云函数 const cloud = require('wx-server-sdk') cloud.init() exports.main = async (event, context) => {   try {     const result = await cloud.openapi.security.imgSecCheck({       media: {          header: {'Content-Type': 'application/octet-stream'},         contentType: 'image/jpg',         content: Buffer.from(event.value)       }     })     return result   } catch (err) {     return {       code: 10,       msg: '检测失败',       error: err     }   } } 前端     wx.getFileSystemManager().readFile({       filePath: tempFilePath,       success: async (res) => {         const imgBase64 = res.data         try {           const checkRes = await cloudInstance.callFunction({             name: 'imgSecCheck',              data: {               value: imgBase64             }           })         } catch (err) {         }       },     }) 一直报错 errCode: 47001, errMsg: "openapi.security.imgSecCheck:fail data format error rid: " 也参考了别人的评论里的代码，为什么不行？