Add basic OAuth client

#4

lib/zotero.rb

@@ -1,5 +1,22 @@
 require "zotero/version"
 
+gem 'oauth', '>= 0.5.1'
+require oauth
+
 module Zotero
-  # Your code goes here...
+  @default_site = 'https://api.zotero.org' # Version can be appended here, or passed in by the user
+
+  # Will create an OAuth Consumer for you.
+  #
+  # You have to register your application on Zotero.org to get a consumer token and secret.
+  #
+  # Default provider site is http://api.zotero.org
+  def self.consumer(consumer_token, consumer_secret, site = @default_site)
+    return OAuth::Consumer.new(consumer_token, consumer_secret, {
+      :site               => site,
+      :request_token_path => "/oauth/request_token",
+      :access_token_path  => "/oauth/access_token",
+      :authorize_path     => "/oauth/authorize"
+    })
+  end
 end

lib/zotero/public_oauth_access_token.rb

@@ -0,0 +1,35 @@
+module Zotero
+
+  # Subclass to force API users to pass a consumer key with each request.
+  class PublicOAuthAccessToken < OAuthActiveResource::FakeOAuthAccessToken
+
+    attr_accessor :token, :secret
+    def initialize(key)
+      @key    = key
+      @token = "public #{key}"
+      @secret = 'Anonymous'
+
+      # ensure that keys are symbols
+      @options = @@default_options
+    end
+    def request(http_method, path, token = nil, request_options = {}, *arguments)
+      # Force a relative path from an absolute path
+      if path !~ /^\//
+        @http = create_http(path)
+      end
+      _uri = URI.parse(path)
+
+      # Append the consumer key to the request
+      if _uri.query.nil?
+        _uri.query = "consumer_key=#{@key}"
+      else
+        _uri.query += "&consumer_key=#{@key}"
+      end
+
+      path = "#{_uri.path}#{_uri.query ? "?#{_uri.query}" : ""}"
+      rsp = http.request(create_http_request(http_method, path, token, request_options, *arguments ))
+
+      rsp
+    end
+  end
+end