为了减少数据库读写次数，
项目需要一次add几十条大记录到云开发的数据库集合中，
方法是中间建一个云函数接受小程序端的record数组，
然后remove掉之前的数据再一次add进去。
但是记录超过80kb，
云函数就会报超时的错误。
后来查得用wx.cloud.cdn标记上传可以解决问题，
然而在云函数中，用获得的wx.cloud.cdn返回url获取上传数据却遇到问题。
首先使用cloud.downloadfile下载（rs.ss=await cloud.downloadfile({fileId:‘http://vweixinf.tc.qq.com/301/20303/stodownload?m=0b867e53c1d233ce9fe49d54549a2323&filekey=3033020101041f301d0202012d0402535a04100b867e53c1d233ce9fe49d54549a232302010d040d00000004627466730000000131&hy=SZ&storeid=323032323036323631333438323130303065646132666439633733343832386536313838303930303030303132643030303034663466&bizid=1023’})），
报错：SaveHouse->wx.cf->house.update.all Error: cloud.callFunction:fail Error: errCode: -504002 functions execute fail | errMsg: Error: downloadFile:fail -501007 invalid parameters.
at toSDKError (:59277/var/user/node_modules/wx-server-sdk/index.js:8089)
at Object.returnAsFinalCloudSDKError (:59277/var/user/node_modules/wx-server-sdk/index.js:8060)
at :59277/var/user/node_modules/wx-server-sdk/index.js:2685
at processTicksAndRejections (:59277/appservice/internal/process/task_queues.js:97) (callId: 1656225486984-0.2214185235687418) (trace: 14:38:6 start->14:38:8 system error (Error: errCode: -504002 functions execute fail | errMsg: Error: downloadFile:fail -501007 invalid parameters.
at toSDKError (:59277/var/user/node_modules/wx-server-sdk/index.js:8089)
at Object.returnAsFinalCloudSDKError (:59277/var/user/node_modules/wx-server-sdk/index.js:8060)
at :59277/var/user/node_modules/wx-server-sdk/index.js:2685
at processTicksAndRejections (:59277/appservice/internal/process/task_queues.js:97)), abort)
at S (WASubContext.js?t=wechat&s=1656201220971&v=2.24.6:2)
at WASubContext.js?t=wechat&s=1656201220971&v=2.24.6:2
at WASubContext.js?t=wechat&s=1656201220971&v=2.24.6:2
at n (WASubContext.js?t=wechat&s=1656201220971&v=2.24.6:2)
遇到这个问题，一直没有找到解决方案
这个方法也试过，
小程序端
wx.cloud.callFunction({
name:'house',
data:{
type:'house.update.all',
opId:that.GetOpid(that),
rows:wx.cloud.CDN(rows)
}
云函数端
rs.ss=await axios.get(event.rows)
但我这边返回的错误如下：
call failed:, Error: cloud.callFunction:fail Error: errCode: -504002 functions execute fail | errMsg: TypeError: Converting circular structure to JSON
--> starting at object with constructor 'ClientRequest'
| property 'socket' -> object with constructor 'Socket'
--- property '_httpMessage' closes the circle
at JSON.stringify (<anonymous>)
at callback (/var/runtime/node12/CallbackContext.js:31:23)
at /var/runtime/node12/CallbackContext.js:81:16
at /var/runtime/node12/Runtime.engine.js:237:13
at processTicksAndRejections (internal/process/task_queues.js:97:5) (callId: 1656226368561-0.25930267181093436) (trace: 14:52:48 start->14:52:49 system error (Error: errCode: -504002 functions execute fail | errMsg: TypeError: Converting circular structure to JSON
--> starting at object with constructor 'ClientRequest'
| property 'socket' -> object with constructor 'Socket'
--- property '_httpMessage' closes the circle
at JSON.stringify (<anonymous>)
at callback (/var/runtime/node12/CallbackContext.js:31:23)
at /var/runtime/node12/CallbackContext.js:81:16
at /var/runtime/node12/Runtime.engine.js:237:13
at processTicksAndRejections (internal/process/task_queues.js:97:5)), abort)
at S (http://127.0.0.1:59277/appservice/__dev__/WASubContext.js?t=wechat&s=1656201220971&v=2.24.6:2:246848)
at http://127.0.0.1:59277/appservice/__dev__/WASubContext.js?t=wechat&s=1656201220971&v=2.24.6:2:273369
at http://127.0.0.1:59277/appservice/__dev__/WASubContext.js?t=wechat&s=1656201220971&v=2.24.6:2:47439
at n (http://127.0.0.1:59277/appservice/__dev__/WASubContext.js?t=wechat&s=1656201220971&v=2.24.6:2:24316)
在云函数端下载可以使用node.js的request-promise（导出数据到excel表格中）
1、引入request-promise
const rp = require('request-promise');
2、从临时链拉取数据,我的数据datas是以字符串的形式传递的
const {datas}=event
const temp = await rp(datas).then((res) => {
//res为请求到的数据，为string类型
console.log('res', res)
return res
})
3、把收到的数据转化为数组，写入excel表格
JSON.parse(temp)