I'm trying to develop a ruby gem for practice and I'm wondering how do I require pry during development and test runs? Is there anyway to require the gem only during development? I'm on Ruby and not Rails and I don't think I have any environment variables setup to rely on. Is there a conventional way to do this?
and
Currently if I run code that hits the above line, I get this error:
NoMethodError: undefined method `pry' for #<Binding:0x007f8d3287c4d8>
from /Users/jwan/programming/interview_questions/gemini/jobcoin_client/lib/jobcoin_client/requests/connection.rb:18:in `post'
A few questions:
How do I properly require pry so this line doesn't throw an error when developing a gem?
I read Yahuda's post but I'm still unclear why adding dependencies in the gemspec vs adding dependencies in the Gemfile. What is the difference?
Currently, after I make changes to the ruby gem, I have to run these series of commands. Is there anything more efficient that I can do?
gem build jobcoin_client.gemspec
WARNING: no homepage specified
WARNING: open-ended dependency on pry (>= 0, development) is not recommended
if pry is semantically versioned, use:
add_development_dependency 'pry', '~> 0'
WARNING: See http://guides.rubygems.org/specification-reference/ for help
Successfully built RubyGem
Name: jobcoin_client
Version: 0.1.0
File: jobcoin_client-0.1.0.gem
$ gem install jobcoin_client
Successfully installed jobcoin_client-0.1.0
Parsing documentation for jobcoin_client-0.1.0
Done installing documentation for jobcoin_client after 0 seconds
1 gem installed
05:45 PM
$ irb
irb(main):001:0> require 'jobcoin_client'
=> true
irb(main):002:0> require 'pry'
=> false
You can install it to the system and use a boolean flag to conditionally require it and set breakpoints.
gem install pry
Then in code, something like this:
SET_BREAKPOINTS = ENV["SET_BREAKPOINTS"] == "true"
require 'pry' if SET_BREAKPOINTS
binding.pry if SET_BREAKPINTS
To turn breakpoints on, you can manipulate env through code:
ENV["SET_BREAKPOINTS"] = "true"
or when calling a script from bash:
env SET_BREAKPOINTS=true irb -r 'your_gem'
I'm developing a gem, and I need to load that gem's code into irb for testing purposes without building/publishing the gem and then installing it onto my system the traditional way via gem install <gem's name>.
To illustrate:
$ pwd
Users/me/development/gem_name/
$ irb
2.2.2 :001 > require 'gem_name'
=> true
The problem is that irb isn't loading the gem's code from my working dir because I added a method to the gem in the working dir and it's not available in the version of the gem that irb loaded above.
How can I load the version of the gem that is in the dir that I'm currently working in (i.e. the gem's dir)?
You could use require_relative to manually load the source code of your gem, for example require_relative './lib/gem_name/gem_name' assuming you have a file located at ./lib/gem_name/gem_name.rb that loads your gem. This guarantees that it is the version you have in your source code.
I'm new to Ruby and I'm having a lot of trouble trying to use Nokogiri. I've been trying to find a resolution for hours now, so any help is appreciated. I tried searching for and using solutions from other related SO posts before caving and posting my own. When I run ruby -v I get: ruby 1.8.7 (2011-06-30 patchlevel 352) [x86_64-linux]
(Edit: I have updated ruby with updates-alternatives --config ruby and selected /usr/bin/ruby1.9.1 but when I do ruby -v it is now showing version 1.9.3 WTF am I doing wrong here?)
I have a new project directory at ~/workspace/ruby/rubycrawler/ and I used Bundler to install nokogiri, which installed correctly:
Using mini_portile (0.5.2)
Using nokogiri (1.6.1)
Using bundler (1.5.1)
Your bundle is complete!
Running bundle show nokogiri returns /var/lib/gems/1.9.1/gems/nokogiri-1.6.1.
In the directory I'm running the script from I have a simple html file named "index.html". The script I'm trying to run is even simpler (or so I thought):
require 'nokogiri'
page = Nokogiri::HTML(open("index.html"))
puts page.class # Nokogiri::HTML::Document
The error is rubycrawler.rb:1:in 'require': no such file to load -- nokogiri (LoadError).
I also added require 'rubygems' even though I read it isn't needed for 1.9+ and still no luck.
A lot of searching shows "Did you put this gem in your Gemfile?". So I generate a Gemfile and add gem 'nokogiri'. I try running the small script again and get the same error. I read "Try deleting Gemfile.lock." so I did but still couldn't get it to work. I then read to try testing it out in irb so I tested "open-uri" and "nokogiri" and here's what I got:
irb(main):001:0> require 'open-uri'
=> true
irb(main):003:0> require 'nokogiri'
LoadError: no such file to load -- nokogiri
I'm really having a lot of trouble figuring this out, so really any help at all is really appreciated.
