使用Multer

Question

我尝试使用 Multer 从我的表单上传图片，当我插入图片时一切正常但是当没有选择图片时我收到了错误。

• 这里是multer配置，所有上传的图像都存储在public / images / uploads中：

//handle file upload

var storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, 'public/images/uploads/')
  },
  filename: function (req, file, cb) {
    cb(null, file.fieldname + '-' + Date.now()+ '.jpg')
  }
});
var upload = multer({ storage: storage })

现在我想取回 mainImageName 的值，但是当我没有插入任何图片时，会发生错误cannot get property filename of undefined.

• 以下是其余的内容：

  //Submit new post
  router.post('/add', upload.single('mainimage'), function(req, res, next) {
  var title = req.body.title;
  var category = req.body.category;
  var body = req.body.body;
  var author = req.body.author;
  var date = new Date();
  
  if(req.file && req.file.mainimage){
  
      var mainImageName = req.file.filename;
      var mainImageMime = req.file.mainimage.mimetype;
      var mainImagePath = req.file.mainimage.path;
      var mainImageSize = req.file.mainimage.size;
  
  }else{
  
      //if there was no image uploaded!!
      //noimage.png should be placed in public/images/uploads
      mainImageName = 'noimage.png';
  }
  
  console.log(mainImageName); //always returns noimage.png !!
  
  //form validation
  req.checkBody('title', 'You forgot the title').notEmpty();
  req.checkBody('body', 'Please fill in the body').notEmpty();
  
  //check errors
  var errors = req.validationErrors();
  
  if(errors){
  

  var mycategories = [];   var categories = db.get（＆＃39; categories＆＃39;）;   categories.find（{}，{}，function（err，categories）{

      for (i=0; i<categories.length; i++) {
            mycategories[i] = categories[i];
          }
   });
  res.render('addpost', {
          'pageTitle': 'Add Post',
          'errors': errors,
          'title': title,
          'body': body,
          'categories': mycategories
  
      });
  
  } else{
          var posts = db.get('posts');
          //submit Post
          posts.insert({   "title": title, 
                           "body": body,
                           "category": category,
                           "date": date,
                           "author": author,
                           "mainimage": mainImageName 
  
                   }, function(err, post) {
              if (err){
          res.send('There was an issue submitting the post.')
           } else {
              req.flash('success_msg', 'Post Submitted');
              res.location('/');
              res.redirect('/');
           }
           });
  }
  

  }）;

Answer 1

我发现问题，条件if(req.file && req.file.mainimage)从未得到满足，因为req.file.mainimage始终未定义，因此我只是将其更改为if(req.file)并且运行正常。

这应该是这样的：

if(req.file){

    var mainImageName = req.file.filename;
    var mainImageMime = req.file.mimetype;
    var mainImagePath = req.file.path;
    var mainImageSize = req.file.size;

}else{

    //if there was no image uploaded!!
    //noimage.png should be placed in public/images/uploads
    mainImageName = 'noimage.png';
}