rubygems interview questions
Top rubygems frequently asked interview questions
I am having some problems when trying to install mysql2 gem for Rails. When I try to install it by running bundle install or gem install mysql2 it gives me the following error:
Error installing mysql2: ERROR: Failed to build gem native extension.
How can I fix this and successfully install mysql2?
Source: (StackOverflow)
If I download a .gem file to a folder in my computer, can I install it later using gem install?
Source: (StackOverflow)
I have several versions of a Ruby gem:
$ gem list
rjb (1.3.4, 1.3.3, 1.1.9)
How can I remove old versions but keep the most recent?
Source: (StackOverflow)
I'd like Bundler to load a local gem. Is there an option for that? Or do I have to move the gem folder into the .bundle directory?
Source: (StackOverflow)
Trying to install a gem (gem install mygem) or update RubyGems (gem update --system) fails with this error:
ERROR: While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /Library/Ruby/Gems/2.0.0 directory.
Anyone having idea how to solve this?
Source: (StackOverflow)
It is pretty easy with the added generator of rspec-rails to setup RSpec for testing a Rails application. But how about adding RSpec for testing a gem in development?
I am not using jeweler or such tools. I just used Bundler (bundle gem my_gem) to setup the structure for the new gem and edit the *.gemspec manually.
I also added s.add_development_dependency "rspec", ">= 2.0.0" to gemspec and did a bundle install.
Is there some nice tutorial what to do next to get RSpec working?
Source: (StackOverflow)
I don't use the RI or RDoc output from the gems I install in my machine or in the servers I handle (I use other means of documentation).
Every gem I install installs RI and RDoc documentation by default, because I forget to set --no-ri --no-rdoc.
Is there a way to make those two flags the default?
Source: (StackOverflow)
When I want to create a Ruby on Rails project, I get the message below.
/usr/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:55: uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
from /usr/lib/ruby/gems/1.8/gems/activesupport-2.3.8/lib/active_support.rb:57
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
from /usr/lib/ruby/gems/1.8/gems/rails-2.3.8/lib/rails_generator.rb:31
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
from /usr/lib/ruby/gems/1.8/gems/rails-2.3.8/bin/rails:15
from /usr/bin/rails:19:in `load'
from /usr/bin/rails:19
What has gone wrong? How do I to fix it?
Source: (StackOverflow)
I get the error shown below when attempting to install the rmagick gem. I am on Snowleopard 10.6 using RVM, Ruby 1.9.2-head and Rails 3.05. Responses to similar questions recommended installing ImageMagick, which I successfully did. Other suggested installing the "libmagick9-dev library", however, I can not figure out how to do this.
I'm a new developer, and any assistance or directions to an existing explanation or resource is greatly appreciated. Thanks!
jjdevenuta(opal)$ gem install rmagick
Fetching: rmagick-2.13.1.gem (100%)
Building native extensions. This could take a while...
ERROR: Error installing rmagick:
ERROR: Failed to build gem native extension.
/Users/jjdevenuta/.rvm/rubies/ruby-1.9.2-head/bin/ruby extconf.rb
checking for Ruby version >= 1.8.5... yes
checking for gcc... yes
checking for Magick-config... no
Can't install RMagick 2.13.1. Can't find Magick-config in /Users/jjdevenuta/.rvm/gems/ruby-1.9.2-head@rails3/bin:/Users/jjdevenuta/.rvm/gems/ruby-1.9.2-head@global/bin:/Users/jjdevenuta/.rvm/rubies/ruby-1.9.2-head/bin:/Users/jjdevenuta/.rvm/bin:/usr/local/bin:/usr/local/sbin:/usr/local/mysql/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/git/bin:/usr/X11/bin
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/Users/jjdevenuta/.rvm/rubies/ruby-1.9.2-head/bin/ruby
UPDATE
If you're a Mac/OS X user I would HIGHLY recommend using Homebrew as your package installer/manager. You can find it HERE. Since originally asking this question I have removed all my prior installs of things like rmagick and imagemagick, and reinstalled them using Homebrew. Super easy with a huge catalog of packages, and updates/uninstalls are a cinch as well!
