# 在云函数中使用存储资源
1. 上传文件：`uploadFile`
>上传文件
```javascript
const cloud = require('wx-server-sdk')
const fs = require('fs')
const path = require('path')
exports.main = async (event, context) => {
const fileStream = fs.createReadStream(path.join(__dirname,'demo.jpg'))
return await cloud.uploadFile({
cloudPath:'demo.jpg',
fileContent:fileStream
})
}
```
2. 下载文件：`downloadFile`
>下载文件
```javascript
const cloud = require('wx-server-sdk')
exports.main = async (event, context) => {
const fileID = 'xxx'
const res = await cloud.downloadFile({
fileID ,
})
const buffer = res.fileCotent
return buffer.toString('utf-8')
}
```
3. 获取文件临时链接：`getTempFileURL`
>获取文件链接
```javascript
const cloud = require('wx-server-sdk')
exports.main = async (event, context) => {
const fileList = ['cloud://xxx','cloud://yyy']
const result = await cloud.getTempFileURL({
fileList
})
return result .fileList
}
```
4. 删除文件：`deleteFile`
>删除文件
```javascript
const cloud = require('wx-server-sdk')
exports.main = async (event, context) => {
const fileIDS= ['xxx','yyy']
const result = await cloud.deleteFile({
fileList:fileIDS
})
return result .fileList
}
```
5. 使用存储资源
* 放置一个按钮
* 创建所需云函数
* 在js里面调用云函数
```javascript
Page({
callFunction:function(){
wx.cloud.callFunction({
name:'queryData'
}).then(console.log)
}
})
```
* 云函数代码
```javascript
// 云函数入口文件
const cloud = require('wx-server-sdk')
cloud.init()
let db =cloud.database();
// 云函数入口函数
exports.main = async (event, context) => {
const fileId = ['cloud://dev-test-mspff.6465-dev-test-mspff-1300181487/123144.png']
return await cloud.getTempFileURL({
fileList:fileId
})
}
```
* 运行效果
