What is the best way to write a function (or something DSLish) that will allow me to write this code in Ruby. How would I construct the function write_pair?
username = "tyndall"
write_pair username
# where write_pair username outputs
username: tyndall
Is it possible to do? Looking for the most simple way to do this.
Sure it is possible!
My solution tests the var by Object#object_id identity: http://codepad.org/V7TXRxmL
It's crippled in the binding passing style ...
Although it works just for local vars yet, it can be easily be made "universal" adding use of the other scope-variable-listing methods like instance_variables etc.
# the function must be defined in such a place
# ... so as to "catch" the binding of the vars ... cheesy
# otherwise we're kinda stuck with the extra param on the caller
#_binding = binding
def write_pair(p, b = #_binding)
eval("
local_variables.each do |v|
if eval(v.to_s + \".object_id\") == " + p.object_id.to_s + "
puts v.to_s + ': ' + \"" + p.to_s + "\"
end
end
" , b)
end
# if the binding is an issue just do here:
# write_pair = lambda { |p| write_pair(p, binding) }
# just some test vars to make sure it works
username1 = "tyndall"
username = "tyndall"
username3 = "tyndall"
# the result:
write_pair(username)
# username: tyndall
If it's possible for you to use a symbol instead of the variable name, you could do something like this:
def wp (s, &b)
puts "#{s} = #{eval(s.to_s, b.binding)}"
end
In use:
irb(main):001:0> def wp (s, &b)
irb(main):002:1> puts "#{s} = #{eval(s.to_s, b.binding)}"
irb(main):003:1> end
=> nil
irb(main):004:0> var = 3
=> 3
irb(main):005:0> wp(:var) {}
var = 3
Note that you must pass the empty block {} to the method or it cannot get the binding to evaluate the symbol.
You can't actually get a variable's name in Ruby. But you could do something like this:
data = {"username" => "tyndall"}
Or even,
username = "tyndall"
data = {"username", "password", "favorite_color"}
data.each { |param|
value = eval(param)
puts "#{param}: #{value}"
}
I made a vim macro for this:
" Inspect the variable on the current line (in Ruby)
autocmd FileType ruby nmap ,i ^"oy$Iputs "<esc>A: #{(<esc>"opA).inspect}"<esc>
Put the variable you'd like to inspect on a line by itself, then type ,i (comma then i) in normal mode. It turns this:
foo
into this:
puts "foo: #{(foo).inspect}"
This is nice because it doesn't have any external dependencies (e.g. you don't have to have a library loaded up to use it).
Building on previous answers relating to symbols & bindings ... if passing in the variable name as a symbol works for you (who doesn't love cutting out extra keystrokes?!), try this:
def wp(var_name_as_sym)
# gets caller binding, which contains caller's execution environment
parent_binding = RubyVM::DebugInspector.open{|i| i.frame_binding(2) }
# now puts the symbol as string + the symbol executed as a variable in the caller's binding
puts %Q~#{var_name_as_sym.to_s} = #{eval("#{var_name_as_sym.to_s}.inspect", parent_binding)}~
end
aa=1
bb='some bb string'
os = OpenStruct.new(z:26, y:25)
Console output:
> wp :aa
aa = 1
=> nil
> wp :bb
bb = "some bb string"
=> nil
> wp :os
os = #<OpenStruct z=26, y=25>
=> nil
Using ruby 2.2.2p95
(Credit to banister for getting binding of calling context)
This is a simple solution:
def write_pair(variable)
puts variable + eval(variable)
end
This is more readable:
def write_pair(variable)
puts 'A' * 100
puts variable + ': ' + eval(variable).inspect
puts 'Z' * 100
end
Invocation:
write_pair "variable"
def write_pair var, binding
puts "#{ var } = #{ eval(var, binding)}"
end
username = "tyndall"
write_pair "username", binding
This seems weird because binding is never defined, but it works. From Ruby: getting variable name:
The binding() method gives a Binding object which remembers the
context at the point the method was called. You then pass a binding
into eval(), and it evaluates the variable in that context.
Be sure to pass a string, not the variable.
# make use of dynamic scoping via methods and instance vars
#_binding = binding
def eval_debug(expr, binding = #_binding)
"#{expr} => #{eval(expr, binding)}"
end
# sample invocation:
x = 10
puts eval_debug "x"
puts eval_debug "x**x"
I want to execute Ruby code if command line argument is present:
ruby sanity_checks.rb --trx-request -e staging_psp -g all
Ruby code:
def execute
command_options = CommandOptionsProcessor.parse_command_options
request_type = command_options[:env]
tested_env = command_options[:trx-request] // check here if flag is present
tested_gateways = gateway_names(env: tested_env, gateway_list: command_options[:gateways])
error_logs = []
if(request_type.nil?)
tested_gateways.each do |gateway|
........
end
end
raise error_logs.join("\n") if error_logs.any?
end
How I can get the argument --trx-request and check is it present?
