" character
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{Row: 8, Col: 0, Content: "Press"},
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{Row: 8, Col: 6, Intense: true, Content: "enter"},
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{Row: 8, Col: 12, Content: "to submit your name."},
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{Row: 10, Col: 0, Intense: true, Color: go3270.Red, Name: "errormsg"}, // a blank field for error messages
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{Row: 14, Col: 0, Content: "Detected code page:"},
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{Row: 14, Col: 20, Name: "codepage"},
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{Row: 15, Col: 0, Content: "The following should be left and right square brackets: [ ]"},
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{Row: 22, Col: 0, Content: "PF3 Exit"},
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}
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var screen2 = go3270.Screen{
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{Row: 0, Col: 27, Intense: true, Content: "3270 Example Application"},
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{Row: 2, Col: 0, Content: "Thank you for submitting your name. Here's what I know:"},
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{Row: 4, Col: 0, Content: "Your first name is"},
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{Row: 4, Col: 19, Name: "fname"}, // We're giving this field a name to replace its value at runtime
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{Row: 5, Col: 0, Content: "And your last name is"},
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{Row: 5, Col: 22, Name: "lname"}, // We're giving this field a name to replace its value at runtime
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{Row: 6, Col: 0, Content: "And your employeed ID is"},
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{Row: 6, Col: 22, Name: "employeeID"}, // We're giving this field a name to replace its value at runtime
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{Row: 7, Col: 0, Name: "passwordOutput"},
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{Row: 9, Col: 0, Content: "Press"},
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{Row: 9, Col: 6, Intense: true, Content: "enter"},
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{Row: 9, Col: 12, Content: "to enter your name again, or"},
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{Row: 9, Col: 41, Intense: true, Content: "PF3"},
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{Row: 9, Col: 45, Content: "to quit and disconnect."},
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{Row: 12, Col: 0, Color: go3270.Turquoise, Highlighting: go3270.ReverseVideo, Content: "Here is a field with extended attributes."},
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{Row: 12, Col: 42}, // remember to "stop" fields with a regular field, to clear the reverse video for example
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{Row: 14, Col: 0, Name: "position"}, // will be filled when displaying
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{Row: 22, Col: 0, Content: "PF3 Exit"},
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}
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var goodbyeScreen = go3270.Screen{
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{Row: 0, Col: 27, Intense: true, Content: "3270 Example Application"},
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{Row: 2, Col: 0, Content: "Thank you using this application. Goodbye."},
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}
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func main() {
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ln, err := net.Listen("tcp", ":3270")
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if err != nil {
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panic(err)
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}
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fmt.Println("LISTENING ON PORT 3270 FOR CONNECTIONS")
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fmt.Println("Press Ctrl-C to end server.")
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for {
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conn, err := ln.Accept()
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if err != nil {
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panic(err)
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}
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go handle(conn)
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}
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}
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// handle is the handler for individual user connections.
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func handle(conn net.Conn) {
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defer conn.Close()
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// Always begin new connection by negotiating the telnet options
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devinfo, err := go3270.NegotiateTelnet(conn)
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if err != nil {
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fmt.Printf("ERROR: %v\n", err)
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return
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}
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fieldValues := make(map[string]string)
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var response go3270.Response
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// We will loop forever until the user quits with PF3
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mainLoop:
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for {
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// Need to set the codepage display field value each time through the
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// loop so it persists between screen1->screen2->screen1 navigation.
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if devinfo.Codepage() == nil {
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fieldValues["codepage"] = "(unknown)"
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} else {
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fieldValues["codepage"] = devinfo.Codepage().ID()
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}
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screen1Loop:
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for {
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// loop until the user passes input validation, or quits
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// Always reset password input to blank each time through the loop
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fieldValues["password"] = ""
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// Show the first screen, and wait to get a client response. Place
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// the cursor at the beginning of the first input field. We're
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// passing in the fieldValues map to carry values over from the
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// previous submission. We could pass nil, instead, if always want
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// the fields to start out blank.
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response, err = go3270.ShowScreenOpts(screen1, fieldValues, conn,
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go3270.ScreenOpts{
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Codepage: devinfo.Codepage(),
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CursorRow: 4,
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CursorCol: 20,
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})
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if err != nil {
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fmt.Println(err)
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return
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}
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// If the user pressed PF3, exit
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if response.AID == go3270.AIDPF3 {
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go3270.ShowScreenOpts(goodbyeScreen, nil, conn,
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go3270.ScreenOpts{
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Codepage: devinfo.Codepage(),
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NoResponse: true,
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})
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time.Sleep(2 * time.Second)
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break mainLoop
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}
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// If anything OTHER than "Enter", restart the loop
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if response.AID != go3270.AIDEnter {
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continue screen1Loop
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}
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// User must have pressed "Enter", so let's check the input.
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fieldValues = response.Values
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if strings.TrimSpace(fieldValues["fname"]) == "" &&
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strings.TrimSpace(fieldValues["lname"]) == "" {
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fieldValues["errormsg"] =
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"First and Last Name fields are required."
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continue screen1Loop
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}
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if strings.TrimSpace(fieldValues["fname"]) == "" {
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fieldValues["errormsg"] = "First Name field is required."
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continue screen1Loop
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}
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if strings.TrimSpace(fieldValues["lname"]) == "" {
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fieldValues["errormsg"] = "Last Name field is required."
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continue screen1Loop
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}
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// At this point, we know the user provided both fields and had
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// hit enter, so we are going to reset the error message for the
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// next time through the loop, and break out of this loop so we
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// move on to screen 2.
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fieldValues["errormsg"] = ""
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break screen1Loop
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}
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// Now we're ready to display screen2
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passwordLength := len(strings.TrimSpace(fieldValues["password"]))
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passwordPlural := "s"
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if passwordLength == 1 {
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passwordPlural = ""
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}
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fieldValues["passwordOutput"] = fmt.Sprintf(
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"Your password was %d character%s long",
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passwordLength, passwordPlural)
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fieldValues["position"] = fmt.Sprintf(
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"When you pressed enter the cursor was at row %d column %d.",
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response.Row+1, response.Col+1)
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response, err := go3270.ShowScreenOpts(screen2, fieldValues, conn,
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go3270.ScreenOpts{Codepage: devinfo.Codepage()})
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if err != nil {
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fmt.Println(err)
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return
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}
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// If the user pressed PF3, exit
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if response.AID == go3270.AIDPF3 {
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go3270.ShowScreenOpts(goodbyeScreen, nil, conn,
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go3270.ScreenOpts{
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Codepage: devinfo.Codepage(),
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NoResponse: true,
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})
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time.Sleep(2 * time.Second)
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break
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}
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// If they pressed anything else, just let the loop continue...
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continue
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}
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fmt.Println("Connection closed")
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}
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