I get this error when installing a gem: “ERROR: While executing gem … (Zlib::GzipFile::Error)” [duplicate]

Answer 1

Something isn't set up properly to fetch the gem from GitHub.

try gem fetch -V

steve@macpro:~$ gem fetch blackbook --version ">= 1.0.7" --source http://github.com/tamoyal/blackbook/tree/master -V
GET 301 Moved Permanently: http://github.com/tamoyal/blackbook/tree/master/specs.4.8.gz
GET 200 OK: http://github.com/tamoyal/blackbook/tree/master/
ERROR:  While executing gem ... (Zlib::GzipFile::Error)
    not in gzip format

You're getting the "not in gzip format" error because gem can't fetch specs.4.8.gz. GitHub returns a 301 redirect back to your project home page, which of course isn't what it wants and isn't gzipped.

Sorry I can't help you further, but I haven't build a gem, much less on GitHub.

Answer 2

This kind of error was coming to me also. Finally I found that the Proxy settings was not correct. Please check that you can reach the gem server from command line. Just ping it :)

Answer 3

You didn't mentioned your system. However it happens on Ubuntu if you do not have zlib library. The solution:

sudo apt-get install libzlib-ruby

P.S. I know the question is more than 2 years old. I just hope it might help someone else.

Answer 4

Possibly your gem sources are not set up correctly. http://gems.rubyforge.org/ used to be a correct path to rubygems, but it no longer exists.

run this command:

gem sources

If you see http://gems.rubyforge.org/ in your list run:

gem sources -r http://gems.rubyforge.org/

You may also need to add in rubygems.org as a valid source

gem sources -a http://rubygems.org