NAME
state
SYNOPSIS
platform agnostic persistent state for ruby processes based on sqlite
DESCRIPTION
state provides an extremely simple to use state mechanism for ruby programs
which require state between invocations. the storage is based on sqlite and
is therefore platform agnostic. using state is no more difficult that using
a hash - only that hash will persist between invocations your ruby program.
see the samples and specs for details.
INSTALL
gem install state
URIS
http://codeforpeople.com/lib/ruby/
http://rubyforge.org/projects/codeforpeople/
SAMPLES
<========< sample/a.rb >========>
~ > cat sample/a.rb
require 'state'
# state provides persistent state for processes. usage requires simply
# accesses the state in a hash-like way.
···
#
# one process can create state
#
child do
State.clear
State['key'] = 'value'
end
# and later processes can have access to it
#
2.times do |i|
child do
value = State['key']
puts "child[#{ i }] => #{ value.inspect }"
end
end
BEGIN {
# we use fork just for demonstation, but this works on windows too 
#
def child &block
Process.waitpid fork(&block)
end
}
~ > ruby sample/a.rb
child[0] => "value"
child[1] => "value"
<========< sample/b.rb >========>
~ > cat sample/b.rb
require 'state'
# state will store it's db in a subdirectory (.state) of your home directory,
# the default database is ~/.state/global, but you may specify a name to
# create a new database
#
db = State.for 'foobar'
db.clear
puts db.path
10.times{|i| db[i] = i}
puts db.keys.inspect
~ > ruby sample/b.rb
/Users/ahoward/.state/foobar
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
<========< sample/c.rb >========>
~ > cat sample/c.rb
require 'state'
# of course you can specify and absolute path
#
db = State.for :path => '/tmp/state'
db.clear
puts db.path
~ > ruby sample/c.rb
/tmp/state
<========< sample/d.rb >========>
~ > cat sample/d.rb
require 'state'
# in general the interface for state is like that of a hash, see the specs for
# more details
db = State.for 'foobar'
db.clear
10.times{|i| db[i] = i**2}
5.times{|i| db.delete i}
p db.keys
p db.values
# use the update method for atomic read-update of a key/val pair
db['key'] = 42
p :current => db['key']
db.update 'key' do |old|
p :old => old
new = 42.0
end
p :update => db['key']
~ > ruby sample/d.rb
[5, 6, 7, 8, 9]
[25, 36, 49, 64, 81]
{:current=>42}
{:old=>42}
{:update=>42.0}
HISTORY
0.4.2
initial version
AUTHORS
ara.t.howard
a @ http://codeforpeople.com/
--
we can deny everything, except that we have the possibility of being better. simply reflect on that.
h.h. the 14th dalai lama