在“浏览”中：私有方法“new”调用了 DNSSD::Service:Class (NoMethodError)
in `browse': private method `new' called for DNSSD::Service:Class (NoMethodError)
我在浏览 GitHub 时发现了 https://github.com/PeterCrozier/AirPrint 并试了一下。
它是几年前写的，所以可能是针对 ruby 的旧版本。我在 macOS Big Sur 11.1 上使用 ruby 2.6.3p62（2019-04-16 修订版 67580）[通用。x86_64-darwin20]
我对 ruby 一无所知，但想看看是否可以得到一些帮助来让它正常工作。
当我 运行 airprintfix.rb 时出现以下错误：
Traceback (most recent call last):
1: from ./airprintfix.rb:160:in `<main>'
./airprintfix.rb:19:in `browse': private method `new' called for DNSSD::Service:Class (NoMethodError)
#!/usr/bin/env ruby -rrubygems
#
require 'dnssd'
require 'timeout'
require 'optparse'
class Airprint
attr_accessor :service, :domain, :script, :timeout
def initialize
self.service="_ipp._tcp"
self.domain="local"
self.script="airprintfix.sh"
self.timeout=5
end
def browse(s=self.service, d=self.domain, t=self.timeout)
browser = DNSSD::Service.new
printers=[]
t = Thread.new do
puts "Browsing for #{s} services in domain #{d}..."
browser.browse s, d do |reply|
resolver = DNSSD::Service.new
resolver.resolve reply do |r|
puts "Resolved #{r.name}"
printers.push r
end
end
end
sleep self.timeout
Thread.kill t
# there might be more than one interface
up = printers.uniq { |r| r.name }
puts "Found #{up.count} unique from #{printers.count} entries" if up.count > 0
up
end
def expand(fd, r, bg)
# Expand out the Bonjour response
puts "Service Name: #{r.name}\nResolved to: #{r.target}:#{r.port}\nService type: #{r.type}"
txt = r.text_record
# remove entry inserted by Bonjour
txt.delete 'UUID'
# Add Airprint txt fields
txt['URF'] = 'none'
txt['pdl'] = 'application/pdf,image/urf'
txt.each_pair do |k,v|
puts "\t#{k} = #{v}"
end
fd.write "#!/bin/bash\n\n"
fd.write "dns-sd -R \"#{r.name} airprint\" _ipp._tcp,_universal . 631"
txt.each_pair do |k,v|
fd.write " \\n\t#{k}=\'#{v}\'"
end
if bg
fd.write ' &'
end
fd.puts
end
end
options = {}
cmd = {}
OptionParser.new do |opts|
opts.banner = "Usage: #{[=12=]} [options] command"
opts.separator ""
opts.separator "Command: Choose only one"
opts.on("-i", "--install", "install permanently, requires sudo") do |v|
cmd[:install] = v
end
opts.on("-u", "--uninstall", "uninstall, requires sudo") do |v|
cmd[:uninstall] = v
end
opts.on("-t", "--test", "test, use CTRL-C to exit") do |v|
cmd[:test] = v
end
opts.separator ""
opts.separator "Options:"
opts.on("-f", "--script_file", "script filename") do |v|
options[:script] = v
end
opts.on_tail("-h", "--help", "print this message") do
puts opts
exit
end
end.parse!
if ARGV.count != 0 or cmd.count > 1
puts "Bad command"
exit
end
# require sudo to update /Library
isRoot = (Process.euid == 0)
if (cmd.key? :install or cmd.key? :uninstall) and !isRoot
puts "Run with sudo to install or uninstall"
exit
end
ap = Airprint.new
# plist for LaunchControl
hostname = `hostname`.strip.gsub(/\..*$/,'')
revhost = "local.#{hostname}.airprintfix"
launchlib = "/Library/LaunchDaemons"
launchfile=revhost + ".plist"
plist=<<EOT
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>#{revhost}</string>
<key>ProgramArguments</key>
<array>
<string>/Library/LaunchDaemons/#{ap.script}</string>
</array>
<key>LowPriorityIO</key>
<true/>
<key>Nice</key>
<integer>1</integer>
<key>UserName</key>
<string>root</string>
<key>RunAtLoad</key>
<true/>
<key>Keeplive</key>
<true/>
</dict>
</plist>
EOT
if cmd.key? :uninstall
system "launchctl unload #{launchfile}"
rc = $?.exitstatus
puts "Uninstalling #{ap.script} from #{launchlib}"
File.delete File.expand_path ap.script, launchlib
puts "Uninstalling #{launchfile} from #{launchlib}"
File.delete File.expand_path launchfile, launchlib
exit rc
end
# determine existing printers
printers = ap.browse
count = printers.count
if count == 0
puts "No shared printers were found"
exit
end
# if not installing, create files in the working directory
wd = cmd.key?(:install) ? launchlib : "."
