用表单直接上传，但是回调的时候失败，file_get_contents('php://input')这个在回调页面也获取不到数据

{"error":"{\"callback_url\":\"http://www.7th.cc/myadmin/spadmin/callback\",\"callback_bodyType\":\"application/x-www-form-urlencoded\",\"callback_body\":\"name=FlNLrzDBpITy5Z7HDYBI_sN-13Ie&hash=FlNLrzDBpITy5Z7HDYBI_sN-13Ie&uid=123\",\"token\":\"QBox il8FUwtEUAb_dsm1pIRhkiduQdpTZ_e0zWrYkl_G:eLvvyowMcGJsoC0Zd2i4kfZbVsk=\",\"err_code\":200,\"error\":\"unexcepted response\"}"}

求解决