```ruby multi_part = nil File.open('/Users/howl/Downloads/babyhead.gif', 'rb') { |photo| multi_part = Nestful::MultiPart.new 'https://open.t.qq.com/api/t/add', { content: 'helloworld', longitude: 113.421234, latitude: 22.354231, syncflag: 0, compatibleflag: 0, format: 'json', access_token: '9895a065c73a06a6d43d9491cc7cfea7', oauth_consumer_key: …

multi_part.rb

# -*- encoding: utf-8 -*-
require 'mime/types'
require 'nestful'
require 'uri'

module Nestful
  class MultiPart

    def initialize(url, parts, crlf = nil)
      @crlf = crlf || "\r\n"
      @url  = url
      build_multipart_bodies(parts)
    end

    def url
      @url
    end

    def body
      @body
    end

    def headers
      @headers
    end

    protected
    
    def build_multipart_bodies(parts)
      boundary = Time.now.to_i.to_s(16)

      body = bin_encode('')

      parts.each do |key, value|
        esc_key = escape(key.to_s)
        body << bin_encode("--#{boundary}#{@crlf}")
        if value.respond_to?(:read)
          filename  = File.basename(value.path)
          mime_type = mime_type( filename )

          body << bin_encode("Content-Disposition: form-data; name=\"#{esc_key}\"; filename=\"#{filename}\"#{@crlf}")
          body << bin_encode("Content-Type: #{mime_type}#{@crlf}")
          body << bin_encode("Content-Transfer-Encoding: binary#{@crlf*2}")
          body << bin_encode(value.read)
        else
          body << bin_encode("Content-Disposition: form-data; name=\"#{esc_key}\"#{@crlf*2}#{value}")
        end
        body << bin_encode(@crlf)

      end 

      body << bin_encode("--#{boundary}--#{@crlf*2}")

      @headers = { "Content-Type" => "multipart/form-data; boundary=#{boundary}" }
      @body    = request(body).execute.body
    end

    private

    def request(body)
      req = Nestful::Request.new(@url)
      req.body    = body
      req.headers = @headers
      req.method  = :post

      return req
    end

    def escape(s)
      URI.encode_www_form_component(s)
    end

    def bin_encode(chunk)
      chunk.force_encoding(Encoding::BINARY) if chunk.respond_to? :force_encoding
    end

    def mime_type(filename)
      MIME::Types.type_for( filename ).first.to_s
    end
  end
end