I'm trying to get simple option handling in my ruby app. Looks like OptionParser does most of what I want, though I can't figure out a way to gracefully handle unexpected arguments.
If any unexpected arguments are provided I want to treat it as if the -h argument was passed (show usage and quit). I'm not seeing any way to handle that though.
If OptionParser can't do it, is there another library I could use for easily parsing command line arguments?
There's probably a slick way to do it, but I don't know it. I've done this:
opts = OptionParser.new
...
opts.on_tail("-h", "--help",
"Show this message") do
puts opts
exit
end
begin
opts.parse!(argv)
rescue OptionParser::InvalidOption => e
puts e
puts opts
exit(1)
end
if you save below as test.rb
#/usr/bin/env ruby
require 'optparse'
test = nil
help = nil
ARGV.options {|opt|
opt.on("--test=test") {|val| test=val}
help = opt.help
begin
opt.parse!
rescue OptionParser::InvalidOption => e
puts help
end
}
and execute below in the terminal,
$./test.rb --foo
you get below.
Usage: test [options]
--test=test
Related
I am learning ruby and trying to write a unit test with rspec for the following method:
def get()
options = {}
OptionParser.new do |opt|
opt.banner = 'Usage: validate-gitlab-ci [options]'
opt.on('-f', '--yaml YAML-PATH', 'Path to .gitlab-ci.yml') { |o| options[:yamlFile] = o }
opt.on('-l', '--base-url GitLab url', 'GitLab API url') { |o| options[:baseUrl] = o + API_PATH }
opt.on('-t', '--timeout[TIMEOUT]', Integer, 'Api timeout in seconds') { |o| options[:timeout] = o || 10 }
opt.on('-v', '--version', 'Program version') { |o| options[:version] = o }
end.parse!
validateUrl!(options[:baseUrl])
validateYamlFile!(options[:yamlFile])
#baseUrl = options[:baseUrl]
#pathToYamlFile = options[:yamlFile]
end
The code for my unit test so far is:
RSpec.describe Gitlab::Lint::Client::Args do
describe "#get" do
context "when arguments are valid" do
it "sets baseUrl and pathToYamlFile" do
io = StringIO.new
io.puts "glab-lint --base-url=https://example.com --yaml=valid.ym\n"
io.rewind
$stdin = io
args = Gitlab::Lint::Client::Args.new
args.get()
expect(args.baseUrl).to.eq("https://example.com")
end
end
end
end
I am trying to mock STDIN for OptionParser. However, upon executing the test the following error is displayed:
OptionParser::InvalidOption:
invalid option: --pattern
This is raised by the end.parse! line in the get() method
Has anyone managed to test OptionsParser with stdin mocked?
Update
I think what is happening is that some RSpec options, e.g. --pattern?? are being captured in STDIN and passed to script??? Or .... RSpec is consuming the stdin options??
Reading this post seems to suggest that the desired functionality is not possible with RSpec....if this is indeed true then I will migrate over to using alternative test frameworks in future for CLI projects that use ARGV. There is a workaround suggested here but that suggests using environment variables for capturing commmand line arguments. In this case that would require further refactoring of the software under test, purely to suit the capabilities of the RSpec test framework!!
If I add a puts statement to display the contents of ARGV in the test script it confirms this is the case, with this output:
--pattern
spec/**{,/*/**}/*_spec.rb
[--base-url=https://gitlab.com --yaml=valid.ym]
So.....as a complete newbie to RSpec.....my options are:
Update the signature of the get method to accept an args array:
def get(args)
options = {}
OptionParser.new do |opt|
...
end.parse!(args)
end
This delays the issue with testing the code that reads from ARGV further up the call hierarchy
Modify ARGV shifting the first two arguments out of the array and then after the test has completed restore ARGV to original state. Looks like something similar has already been tried here without success.
