How to list gem dependencies for some non-intalled gem?

Question

I'm trying to install rails in my Arch Linux computer. I'm running into network problems that I know that have already appeared here. I didn't find a satisfactory answer anywhere.

Since everytime I try, gem fails downloading a different gem (I think all are dependencies of rails), I want to try to download these separately, and only when I have all installed, try to install rails again.

This is what is looks to try to install rails:

[lurch ~]$ time gem install rails
ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)
    Errno::ETIMEDOUT: Connection timed out - connect(2) for "api.rubygems.org" port 443 (https://api.rubygems.org/api/v1/dependencies?gems=rails-html-sanitizer)

real    4m59.698s
user    0m1.170s
sys     0m0.117s


[lurch ~]$ gem install rails
ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)
    Errno::ETIMEDOUT: Connection timed out - connect(2) for "api.rubygems.org" port 443 (https://api.rubygems.org/quick/Marshal.4.8/thread_safe-0.3.4.gemspec.rz)


[lurch ~]$ gem install rails
ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)
    Errno::ETIMEDOUT: Connection timed out - connect(2) for "api.rubygems.org" port 443 (https://api.rubygems.org/api/v1/dependencies?gems=i18n)


[lurch ~]$ time gem install rails
ERROR:  While executing gem ... (Gem::RemoteFetcher::UnknownHostError)
    no such name (https://api.rubygems.org/api/v1/dependencies?gems=bundler)

real    1m28.495s
user    0m0.883s
sys     0m0.083s


[lurch ~]$ gem update --system
ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)
    Errno::ETIMEDOUT: Connection timed out - connect(2) for "s3.amazonaws.com" port 443 (https://api.rubygems.org/specs.4.8.gz)

Now, my question is: where can I get a list of all gem dependencies of rails? The gem dependency command doesn't work:

[lurch ~]$ gem dependency rails     
No gems found matching rails (>= 0)

In fact, this documentation page describes the gem dependency command as [emphasis mine] "Show the dependencies of an installed gem".

So, just to be clear, my question is: How to get a list of all gem dependencies of some specific gem? Of course, if someone manages to solve the strange network problem in the command gem install rails, I will be very happy also.

EDIT: version information

[lurch ~]$ uname -a
Linux lurch 3.17.6-1-ARCH #1 SMP PREEMPT Sun Dec 7 23:43:32 UTC 2014 x86_64 GNU/Linux
[lurch ~]$ gem --version
2.2.2
[lurch ~]$ ruby --version
ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-linux]

Answer 1

I know that this is a bit of a necro, but I think that you can use gem install --explain rails.

from http://guides.rubygems.org/command-reference/#gem-install

-​-explain - Rather than install the gems, indicate which would be installed

You may have to run that command from another system that CAN access the rubygems.org server, get the list of gems, pull them down, and install them on your system instead of hitting rubygems directly (till you get your network problem figured out)

Answer 2

Found the real answer to the question: RubyGems.org

gem dependency rails
Gem rails-4.1.6
  actionmailer (= 4.1.6)
  actionpack (= 4.1.6)
  actionview (= 4.1.6)
  activemodel (= 4.1.6)
  activerecord (= 4.1.6)
  activesupport (= 4.1.6)
  bundler (< 2.0, >= 1.3.0)
  railties (= 4.1.6)
  sprockets-rails (~> 2.0)

or Gemfile.lock

rails (4.1.6)
  actionmailer (= 4.1.6)
  actionpack (= 4.1.6)
  actionview (= 4.1.6)
  activemodel (= 4.1.6)
  activerecord (= 4.1.6)
  activesupport (= 4.1.6)
  bundler (>= 1.3.0, < 2.0)
  railties (= 4.1.6)
  sprockets-rails (~> 2.0)