如何获取 Ruby 中“必需"的文件列表? [英] How do I get a list of files that have been `required` in Ruby?

问题描述

这纯粹是一个实验，但我想知道是否可以通过某种元编程在运行时获取 require 的 gem 列表.例如，假设我有:

This is purely an experiment, but I'm wondering if it's possible to get a list of the require'd gems at runtime via some kind of metaprogramming. For example, say I have:

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

# don't know what to do here

如何在运行时打印出以下内容?

How can I print out the following at runtime?

this app needs rubygems, sinatra, nokogiri

推荐答案

你不能完全做到这一点，因为需要一个文件可能需要其他文件，而 Ruby 无法区分文件之间的区别你 需要和其他人需要的文件.

You can't do this exactly, because requiring one file may require others, and Ruby can't tell the difference between the file that you required and the file that someone else required.

您可以查看 $LOADED_FEATURES 以获取所需的每项内容的列表.但是如果你想明确指定依赖关系，你应该使用 Bundler.

You can check out $LOADED_FEATURES for a list of every single thing that's been required. But you should use Bundler if you want to specify dependencies explicitly.

这是猜测宝石名称并枚举所有内容的完全不完美的方法:

Here's a thoroughly imperfect way to guess at the gem names and enumerate everything:

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"] 

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