遇到一个问题，是在云函数端的错误。
代码是这样的，在云函数端更改一个数据记录。
var handleGoods =function(goods,storenum){
var _ = db.command;
return db.collection('goods').doc(goods._id).update({
data:{
store_num:_.inc(storenum*-1),
sale_num:_.inc(storenum)
}
});
}
结果是
Error: errCode: -501001 resource system error | errMsg: signature calculated is different from client signature;
at new CloudSDKError (/Users/skymxc/Documents/project/WeChat/shop/cloudfunctions/handleOrder/node_modules/wx-server-sdk/index.js:4332:28)
at Object.returnAsCloudSDKError (/Users/skymxc/Documents/project/WeChat/shop/cloudfunctions/handleOrder/node_modules/wx-server-sdk/index.js:4384:16)
at Object.checkError (/Users/skymxc/Documents/project/WeChat/shop/cloudfunctions/handleOrder/node_modules/wx-server-sdk/index.js:1401:23)
at DocumentReference.<anonymous> (/Users/skymxc/Documents/project/WeChat/shop/cloudfunctions/handleOrder/node_modules/wx-server-sdk/index.js:1334:41)
at step (/Users/skymxc/Documents/project/WeChat/shop/cloudfunctions/handleOrder/node_modules/tslib/tslib.js:133:27)
at Object.next (/Users/skymxc/Documents/project/WeChat/shop/cloudfunctions/handleOrder/node_modules/tslib/tslib.js:114:57)
at fulfilled (/Users/skymxc/Documents/project/WeChat/shop/cloudfunctions/handleOrder/node_modules/tslib/tslib.js:104:62)
at <anonymous>
at process._tickCallback (internal/process/next_tick.js:188:7)
返回的错误是 signature calculated is different from client signature; 签名和客户端不同
因为是在云函数端，也不存在权限问题吧。很是不解。
有没有大神帮忙看一下子，万分感谢。
解决方法：将依赖的wx-server-sdk通过NPM升级到最新版本。 npm update wx-server-sdk --save 确保云函数下的package.json为最新版本 { "dependencies": { "wx-server-sdk": "^2.3.3" } }