Class: LongURL::Expander

Inherits:
Object
  • Object
show all
Defined in:
lib/longurl/expander.rb

Overview

URL Expander class.

Will use Service and Direct classes to expand an url. Each call to external services is cached to save time and cache object is customizable. You can for example use MemCache for the cache. it will allow different instances of Expander and Service to share the same cache.

Examples

# Simple usage
e = LongURL::Expander.new
e.expand("http://tinyurl.com/1c2")                              # => "http://www.google.com"
e.expand("http://tinyurl.com/blnhsg")                           # => "http://www.google.com/search?q=number+of+horns+on+a+unicorn&ie=UTF-8"
e.expand("http://is.gd/iUKg")                                   # => "http://fabien.jakimowicz.com"

# not expandable urls
e.expand("http://www.linuxfr.org")                              # => "http://www.linuxfr.org"

# not expandable urls, calling longurl.org only
e.expand("http://www.linuxfr.org", :direct_resolution => true)  # => "http://www.linuxfr.org/pub"

# not expandable urls, direct resolution only
e.direct_resolution("http://www.linuxfr.org")                   # => "http://www.linuxfr.org/pub"

# MemCache as cache
e = LongURL::Expander.new(:cache => MemCache.new("localhost:11211", :namespace => "LongURL"))
e.expand("http://is.gd/iUKg")                                   # => "http://fabien.jakimowicz.com"

Exceptions

  • LongURL::InvalidURL : will occurs if given url is nil, empty or invalid

  • LongURL::NetworkError : a network (timeout, host could be reached, …) error occurs

  • LongURL::UnknownError : an unknown error occurs

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Expander

Initialize a new Expander.

Options

  • :cache: define a cache which Expander can use. It must implements [] and []= methods. It can be disabled using false.

  • :first_only : if true, users all-redirects option to the API to fetch only the first redirect instead of following all of them. Useful to identify the original URL that was shortened, not the destination.



45
46
47
48
49
50
51
52
53
54
55
56
 
# File 'lib/longurl/expander.rb', line 45

def initialize(options = {})
  # OPTIMIZE : This code is a complete duplicate of cache handling in service.
  if options[:cache].nil?
    @@cache = Hash.new
  elsif options[:cache] == false
    @@cache = nil
  else
    @@cache = options[:cache]
  end
  @@service = Service.new(:cache => @@cache)
  @first_only = options[:first_only]
end

Instance Attribute Details

#first_only ⇒ Object

Returns the value of attribute first_only.



36
37
38
 
# File 'lib/longurl/expander.rb', line 36

def first_only
  @first_only
end

Instance Method Details

#direct_resolution(url) ⇒ Object

Try to directly resolve url using LongURL::Direct to get final redirection. This call is cached.



68
69
70
71
72
73
74
75
 
# File 'lib/longurl/expander.rb', line 68

def direct_resolution(url)
  # OPTIMIZE : this code is almost identical as the one in service for handling service retrieval.
  if @@cache
    @@cache[url] ||= Direct.follow_redirections(url)
  else
    Direct.follow_redirections(url)
  end
end

#expand(url, options = { }) ⇒ Object

Expand given url using LongURL::Service class first and then try a direct_resolution, unless :direct_resolution is set to false in options hash.



60
61
62
63
64
 
# File 'lib/longurl/expander.rb', line 60

def expand(url, options={ })
  @@service.query_supported_service_only url, :first_only => first_only
rescue UnsupportedService
  options[:direct_resolution] == false ? raise(UnsupportedService) : direct_resolution(url)
end

#expand_each_in(text, options = {}) ⇒ Object

Expand all url in the given string, if an error occurs while expanding url, then the original url is used. options accepts same options as expand, see expand for more details.



79
80
81
82
83
84
85
86
87
88
89
90
91
92
 
# File 'lib/longurl/expander.rb', line 79

def expand_each_in(text, options = {})
  text.gsub(ShortURLMatchRegexp) do |shorturl| 
    begin
      expand shorturl
    rescue  InvalidURL,
            NetworkError,
            TooManyRedirections,
            UnknownError,
            UnsupportedService,
            JSON::ParserError
      shorturl
    end
  end
end