Added two new middleware classes (UserAgent & Cache)

[glenux]

UserAgent

I think UserAgent is quite explicit, but here is an use case :

require 'spore/middleware/useragent'

foobar = Spore.new("foobar.json")
foobar.enable(Spore::Middleware::UserAgent, 
    :useragent => 'Mozilla/5.0 (X11; Linux x86_64; rv:2.0b4) Gecko/20100818 Firefox/4.0b4')
foobar.api_call(...)

Cache

A very simple example:

require 'spore/middleware/cache'

foobar = Spore.new("foobar.json")
foobar.enable(Spore::Middleware::Cache, :storage => {} )
foobar.api_call(...)

A more complex example, using files for cache

require 'spore/middleware/cache'
require 'base64'
require 'fileutils'

class DirectoryCache
    include Enumerable

    def initialize directory
        @root = File.expand_path directory

        FileUtils.mkdir_p @root if not File.exist? @root
    end

    def include? key
        path = _key_to_path key
        return (File.exist? path)
    end

    def []= key, value
        path = _key_to_path key
        File.open path, "w" do |fh|
            fh.puts value   
        end
    end

    def each &blk
        d = Dir.new @root
        d.each do |x|
            next if x == '.' or x == '..'
            yield x
        end
    end

    private

    def _key_to_path key
        path =  File.join @root, Base64.encode64(key)
        return path
    end

end

cache = DirectoryCache.new "cache.d"

foobar = Spore.new("foobar.json")
foobar.enable(Spore::Middleware::Cache, :storage => cache )
foobar.api_call(...)