# write script to register them
bg = (count > 1)
f = File.expand_path(ap.script, wd)
File.open f, 'w', 0755 do |fd|
printers.each { |r| ap.expand fd, r, bg }
end
# write a plist file to launch it
File.open File.expand_path(launchfile, wd), 'w', 0644 do |fd|
fd.write plist
end
if cmd.key? :install
plist = File.expand_path(launchfile, wd)
system "launchctl load -w #{plist}"
rc = $?.exitstatus
puts (rc == 0) ? "Installed" : "Failed to install #{plist}, rc=#{rc}"
exit rc
end
if cmd.key? :test
puts "Registering printer, use CTRL-C when done"
trap 'INT' do exit end
system "/bin/bash #{ap.script}"
exit $?.exitstatus
end
exit
知道是什么原因导致错误以及如何修复它吗？
谢谢！
吉姆
你应该能够解决这个问题
def browse(s=self.service, d=self.domain, t=self.timeout)
browser = DNSSD::Service.new #REMOVE this line
printers=[]
t = Thread.new do
puts "Browsing for #{s} services in domain #{d}..."
DNSSD.browse s, d do |reply| #EDIT this Line
resolver = DNSSD::Service.new #REMOVE this line
DNSSD.resolve reply do |r| #EDIT this Line
puts "Resolved #{r.name}"
printers.push r
end
end
end
sleep self.timeout
Thread.kill t
# there might be more than one interface
up = printers.uniq { |r| r.name }
puts "Found #{up.count} unique from #{printers.count} entries" if up.count > 0
up
end
似乎 DNSSD::Service 公开了 browse and resolve 作为 class 实例方法并且 DNSSD 提供了顶级 DSL 作为这些方法的传递。
我没有编写这个库，也无法确认其中包含的任何代码，但这会让你度过这个难关。
我在浏览 GitHub 时发现了 https://github.com/PeterCrozier/AirPrint 并试了一下。 它是几年前写的，所以可能是针对 ruby 的旧版本。我在 macOS Big Sur 11.1 上使用 ruby 2.6.3p62（2019-04-16 修订版 67580）[通用。x86_64-darwin20] 我对 ruby 一无所知，但想看看是否可以得到一些帮助来让它正常工作。
当我 运行 airprintfix.rb 时出现以下错误：
Traceback (most recent call last):
1: from ./airprintfix.rb:160:in `<main>'
./airprintfix.rb:19:in `browse': private method `new' called for DNSSD::Service:Class (NoMethodError)
#!/usr/bin/env ruby -rrubygems
#
require 'dnssd'
require 'timeout'
require 'optparse'
class Airprint
attr_accessor :service, :domain, :script, :timeout
def initialize
self.service="_ipp._tcp"
self.domain="local"
self.script="airprintfix.sh"
self.timeout=5
end
def browse(s=self.service, d=self.domain, t=self.timeout)
browser = DNSSD::Service.new
printers=[]
t = Thread.new do
puts "Browsing for #{s} services in domain #{d}..."
