在使用 Multer 将文件上传到文件夹之前删除和创建文件夹

Posted 2023-03-07

【中文标题】在使用 Multer 将文件上传到文件夹之前删除和创建文件夹

【英文标题】：delete and create folder before uploading files into the folder using Multer

【发布时间】：2019-05-15 11:53:48

【问题描述】：

我正在尝试使用 multer 将文件上传到文件夹中，它工作正常。 现在我的要求是在将文件上传到“上传”文件夹之前，它应该先将其删除，创建上传文件夹然后上传。 我只想对上传的文件进行操作，而不是对以前存储的数据进行操作。 代码：

const fs = require("fs-extra");
const path = require("path");
const uploadPath = path.resolve(__dirname, "uploads");
const multer = require("multer");

const storage = multer.diskStorage(
  destination: "./uploads/",
  filename: function(req, file, cb) 
    cb(null, file.originalname);
  
);

const upload = multer( storage: storage );

router.post("/fileupload", upload.array("docs", 10), async function(
  req,
  res,
  next
) 
  let result = ;
  try 

    if (fs.existsSync(uploadPath)) 
      fs.removeSync(uploadPath);
      console.log("dir removed");
      fs.ensureDirSync(uploadPath);
      console.log("directory created");
     else 
      fs.ensureDirSync(uploadPath);
      console.log("directory created");
    

    const uploadObj = util.promisify(upload.any());
    await uploadObj(req, res);

    result.message = "Upload successful";
    res.send(result);
   catch (e) 
    console.error(e);
    console.error("Upload error");
  
);

我也尝试使代码异步，但之后它没有上传任何文件。我的理解是upload.array 是一个中间件，所以它在调用POST 请求时首先运行，然后在此之后运行。所以 multer 正在上传现有文件夹中的数据，然后一旦进入 POST fs 就会删除并再次创建它。 我怎样才能让它工作？ 谢谢

【参考方案1】：

我找到了让它工作的方法。 由于 multer 是一个中间件，它首先执行，然后执行其余代码。所以我把那个中间件放在我的代码中，而不是放在标题中。下面是完整的代码。

const create_upload_dir = () => 
  if (fs.existsSync(uploadPath)) 
    fs.removeSync(uploadPath);
    console.log("dir removed");
    fs.ensureDirSync(uploadPath);
    console.log("directory created");
   else 
    fs.ensureDirSync(uploadPath);
    console.log("directory created");
  
  return Promise.resolve("Success");
;


const multer = require("multer");

const upload_documents = () => 
  const storage = multer.diskStorage(
    destination: "./uploads/",
    filename: function(req, file, cb) 
      cb(null, file.originalname);
    
  );

  const upload = multer( storage: storage );

  return upload;
;

router.post("/fileupload", async function(req, res, next) 
    let result = ;
    try 
      await create_upload_dir();

      const upload = upload_documents();

      upload.array("docs", 10);

      const uploadObj = util.promisify(upload.any());

      await uploadObj(req, res);

      console.log("upload successful");

      res.send("Upload successful");
     catch (e) 
      console.error(e);
      console.error("Upload error");
    
  );

注意我放入了 try 块

upload.array("文档", 10);

而不是

router.post("/fileupload",upload.array("docs", 10), 异步函数(req, res, next)