如何增加读取主机读取的最大字符数?

Question

我需要获取一个很长的字符串输入(大约 9,000 个字符(，但大约 8,000 个字符后Read-Host会被截断。 如何延长此限制？

Answer 1

以下是可能的解决方法。 解决方法 1 的优点是，它将适用于需要键盘输入的 PowerShell 后台作业。请注意，如果您尝试粘贴包含新行的剪贴板内容，则 Read-HostLine 将仅读取第一行，但 Read-Host 具有相同的行为。

解决方法 1：

<#
.SYNOPSIS
Read a line of input from the host.
.DESCRIPTION
Read a line of input from the host. 
.EXAMPLE
$s = Read-HostLine -prompt "Enter something"
.NOTES
Read-Host has a limitation of 1022 characters.
This approach is safe to use with background jobs that require input.
If pasting content with embedded newlines, only the first line will be read.
A downside to the ReadKey approach is that it is not possible to easily edit the input string before pressing Enter as with Read-Host.
#>
function Read-HostLine ($prompt = $null) {
if ($prompt) {
"${prompt}: " | Write-Host
}
$str = ""
while ($true) { 
$key = $host.UI.RawUI.ReadKey("NoEcho, IncludeKeyDown"); 
# Paste the clipboard on CTRL-V        
if (($key.VirtualKeyCode -eq 0x56) -and  # 0x56 is V
(([int]$key.ControlKeyState -band [System.Management.Automation.Host.ControlKeyStates]::LeftCtrlPressed) -or 
([int]$key.ControlKeyState -band [System.Management.Automation.Host.ControlKeyStates]::RightCtrlPressed))) { 
$clipboard = Get-Clipboard
$str += $clipboard
Write-Host $clipboard -NoNewline
continue
}
elseif ($key.VirtualKeyCode -eq 0x08) {  # 0x08 is Backspace
if ($str.Length -gt 0) {
$str = $str.Substring(0, $str.Length - 1)
Write-Host "`b `b" -NoNewline    
}
}        
elseif ($key.VirtualKeyCode -eq 13) {  # 13 is Enter
Write-Host
break 
}
elseif ($key.Character -ne 0) {
$str += $key.Character
Write-Host $key.Character -NoNewline
}
}
return $str
}

解决方法 2：

$maxLength = 65536
[System.Console]::SetIn([System.IO.StreamReader]::new([System.Console]::OpenStandardInput($maxLength), [System.Console]::InputEncoding, $false, $maxLength))
$s = [System.Console]::ReadLine()

解决方法 3：

function Read-Line($maxLength = 65536) {
$str = ""
$inputStream = [System.Console]::OpenStandardInput($maxLength);
$bytes = [byte[]]::new($maxLength);
while ($true) {
$len = $inputStream.Read($bytes, 0, $maxLength);
$str += [string]::new($bytes, 0, $len)
if ($str.EndsWith("`r`n")) {
$str = $str.Substring(0, $str.Length - 2)
return $str
}
}
}
$s = Read-Line

更多讨论：
Console.ReadLine(( max length？
为什么 Console.Readline(( 对允许的文本长度有限制？
https://github.com/PowerShell/PowerShell/issues/16555