I have a Ruby app which uses readline with command completion.
After the first string (the command) was typed, I would like to be able to complete its arguments. The arguments list should be based on the chosen command.
Does someone have a quick example?
These are the commands:
COMMANDS = [
'collect', 'watch'
].sort
COLLECT = [
'stuff', 'otherstuff'
].sort
comp = proc do |s|
COMMANDS.grep( /^#{Regexp.escape(s)}/ )
end
Readline.completion_proc = comp
Each time I press TAB, the proc block is executed and a command from the COMMANDS array is matched.
After one of the commands was fully matched I would like to start searching for the argument only in the COLLECT array.
Since your question popped up first every time I looked for something like this I want to share my code for any one else.
#!/usr/bin/env ruby
require 'readline'
module Shell
PROMPT = "shell> "
module InputCompletor
CORE_WORDS = %w[ clear help show exit export]
SHOW_ARGS = %w[ list user ]
EXPORT_ARGS = %w[ file ]
COMPLETION_PROC = proc { |input|
case input
when /^(show|export) (.*)/
command = $1
receiver = $2
DISPATCH_TABLE[$1].call($2)
when /^(h|s|c|e.*)/
receiver = $1
CORE_WORDS.grep(/^#{Regexp.quote(receiver)}/)
when /^\s*$/
puts
CORE_WORDS.map{|d| print "#{d}\t"}
puts
print PROMPT
end
}
def self.show(receiver)
if SHOW_ARGS.grep(/^#{Regexp.quote(receiver)}/).length > 1
SHOW_ARGS.grep(/^#{Regexp.quote(receiver)}/)
elsif SHOW_ARGS.grep(/^#{Regexp.quote(receiver)}/).length == 1
"show #{SHOW_ARGS.grep(/^#{Regexp.quote(receiver)}/).join}"
end
end
def self.export(receiver)
if EXPORT_ARGS.grep(/^#{Regexp.quote(receiver)}/).length > 1
EXPORT_ARGS.grep(/^#{Regexp.quote(receiver)}/)
elsif EXPORT_ARGS.grep(/^#{Regexp.quote(receiver)}/).length == 1
"export #{EXPORT_ARGS.grep(/^#{Regexp.quote(receiver)}/).join}"
end
end
DISPATCH_TABLE = {'show' => lambda {|x| show(x)} ,
'export' => lambda {|x| export(x)}}
end
class CLI
Readline.completion_append_character = ' '
Readline.completer_word_break_characters = "\x00"
Readline.completion_proc = Shell::InputCompletor::COMPLETION_PROC
def initialize
while line = Readline.readline("#{PROMPT}",true)
Readline::HISTORY.pop if /^\s*$/ =~ line
begin
if Readline::HISTORY[-2] == line
Readline::HISTORY.pop
end
rescue IndexError
end
cmd = line.chomp
case cmd
when /^clear/
system('clear')
when /^help/
puts 'no help here'
when /show list/
puts 'nothing to show'
when /^show\s$/
puts 'missing args'
when /export file/
puts 'nothing to export'
when /^export\s$/
puts 'missing args'
when /^exit/
exit
end
end
end
end
end
Shell::CLI.new
After thinking a while, the solution was very simple:
comp = proc do |s|
if Readline.line_buffer =~ /^.* /
COLLECT.grep( /^#{Regexp.escape(s)}/ )
else
COMMANDS.grep( /^#{Regexp.escape(s)}/ )
end
end
Now I just need to turn it into something more flexible/usable.
Related
Capistrano 3 does not use command cap env shell anymore.
Now we should use cap env console
But it is not interactive and we can not use for example arrow keys for history or autocompletion on tab button
And what should I do?
I suggest to write your own little rake task to do it. Use readline gem
First of all thanks to follow materials:
https://thoughtbot.com/blog/tab-completion-in-gnu-readline-ruby-edition
How to write a Ruby command line app that supports tab completion?
desc "Remote console"
task :console do
require 'readline'
# https://thoughtbot.com/blog/tab-completion-in-gnu-readline-ruby-edition
host_args = (ENV['HOSTS'] || '').split(',').map { |r| r.to_sym }
role_args = (ENV['ROLES'] || '').split(',').map { |r| r.to_sym }
LIST = `ls /usr/bin`.split("\n").sort + `ls /bin`.split("\n").sort
comp = proc { |s| LIST.grep(/^#{Regexp.escape(s)}/) }
Readline.completion_append_character = " "
Readline.completion_proc = comp
while line = Readline.readline('cap> ', true)
begin
next if line.strip.empty?
exec_cmd(line, host_args, role_args)
rescue StandardError => e
puts e
puts e.backtrace
end
end
end
def exec_cmd(line, host_args, role_args)
line = "RAILS_ENV=#{fetch(:stage)} #{line}" if fetch(:stage)
cmd = "bash -lc '#{line}'"
puts "Final command: #{cmd}"
if host_args.any?
