I've searched on Google, and I just found the uses of gem. As in, gem install, etc.
Are gems collections of .rb scripts?
If I build a series of scripts, for example that wraps the functionality of Google translate, is the preferred way of distributing that for usage a gem?
If not, how would I distribute this code?
According to RubyGems Wiki - RubyGems is a package manager for the Ruby programming language that provides a standard format for distributing Ruby programs and libraries (in a self-contained format called a "gem"), a tool designed to easily manage the installation of gems, and a server for distributing them.
The gem command is used to build, upload, download, and install Gem packages.
Gem Usage
RubyGems is very similar to apt-get, portage, and yum in functionality.
Installation:
gem install mygem
Uninstallation:
gem uninstall mygem
Listing installed gems:
gem list --local
Gem Package Building
The gem command may also be used to build and maintain .gemspec and .gem files.
Build .gem from a .gemspec file:
gem build mygem.gemspec
For more info, refer to RubyGems Manuals.
Here are some nice tutorials :)
http://railscasts.com/episodes/135-making-a-gem
http://railscasts.com/episodes/245-new-gem-with-bundler
A gem is a module/Library that you can install and use in every project on your server.
A plugin is a module/Library that you can use inside your project
Indeed, if you make some code what you like to share you can make a gem or plugin of it. You can publish it on for example github.com. You can check the source of the existing gems on github if you like to know how to make a gem as well.
Gem Package Building
Step : gem build your_gem_name.gemspec
simple steps follow click here
Related
I am wondering, while I'm sifting through samples, how I locate the source library when installing gems. For example, I have
require 'oauth2'
and to install, I run
gem install oauth2
What repository is pulled from for gem installs? I want to use reflection to reverse engineer some of the calls in the samples.
By default gem pulls from Rubygems, the main gem repository, but you can install from anywhere if you give it a URL or use the --source option to specify an alternate source. Some prefer to use private gem hosting for their dependencies.
Why not use a Gemfile to manage your dependencies? It makes it a lot more clear:
source 'https://rubygems.org/'
gem 'oauth2'
Then you install:
bundle install
Then you can see where it got installed:
bundle show oauth2
From there you can look at the source. You can also look at the gem listing page for oauth2 where links to documentation and source are provided.
There are a few useful options for looking at source code for ruby gems.
As #tadman has mentioned you generally can expect the default gem source to be hosted at https://rubygems.org and using Bundler is also highly recommended.
In many cases the open source code will be hosted on https://github.com. I tend to prefer to fork the gem source and download my fork locally where I can analyze it in my editor without fear of accidentally breaking anything since your forked repo will contain the full git history/repo etc.
If you're new to ruby, I would highly recommend you use a ruby version manager, i.e. RVM or perhaps RBENV, although I tend to find RVM a bit simpler and less problematic.
My other personal favorite ruby code hacking/inspecting tool is PRY
I'm developing a couple of private gems and I think I don't understand correctly the PATH/GEM_PATH and/or Bundler/RVM installation flow, would love if someone could chip in.
I have a repository with two gems (A & B for simplicity sake). I've developed the gems using the scaffolding + following the guidelines provided by this bundler tutorial.
Thanks to the Bundler project I have a few Rakefile tasks like rake build, rake install, rake install:local and rake release. Because of the private nature of these gems I can't release them to RubyGems (and we haven't looked into hosting our rubygems).
My machines are using RVM to manage ruby versions and Bundler version 1.15.1
What I want to do: Assuming a new machine/developer trying out the project, ideally we would cd into each of the subfolders (currently 2, gem A and gem B), run rake install and after that we should have the gems available system wide for the current user.
What is happening: The gems are built and work properly, but they are only available inside the subfolder of each gem i.e. gem A is only available inside the subfolder A and gem B is only available inside subfolder B.
