How can I use "to_xs" in Rails 3.2? - ruby

I know this is in the builder gem. So I put it in my Gemfile. Then I bundle install.
Running in the console, I type:
x = "akwf"
then:
x.to_xs
and am rewarded with:
NoMethodError: undefined method `to_xs' for "akwf":String
When I try require 'builder' and require 'builder/xchar' I am met with false.
What basic item am I missing in order for me to perform this basic function?

First, note that Rails includes builder already, so no need to add it to the Gemfile.
Second, a false return value when requiring isn't really bad. It just means that the library has already been successfully required and didn't need to be re-required. If require is having trouble loading a library, it'll raise an exception, not return false.
Third, builder/xchar.rb specifies that, if String#encode is defined, then it skips the old String#to_xs definition and instead defines Builder::XChar.encode(string), which seems to serve the same purpose. Try requiring builder/xchar and giving that a shot.

Related

What are the ways to override a frozen variable in ruby?

This is a selenium-webdriver commands.rb file where I want to edit the upload_file key of COMMANDS variable from [:post, 'session/:session_id/se/file'] to [:post, 'session/:session_id/file']. I want to extend this class to one of mine's and make this change permanent so that even if i bundle install it, this change shouldn't be gone.
module Selenium
module WebDriver
module Remote
module W3C
class Bridge
COMMANDS = {
upload_file: [:post, 'session/:session_id/se/file']
}.freeze
end
end
end
end
end
You can get around the issue of unfreezing by just assigning the constant to a new value:
Selenium::WebDriver::Remote::W3C::Bridge.const_set(:COMMANDS, {
upload_file: [:post, 'session/:session_id/file']
}.freeze)
You will get a warning, but it will work.
If you really want to unfreeze, I have to point you to another question on the topic: How to unfreeze an object in Ruby?
in response to comment
The easiest way is to use ActiveSupport Hash#deep_dup from ActiveSupport. If this is a non-rails project, you can add the activesupport gem and require 'active_support/all':
my_commands = Selenium::WebDriver::Remote::W3C::Bridge::COMMANDS.deep_dup
# Here we can change one key only, or do any other manipulation:
my_commands[:upload_file] = [:post, 'session/:session_id/file']
Selenium::WebDriver::Remote::W3C::Bridge.const_set(:COMMANDS, my_commands)
You can also do it without ActiveSupport, but you will need to be a little more careful about how you clone the object because deep_dup is not available, something like this would work instead:
my_commands = Selenium::WebDriver::Remote::W3C::Bridge::COMMANDS.clone.transform_values(&:clone)
And then run the same stuff as in the previous example.
To understand this, read up on the difference between a "shallow" vs "deep" copy of an Object in Ruby, or the difference between "clone" and "deep_dup". Also see Hash#transform_values which I used in that snippet, if you're not familiar with it.

Unknown response for all methods and commands in ruby-asterisk

Testing ruby-asterisk manager interface with ruby version 1.9.3p0 and gem 1.8.11, for all command and methods its printing the the same output.
Anyone faced similar problem.
Code:
#!/usr/bin/env ruby
require 'ruby-asterisk'
#ami = RubyAsterisk::AMI.new("192.168.1.5",5038)
#ami.login("admin","passs")
puts #ami.command("sip show peers")
Output:
#<RubyAsterisk::Response:0x000000016af710>
Project URL
Problem solved. Didn’t check the readme RESPONSE OBJECT section.
It's working.
var = #ami.command(""sip show peers)
puts var.data
You are putting the Instance of the RubyAsterix. I think after haveing a brief look at the project that most/all of the instance methods returns the instance it self. The reason for doing it that way is that it makes it very easy to chain multiplie actions which makes for a nice syntax/usage.
I think you should remove the puts and allow the gem to display what it wants to display.

Ruby load module in test

I am running a padrino application and have started with the included mailers. I want to test that a mail is sent and had previously had no trouble accessing the Mail::TestMailer object to look at the mails delivered during the test.
That is the background about what I am doing but not precisely the question. I want to know how can a module become available to the runtime environment.
I have this test in two versions
first
def test_mailer
Mail::TestMailer.deliveries.clear
get '/owners/test'
e = Mail::TestMailer.deliveries.pop
puts e.to.to_s
end
second
def test_mailer
get '/owners/test'
Mail::TestMailer.deliveries.clear
e = Mail::TestMailer.deliveries.pop
puts e.to.to_s
end
In the second version this test fails with the error message NoMethodError: undefined method to' for nil:NilClass This makes sense to me. I clear the messages then ask for the last one which should be nil. However when I run the test on the first version the error is NameError: uninitialized constant OwnersControllerTest::Mail
So somehow the get method is causing the Mail object/module to be made available. I don't understand how it can do this. I don't know if this is a rack-test or padrino thing so am unsure what extra information to copy in here.
Add require 'mail' to your test helper.
The issue is explained here: https://github.com/padrino/padrino-framework/issues/1797

