我有一个应用程序,在该应用程序中,我想使用一些文件上传机制。
我的要求是:
上传文件后,其名称将更改为唯一的东西,例如uuid4()。我将稍后将此名称存储在数据库中。
我写了类似的东西,但是我有几个问题:
const multer = require('multer');
const upload = multer();
router.post('/', middleware.checkToken, upload.single('file'), (req,res,next)=>{
// key:
// file : "Insert File Here"
console.log("req:");
console.log(req.file);
const str = req.file.originalname
var filename = str.substring(0,str.lastIndexOf('.'));
// I will use filename and uuid for storing it in the database
// I will generate unique uuid for the document and store the document
// with that name
var extension = str.substring(str.lastIndexOf('.') + 1, str.length);
// HERE!
res.status(200).json();
})
我已经看到将其存储在diskstorage中的示例:
var storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, '/tmp/my-uploads')
},
filename: function (req, file, cb) {
cb(null, file.fieldname + '-' + Date.now())
}
})
var upload = multer({ storage: storage })
但是,据我了解,这是API呼叫之外的配置。这意味着我每次调用此API都无法修改它。我想为文件分配不同的名称,我需要该名称(uuid)将该名称保存在数据库中。
如何保留此类功能?
感谢@rashomon和@eimran Hossain Eimon,我解决了问题。如果有人想知道解决方案,这里是:
const multer = require('multer');
var storage = multer.diskStorage({
destination: function (req, file, cb) {
// the file is saved to here
cb(null, '/PATH/TO/FILE')
},
filename: function (req, file, cb) {
// the filename field is added or altered here once the file is uploaded
cb(null, uuidv4() + '.xlsx')
}
})
var upload = multer({ storage: storage })
router.post('/', middleware.checkToken, upload.single('file'), (req,res,next)=>{
// the file is taken from multi-form and the key of the form must be "file"
// visible name of the file, which is the original, uploaded name of the file
const name = req.file.originalname;
// name of the file to be stored, which contains unique uuidv4
const fileName = req.file.filename;
// get rid of the extension of the file ".xlsx"
const file_id = fileName.substring(0, fileName.lastIndexOf('.'));
// TODO
// Right now, only xlsx is supported
const type = "xlsx";
const myObject = new DatabaseObject({
_id : new mongoose.Types.ObjectId(),
file_id: file_id,
name : name,
type: "xlsx"
})
myObject .save()
.then(savedObject=>{
// return some meaningful response
}).catch(err=>{
// return error response
})
})
这解决了我当前的问题。感谢您的帮助。对于将来的改进,我将添加错误案例:
如果UUIDV4返回已经存在的ID(我认为由于对象包含某些时间戳数据,这是极不可能的),请重新运行重命名函数。
如果保存到数据库存在错误,我应该删除上传的文件以避免将来的冲突。
如果您也有解决这些问题的解决方案,我非常感谢。
我想你错了...你说
我每次调用此api时都无法修改它。
但实际上,每次为每个文件都调用filename
。让我解释一下代码的这一部分...
filename: function (req, file, cb) {
cb(null, file.fieldname + '-' + Date.now())
}
在这里查看callback
函数(由cb
表示):
- 回调函数中的第一个参数
null
就像 justnument 。您始终将null
作为回调函数中的第一个参数传递。请参阅此参考 - 第二个参数确定在
destination
文件夹中应命名的文件。因此,您可以在这里指定任何功能,每次都可以返回 unique fileName。
因为您正在使用猫鼬...我认为,如果您使用架构中的mongoose method
(在其中保存文件路径)中实现function uniqueFileName()
并将其调用在路由处理程序中,那会更好。了解更多
-
无需。因为您正在使用时间戳。
-
如果保存到数据库中的错误,您可以使用此代码删除上传文件,以避免将来的冲突。尝试以下操作:
const multer = require('multer'); const fs = require('fs'); // add this line var storage = multer.diskStorage({ destination: function (req, file, cb) { // the file is saved to here cb(null, '/PATH/TO/FILE') }, filename: function (req, file, cb) { // the filename field is added or altered here once the file is uploaded cb(null, uuidv4() + '.xlsx') } }) var upload = multer({ storage: storage }) router.post('/', middleware.checkToken, upload.single('file'), (req,res,next)=>{ // the file is taken from multi-form and the key of the form must be "file" // visible name of the file, which is the original, uploaded name of the file const name = req.file.originalname; // name of the file to be stored, which contains unique uuidv4 const fileName = req.file.filename; // get rid of the extension of the file ".xlsx" const file_id = fileName.substring(0, fileName.lastIndexOf('.')); // TODO // Right now, only xlsx is supported const type = "xlsx"; const myObject = new DatabaseObject({ _id : new mongoose.Types.ObjectId(), file_id: file_id, name : name, type: "xlsx" }) myObject .save() .then(savedObject=>{ // return some meaningful response }).catch(err=>{ // add this // Assuming that 'path/file.txt' is a regular file. fs.unlink('path/file.txt', (err) => { if (err) throw err; console.log('path/file.txt was deleted'); }); }) })
另请参见Nodejs文件系统doc