on hosts host_args do
execute cmd
end
elsif role_args.any?
on roles role_args do
execute cmd
end
else
on roles :all do
execute cmd
end
end
end
And do what you want with it, cheers! =))
I have the following sqlite code as a standalone file. It works.
the schema is basic. foo.db table bar Id, Text, Value, Etc are my columns
#!/usr/bin/env ruby
require 'sqlite3'
puts "enter a number"
input = gets.chomp.to_i
begin
db = SQLite3::Database.open('foo.db')
find_data = db.execute2 "select * from bar where Value = #{input}"
find_data.each do |f|
puts "[%-8s] %-8s | %-8s" % [f[1], f[2], f[3]]
end
rescue SQLite::Exception => e
puts e
ensure
db.close if db
end
execute2 locates the line and find_data.each prints out.
However when I take the above snippet and place into a method in a larger program, I get `no such column: [input]"
In my method. I have condensed the code:
...
def find_info(info)
begin
db = SQLite3::Database.open('foo.db')
puts db.get_first_value "select SQLite_VERSION()"
return "create a directory first" unless File.exist?('foo.db')
#line below does not work at print_out below
print_out = db.execute2 "SELECT * FROM Bar WHERE Value=#{info}"
#but making the following changes works:
#info_in = info; print_out = db.execute2 "select * from BAR WHERE Value = :info_in", info_in
return "no match" unless print_out != nil
print_out.each do |line|
puts "[%-8s] %-8s | %-8s" % [line[1], line[2], line[3]]
end
rescue SQLite3::Exception => e
puts e
ensure
db.close if db
end
end
...
print 'enter text to search for'
info = gets.chomp.to_s
X.NewInstance.new; X.find_info(info)
My question: Why am I obligated to use a placeholder in print_out? I believe I should be able just throw in a variable as print_out = db.execute2 "select * from Bar WHERE Value=#{info}"
please help. I am dumbfounded.
(Also: there must be a way on SO to indent blocks of code most efficiently than hitting 4 spaces for each line of code...I spend more time formatting the code than I do typing the question...pls advise?)
String interpolation fails in this instance. Placeholders can be utilized.
print_out = db.execute2 "select * from BAR WHERE Value = :info", info
print_out.each do |p|
puts "%s %s %s" % [p[1],p[2],p[3]]
end
I need to create a program in which the user can take different tests. As i dont want to copy paste my code all over for every test, i have tried to setup a class for that purpose - but i have problems with this class.
Error message = undefined variables or method in 'display_test'
I have predefined som test as a .txt file
I want to choose the file in the class depending on what the user answer - is that possible?
Class code:
class Test
#correct_answers = 0
def display_question( question, options, answer )
puts question
options.each_with_index { |option, idx| puts "#{ idx + 1 }: #{ option
}" }
print 'Answer: '
reply = gets.to_i
if answer == reply
puts 'Correct!'
#correct_answers += 1
puts "#{#correct_answers}"
else
puts 'Wrong. The correct answer was: ' + answer.to_s
end
end
def display_test()
f = File.new(userinput, 'r')
while ! (f.eof?) #logikken til at splitte
line = f.gets()
question = line.split("|")
question[1] = question[1].split(";")
display_question question[0], question[1], question[2].to_i
end
end
display_test
puts "________________________________________________________"
puts "Total score:"
puts "You've got" + " #{#correct_answers}" + " correct answers!"
Before hand i have used ("geografitest.txt") instead of username in the File.new so it looked like this:
f = File.new('geografitest.txt','r')
But now i am trying to let the user decide what test to take.
I am very new to ruby, so please bear with me.
I have tried to do it this way, which obviously is not working.
puts "Which test do you want to take?"
select = 0
while (select != 3)
puts "Press 1 to take Geografi test."
puts "Press 2 to take Math test."
puts "Press 3 to take Religion test."
puts "Press 3 to exit"
select = gets.chomp.to_i
if (select == 1)
gets.chomp = userinput
userinput =`geografitest.txt`
echo $userinput
end
if (select == 2)
gets.chomp = userinput
userinput =`matematiktest.txt`
echo $userinput
end
if (select == 3)
gets.chomp = userinput
userinput =`religionstest.txt`
echo $userinput
end
if (select > 4)
puts "Not a correct selection"
elsif (select == 4)
puts "Goodbye"
end
end
abort
So my questions is now;
How can i make the user choose what test to take? Can i make a variable instead of the textfile as i have tried, but in a different way? Or is there a smarter way?
And in what way is my class wrong and how do i fix it? I know its not the way to make it, but i simple cant get my head around how to make it right.
Please help a rookie out.
Cheers!
