220

这很容易用一个简单的哈希，比如

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

这将转化为

"a=a&b=b"

但是你如何处理更复杂的事情，比如

{: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）类似于：

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

感谢您对此提供的非常感谢的帮助！

4

14 回答 14

294

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

于 2010-09-30T17:32:36.477 回答
168

如果您使用的是 Ruby 1.9.2 或更高版本，则可以URI.encode_www_form在不需要数组的情况下使用。

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"

您会注意到数组值没有使用包含[]我们在查询字符串中已经习惯的键名来设置。使用的规范encode_www_form符合 HTML5application/x-www-form-urlencoded数据定义。

于 2012-06-28T19:35:42.760 回答
90

更新：此功能已从 gem 中删除。

朱利安，你的自我回答很好，我无耻地借鉴了它，但它没有正确地转义保留字符，而且还有一些其他极端情况会崩溃。

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
于 2009-04-29T16:00:12.833 回答
68

无需加载臃肿的 ActiveSupport 或自行滚动，您可以使用Rack::Utils.build_query和Rack::Utils.build_nested_query. 这是一篇博客文章，它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"

它甚至可以处理数组：

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"]}

或者更困难的嵌套内容：

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"}]}
于 2013-01-08T19:24:25.190 回答
12

如果您只需要支持简单的 ASCII 键/值查询字符串，这里有一个简短而甜蜜的语句：

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"
于 2013-06-05T13:54:24.660 回答
10

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

于 2009-04-28T16:24:04.187 回答
5 
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
于 2009-04-28T17:06:17.770 回答
4 
{:a=>"a", :b=>"b", :c=>"c"}.map{ |x,v| "#{x}=#{v}" }.reduce{|x,v| "#{x}&#{v}" }

"a=a&b=b&c=c"

这是另一种方式。对于简单的查询。

于 2013-09-01T17:12:16.050 回答
3

我知道这是一个老问题，但我只是想发布这段代码，因为我找不到一个简单的 gem 来为我完成这项任务。

module QueryParams

  def self.encode(value, key = nil)
    case value
    when Hash  then value.map { |k,v| encode(v, append_key(key,k)) }.join('&')
    when Array then value.map { |v| encode(v, "#{key}[]") }.join('&')
    when nil   then ''
    else            
      "#{key}=#{CGI.escape(value.to_s)}" 
    end
  end

  private

  def self.append_key(root_key, key)
    root_key.nil? ? key : "#{root_key}[#{key.to_s}]"
  end
end

在这里作为宝石卷起来：https ://github.com/simen/queryparams

于 2011-10-29T19:06:14.570 回答
2

最好的方法是使用 Hash.to_params ，它可以很好地处理数组。

{a: 1, b: [1,2,3]}.to_param
"a=1&b[]=1&b[]=2&b[]=3"
于 2017-11-08T11:15:17.370 回答
2 
require 'uri'

class Hash
  def to_query_hash(key)
    reduce({}) do |h, (k, v)|
      new_key = key.nil? ? k : "#{key}[#{k}]"
      v = Hash[v.each_with_index.to_a.map(&:reverse)] if v.is_a?(Array)
      if v.is_a?(Hash)
        h.merge!(v.to_query_hash(new_key))
      else
        h[new_key] = v
      end
      h
    end
  end

  def to_query(key = nil)
    URI.encode_www_form(to_query_hash(key))
  end
end

2.4.2 :019 > {:a => "a", :b => "b"}.to_query_hash(nil)
 => {:a=>"a", :b=>"b"}

2.4.2 :020 > {:a => "a", :b => "b"}.to_query
 => "a=a&b=b"

2.4.2 :021 > {:a => "a", :b => ["c", "d", "e"]}.to_query_hash(nil)
 => {:a=>"a", "b[0]"=>"c", "b[1]"=>"d", "b[2]"=>"e"}

2.4.2 :022 > {:a => "a", :b => ["c", "d", "e"]}.to_query
 => "a=a&b%5B0%5D=c&b%5B1%5D=d&b%5B2%5D=e"
于 2018-08-30T21:27:05.203 回答
2

如果您在 Faraday 请求的上下文中，您也可以将 params 哈希作为第二个参数传递，并且 faraday 会负责将正确的 param URL 作为其中的一部分：

faraday_instance.get(url, params_hsh)
于 2020-01-07T08:46:23.617 回答
0

我喜欢使用这个宝石：

https://rubygems.org/gems/php_http_build_query

示例用法：

puts PHP.http_build_query({"a"=>"b","c"=>"d","e"=>[{"hello"=>"world","bah"=>"black"},{"hello"=>"world","bah"=>"black"}]})

# a=b&c=d&e%5B0%5D%5Bbah%5D=black&e%5B0%5D%5Bhello%5D=world&e%5B1%5D%5Bbah%5D=black&e%5B1%5D%5Bhello%5D=world
于 2015-04-03T23:13:38.110 回答
0 
2.6.3 :001 > hash = {:a => "a", :b => ["c", "d", "e"]}
=> {:a=>"a", :b=>["c", "d", "e"]}
2.6.3 :002 > hash.to_a.map { |x| "#{x[0]}=#{x[1].class == Array ? x[1].join(",") : x[1]}" 
}.join("&")
=> "a=a&b=c,d,e"
于 2020-10-01T15:45:11.690 回答