Most appropriate place to require library in Padrino/Sinatra

I'm using "therubyracer" in a model, and I'm requiring at the top of the model as so:
require 'v8'
class Thing
def self.ctx; ##ctx ||= V8::Context.new; end;
def self.eval(script); ctx.eval(script); end;
end
However, I intermittently get:
NameError - uninitialized constant Thing::V8:
/app/thing.rb:3:in `ctx'
When testing requests through a local Padrino server, apparently after I modify code in Thing. This is corrected by restarting the padrino server. I'm assuming requiring v8 somewhere else would fix this problem, wheres the correct place?
This looks like it might be caused by the Padrino reloader getting confused when it reloads your thing.rb file, causing Ruby to look for V8 in the Thing namespace.
Try explicitly specifying V8 is in the top level using the :: prefix:
def self.ctx; ##ctx ||= ::V8::Context.new; end;
You can put it wherever you want if you add it on the Gemfile. Did you added it?
Thanks!

How to create a sandboxed RSpec environment?

Essentially, I want to create a program that will run some untrusted code that defines some method or class, and then run an untrusted rspec spec against it.
I've looked into sandboxing Ruby a bit, and this video from rubyconf was particularly helpful. After looking at several solutions, the two that appear to be the most helpful are rubycop, which essentially does static analysis on the code, and the jruby sandbox (both covered in above video). My instinct tells me that the jruby sandbox is probably safer, but I could well be wrong.
Here's a completely unsafe example of what I want to do:
code = <<-RUBY
class Person
def hey
"hey!"
end
end
RUBY
spec = <<-RUBY
describe Person do
let(:person) { Person.new }
it "says hey" do
person.hey.should == "hey!"
end
end
RUBY
# code and spec will be from user input (unsafe)
eval code
require 'rspec/autorun'
eval spec
Which all works fine, but the code obviously needs to be sandboxed. It will be a matter of minutes before some genius submits system("rm -rf /*"), fork while fork or something equally dangerous.
I made various attempts with the jruby sandbox...
sand = Sandbox::Safe.new
sand.eval("require 'rspec/autorun'")
sand.activate! # lock it down
sand.eval code
puts sand.eval spec
That code throws this exception:
Sandbox::SandboxException: NoMethodError: undefined method `require' for #<RSpec::Core::Configuration:0x7c3cfaab>
This is because RSpec tries to require some stuff after the sandbox has been locked down.
So, I tried to force RSpec to require stuff before the sandbox gets locked down by calling an empty describe:
sand = Sandbox::Safe.new
sand.eval("require 'rspec/autorun'")
sand.eval("describe("") { }")
sand.activate! # lock it down
sand.eval code
sand.eval spec
And I get this:
Sandbox::SandboxException: NameError: uninitialized constant RSpec
Which basically means that RSpec doesn't exist in the sandbox. Which is odd, considering sand.eval("require 'rspec/autorun'") returns true, and that the earlier example actually worked (RSpec's autoloader started to run).
It may be a problem with gems and this particular sandbox though. The sandbox object actually supports a method #require, which is essentially bound to Kernel.require, and therefore can't load gems.
It's starting to look like using this sandbox just might not really be possible with rspec. The main problem is trying to actually load it into the sandbox. I even tried something like this:
require 'rspec'
sand.ref(RSpec) # open access to local rspec
But it wasn't having any of it.
So, my question is two-fold:
Does anyone have any bright ideas on how to get this to work with the jruby sandbox?
If not, how secure is rubycop? Apparently codeschool use it, so it must be pretty well tested... it would be nice to be able to use ruby 1.9 instead of jruby as well.
It looks like the sand box environment isn't loading the bundle/gemset. RVM could be at fault here if you are using a gemset or something.
One might try loading the Bundle again once sand boxed.
I would look at ruby taint modes
$SAFE The security level
0 --> No checks are performed on externally supplied (tainted) data. (default)
1 --> Potentially dangerous operations using tainted data are forbidden.
2 --> Potentially dangerous operations on processes and files are forbidden.
3 --> All newly created objects are considered tainted.
4 --> Modification of global data is forbidden.
I have been trying to figure out a similar problem. I want to use some gems like json and rest-client inside my sandbox after activating it. I tried following.
require "sandbox"
s=Sandbox.safe
s.eval <<-RUBY
require 'bundler'
Bundler.require :sandbox
RUBY
s.activate!
Gemfile.rb
group :sandbox do
platforms :jruby do
gem 'json'
gem 'rest-client'
end
end
This way, I was able to require gems in my sandbox. But, then there were some gem specific issues with sandbox. For eg, I had to add a method initialize_dup to whitelist for safe.rb in jruby-sandbox. RestClient has some problem with Fake File Sytem ALT_SEPARATOR which I am trying to patch. You can try this approach for RSpec and see if everything goes through.

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