Getting Gem Version from Within a Gem

Ruby
1

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

Thanks!
-fREW

2

On 7/10/07, Frew S. [email protected] wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

Using ‘gem’ , you can execute sth. like:

gem list --local | grep <your_prog_name>

but i’m not sure, is it what you expect.

Best Regards, Kuba.

3

Kuba wrote:

On 7/10/07, Frew S. [email protected] wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

Using ‘gem’ , you can execute sth. like:

gem list --local | grep <your_prog_name>

but i’m not sure, is it what you expect.

Best Regards, Kuba.

So there’s not a variable inside the program that I can access that
contains the Gem info?

4

On Jul 10, 2007, at 09:37 , Frew S. wrote:

So there’s not a variable inside the program that I can access that
contains the Gem info?

Frew,

The usual method of accessing the version of a gem from within a
running Ruby app is:

GemConstName::Version::STRING

This works if the author followed convention.

5

Wayne E. Seguin wrote:

On Jul 10, 2007, at 09:37 , Frew S. wrote:

So there’s not a variable inside the program that I can access that
contains the Gem info?

Frew,

The usual method of accessing the version of a gem from within a
running Ruby app is:

GemConstName::Version::STRING

This works if the author followed convention.

I am the author of the application in question. I tested your
suggestion by doing a

puts GemConstName::Version::STRING

to see if it would have the variable defined by the gem system as
defined in my gemspec, but it didn’t work. Is there something I need to
do to make this work?

Thanks for your help!

-fREW

6

Frew S. wrote:

Kuba wrote:

On 7/10/07, Frew S. [email protected] wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

Using ‘gem’ , you can execute sth. like:

gem list --local | grep <your_prog_name>

but i’m not sure, is it what you expect.

Best Regards, Kuba.

So there’s not a variable inside the program that I can access that
contains the Gem info?

I think, it depends on your gems’ library/program.
There is no general variable (fix me if i’m wrong).

E.g.: In module ‘Inline’ is defined const. VERSION, so you can print
Inline::VERSION, but ‘rake’ defined const. RAKEVERSION

7

E.g.: In module ‘Inline’ is defined const. VERSION, so you can print
Inline::VERSION, but ‘rake’ defined const. RAKEVERSION

So what I really need to do here is define a constant in a separate file
as a module and include it in the gemspec and my other code. Is that
correct?

8

On Jul 10, 2007, at 11:13 , Wayne E. Seguin wrote:

SSH_REQUIRED = [1,0,10] SFTP_REQUIRED = [1,1,0]

Sorry, these aren’t required, they were specific to my gem.

9

On Jul 10, 2007, at 11:05 , Frew S. wrote:

Thanks for your help!
Frew, why yes there is!!! Thank you for clarifying the question. Tis
simple!

In lib/gem_name/version.rb place code like:

module GemName
module Version
# A method for comparing versions of required modules. It
expects two
# arrays as parameters, and returns true if the first is no more
than the
# second.
def self.check(expected, actual) #:nodoc:
good = false
if actual[0] > expected[0]
good = true
elsif actual[0] == expected[0]
if actual[1] > expected[1]
good = true
elsif actual[1] == expected[1] && actual[2] >= expected[2]
good = true
end
end

   good
 end

 MAJOR = 0
 MINOR = 1
 TINY  = 2

 STRING = [MAJOR, MINOR, TINY].join(".")

 SSH_REQUIRED = [1,0,10]
 SFTP_REQUIRED = [1,1,0]

end
end

Then require the version file in one of the main entry point files:

require “lib/gem_name/version”

Hope this helps! Gems are so much fun to develop.

10

Wayne E. Seguin wrote:

On Jul 10, 2007, at 11:05 , Frew S. wrote:

Thanks for your help!
Frew, why yes there is!!! Thank you for clarifying the question. Tis
simple!

In lib/gem_name/version.rb place code like:

module GemName
module Version
# A method for comparing versions of required modules. It
expects two
# arrays as parameters, and returns true if the first is no more
than the
# second.
def self.check(expected, actual) #:nodoc:
good = false
if actual[0] > expected[0]
good = true
elsif actual[0] == expected[0]
if actual[1] > expected[1]
good = true
elsif actual[1] == expected[1] && actual[2] >= expected[2]
good = true
end
end

   good
 end

 MAJOR = 0
 MINOR = 1
 TINY  = 2

 STRING = [MAJOR, MINOR, TINY].join(".")

 SSH_REQUIRED = [1,0,10]
 SFTP_REQUIRED = [1,1,0]

end
end

Then require the version file in one of the main entry point files:

require “lib/gem_name/version”

Hope this helps! Gems are so much fun to develop.

Ok, I want to ensure that I am doing this the correct way, so is this
right?

lib/delish/version.rb

module Delish

module Version
MAJOR = 0
MINOR = 7
TINY = 9

STRING = [MAJOR, MINOR, TINY].join(".")

end

end

11

Looks correct to me. You still might want to provide the check method
as it provides an interface for versioning checks.

So now you should be able to report the version from within your app
via:
Delish::Version::STRING

So if I did end up using the check method would I do something like this

Delish::Version::check(GTK::Version, Delish::Version::GTK_VERSION)

Some gtk code here

Or something like that?

What’s the use of this if the gemspec already has dependencies like
this?

Thanks again for your help!

-fREW

12

On Jul 10, 2007, at 11:24 , Frew S. wrote:

MINOR = 7
TINY  = 9

STRING = [MAJOR, MINOR, TINY].join(".")

end

end

Looks correct to me. You still might want to provide the check method
as it provides an interface for versioning checks.

So now you should be able to report the version from within your app
via:
Delish::Version::STRING

13

On Jul 10, 2007, at 08:24, Frew S. wrote:

TINY  = 9

STRING = [MAJOR, MINOR, TINY].join(".")

end

end

UGH!

KISS, or employ YAGNI.

module Delish

VERSION = ‘0.7.9’

end

You don’t need major/minor/tiny.

14

On Jul 9, 2007, at 23:40, Frew S. wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is
installed
from?

Gem.loaded_specs.map do |n,s| s.full_name end

Better to just have a VERSION constant somewhere, though.

15

On Jul 10, 2007, at 21:01 , Ryan D. wrote:

require ‘rubygems’
require ‘hoe’

require ‘./lib/blah.rb’

Hoe.new(“Blah”, Blah::VERSION) do |p| # this builds the gemspec and
defines a lot of commands

…

end

Frew,

If you don’t mind requiring Hoe then this is an excellent approach to
use.

16

On Jul 9, 2007, at 23:40 , Frew S. wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is
installed
from?

invert!

Have your program know what its version is and have your gemspec ask it:

=== lib/blah.rb

class Blah
VERSION = “1.2.3”

…

end

=== Rakefile

require ‘rubygems’
require ‘hoe’

require ‘./lib/blah.rb’

Hoe.new(“Blah”, Blah::VERSION) do |p| # this builds the gemspec and
defines a lot of commands

…

end

17

On Jul 11, 2007, at 14:11 , Wayne E. Seguin wrote:

require ‘./lib/blah.rb’

Hoe.new(“Blah”, Blah::VERSION) do |p| # this builds the gemspec
and defines a lot of commands

…

end

If you don’t mind requiring Hoe then this is an excellent approach
to use.

Huh? Even without hoe the point and the example still stand.