browser.browse s, d do |reply|
resolver = DNSSD::Service.new
resolver.resolve reply do |r|
puts "Resolved #{r.name}"
printers.push r
end
end
end
sleep self.timeout
Thread.kill t
# there might be more than one interface
up = printers.uniq { |r| r.name }
puts "Found #{up.count} unique from #{printers.count} entries" if up.count > 0
up
end
def expand(fd, r, bg)
# Expand out the Bonjour response
puts "Service Name: #{r.name}\nResolved to: #{r.target}:#{r.port}\nService type: #{r.type}"
txt = r.text_record
# remove entry inserted by Bonjour
txt.delete 'UUID'
# Add Airprint txt fields
txt['URF'] = 'none'
txt['pdl'] = 'application/pdf,image/urf'
txt.each_pair do |k,v|
puts "\t#{k} = #{v}"
end
fd.write "#!/bin/bash\n\n"
fd.write "dns-sd -R \"#{r.name} airprint\" _ipp._tcp,_universal . 631"
txt.each_pair do |k,v|
fd.write " \\n\t#{k}=\'#{v}\'"
end
if bg
fd.write ' &'
end
fd.puts
end
end
options = {}
cmd = {}
OptionParser.new do |opts|
opts.banner = "Usage: #{[=12=]} [options] command"
opts.separator ""
opts.separator "Command: Choose only one"
opts.on("-i", "--install", "install permanently, requires sudo") do |v|
cmd[:install] = v
end
opts.on("-u", "--uninstall", "uninstall, requires sudo") do |v|
cmd[:uninstall] = v
end
opts.on("-t", "--test", "test, use CTRL-C to exit") do |v|
cmd[:test] = v
end
opts.separator ""
opts.separator "Options:"
opts.on("-f", "--script_file", "script filename") do |v|
options[:script] = v
end
opts.on_tail("-h", "--help", "print this message") do
puts opts
exit
end
end.parse!
if ARGV.count != 0 or cmd.count > 1
puts "Bad command"
exit
end
# require sudo to update /Library
isRoot = (Process.euid == 0)
if (cmd.key? :install or cmd.key? :uninstall) and !isRoot
puts "Run with sudo to install or uninstall"
exit
end
ap = Airprint.new
# plist for LaunchControl
hostname = `hostname`.strip.gsub(/\..*$/,'')
revhost = "local.#{hostname}.airprintfix"
launchlib = "/Library/LaunchDaemons"
launchfile=revhost + ".plist"
plist=<<EOT
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>#{revhost}</string>
<key>ProgramArguments</key>
<array>
<string>/Library/LaunchDaemons/#{ap.script}</string>
</array>
<key>LowPriorityIO</key>
<true/>
<key>Nice</key>
<integer>1</integer>
<key>UserName</key>
<string>root</string>
<key>RunAtLoad</key>
<true/>
<key>Keeplive</key>
<true/>
</dict>
</plist>
EOT
if cmd.key? :uninstall
system "launchctl unload #{launchfile}"
rc = $?.exitstatus
puts "Uninstalling #{ap.script} from #{launchlib}"
File.delete File.expand_path ap.script, launchlib
puts "Uninstalling #{launchfile} from #{launchlib}"
File.delete File.expand_path launchfile, launchlib
exit rc
end
# determine existing printers
printers = ap.browse
count = printers.count
if count == 0
puts "No shared printers were found"
exit
end
# if not installing, create files in the working directory
wd = cmd.key?(:install) ? launchlib : "."
# write script to register them
bg = (count > 1)
f = File.expand_path(ap.script, wd)
File.open f, 'w', 0755 do |fd|
printers.each { |r| ap.expand fd, r, bg }
end
# write a plist file to launch it
File.open File.expand_path(launchfile, wd), 'w', 0644 do |fd|
fd.write plist
end
if cmd.key? :install
plist = File.expand_path(launchfile, wd)
system "launchctl load -w #{plist}"
rc = $?.exitstatus
puts (rc == 0) ? "Installed" : "Failed to install #{plist}, rc=#{rc}"
exit rc
end
if cmd.key? :test
puts "Registering printer, use CTRL-C when done"
trap 'INT' do exit end
system "/bin/bash #{ap.script}"
exit $?.exitstatus
end
exit
知道是什么原因导致错误以及如何修复它吗？
谢谢！
吉姆
你应该能够解决这个问题
def browse(s=self.service, d=self.domain, t=self.timeout)
browser = DNSSD::Service.new #REMOVE this line
printers=[]
t = Thread.new do
puts "Browsing for #{s} services in domain #{d}..."
DNSSD.browse s, d do |reply| #EDIT this Line
resolver = DNSSD::Service.new #REMOVE this line
DNSSD.resolve reply do |r| #EDIT this Line
puts "Resolved #{r.name}"
printers.push r
end
end
end
sleep self.timeout
Thread.kill t
# there might be more than one interface
up = printers.uniq { |r| r.name }
puts "Found #{up.count} unique from #{printers.count} entries" if up.count > 0
up
end
似乎 DNSSD::Service 公开了 browse and resolve 作为 class 实例方法并且 DNSSD 提供了顶级 DSL 作为这些方法的传递。
我没有编写这个库，也无法确认其中包含的任何代码，但这会让你度过这个难关。