问题描述：

公司某个项目会对请求头进行校验，而请求头会通过前置脚本进行计算。同样的前置脚本同样的环境，在apipost上调测报错显示请求头校验不通过，而在postman上通过，这是什么原因导致的？

前置脚本如下:

function uuid() {

    var s = [];

    var hexDigits = "0123456789abcdef";

    for (var i = 0; i < 36; i++) {

        s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);

    }

    s[14] = "4"; // bits 12-15 of the time_hi_and_version field to 0010

    s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1); // bits 6-7 of the clock_seq_hi_and_reserved to 01

    s[8] = s[13] = s[18] = s[23] = "-";

    var uuid = s.join("");

    return uuid;

}

var timestamp = new Date().getTime();

var apptoken = pm.environment.get("accesstoken");

var appsecret = pm.environment.get("secret");

var nonce = uuid();

var initNonce = pm.environment.get("nonce");

var signature = '';

if (initNonce != null) {

    signature = CryptoJS.MD5(apptoken + appsecret + timestamp + nonce).toString();

    pm.environment.set("nonce", nonce);

} else {

    signature = CryptoJS.MD5(apptoken + appsecret + timestamp).toString();

}

pm.environment.set("timestamp", timestamp);

pm.environment.set("signature", signature);