Cannot install Puma gem on Ruby on Rails

Question

I'm trying to install the puma gem, but when I run

gem install puma 

I get this error message:

Temporarily enhancing PATH to include DevKit Building native extensions.  This could take a while... ERROR:  Error installing puma:         ERROR: Failed to build gem native extension.      C:/Ruby193/bin/ruby.exe extconf.rb creating Makefile  make                                                 generating puma_http11-i386-mingw32.def                               compiling http11_parser.c        ext/http11/http11_parser.rl: In function 'puma_parser_execute':   ext/http11/http11_parser.rl:111:3: warning: comparison between signed and unsigned integer   expressions     compiling io_buffer.c    io_buffer.c: In function 'buf_to_str':              io_buffer.c:119:3: warning: pointer targets in passing argument 1 of 'rb_str_new'      differ in signedness              c:/Ruby193/include/ruby-1.9.1/ruby/intern.h:653:7: note: expected 'const char *' but argument is of type 'uint8_t *'                     compiling mini_ssl.c                                          In file included from mini_ssl.c:3:0:                                         c:/Ruby193/include/ruby-1.9.1/ruby/backward/rubyio.h:2:2: warning: #warning use "ruby/io.h" instead of "rubyio.h"               mini_ssl.c:4:25: fatal error: openssl/bio.h: No such file or directory                compilation terminated.                      make: *** [mini_ssl.o] Error 1               Gem files will remain installed in C:/Ruby193/lib/ruby/gems/1.9.1/gems/puma-2.6.0 for inspection. Results logged to C:/Ruby193/lib/ruby/gems/1.9.1/gems/puma-2.6.0/ext/puma_http11/gem_make.out 

Adding gem 'puma' to my Gemfile and running bundle install isn't an option, because that just doesn't work with any gem and gives me an error message (which is a separate issue, one that I've circumvented with the other gems I've used by installing them via gem install).

Answer 1

Came across very same issue.

sudo apt-get install libssl-dev 

fixed it for me.