从同济大学选课网站上爬取信息，输出绩点（支持统一认证登录）

score_spider.rb

require 'mechanize'

# xuanke.tongji.edu.cn 现采用统一认证登录，原登录方式不再使用
class NewGpaSpider
  # 学期内所有课程
  attr_reader :courses

  def initialize(userid, password, term)
    @agent = Mechanize.new

    welcome_page = @agent.get('http://xuanke.tongji.edu.cn')
    rp1 = @agent.click(welcome_page.search('font')[2].children[0])
    rp2 = @agent.get(rp1.parser.at('meta[http-equiv="refresh"]')['content'][/url=(.+)/, 1])
    rp3 = rp2.forms[0].submit
    login_form = rp3.form('IDPLogin')
    login_form['Ecom_User_ID'] = userid
    login_form['Ecom_Password'] = password
    rp4 = @agent.submit(login_form)
    rp5 = @agent.get('https://ids.tongji.edu.cn:8443/nidp/saml2/sso?sid=0&sid=0')
    rp6 = rp5.forms[0].submit
    rp7 = @agent.get('http://xuanke.tongji.edu.cn/tj_login/redirect.jsp'+ 
                   '?link=/tj_xuankexjgl/score/query/student/cjcx.jsp' + 
                   '?qxid=20051013779916&mkid=20051013779901&qxid=20051013779916')
    rp7.forms[0].fields[1].value = term
    @main_page = rp7.forms[0].submit

    get_courses
  end

  # 总绩点
  def overall_gpa
    @overall_gpa ||= statistic_params(1)
  end

  # 总学分
  def overall_credits
    @overall_credits ||= statistic_params(6)
  end

  # 挂科学分
  def failed_credits
    @failed_credits ||= statistic_params(8)
  end

  #挂科数量
  def failed_courses
    @failed_courses ||= statistic_params(13)
  end

  # 学期平均绩点
  def term_gpa
    @term_gpa ||= @main_page.search('font').last.inner_text.strip
  end

  # 学期名
  def term_name
    @term_name ||= @main_page.css('#T1').children[7].children[1].children[0].children[0].text
  end

  private

  def statistic_params(id)
    @main_page.css('#T1').children[3].children[0].children[id].children[0].text.strip
  end

  def get_courses
    start_rank = 11
    @courses = []
    start_dom = @main_page.css('#T1').children
    while start_dom[start_rank]&.children&.[](5)
      @courses << (1..17).step(2).map do |nid|
        start_dom[start_rank].children[nid].children[0].children[0].children[0].text
      end
      start_rank += 2
    end
  end
end

@sid = '你的学号'
@pwd = '你的密码'
@term = '你的学期' # 比如 20172 就是 2017-2018 第 2 学期
spider = NewGpaSpider.new(@sid, @pwd, @term)