I'm trying to install OpenGraph gem in ruby - ruby-on-rails

Question

I've searched entire web looking for a way to get over this error. But it won't budge. I installed all the libraries and dependencies according to my knowledge even uninstalled ruby and nokogiri and reinstalled again. But this error remains here.
Gem files will remain installed in /home/$User/.rbenv/versions/2.4.2/lib/ruby/gems/2.4.0/gems/nokogiri-1.4.7 for inspection.
Results logged to /home/$User/.rbenv/versions/2.4.2/lib/ruby/gems/2.4.0/extensions/x86_64-linux/2.4.0-static/nokogiri-1.4.7/gem_make.out
This is from the gem_make.out log file from this location -> /.rbenv/versions/2.4.2/lib/ruby/gems/2.4.0/extensions/x86_64-linux/2.4.0-static/nokogiri-1.4.7/gem_make.out
ERROR: Error installing opengraph:
ERROR: Failed to build gem native extension.
current directory: /home/$User/.rbenv/versions/2.4.2/lib/ruby/gems/2.4.0/gems/nokogiri-1.4.7/ext/nokogiri
/home/$User/.rbenv/versions/2.4.2/bin/ruby -r ./siteconf20171125-15877-nibcps.rb extconf.rb --with-nokogiri-dir=/home/$User/.rbenv/versions/2.4.2/lib/ruby/gems/2.4.0/gems/
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/home/$User/.rbenv/versions/2.4.2/bin/$(RUBY_BASE_NAME)
extconf.rb:10:in `<main>': uninitialized constant Config (NameError)
Did you mean? RbConfig
CONFIG
extconf failed, exit code 1
I'd be very thankful to you if you could tell me what's wrong with it. Is it a bug in OpenGraph.
P.S: I'm not using opengraph_parser because it has a fallback method. I need opengraph gem because I need to catch the exception.

Answer 1

It's not opengraph, but rather nokogiri.
Nokogiri is a dependency for opengraph.
https://rubygems.org/gems/opengraph/versions/0.0.4
So, it must be related on your machine not having the dependencies needed to support nokogiri (libxml2).
Install these dependencies on your machine (assuming your on Debian/Ubuntu):
sudo apt-get install build-essential patch ruby-dev zlib1g-dev liblzma-dev
Fedora/Red Hat/CentOS:
sudo yum install -y gcc ruby-devel zlib-devel
sudo yum install -y rubygem-nokogiri (alternative)
Then try installing nokogiri by gem install nokogiri
For other variants, or OS:
http://www.nokogiri.org/tutorials/installing_nokogiri.html
For Fedora 26:
Until further notice, install nokogiri version < 1.8