src/ConfigParser.ps1
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# This is a Powershell port of the ssh-config node module https://github.com/dotnil/ssh-config # Regexes used in parsing $script:RE_SPACE = [regex]::new("\s") $script:RE_LINE_BREAK = [regex]::new("\r|\n") $script:RE_SECTION_DIRECTIVE = [regex]::new("^(Host|Match)$", [System.Text.RegularExpressions.RegexOptions]::IgnoreCase) $script:RE_QUOTED = [regex]::new('^(")(.*)\1$') class ConfigNode { [string] $Before [string] $After [string] $Type [string] $Content [string] $Param [string] $Separator [string] $Value [bool] $Quoted [SshConfig] $Config } class SshConfig { [System.Collections.Generic.List[ConfigNode]] $Nodes; SshConfig() { $this.Nodes = [System.Collections.Generic.List[ConfigNode]]::new() } RemoveHost([string] $sshHost) { $result = $this.Find($sshHost) if ($result) { $this.Nodes.Remove($result); } } Add([Hashtable] $opts) { $config = $this; $configWas = $this; $indent = " "; foreach ($line in $this.Nodes) { if ($script:RE_SECTION_DIRECTIVE.IsMatch($line.Param)) { foreach ($subline in $line.Config.Nodes) { if ($subline.Before) { $indent = $subline.Before; break; } } } } # Make sure host/match are first. $keys = $opts.Keys | Sort-Object { $script:RE_SECTION_DIRECTIVE.IsMatch($_) } -Descending foreach ($key in $keys) { $line = [ConfigNode]::new() $line.Type = 'Directive' $line.Param = $key $line.Separator = " " $line.Value = $opts[$key] $line.Before = "" $line.After = "`n" # Do we want to support CRLF? if ($script:RE_SECTION_DIRECTIVE.IsMatch($key)) { $config = $configWas; # Make sure we insert before any wildcard lines. # find the index of the first wildcard $index = 0 foreach($node in $config.Nodes) { if ($node.Value.Contains("*") -or $node.Value.Contains("?")) { # Found a wildcard. Make sure we insert before this. break; } $index++; } if ($config.Nodes.Count -eq 0) { $config.Nodes.Add($line) } else { $config.Nodes.Insert($index, $line) } $config = $line.Config = [SshConfig]::new() } else { $line.Before = $indent; $config.Nodes.Add($line); } } $config.Nodes[$config.Nodes.Count - 1].After += "`n" # Do we want to support CRLF? } [ConfigNode] Find([string]$sshHost) { return $this.Nodes | Where-Object { $_.Type -eq "Directive" -and $_.Param -eq 'Host' -and $_.Value -eq $sshHost } | Select-Object -First 1 } [string] Stringify() { $output = [System.Text.StringBuilder]::new() $formatter = { param([ConfigNode] $node) $output.Append($node.Before); if ($node.Type -eq 'Comment') { $output.Append($node.Content); } elseif ($node.Type -eq 'Directive') { $str = ""; if ($node.Quoted -or ($node.Param -eq "IdentityFile" -and $script:RE_SPACE.IsMatch($node.Value))) { $str = $node.Param + $node.Separator + '"' + $node.Value + '"' } else { $str = $node.Param + $node.Separator + $node.Value } $output.Append($str); } $output.Append($node.After); if ($node.Config) { foreach ($child in $node.Config.Nodes) { & $formatter $child } } } foreach ($node in $this.Nodes) { & $formatter $node } return $output.ToString(); } [Hashtable] Compute([string]$sshHost) { $result = @{} $setProperty = { param([string] $name, [string] $value); if ($name -eq "IdentityFile") { if (!$result.ContainsKey($name)) { $result[$name] = @($value) } else { $result[$name] += $value } } elseif (!$result.ContainsKey($name)) { $result[$name] = $value } } $foundHost = $false foreach($node in $this.Nodes) { if ($node.Type -ne "Directive") { continue } elseif ($node.Param -eq "Host") { if($node.Value -eq $sshHost) { $foundHost = $true } if(Test-Glob $node.Value $sshHost) { & $setProperty $node.Param $node.Value foreach($childNode in $node.Config.Nodes) { if($childNode.Type -eq "Directive") { & $setProperty $childNode.Param $childNode.Value } } } } elseif ($node.Param -eq "Match") { # no op } else { & $setProperty $node.Param $node.Value } } if($foundHost) { return $result } else { return $null } } } <# .SYNOPSIS Parses the contents of an OpenSSH config file into an object model. .DESCRIPTION Takes the contents of an SSH config file and converts it into an object model. The root object is an SshConfig instance which contains methods for retrieving and manipulating config entries. These entries can either be returned as hashtables that represent config entries, for for more advanced uses can be returned as raw config nodes. .EXAMPLE PS C:\> Parse-SshConfig (Get-Content "~/.ssh/config" -Raw) Parses teh contents of the config file at the specified path and returns an object model .PARAMETER str The contents of the openssh config file. #> function Parse-SshConfig([string]$str) { $config = [SshConfig]::new() $rootConfig = $config $context = @{ Count = 0 Char = $null } $next = { # Force string instead of char return [string]($str[$context.Count++]) } $space = { $spaces = ""; while ($context.Char -and $script:RE_SPACE.IsMatch($context.Char)) { $spaces += $context.Char $context.Char = & $next } return $spaces; } $linebreak = { $breaks = ""; while ($context.Char -and $script:RE_LINE_BREAK.IsMatch($context.Char)) { $breaks += $context.Char $context.Char = & $next } return $breaks } $option = { $opt = ""; while ($context.Char -and $context.Char -ne " " -and $context.Char -ne "=") { $opt += $context.Char; $context.Char = & $next; } return $opt; } $separator = { $sep = & $space if ($context.Char -eq "=") { $sep += $context.Char; $context.Char = & $next; } return $sep + (& $space) } $value = { $val = ""; while ($context.Char -and !$script:RE_LINE_BREAK.IsMatch($context.Char)) { $val += $context.Char; $context.Char = & $next; } return $val.Trim() } $comment = { $type = 'Comment'; $content = ""; while ($context.Char -and !$script:RE_LINE_BREAK.IsMatch($context.Char)) { $content += $context.Char; $context.Char = & $next; } $node = [ConfigNode]::new() $node.Type = $type $node.Content = $content return $node } $directive = { $node = [ConfigNode]::new() $node.Type = 'Directive' $node.Param = & $option $node.Separator = & $separator $node.Value = & $value return $node; } $line = { $before = & $space $node = $null if ($context.Char -eq "#") { $node = & $comment } else { $node = & $directive } $after = & $linebreak $node.Before = $before $node.After = $after if ($node.Value -and $script:RE_QUOTED.IsMatch($node.Value)) { $node.Value = $script:RE_QUOTED.Replace($node.Value, '$2'); $node.Quoted = $true; } return $node; } # Start the process by getting the first character. $context.Char = & $next; while ($context.Char) { $node = & $line if ($node.Type -eq 'Directive' -and $script:RE_SECTION_DIRECTIVE.IsMatch($node.Param)) { $config = $rootConfig; $config.Nodes.Add($node); $config = $node.Config = [SshConfig]::new() } else { $config.Nodes.Add($node); } } return $rootConfig; } |