EDIT:
Command parser:
class CommandOptionsProcessor
def self.parse_command_options
command_options = {}
opt_parser = OptionParser.new do |opt|
opt.banner = 'Usage: ruby sanity_checks.rb [OPTIONS]'
opt.separator "Options:"
opt.on('-e TEST_ENV', '--env TEST_ENV','Set tested environment (underscored).') do |setting|
command_options[:env] = setting
end
opt.on('-g X,Y,Z', '--gateways X,Y,Z', Array, 'Set tested gateways (comma separated, no spaces).') do |setting|
command_options[:gateways] = setting
end
end
opt_parser.parse!(ARGV)
command_options
end
end
Can you advice?
You will need to add a boolean switch option to your OptionParser like so
opt.on('-t','--[no-]trx-request','Signifies a TRX Request') do |v|
# note we used an underscore rather than a hyphen to make this symbol
# easier to access
command_options[:trx_request] = v
end
Then in your execute method you can access this as
command_options[:trx_request]
If you need to have a default value you can add one in the parse_command_options method by setting it outside the OptionParser as command_options[:trx_request] = false
Hi I have a string passed back from rspec.
It should show
"alias/public_html/ab1/ab2/"
but I am getting "\"alias/public_html/ab1/ab2/\""
I am getting the rspec error below:
WebServer::HttpdConf#alias_path returns the aliased path
Failure/Error: expect(httpd_file.alias_path('/ab/')).to eq 'alias/public_html/ab1/ab2/'
expected: "alias/public_html/ab1/ab2/"
got: "\"alias/public_html/ab1/ab2/\""
(compared using ==)
# ./spec/lib/config/httpd_conf_spec.rb:90:in `(root)'
And here is my actual program file
def alias_path(path)
#hash_httpd['Alias'][path]
end
Please help
EDIT
Sorry, I am new to RUby, here is the httpd_file
def initialize(httpd_file_content)
#hash_httpd = Hash.new
httpd_file_content.each_line do | line |
#commands = line.split
if #commands.length == 2
#hash_httpd[#commands[0]] = #commands[1]
else
if !#hash_httpd.has_key?(#commands[0])
al = Hash.new
#hash_httpd[#commands[0]] = al
else
al = #hash_httpd[#commands[0]]
end
al[#commands[1]] = #commands[2]
end
end
end
If you are sure that your alias_path output will be "alias/public_html/ab1/ab2/", then you can just modify your alias_path method definition by removing the quotes (if any) from the returned path:
def alias_path(path)
#hash_httpd['Alias'][path].gsub('"', '')
end
I am developing some test cases in Ruby using rspec.
I am attempting to mock the popen3 function.
However, while still keeping the blocking form, I am unable to capture the expected output information:
Class MyClass
def execute_command
Open3.popen3(command) do |stdin, stdout, stderr, wait_thr|
output['wait_thr'] = wait_thr.value
while line = stderr.gets
output['stderr'] += line
end
end
return output
end
end
To mock out the function, I am doing the following:
it 'should do something'
response = []
response << 'stdin'
response << 'stdout'
response << 'test'
response << 'exit 0'
# expect
allow(Open3).to receive(:popen3).with(command).and_yield(response)
# when
output = myClassInstance.execute_script
#then
expect(output['wait_thr'].to_s).to include('exit 0')
Mocking out the function doesn't enter the "do" code and I'm left with an empty data structure.
I was wondering how I could properly do this?
Thanks!
To add some more context to Chris Reisor's answer, this is the approach that worked for me:
I have a piece of code that reads as shown here.
Open3.popen2e(*cmd) do |_, stdout_and_stderr, wait_thr|
while (line = stdout_and_stderr.gets)
puts line
end
raise NonZeroExitCode, "Exited with exit code #{wait_thr.value.exitcode}" unless wait_thr.value.success?
end
And my testing setup looks like shown below.
let(:wait_thr) { double }
let(:wait_thr_value) { double }
let(:stdout_and_stderr) { double }
before do
allow(wait_thr).to receive(:value).and_return(wait_thr_value)
allow(wait_thr_value).to receive(:exitcode).and_return(0)
allow(wait_thr_value).to receive(:success?).and_return(true)
allow(stdout_and_stderr).to receive(:gets).and_return('output', nil)
allow(Open3).to receive(:popen2e).and_yield(nil, stdout_and_stderr, wait_thr)
end
I think you needed to put "*response" instead of "response."
allow(Open3).to receive(:popen3).with(command).and_yield(*response)
That will send 4 string args to and_yield ("arity of 4"), rather than one arg which is an array.
I have an assortment of test cases that I want to run. The dumbed-down code is like this:
class TestCase
def initialize(caseName)
name = caseName
...a bunch more code...
end
end
#TC001 = new TestCase("Case 1")
#TC002 = new TestCase("Case 2")
...
#TC100 = new TestCase("Case 100")
Then I'm trying to pass in to the command line which test cases I need to run this time. The Runner file looks something like:
testCaseArray = Array.new
i = 0
while i < ARGV.length
testCaseArray < ARGV[i]
i += 1
end
runTestCases(myArray)
myArray.each do |thisCase|
puts thisCase.name
end
end
runTestCases(testCaseArray)
So then when I go to the command line and enter:
ruby Runner.rb #TC027 #TC030 #TC075
I get an error because it's not recognizing #TC027 as a variable but is instead recognizing it as a string, and (string).name isn't valid.
How do I get it to read the string as a variable?
You can look up an instance variable named by a string with instance_variable_get.