Ruby tools like RVM, Bundler, etc., to the novice, appear to do a lot of magic, but really, there is no magic to them. The key here lies in what Bundler actually does for you. It manages a manifest of dependencies, BUT at runtime, those dependencies STILL have to get loaded somehow, and my gut feeling is that is what is not happening here.
Regardless of what version of Ruby you are using, if you are using Bundler, there's an easy way to do this. Precede the command that starts your program with "bundle exec" and that will make Bundler edit Ruby's load path so that it includes all the things in the manifest (Gemfile.lock).
For example:
$ bundle exec ruby foo.rb
A additional note for anyone using RVM: RVM generally will modify the shebangs in the scripts that launch programs like "ruby" or "rake" so that they use the "ruby_no_exec" shell (or similar) instead of the plain old "ruby" shell. That alternate shell is Bundler-aware and makes it generally unnecessary to type "bundle exec," but since the OP is using system Ruby, that's not applicable and commands should be manually prefixed with "bundle exec".
Hope this helps!
In addition to Kent's answer, I would recommend switching to RVM instead of using the system installed ruby. System rubies tend to be horribly out of date, especially when it comes to important things like features and security updates. It might not help you in your current situation, but it would be well worth the time. If you are unfamiliar: http://rvm.io
-- UPDATE --
Ok its fixed. This is what I did. remove all ruby and rubygems completely. then install ruby1.9.1-full and rubygems1.9.1 then install the twitter gem.
Hi guys,
I am having trouble working with the Twitter gem. I am using ruby 1.8.7
After installing when I try to run a simple script I get this error
ruby twitter.rb
./twitter.rb:5: uninitialized constant Twitter (NameError)
from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require'
from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:inrequire'
from twitter.rb:2
I running this on a Ubuntu box. I checked with gem -list and I see the Twitter (1.1.0) is listed there.
this is the code I am trying to run
require "rubygems"
require 'twitter'
puts Twitter.user_timeline("test").first.text
Any ideas ?
I believe it only works with Ruby 1.9 If you want to use twitter gem try version 0.9 with Ruby 1.8.x
This works for me:
ruby-1.9.2-p0 > require 'twitter'
=> true
ruby-1.9.2-p0 > puts Twitter.user_timeline("test").first.text
TExES Pedagogy and Professional Responsibilities EC-12 Teacher Certification Test Prep Study Guid… - by Sharon A Wynne http://amzn.to/f3kF74
=> nil
which version of ruby are you using?
gouravtiwari21's comment seems to fix the problem, but it's wrong to suggest that the twitter gem requires 0.9.0 if you want to run it using Ruby 1.8.x.
You can check out the version compatibility here:
http://travis-ci.org/#!/jnunemaker/twitter
It shows the twitter gem working with Ruby installs as low as 1.8.7.
For me, it was an issue with having the correct dependent gems, as well as the correct versions.
Here's how I got it working:
I ran:
sudo gem list
And compared the versions of specific gems with what I found here:
https://github.com/jnunemaker/twitter/blob/master/HISTORY.md (I simply searched for the word 'dependency' to see which versions twitter cared about.
I also found this diff:
https://github.com/jnunemaker/twitter/commit/ac8114c1f6ba2da20c2267d3133252c2ffc6b6a3
And I compared the gems listed there with what I had installed, and I just made sure my system lined up with what I was seeing in the version notes. Oftentimes what happened is that I had multiple versions of a gem, and for some reason, the lower version was taking precedence.
I'm not sure why I still have to add
gem 'twitter', '1.7.1'
to my Gemfile, but alas, that's the last step required in order to get this stuff working.
Don't forget to restart your server, and you should be good!
The question I'm really asking is why require does not take the name of the gem. Also, In the case that it doesn't, what's the easiest way to find the secret incantation to require the damn thing!?
As an example if I have memcache-client installed then I have to require it using
require 'rubygems'
require 'memcache'
My system also doesn't seem to know about RubyGems' existence - unless I tell it to. The 'require' command gets overwritten by RubyGems so it can load gems, but unless you have RubyGems already required it has no idea how to do that. So if you're writing your own, you can do:
require 'rubygems'
require 'gem-name-here'
If you're running someone else's code, you can do it on the command line with:
ruby -r rubygems script.rb
Also, there's an environment variable Ruby uses to determine what it should load up on startup:
export RUBYOPT=rubygems
(from http://www.rubygems.org/read/chapter/3. The environment variable thing was pointed out to me by Orion Edwards)
(If "require 'rubygems' doesn't work for you, however, this advice is of limited help :)
There is no standard for what the file you need to include is. However there are some commonly followed conventions that you can can follow try and make use of:
Often the file is called the same
name as the gem. So require mygem
will work.
