How to find Operating system

Ruby
1

Hi…
Here me looking for some help…
how to find web server’s operating system …

whether it is running under windows or linux…

Any helps

Thanks

2

On 08.04.2009 12:09, Newb N. wrote:

Here me looking for some help…
how to find web server’s operating system …

Do you mean remotely?

whether it is running under windows or linux…

It depends what the server in question is willing to provide as
information. You can try to look at HTTP response header “Server” and
draw your conclusions (if it is IIS then the server must be some kind of
Windows).

Kind regards

robert

3

You can reach into the ENV object for a whole load of information about
your
current execution environment:

ENV.to_hash.each do |key, value|
puts("#{key} - #{value}")
end

4

On Apr 8, 4:27 am, Eleanor McHugh [email protected]
wrote:

end
Thanks, Eleanor! If I may suggest an additional clause
(with meaning in both the individual and group sense):

require ‘rbconfig’
case Config::CONFIG[‘host_os’]
when /darwin/i
puts “Ah, Darwin :)”
when /linux-gnu/i
puts “GNU/Linux - The World Community expands Consciousness”
when /mswin|windows/i
raise “You call that an operating system?”
else
raise “I haven’t the foggiest”
end

5

On 8 Apr 2009, at 11:53, Ben L. wrote:

You can reach into the ENV object for a whole load of information
about your
current execution environment:

ENV.to_hash.each do |key, value|
puts(“#{key} - #{value}”)
end

Or you can use rbconfig:

require ‘rbconfig’
case Config::CONFIG[‘host_os’]
when /darwin/i
puts “Ah, Darwin :)”
when /mswin|windows/i
raise “You call that an operating system?”
else
raise “I haven’t the foggiest”
end

However be aware that if you’re using JRuby it will still report the
underlying OS which might not be as informative as you’d like so
you’ll also need to check other CONFIG options.

Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net

raise ArgumentError unless @reality.responds_to? :reason

6

On 8 Apr 2009, at 13:30, Mark S Bilk wrote:

raise "You call that an operating system?"

else
raise “I haven’t the foggiest”
end

grumble grumble GPL grumble ;p

Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net

raise ArgumentError unless @reality.responds_to? :reason

7

Hi,

Could anyone suggest an elegant way of doing something like:

$directXSDKBootstrapped = false

def bootstrapDirectXSDK
if !$directXSDKBootstrapped
bootstrapBuildToolsDirectory(“DirectX/#{DIRECTX_VERSION}”)
$directXSDKBootstrapped = true
$directXSDKBootstrapped.freeze
end
end

Obviously the intention is to only do something the first time it is
called. Maybe some little reusable util? I have a number of different
bootstrap functions I want to apply this to.

Cheers,
James

8

Don’t think of them as “functions”. Think of them as “methods”, and
always put
them inside classes.

James F. wrote:

$directXSDKBootstrapped.freeze

end
end

class Whatever
def bootstrapDirectXSDK
@@directXSDKBootstrapped ||=
bootstrapBuildToolsDirectory(“DirectX/#{DIRECTX_VERSION}”)
end
end

That’s teh “proxy pattern” in Ruby…

9

One way to do it, which requires a good understanding of
metaprogramming, could be as follows:

class Class

Replaces the method whose name is provided by a

method that calls the original one the first time it is called

and by a noop method for subsequent calls.

def one_call_only(method_name)
# implement me
end

end

class MyClass
def bootstrapDirectXSDK
bootstrapBuildToolsDirectory(“DirectX/#{DIRECTX_VERSION}”)
end
one_call_only :bootstrapDirectXSDK
end

I’m not sure it’s the simplest way to do it. I can sketch the actual
code of one_call_only if it helps.

blambeau

On Wed, Apr 8, 2009 at 4:29 PM, James F.

10

end
One way of doing this is as follows:

class Proc
def runs(n)
wrapped, count = self, 0
lambda { |*args|
count += 1
count <= n ? wrapped.call(*args) : nil
}
end
end

foo = lambda { |arg| puts arg }.runs(3)
#=> #Proc:0xb7d310dc@:33(irb)

foo[‘look!’]
look!
=> nil

foo[‘look!’]
look!
=> nil

foo[‘look!’]
look!
=> nil

foo[‘look!’]
=> nil

Notice nothing is printed the fourth time. So using this, you could
write
you function as:

bootstrapDirectXSDK = lambda {
bootstrapBuildToolsDirectory(“DirectX/#{DIRECTX_VERSION}”)
}.runs(1)

Which will only allow its contents to be executed once.

11

Look in the response headers, the server software should be there (and
often the OS)

Regards,
Henrik H.

12

I see I still have some way to go with ruby :slight_smile: Nice! Can’t believe how
quick you knocked that up…

13

I have to admit though, I don’t understand the ‘wrapped, count = self,
0’ line…

14

$directXSDKBootstrapped = false

def bootstrapDirectXSDK
if !$directXSDKBootstrapped
bootstrapBuildToolsDirectory(“DirectX/#{DIRECTX_VERSION}”)
$directXSDKBootstrapped = true
$directXSDKBootstrapped.freeze
end
end

You could redefine bootstrapDirectXSDK:

$directXSDKBootstrapped = false

def bootstrapDirectXSDK
bootstrapBuildToolsDirectory(“DirectX/#{DIRECTX_VERSION}”)
$directXSDKBootstrapped = true
$directXSDKBootstrapped.freeze
def bootstrapDirectXSDK
end
end

15

Ahh, thanks.

16

2009/4/8 James F. [email protected]

I have to admit though, I don’t understand the ‘wrapped, count = self, 0’
line…

That’s just parallel assignment, it’s equivalent to:

wrapped = self
count = 0

17

On 08.04.2009 16:29, James F. wrote:

Please do not hijack other threads.

Could anyone suggest an elegant way of doing something like:

$directXSDKBootstrapped = false

def bootstrapDirectXSDK
if !$directXSDKBootstrapped
bootstrapBuildToolsDirectory(“DirectX/#{DIRECTX_VERSION}”)
$directXSDKBootstrapped = true
$directXSDKBootstrapped.freeze

Freezing has no effect here because it does not prevent reassignment to
the variable.

end
end

Obviously the intention is to only do something the first time it is called Maybe some little reusable util?I have a number of different bootstrap functions I want to apply this to.

Why can’t you just invoke the initialization once and be done? If this
is in a file which is required then Ruby will take care of this
automatically.

Another solution:

class OnlyOnce
def initialize(&b)
raise “Need a block!” unless b
@block = b
end

def get
if @block
@val = block.call
@block = nil
end

 @val

end
end

$directXSDKBootstrapped = OnlyOnce.new do
bootstrapBuildToolsDirectory(“DirectX/#{DIRECTX_VERSION}”)
end

Cheers

robert

18

I like it, but you get a warning with -w…

19

On Wed, Apr 8, 2009 at 10:29 PM, James F.
[email protected] wrote:

Obviously the intention is to only do something the first time it is called. Maybe some little reusable util? I have a number of different bootstrap functions I want to apply this to.

sometimes, i apply ruby’s nested methods feature…

eg,

botp@jedi-hopeful:~$ cat test.rb
def only_once_dumper
def only_once
end
end

def only_once
puts “i ran once!”
only_once_dumper
end

only_once
only_once
only_once

botp@jedi-hopeful:~$ ruby test.rb
i ran once!
botp@jedi-hopeful:~$

kind regards -botp