Some other configuration that I am not aware of as a newbie to RSpec
Investigate alternative options, e.g. minitest, that maybe do not modify the ARGV array??
Further information regarding options 3 and 4 appreciated....
You can use RSpec to mock STDIN. For example:
STDIN.should_receive(:read).and_return("glab-lint --base-url=https://example.com --yaml=valid.yml")
Alternatively, you can invoke your actual command line program using backticks or system, and assert on the response.
This is homework and I do not expect you to give me the complete answer.
I'm trying to parse a command line entry such as:
./apacheReport.rb -u testlog.txt
When I enter this:
./apacheReport.rb -u testlog.txt
I get:
Argument required
My code is:
require_relative 'CommonLog'
require 'optparse'
# puts ARGV.inspect
optparser = OptionParser.new
optU = false
optI = false
optS = false
optH = false
optparser.banner = "apacheReport.rb [options] filename"
optparser.parse!
rescue => m
puts m.message
puts optparser
exit
end
if ARGV.length < 1
puts "Argument required"
exit
end
userInputFile = ARGV[0]
userInputFile.to_s
file = CommonLog.new(userInputFile)
It should parse the leftover portion of the command into ARGV[0] then should store it as userInputFile and then create a CommonLog object using the file as the constructor. At that point I call the methods that were specified in the command.
It seems that for some reason my ARGV is not being returned. I'm not sure what the issue is.
Ruby's OptionParser is easy to use, but you have to puzzle through the documentation. Here's a little example that'd be useful for your code:
require 'optparse'
options = {}
OptionParser.new do |opt|
opt.on('-u', '--use_this FILE', 'Use this file') { |o| options[:use_this] = o }
end.parse!
options will contain the flags. In this case, if you pass in -u foo, options[:use_this] will be foo.
Save that and try running it without and with a parameter. Also try running it with just a -h flag.
You can search StackOverflow for more answers where I was dealing with OptionParser.
It's hard to tell what's wrong since you code doesn't seem to be working at the moment. The problem may be that the parse! method removes found options from ARGV. So when you write:
optparser.parse!
It removes your two parameters (-u testlog.txt) and this code always fails:
if ARGV.length < 1
puts "Argument required"
exit
end
Instead of looking at ARGV, you need to set up optparser correctly. Perhaps something like:
optparser = OptionParser.new do |opts|
opts.banner = "apacheReport.rb [options] filename"
opts.on("-u", "--u-short-for-this", "Whatever u stands for") do |u|
optU = u
end
end
Then optU will be true only if the user passed -u and the filename will be in ARGV[0].
How do I use command options in scripts?
I have a script that connects to a device, runs commands and prints the output. I would like to use a file for the hosts, and one for the user and passwd info. When I try to run the script I get these errors:
ruby threat_detection.rb --host_file=hosts --config_file=config
threat_detection.rb:61:in '<main>': needless argument: --host_file=hosts (OptionParser::NeedlessArgument)
ruby threat_detection.rb '--host_file=hosts' '--config_file=config'
threat_detection.rb:61:in '<main>': needless argument: --host_file=hosts (OptionParser::NeedlessArgument)
ruby threat_detection.rb --host_file-hosts --config_file-config
threat_detection.rb:61:in '<main>': invalid option: --host_file-hosts (OptionParser::InvalidOption)
This is the code:
options ={}
opt_parser = OptionParser.new do |opt|
opt.banner = 'Usage: opt_parser COMMAND [OPTIONS]'
opt.on('--host_file', 'I need hosts, put them here') do |host_file|
options[:host_file] == host_file
end
opt.on('--config_file', 'I need config info, put it here') do |config_file|
options[:config_file] == config_file
end
opt.on('-h', '--help', 'What your looking at') do |help|
options[:help] == help
puts opt
end
end
opt_parser.parse!