Often the file is
the only .rb file in the lib
subdirectory of the gem, So if you
can get the name of the gem (maybe
you are itterating through
vendor/gems in a pre 2.1 rails
project), then you can inspect
#{gemname}/lib for .rb files, and
if there is only one, its a pretty
good bet that is the one to require
If all of that works, then all you can do is look into the gem's directory (which you can find by running gem environment | grep INSTALLATION | awk '{print $4}' and looking in the lib directory, You will probably need to read the files and hope there is a comment explaining what to do
The require has to map to a file in ruby's path. You can find out where gems are installed by running 'gem environment' (look for INSTALLATION DIRECTORY):
kburton#hypothesisf:~$ gem environment
RubyGems Environment:
- RUBYGEMS VERSION: 1.2.0
- RUBY VERSION: 1.8.7 (2008-08-08 patchlevel 71) [i686-linux]
- INSTALLATION DIRECTORY: /usr/local/ruby/lib/ruby/gems/1.8
- RUBY EXECUTABLE: /usr/local/ruby/bin/ruby
- EXECUTABLE DIRECTORY: /usr/local/ruby/bin
- RUBYGEMS PLATFORMS:
- ruby
- x86-linux
- GEM PATHS:
- /usr/local/ruby/lib/ruby/gems/1.8
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :benchmark => false
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
- http://gems.rubyforge.org/
kburton#editconf:~$
You can then look for the particular .rb file you're attempting to require. Additionally, you can print the contents of $: from irb to see the list of paths that ruby will search for modules:
kburton#hypothesis:~$ irb
irb(main):001:0> $:
=> ["/usr/local/ruby/lib/ruby/site_ruby/1.8", "/usr/local/ruby/lib/ruby/site_ruby/1.8/i686-linux", "/usr/local/ruby/lib/ruby/site_ruby", "/usr/local/ruby/lib/ruby/vendor_ruby/1.8", "/usr/local/ruby/lib/ruby/vendor_ruby/1.8/i686-linux", "/usr/local/ruby/lib/ruby/vendor_ruby", "/usr/local/ruby/lib/ruby/1.8", "/usr/local/ruby/lib/ruby/1.8/i686-linux", "."]
irb(main):002:0>
Also rails people should remember to restart the rails server after installing a gem
You need to include "rubygems" only if you installed the gem using gem . Otherwise , the secret incantation would be to fire up irb and try different combinations . Also , you can pass the -I option to the ruby interpreter so that you include the instalation directory of the gem , in the LOAD_PATH .
Note that $LOAD_PATH is an array , which means you can add directories to it from within your script.
The question I'm really asking is why require does not take the name of the gem.
Installing a gem gets the files onto your system. It doesn't make any claims as to what those files will be called.
As laurie points out there are several conventions for how they are named, but there's nothing to enforce that, and many gem authors unfortunately don't stick to them.
Also, In the case that it doesn't, what's the easiest way to find the secret incantation to require the damn thing!?
Read the docs for your gem?
I find googling for rdoc gemname will usually find the official rdocs for your gem, which usually show you how to use it.
Memcache is perhaps not the best example, as they assume you'll be using it from rails, and the 'require' will have already been done for you, but most other ones I've seen have examples which show the correct 'require' incantations
I had this problem because I use rvm and was trying to use the wrong version of ruby. The gem in question needed 1.9.2 and I had set 2.0.0 as my default! Maybe a dumb error but one that someone else arriving on this page will probably have made.
An issue I just ran into was that the actual built gem was not including all the files that it should have.
The issue with files was that there was a syntax mistake in the in the gemspec, but no errors were thrown during the build.
Just adding this here in case anybody else runs into the same issue.
It could also be the gem name mismatch:
e.g.
dummy-spi-0.1.1/lib/spi.rb should be named dummy-spi-0.1.1/lib/dummy-spi.rb
then you can
require 'dummy-spi'
I too had this problem since installing OS X Lion, and found that even if I ran the following code I would still get the warning message.
require 'rubygems'
require 'nokogiri'
I tried loads of solutions posted here and on the web, but in the end my work around solution was to simply follow the instructions at http://martinisoftware.com/2009/07/31/nokogiri-on-leopard.html to reinstall LibXML & LibXSLT from source, but ensuring the version of LibXML I installed matched the one that was expected by Nokogiri.
Once I had done that, the warnings went away.
Watch source of gem and check lib directory. If there is no rb file then you must point to gem main rb file in subdirectory:
require 'dir/subdir/file'
for /lib/dir/subdir/file.rb.