multer 文件上传 - 如何在路由中从 multer 获取值？答案

【问题标题】：multer file upload - how to get a value from multer in route?multer 文件上传 - 如何在路由中从 multer 获取值？
【发布时间】：2020-09-08 09:47:04
【问题描述】：

我正在使用带有 Express 的 multer 上传文件。

我想从路由内 multer 的 storage 对象访问一个值。
我该怎么做？

Multer 配置（目前我只知道如何记录密钥）：

const aws = require("aws-sdk");
const multer = require("multer");
const multerS3 = require("multer-s3");

function configureUpload () {
    
  const s3 = new aws.S3({...my credentials...});

  const upload = multer({
    storage: multerS3({
      s3: s3,
      bucket: process.env.S3_BUCKET_NAME,
      metadata: (req, file, cb) => cb(null, { fieldName: file.fieldname }),
      key: (req, file, cb) => {
        const key = `${new Date().toISOString()}-${file.originalname}`;
        return cb(console.log("KEY: ", key), key); // The string I need to access in route
      },
    }),
  });

  return upload;
}

路线：

const express = require("express");
const Person = require("../../../db/models/person");
const configureUpload = require("../../../configureUpload ");

const router = express.Router();

// Saving to MongoDB with mongoose

router.post("/", configureUpload ().any(), async (req, res) => {
  Person.create({
    ...req.body,
    files: [] // I want to add the string in multer.storage.key to this array
  })
  .then((person) => {
    ...
   })
   .catch((err) => {
    ...
   });

});

module.exports = router;

【问题讨论】：

标签： express file-upload multer

【解决方案1】：

您可以简单地添加 req.key = keyValue 然后您可以使用 req.key 名称在下一条路线中访问

或者你也可以在路由中访问 req.file 或 req.files 对象

所有东西都是一个中间件，所以你可以很容易地在下一个中间件中传递和访问

【讨论】：

【解决方案2】：

这是 Tarique Akhtar Ansari 已经说过的话的一个例子。将您的密钥添加到 req 对象，以便您可以访问控制器/路由中的 key 值，如下所示：

const aws = require("aws-sdk");
 const multer = require("multer");
 const multerS3 = require("multer-s3");

function configureUpload () {
    
  const s3 = new aws.S3({...my credentials...});

  const upload = multer({
    storage: multerS3({
      s3: s3,
      bucket: process.env.S3_BUCKET_NAME,
      metadata: (req, file, cb) => {cb(null, { fieldName: file.fieldname })},
      key: (req, file, cb) => {
        
        const key = `${new Date().toISOString()}-${file.originalname}`;
        req.key = key; // added the key to req object

        // return cb(console.log("KEY: ", key), key); // The string I need to access in route
      },
    }),
  });

  return upload;
}

访问控制器或路由内部密钥的value

const express = require("express");
const Person = require("../../../db/models/person");
const configureUpload = require("../../../configureUpload ");

const router = express.Router();

// Saving to MongoDB with mongoose

router.post("/", configureUpload ().any(), async (req, res) => {

 console.log('here is the value your key', req.key); // it's that simple.

  Person.create({
    ...req.body,
    files: [] // I want to add the string in multer.storage.key to this array
  })
  .then((person) => {
    ...
   })
   .catch((err) => {
    ...
   });

});

module.exports = router;

【讨论】：