使用变量中的机械化填充表单

Question

我正在尝试在ror中设置机制以填写并提交表单，以便能够抓取下一页的搜索结果。

我已将代码跟踪到错误发生的位置。当我对这样的表单变量进行硬编码时它非常有效：

  form['l'] = 'salzburg'    # location (works)
  form['t'] = 'all:rental'  # SELECT 'all:sale' (works)
  form['pf'] = 1            # price from (works)
  form['pt'] = 800          # price to (works)
  form['rf'] = 2            # rooms from (works)
  form['rt'] = 5            # rooms to (works)

但是一旦我尝试从变量填写表单，它就不再提交表单了：

  pf = @criterium.price_from.to_i.to_s
  pt = @criterium.price_to.to_i 
  rf = @criterium.rooms_from.to_i 
  rt = @criterium.rooms_to.to_i 

  puts pf   # successfully logs => 1
  puts pt   # successfully logs => 800
  puts rf   # successfully logs => 2
  puts rt   # successfully logs => 5

  form['l'] = @criterium.location    # location (works)
  form['t'] = 'all:rental'           # SELECT 'all:sale',
  form['pf'] = pf                    # price from (doesn't work)
  form['pt'] = pt                    # price to (doesn't work)
  form['rf'] = rf                    # rooms from (doesn't work)
  form['rt'] = rt                    # rooms to (doesn't work)

奇怪的是，puts pf，pt，rf，rt命令成功将变量记录到控制台。

但提交失败..

page = agent.submit(form)

没有错误输出，我只是在提交之前和之后通过puts page.title看到，它保留在同一页面上（=表示表单未提交）。

感谢关于为什么表格没有从变量填充的每个提示。