Source: (StackOverflow)
This question already has an answer here:
When I run bundle install for my Rails 3 project on Centos 5.5 it fails with an error:
Gem::RemoteFetcher::FetchError: SSL_connect returned=1 errno=0 state=SSLv3
read server certificate B: certificate verify failed
(https://bb-m.rubygems.org/gems/multi_json-1.3.2.gem)
An error occured while installing multi_json (1.3.2), and Bundler cannot continue.
Make sure that `gem install multi_json -v '1.3.2'` succeeds before bundling.
When I try to install the gem manually (by gem install multi_json -v '1.3.2') it works. The same problem occurs with several other gems. I use RVM (1.12.3), ruby 1.9.2, bundler 1.1.3.
How to fix it?
Source: (StackOverflow)
I have ruby 1.9.2p180 (2011-02-18) [i386-mingw32] installed on my windows 7 machine. Now I tried to install the json gem using the command, "gem install json" and got the following error.
ERROR: Error installing json:
The 'json' native gem requires installed build tools.
Please update your PATH to include build tools or download the DevKit
from '[http://rubyinstaller.org/downloads][1]' and follow the instructions
at '[http://github.com/oneclick/rubyinstaller/wiki/Development-Kit][2]'
Then I went and downloaded DevKit-4.5.0-20100819-1536-sfx.exe. Extracted it to C:\DevKit. And then from the command prompt I executed the following commands.
ruby dk.rb init
After the above command is executed, i verified that config.yaml is generated and it has the path for my ruby folder added automatically. This is the line at the bottom of the config.yaml file "- C:/Ruby192"
ruby dk.rb review
I got the message that devkit functionaliy will be injected into the rubies when you run "ruby dk.rb install"
ruby dk.rb install
I got the following message.
[INFO] RubyGems override already in place for C:/Ruby192, skipping.
[INFO] Installing C:/Ruby192/lib/ruby/site_ruby/devkit.rb
Now I tried executing the JSON gem again using the command gem install json. Then got the same error message as before.
ERROR: Error installing json:
The 'json' native gem requires installed build tools.........
Am I missing something.
Source: (StackOverflow)
I've been struggling with this for some time.
I've installed Rails 3, gem, mysql on my Snow Leopard machine. All was going well until I created my first project and tried to run
rails server
Upon running this I get:
jontybrook$ rails server
/Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle: dlopen(/Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle, 9): Library not loaded: libmysqlclient.16.dylib (LoadError)
Referenced from: /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle
Reason: image not found - /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle
from /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2.rb:7
from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:64:in `require'
from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:64:in `require'
from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:62:in `each'
from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:62:in `require'
from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:51:in `each'
from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:51:in `require'
from /Library/Ruby/Gems/1.8/gems/bundler-1.0.7/lib/bundler.rb:112:in `require'
from /Users/jontybrook/Dropbox/CODING/simple_cms/config/application.rb:7
from /Library/Ruby/Gems/1.8/gems/railties-3.0.3/lib/rails/commands.rb:28:in `require'
from /Library/Ruby/Gems/1.8/gems/railties-3.0.3/lib/rails/commands.rb:28
from /Library/Ruby/Gems/1.8/gems/railties-3.0.3/lib/rails/commands.rb:27:in `tap'
from /Library/Ruby/Gems/1.8/gems/railties-3.0.3/lib/rails/commands.rb:27
from script/rails:6:in `require'
from script/rails:6
jontybrook$
As far as I can tell the problem is with the mysql2 gem. MySQL seems to be running fine and my Gemfile references mysql2, my database.yml file seems ok also.
The error mentions
Reason: image not found - /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle
And yet
jontybrook$ cd /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2
jontybrook$ ls
client.rb em.rb error.rb mysql2.bundle result.rb
MySQL2.bundle is there!?
If I use the old mysql gem, WEBrick boots fine. But that's not ideal, is it?
I've tried everything google can give me! Any help much appreciated.
Source: (StackOverflow)
The firewall I'm behind is running Microsoft ISA server in NTLM-only mode. Hash anyone have success getting their Ruby gems to install/update via Ruby SSPI gem or other method?
... or am I just being lazy?
Note: rubysspi-1.2.4 does not work.
This also works for "igem", part of the IronRuby project
Source: (StackOverflow)