我正在阅读“Crafting Rails”一书，我已经遇到了障碍我在最后一章（第7章）中无法克服
当我尝试在7.3结束时运行项目时，我得到：
MultiJson::DecodeError - 756: unexpected token at '"Validation failed: %{errors}"':
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/json-1.6.5/lib/json/common.rb:148:in `parse'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/json-1.6.5/lib/json/common.rb:148:in `parse'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/multi_json-1.1.0/lib/multi_json/engines/json_common.rb:9:in `decode'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/multi_json-1.1.0/lib/multi_json.rb:79:in `decode'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/activesupport-3.2.2/lib/active_support/json/decoding.rb:12:in `decode'
/Users/john/Manuals/Rails/Crafting Rails/Chap7/translator-old/lib/translator/app.rb:32:in `locale_value'
/Users/john/Manuals/Rails/Crafting Rails/Chap7/translator-old/lib/translator/app.rb:55:in `block in evaluate_source'
/Users/john/Manuals/Rails/Crafting Rails/Chap7/translator-old/lib/translator/app.rb:54:in `each'
/Users/john/Manuals/Rails/Crafting Rails/Chap7/translator-old/lib/translator/app.rb:54:in `evaluate_source'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/tilt-1.3.3/lib/tilt/template.rb:209:in `instance_eval'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/tilt-1.3.3/lib/tilt/template.rb:209:in `evaluate_source'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/tilt-1.3.3/lib/tilt/template.rb:144:in `cached_evaluate'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/tilt-1.3.3/lib/tilt/template.rb:127:in `evaluate'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/tilt-1.3.3/lib/tilt/haml.rb:24:in `evaluate'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/tilt-1.3.3/lib/tilt/template.rb:76:in `render'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:636:in `render'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:532:in `haml'
/Users/john/Manuals/Rails/Crafting Rails/Chap7/translator-old/lib/translator/app.rb:19:in `exhibit_translations'
/Users/john/Manuals/Rails/Crafting Rails/Chap7/translator-old/lib/translator/app.rb:10:in `block in <class:App>'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:1211:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:1211:in `block in compile!'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:785:in `[]'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:785:in `block (3 levels) in route!'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:801:in `route_eval'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:785:in `block (2 levels) in route!'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:822:in `block in process_route'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:820:in `catch'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:820:in `process_route'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:784:in `block in route!'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:783:in `each'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:783:in `route!'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:886:in `dispatch!'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:719:in `block in call!'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:871:in `block in invoke'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:871:in `catch'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:871:in `invoke'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:719:in `call!'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:705:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-protection-1.2.0/lib/rack/protection/xss_header.rb:22:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-protection-1.2.0/lib/rack/protection/path_traversal.rb:16:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-protection-1.2.0/lib/rack/protection/json_csrf.rb:17:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-protection-1.2.0/lib/rack/protection/base.rb:47:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-protection-1.2.0/lib/rack/protection/xss_header.rb:22:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/nulllogger.rb:9:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/head.rb:9:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:1334:in `block in call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:1416:in `synchronize'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sinatra-1.3.2/lib/sinatra/base.rb:1334:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/journey-1.0.3/lib/journey/router.rb:68:in `block in call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/journey-1.0.3/lib/journey/router.rb:56:in `each'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/journey-1.0.3/lib/journey/router.rb:56:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/routing/route_set.rb:594:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/sass-3.1.15/lib/sass/plugin/rack.rb:54:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/etag.rb:23:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/conditionalget.rb:25:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/head.rb:14:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/params_parser.rb:21:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/flash.rb:242:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:205:in `context'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:200:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/cookies.rb:338:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/activerecord-3.2.2/lib/active_record/query_cache.rb:64:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:443:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:405:in `_run__2584460681594678013__call__1225515721622234840__callbacks'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:405:in `__run_callback'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:81:in `run_callbacks'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/callbacks.rb:27:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/reloader.rb:65:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.2.2/lib/rails/rack/logger.rb:26:in `call_app'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.2.2/lib/rails/rack/logger.rb:16:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/request_id.rb:22:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/methodoverride.rb:21:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/runtime.rb:17:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/activesupport-3.2.2/lib/active_support/cache/strategy/local_cache.rb:72:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/lock.rb:15:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.2.2/lib/action_dispatch/middleware/static.rb:61:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.2.2/lib/rails/engine.rb:479:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.2.2/lib/rails/application.rb:220:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/content_length.rb:14:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.2.2/lib/rails/rack/log_tailer.rb:14:in `call'
/Users/john/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.4.1/lib/rack/handler/webrick.rb:59:in `service'
/Users/john/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
/Users/john/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
/Users/john/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'
我尝试从该字符串中删除所有符号，但没有快乐 - 同样的问题。知道这里可能出了什么问题吗？我完全复制了＆amp;从书中粘贴，所以我认为这不是一个错字。可能是一个redis问题（我不熟悉它），但似乎工作正常。
赞赏任何想法
答案 0 :(得分：2)
在宝石文件声明中
gem'yajl-ruby'
它用于将多个JSON对象与流或字符串连续解析和编码。
需要'yajl / json_gem'
在config / application.rb