如何获取Ruby中已被'required'使用的文件列表？

Question

这纯粹是一个实验，但我想知道是否有可能通过某种元编程获得require'd宝石的列表。例如，假设我有：

require 'rubygems' 
require 'sinatra' 
require 'nokogiri' 

# don't know what to do here 

我如何可以打印出在运行时以下？

this app needs rubygems, sinatra, nokogiri 

Answer 1

你不能这样做完全是，因为需要一个文件可能需要别人和Ruby不能告诉你需要是文件和其他人所需要的文件之间的差异。

你可以检查出$LOADED_FEATURES列出所有需要的东西。但是如果你想明确指定依赖关系，你应该使用Bundler。

这里是在宝石名称猜测和枚举一切彻底不完美的方式：

ruby-1.9.2-p180 :001 > $LOADED_FEATURES. 
    select { |feature| feature.include? 'gems' }. 
    map { |feature| File.dirname(feature) }. 
    map { |feature| feature.split('/').last }. 
    uniq.sort 
=> ["1.9.1", "action_dispatch", "action_pack", "action_view", "actions", "active_model", "active_record", "active_support", "addressable", "agent", "array", "aws", "builder", "bundler", "cache_stores", "cancan", "cdn", "class", "client", "common", "compute", "connection", "control", "controllers", "core", "core_ext", "core_extensions", "css", "data_mapper", "decorators", "dependencies", "dependency_detection", "deprecation", "devise", "digest", "dns", "encodings", "encryptor", "engine", "errors", "excon", "ext", "failure", "faraday", "fields", "fog", "formatador", "geographer", "haml", "hash", "helpers", "heroku_san", "hmac", "hooks", "hoptoad_notifier", "html", "http", "i18n", "idna", "importers", "inflector", "initializers", "instrumentation", "integrations", "interpolate", "interval_skip_list", "jquery-rails", "json", "kaminari", "kernel", "lib", "mail", "metric_parser", "mime", "mixins", "model_adapters", "models", "module", "mongo_mapper", "mongoid", "multibyte", "new_relic", "node", "nokogiri", "numeric", "oauth", "object", "omniauth", "orm_adapter", "package", "parser", "parsers", "plugin", "pp", "providers", "queued", "rack", "rails", "railtie", "redis", "request", "request_proxy", "resp ruby-1.9.2-p180 :008 >onse", "resque", "retriever_methods", "routing", "ruby_extensions", "ruby_flipper", "rubygems", "runtime", "samplers", "sass", "sax", "script", "scss", "selector", "sequel", "ses", "shell", "signature", "simple_geo", "state_machine", "stats_engine", "storage", "strategies", "string", "tar_reader", "template", "terremark", "thor", "tokens", "tree", "treetop", "twitter", "us", "util", "vendor", "version_specific", "visitors", "warden", "xml", "xml_mini", "xpath", "xslt"] 

Answer 2

这里有一个办法让所有的呼叫需要。创建这个文件：show_requires.rb

alias :orig_require :require 
def require s 
    print "Requires #{s}\n" if orig_require(s) 
end 

然后用

红宝石开始你的应用-r show_requires.rb myapp.rb

这会产生这样的：

C:\code\test>ruby -r show_requires.rb test.rb 
Requires stringio 
Requires yaml/error 
Requires syck 
Requires yaml/ypath 
Requires yaml/basenode 
Requires yaml/syck 
Requires yaml/tag 
Requires yaml/stream 
Requires yaml/constants 
Requires date/format 
Requires date 
Requires yaml/rubytypes 
Requires yaml/types 
Requires yaml 
Requires etc 
Requires dl 
Requires rbreadline 
Requires readline 

如果您只想要顶层需求，请添加全局以跟踪嵌套层次：

$_rq_lvl = 0 
alias :orig_require :require 
def require s 
    $_rq_lvl+=1 
    print "Requires #{s}\n" if orig_require(s) and $_rq_lvl == 1 
    $_rq_lvl -=1 
end 

然后你得到：

C:\code\test>ruby -r require_test.rb test.rb 
Requires yaml 
Requires readline