You can pass file as dependency to you Test class based on user input with object constructor. Something like this
class Test
attr_reader :correct_answers_count
def initialize(file)
#file = file
#correct_answers_count = 0
end
#other code goes here
end
loop do
case user_input = gets.chomp
when '1'
file_name = 'some_file1'
when '2'
file_name = 'some_file1'
when '3'
break
else
puts 'wrong variant'
end
test = Test.new(File.new(file_name, 'r'))
test.display
end
I have done a program that sends requests to a url and saves them in a file. The program is this, and is working perfectly:
require 'open-uri'
n = gets.to_i
out = gets.chomp
output = File.open( out, "w" )
for i in 1..n
response = open('http://slowapi.com/delay/10').read
output << (response +"\n")
puts response
end
output.close
I want to modify it so that I can execute it from command line. I must run it like this:
fle --test abc -n 300 -f output
What must I do?
Something like this should do the trick:
#!/usr/bin/env ruby
require 'open-uri'
require 'optparse'
# Prepare the parser
options = {}
oparser = OptionParser.new do |opts|
opts.banner = "Usage: fle [options]"
opts.on('-t', '--test [STRING]', 'Test string') { |v| options[:test] = v }
opts.on('-n', '--count COUNT', 'Number of times to send request') { |v| options[:count] = v.to_i }
opts.on('-f', '--file FILE', 'Output file', :REQUIRED) { |v| options[:out_file] = v }
end
# Parse our options
oparser.parse! ARGV
# Check if required options have been filled, print help and exit otherwise.
if options[:count].nil? || options[:out_file].nil?
$stderr.puts oparser.help
exit 1
end
File::open(options[:out_file], 'w') do |output|
options[:count].times do
response = open('http://slowapi.com/delay/10').read
output.puts response # Puts the response into the file
puts response # Puts the response to $stdout
end
end
Here's a more idiomatic way of writing your code:
require 'open-uri'
n = gets.to_i
out = gets.chomp
File.open(out, 'w') do |fo|
n.times do
response = open('http://slowapi.com/delay/10').read
fo.puts response
puts response
end
end
This uses File.open with a block, which allows Ruby to close the file once the block exits. It's a much better practice than assigning the file handle to a variable and use that to close the file later.
How to handle passing in variables from the command-line as options is handled in the other answers.
The first step would be to save you program in a file, add #!/usr/bin/env ruby at the top and chmod +x yourfilename to be able to execute your file.
Now you are able to run your script from the command line.
Secondly, you need to modify your script a little bit to pick up command line arguments. In Ruby, the command line arguments are stored inside ARGV, so something like
ARGV.each do|a|
puts "Argument: #{a}"
end
allows you to retrieve command line arguments.
I want to bulid a multi threaded application. If i do not use threads, everything works fine. When i try to use threads, then nothing is displayed on the browser. when i use the syntax 'puts "%s" %io.read' then it displays on the command prompt and not on the browser. Any help would be appreciated.
require 'sinatra'
require 'thread'
set :environment, :production
get '/price/:upc/:rtype' do
Webupc = "#{params[:upc]}"
Webformat = "#{params[:rtype]}"
MThread = Thread.new do
puts "inside thread"
puts "a = %s" %Webupc
puts "b = %s" %Webformat
#call the price
Maxupclen = 16
padstr = ""
padupc = ""
padlen = (Maxupclen - Webupc.length)
puts "format type: #{params[:rtype]}"
puts "UPC: #{params[:upc]}"
puts "padlen: %s" %padlen
if (Webformat == 'F')
puts "inside format"
if (padlen == 0 ) then
IO.popen("tstprcpd.exe #{Webupc}")
{ |io|
"%s" %io.read
}
elsif (padlen > 0 ) then
for i in 1 .. padlen
padstr = padstr + "0"
end
padupc = padstr + Webupc
puts "padupc %s" %padupc
IO.popen("tstprcpd.exe #{padupc}") { |io|
"%s" %io.read
}
elsif (padlen < 0 ) then
IO.popen("date /T") { |io|
"UPC length must be 16 digits or less." %io.read
}
end
end
end
end
Your code has several problems:
It is not formatted properly
You are using Uppercase names for variables; that makes them constants!
puts will not output to the browser, but to the console. The browser will recieve the return value of the block, i.e. the return value of the last statement in the block. Therefore, you need to build your output differently (see below).
You are never joining the thread
Here's a minimal sinatra app that uses a thread. However, the thread makes no sense in this case because you must wait for its termination anyway before you can output the result to the browser. In order to build the output I have used StringIO, which you can use with puts to build a multiline string conveniently. However, you could also simply initialize res with an empty string with res = "" and then append your lines to this string with res << "new line\n".
require 'sinatra'
require 'thread'
require 'stringio'
get '/' do
res = StringIO.new
th = Thread.new do
res.puts 'Hello, world!'
end
th.join
res.string
end