Ruby:如何将哈希转换为HTTP参数？

Question

用简单的哈希就很容易了

{:a => "a", :b => "b"} 

这将转化为

"a=a&b=b"

但你如何处理更复杂的事情呢？

{:a => "a", :b => ["c", "d", "e"]} 

这应该转化为

"a=a&b[0]=c&b[1]=d&b[2]=e" 

或者更糟糕的是,(做什么)有类似的事情:

{:a => "a", :b => [{:c => "c", :d => "d"}, {:e => "e", :f => "f"}]

感谢非常感谢的帮助!

Answer 1

对于基本的非嵌套哈希,Rails/ActiveSupport具有Object#to_query.

>> {:a => "a", :b => ["c", "d", "e"]}.to_query
=> "a=a&b%5B%5D=c&b%5B%5D=d&b%5B%5D=e"
>> CGI.unescape({:a => "a", :b => ["c", "d", "e"]}.to_query)
=> "a=a&b[]=c&b[]=d&b[]=e"

http://api.rubyonrails.org/classes/Object.html#method-i-to_query

Answer 2

如果您使用的是Ruby 1.9.2或更高版本,URI.encode_www_form则可以在不需要数组时使用.

例如(来自1.9.3中的Ruby文档):

URI.encode_www_form([["q", "ruby"], ["lang", "en"]])
#=> "q=ruby&lang=en"
URI.encode_www_form("q" => "ruby", "lang" => "en")
#=> "q=ruby&lang=en"
URI.encode_www_form("q" => ["ruby", "perl"], "lang" => "en")
#=> "q=ruby&q=perl&lang=en"
URI.encode_www_form([["q", "ruby"], ["q", "perl"], ["lang", "en"]])
#=> "q=ruby&q=perl&lang=en"

您会注意到,数组值未使用包含[]我们在查询字符串中习惯使用的键名来设置.使用的规范encode_www_form符合HTML5 application/x-www-form-urlencoded数据定义.

Answer 3

更新:此功能已从gem中删除.

朱利安,你的自我回答是一个很好的答案,我无耻地借用它,但它没有正确地逃脱保留字符,还有一些其他边缘情况,它崩溃了.

require "addressable/uri"
uri = Addressable::URI.new
uri.query_values = {:a => "a", :b => ["c", "d", "e"]}
uri.query
# => "a=a&b[0]=c&b[1]=d&b[2]=e"
uri.query_values = {:a => "a", :b => [{:c => "c", :d => "d"}, {:e => "e", :f => "f"}]}
uri.query
# => "a=a&b[0][c]=c&b[0][d]=d&b[1][e]=e&b[1][f]=f"
uri.query_values = {:a => "a", :b => {:c => "c", :d => "d"}}
uri.query
# => "a=a&b[c]=c&b[d]=d"
uri.query_values = {:a => "a", :b => {:c => "c", :d => true}}
uri.query
# => "a=a&b[c]=c&b[d]"
uri.query_values = {:a => "a", :b => {:c => "c", :d => true}, :e => []}
uri.query
# => "a=a&b[c]=c&b[d]"

宝石是' 可寻址的 '

gem install addressable

Answer 4

无需加载膨胀的ActiveSupport或滚动自己的,你可以使用Rack::Utils.build_query和Rack::Utils.build_nested_query.这是一篇博文,给出了一个很好的例子:

require 'rack'

Rack::Utils.build_query(
  authorization_token: "foo",
  access_level: "moderator",
  previous: "index"
)

# => "authorization_token=foo&access_level=moderator&previous=index"

它甚至处理数组:

Rack::Utils.build_query( {:a => "a", :b => ["c", "d", "e"]} )
# => "a=a&b=c&b=d&b=e"
Rack::Utils.parse_query _
# => {"a"=>"a", "b"=>["c", "d", "e"]}

或者更难嵌套的东西:

Rack::Utils.build_nested_query( {:a => "a", :b => [{:c => "c", :d => "d"}, {:e => "e", :f => "f"}] } )
# => "a=a&b[][c]=c&b[][d]=d&b[][e]=e&b[][f]=f"
Rack::Utils.parse_nested_query _
# => {"a"=>"a", "b"=>[{"c"=>"c", "d"=>"d", "e"=>"e", "f"=>"f"}]}

Answer 5

从Merb窃取:

# File merb/core_ext/hash.rb, line 87
def to_params
  params = ''
  stack = []

  each do |k, v|
    if v.is_a?(Hash)
      stack << [k,v]
    else
      params << "#{k}=#{v}&"
    end
  end

  stack.each do |parent, hash|
    hash.each do |k, v|
      if v.is_a?(Hash)
        stack << ["#{parent}[#{k}]", v]
      else
        params << "#{parent}[#{k}]=#{v}&"
      end
    end
  end

  params.chop! # trailing &
  params
end

见http://noobkit.com/show/ruby/gems/development/merb/hash/to_params.html

Answer 6

如果您只需要支持简单的ASCII键/值查询字符串,这里有一个短而甜的单行:

hash = {"foo" => "bar", "fooz" => 123}
# => {"foo"=>"bar", "fooz"=>123}
query_string = hash.to_a.map { |x| "#{x[0]}=#{x[1]}" }.join("&")
# => "foo=bar&fooz=123"

Answer 7

class Hash
  def to_params
    params = ''
    stack = []

    each do |k, v|
      if v.is_a?(Hash)
        stack << [k,v]
      elsif v.is_a?(Array)
        stack << [k,Hash.from_array(v)]
      else
        params << "#{k}=#{v}&"
      end
    end

    stack.each do |parent, hash|
      hash.each do |k, v|
        if v.is_a?(Hash)
          stack << ["#{parent}[#{k}]", v]
        else
          params << "#{parent}[#{k}]=#{v}&"
        end
      end
    end

    params.chop! 
    params
  end

  def self.from_array(array = [])
    h = Hash.new
    array.size.times do |t|
      h[t] = array[t]
    end
    h
  end

end