What I've tried: So, after rake build/install/install:local a new .gem file is generated under pkg. I've tried to manually install the "compiled" file using gem install pkg/A.gem, gem install --local pkg/A.gem and gem install --local --user-install pkg/A.gem without success. (there are plenty of SO questions/answers about this)
I believe this has something to do with the PATH variables, but like I said before I don't fully understand the way they are managed. I get the following results from these commands:
# Our gem
> gem which A
/home/ubuntu/.rvm/gems/ruby-2.4.0/gems/A-0.1.8/lib/A.rb
# Pry, available globally
> gem which pry
/home/ubuntu/.rvm/gems/ruby-2.4.0/gems/pry-0.11.1/lib/pry.rb
I've been lost and frustrated for far too long now, any help is appreciated. Also open to hear suggestions of better private gem installation flows :)
Yes, it has something to do with your PATH variables. Your installation seems to be good.
I advise you to first affirm your gems installation path with:
echo $GEM_HOME
The double check your PATH to ensure its present and also confirm that the GEM home is also where the gem got installed into from the rake install
echo $PATH
If not, put it in your path and you should be fine with something like this:
echo PATH=$PATH:$GEM_HOME >> ~/.bashrc
source ~/.bashrc
Build your gem as per that guide you linked. You should end up with a gem file. Distribute this as you see fit (I use rsync/crontab to download newer gem versions but anything goes). User can install the gem as follows:
gem install --user-install /path/to/your/file.gem
This will install the gem in the user's ~/.gem/ruby/<version>/gems/<your-gem-name> directory.
Tried it with an empty gem (foodie, as in that example guide) and it works fine. But if you don't specify the --user-install parameter it will try to install in the system ruby dir (/usr/lib/ruby/gems...)
I'm working on a command line tool (a ruby gem) to quickly and easily generate custom jekyll repositories from some basic user input for my company. I would like to add a feature where the gem can automatically build the repo and output the finished directory, but the jekyll gem doesn't seem to provide any internal ruby interface to do that, at least not one that would be easy to implement.
Is there a way I could have my gem call their gem as a program, i.e. system 'jekyll build', but without having to worry about whether or not the user has the jekyll gem installed?
You can add jekyll to your gems list of dependencies, by adding the following to your gem's .gemspec file. That means whenever someone installs your gem, jekyll would also be installed.
spec.add_dependency 'jekyll'
I started developing ruby lately and I really like it, But I feel somehow lost. I developed a script that does "whatever" and that scripts requires many gems like nokogiri and colorize. I now want to deploy the script, so after reading a while I found many people saying that deploying as a gem is the best approach. So my question is simple? Is there any tool that I can use to create a gem of my script file and include all the gem dependencies(nokogiri) in the new gem?
I am using ubuntu!
Thanks alot
Building a gem consists of basically creating a simple directory structure for your script, and a special file known as a gemspec that will list all its dependencies. That gemspec can be used with rubygems to create a gem file (*.gem), which can be installed using rubygems or uploaded to rubygems.org for public consumption.
There are several tools that automate part of this process. A relatively simple one is the Bundler gem, which will both take care of dependencies during development, and make it easy for you to package your gem. This article contains enough information to get you started with gem development using bundler.
The best way to make a gem is to use the bundler program to build a skeleton:
# bundler gem (gem_name)
bundler gem geil_gem
This will create a template gemspec file and give you the basic structure needed for your gem to have a setup command, a console and be ready to build into a working gem (both found in the bin folder of your skeleton project). From here you can add a command binary or build out the gem as a library using the lib directory or start with tests by adding rspec to the gemspec and creating a test folder.
I am trying to install the mechanize gem that is supposed to work with 1.9 from here: http://github.com/kemiller/mechanize but I do not know how to add it manually.
I am using Windows, I could just copy the folder to the gems directory, but how do I initialize it?
I'm not sure I understand the problem. gem install mechanize doesn't work? It produces version 0.9.3 for me, which matches the gemspec of the library you linked to.
EDIT: you're on 1.9. I knew that. Disregard my hasty post, not familiar enough with Windows to offer any help on building the extensions.
I would use the bundler gem using the command gem install bundler. This will create a file called Gemfile in your project directory where you can put your dependencies for the specific project that you are working on. In the Gemfile, you will need to specify gem mechanize. If you want a specific version include ~> VERSION after. After, run the command bundle install. This will install the gem you want and use it in your project.