How do I make these options get read? This is my guess (based off python experience). I'm just looking for it to print the lines right now:
if :config_file == true
File.open(:config_file, r) do |params|
puts params
end
end
if :host_file == true
File.open(:host_file, r) do |host|
put host
end
end
For taking arguments you need to use the following formats
"--switch=MANDATORY" or "--switch MANDATORY" # mandatory argument
"--switch[=OPTIONAL]" # optional argument
"--switch" # no argument
You are currently using the third format, which is being interpreted as taking no argument. You should use the first or second.
Also worth noting you probably want to be doing an assignment instead of a comparison when a flag is on
You want this
options[:host_file] = host_file
not this
options[:host_file] == host_file
The code below works, but I am manually raising argument errors for the required arguments using fetch, when I want to build the required arguments into the native OptionParser sytax for required parameters:
# ocra script.rb -- --type=value
options = {}
OptionParser.new do |opts|
opts.banner = "Usage: example.rb [options]"
opts.on("--type [TYPE]",String, [:gl, :time], "Select Exception file type (gl, time)") do |t|
options["type"] = t
end
opts.on("--company [TYPE]",String, [:jaxon, :doric], "Select Company (jaxon, doric)") do |t|
options["company"] = t
end
end.parse!
opts = {}
opts['type'] = options.fetch('type') do
raise ArgumentError,"no 'type' option specified as a parameter (gl or time)"
end
opts['company'] = options.fetch('company') do
raise ArgumentError,"no 'company' option specified as a parameter (doric or jaxon)"
end
There's a similar question with an answer that may help you:
"How do you specify a required switch (not argument) with Ruby OptionParser?"
In short: there doesn't seem to be a way to make an option required (they are called options after all).
There is an OptionParser::MissingArgument exception that you could raise rather than the ArgumentError you're currently throwing.
Faced with the same situation, I ended up with an option like this. If not all of my mandatory options are provided, output the user-friendly help text generated by OptionParser based on my defined options. Feels cleaner than throwing an exception and printing a stack trace to the user.
options = {}
option_parser = OptionParser.new do |opts|
opts.banner = "Usage: #{$0} --data-dir DATA_DIR [options]"
# A non-mandatory option
opts.on('-p', '--port PORT', Integer, 'Override port number') do |v|
options[:port] = v
end
# My mandatory option
opts.on('-d', '--data-dir DATA_DIR', '[Mandatory] Specify the path to the data dir.') do |d|
options[:data_dir] = d
end
end
option_parser.parse!
if options[:data_dir].nil?
puts option_parser.help
exit 1
end
I'm trying to use optparse to parse command line arguments. I would like my program to accept arguments like that:
$ ./myscript.rb [options] filename
I can easily manage the [options] part:
require 'optparse'
options = { :verbose => false, :type => :html }
opts = OptionParser.new do |opts|
opts.on('-v', '--verbose') do
options[:verbose] = true
end
opts.on('-t', '--type', [:html, :css]) do |type|
options[:type] = type
end
end
opts.parse!(ARGV)
But how do I get the filename?
I could extract it manually from ARGV, but there has to be a better solution, just can't figure out how
The "parse" method returns the unprocessed ARGV. So in your example, it will return a one element array with the filename in it.
I can't just use ARGV.pop. For example
when the last argument is "css" it
could either be a file or belong to
--type switch.
But if your script requires the last argument to be a filename (which is what your usage output inquires) this case should never happen the script should exit with a non-zero and the user should get a usage report or error.
Now if you want to make a default filename or not require a filename as the last argument but leave it optional then you could just test to see if the last argument is a valid file. If so use it as expected otherwise continue without etc.
Hope this answer can still be useful.
Ruby has one built-in variable __FILE__ can do this type of work.
puts __FILE__
it will print out your file's name.
I don't think extracting it before sending it to OptionParser is bad, I think it makes sense. I probably say this because I have never used OptionParser before, but oh well.
require 'optparse'
file = ARGV.pop
opts = OptionParser.new do |opts|
# ...
end