class Net::SSH::Config

The Net::SSH::Config class is used to parse OpenSSH configuration files, and translates that syntax into the configuration syntax that Net::SSH understands. This lets Net::SSH scripts read their configuration (to some extent) from OpenSSH configuration files (~/.ssh/config, /etc/ssh_config, and so forth).

Only a subset of OpenSSH configuration options are understood:

Note that you will never need to use this class directly--you can control whether the OpenSSH configuration files are read by passing the :config option to Net::SSH.start. (They are, by default.)

Public Class Methods

default_files() click to toggle source

Returns an array of locations of OpenSSH configuration files to parse by default.

# File lib/net/ssh/config.rb, line 41
def default_files
  @@default_files
end
for(host, files=default_files) click to toggle source

Loads the configuration data for the given host from all of the given files (defaulting to the list of files returned by default_files), translates the resulting hash into the options recognized by Net::SSH, and returns them.

# File lib/net/ssh/config.rb, line 49
def for(host, files=default_files)
  translate(files.inject({}) { |settings, file| load(file, host, settings) })
end
load(path, host, settings={}) click to toggle source

Load the OpenSSH configuration settings in the given file for the given host. If settings is given, the options are merged into that hash, with existing values taking precedence over newly parsed ones. Returns a hash containing the OpenSSH options. (See translate for how to convert the OpenSSH options into Net::SSH options.)

# File lib/net/ssh/config.rb, line 59
def load(path, host, settings={})
  file = File.expand_path(path)
  return settings unless File.readable?(file)
  
  globals = {}
  matched_host = nil
  multi_host = []
  seen_host = false
  IO.foreach(file) do |line|
    next if line =~ %r^\s*(?:#.*)?$/
    
    if line =~ %r^\s*(\S+)\s*=(.*)$/
      key, value = $1, $2
    else
      key, value = line.strip.split(%r\s+/, 2)
    end

    # silently ignore malformed entries
    next if value.nil?

    key.downcase!
    value = $1 if value =~ %r^"(.*)"$/
    
    value = case value.strip
      when %r^\d+$/ then value.to_i
      when %r^no$/ then false
      when %r^yes$/ then true
      else value
      end
    
    if key == 'host'
      # Support "Host host1 host2 hostN".
      # See http://github.com/net-ssh/net-ssh/issues#issue/6
      multi_host = value.to_s.split(%r\s+/)
      matched_host = multi_host.select { |h| host =~ pattern2regex(h) }.first
      seen_host = true
    elsif !seen_host
      if key == 'identityfile'
        (globals[key] ||= []) << value
      else
        globals[key] = value unless settings.key?(key)
      end
    elsif !matched_host.nil?
      if key == 'identityfile'
        (settings[key] ||= []) << value
      else
        settings[key] = value unless settings.key?(key)
      end
    end
  end
  
  settings = globals.merge(settings) if globals
  
  return settings
end
translate(settings) click to toggle source

Given a hash of OpenSSH configuration options, converts them into a hash of Net::SSH options. Unrecognized options are ignored. The settings hash must have Strings for keys, all downcased, and the returned hash will have Symbols for keys.

# File lib/net/ssh/config.rb, line 119
def translate(settings)
  settings.inject({}) do |hash, (key, value)|
    case key
    when 'bindaddress' then
      hash[:bind_address] = value
    when 'ciphers' then
      hash[:encryption] = value.split(%r,/)
    when 'compression' then
      hash[:compression] = value
    when 'compressionlevel' then
      hash[:compression_level] = value
    when 'connecttimeout' then
      hash[:timeout] = value
    when 'forwardagent' then
      hash[:forward_agent] = value
    when 'identitiesonly' then
      hash[:keys_only] = value
    when 'globalknownhostsfile'
      hash[:global_known_hosts_file] = value
    when 'hostbasedauthentication' then
      if value
        hash[:auth_methods] ||= []
        hash[:auth_methods] << "hostbased"
      end
    when 'hostkeyalgorithms' then
      hash[:host_key] = value.split(%r,/)
    when 'hostkeyalias' then
      hash[:host_key_alias] = value
    when 'hostname' then
      hash[:host_name] = value
    when 'identityfile' then
      hash[:keys] = value
    when 'macs' then
      hash[:hmac] = value.split(%r,/)
    when 'passwordauthentication'
      if value
        hash[:auth_methods] ||= []
        hash[:auth_methods] << "password"
      end
    when 'port'
      hash[:port] = value
    when 'preferredauthentications'
      hash[:auth_methods] = value.split(%r,/)
    when 'proxycommand'
      if value and !(value =~ %r^none$/)
        require 'net/ssh/proxy/command'
        hash[:proxy] = Net::SSH::Proxy::Command.new(value)
      end
    when 'pubkeyauthentication'
      if value
        hash[:auth_methods] ||= []
        hash[:auth_methods] << "publickey"
      end
    when 'rekeylimit'
      hash[:rekey_limit] = interpret_size(value)
    when 'user'
      hash[:user] = value
    when 'userknownhostsfile'
      hash[:user_known_hosts_file] = value
    end
    hash
  end
end