如何解码从nodejs中的mongodb检索到的二进制图像数据

Question

我正在尝试通过 nodejs 和 mutter 向 mongodb 上传和检索图像。但我被困在某个地方，我希望我能成功上传图像作为二进制数据。但在我的 .ejs 文件中没有显示图像。

路线文件

    const express=require('express');
    const adminRouter=express.Router();
    const Bookdata=require('../model/Bookdata')
    const multer = require('multer');
    const path = require('path');
    var fs = require('fs');
    const {
      GridFsStorage
    } = require("multer-gridfs-storage");
     
    require("dotenv")
      .config();
    
    
    // set up multer for storing uploaded files
    const storage=multer.diskStorage({
      //destination for files
      destination:function(request,file,callback){
        callback(null,'../LibraryApps/public/uploads/images');
      },
      //add back the extensions
      filename:function(request,file, callback){
      
        callback(null,file.fieldname+Date.now()+path.extname(file.originalname));
      }
    })
    
    //upload parameters for mutter
    const upload = multer({ 
      storage: storage,
      limits:{
        fileSize: 1000000
      },
      fileFilter:function(req,file,callback){
        checkFileType(file, callback);
      }
    });
    //Check file type
    function checkFileType(file, callback){
    
      // allowed extension
      const filetypes = /jpeg|jpg|png|gif/;
      //check extension
      const extname=filetypes.test(path.extname(file.originalname).toLowerCase());
      //check mime
      const mimetype=filetypes.test(file.mimetype);
      if(mimetype&&extname){
        return callback(null, true);
      }else{
        callback('Error: Images only');
      }
    }
    var imgModel = require('../model/Bookdata');
    
    function router(nav){
    adminRouter.get('/',function(req,res){
       
    
        imgModel.find({}, (err, items) => {
          if (err) {
              console.log(err);
              res.status(500).send('An error occurred', err);
          }
          else {
              //res.render('imagesPage', { items: items });
              res.render('addBook',{
                nav,
                title:'Library'
                
            })
          }
      });
    })
    
    adminRouter.post('/add',upload.single(`image`), function(req,res){
      // res.send("Hey I am Added");
      console.log(req.file);
      var item={
        title: req.body.title,
        author: req.body.author,
        genre: req.body.genre,
        //image: req.file.image,
        image: {
          data: fs.readFileSync(path.join('../LibraryApps/public/uploads/images/' + req.file.filename)),
          contentType: 'image/png'
      }
      }
      imgModel.create(item, (err, item) => {
        if (err) {
            console.log(err);
        }
        else {
          var book=Bookdata(item);
          book.save();
          res.redirect('/books');
        }
    });
     
    
    });
    return adminRouter;
    }
    module.exports=router;

my model file

    //Accessing Mongose package
    const mongoose=require('mongoose');
    
    //Database connection
    // mongoose.connect('mongodb://localhost:27017/library');
    mongoose.connect('mongodb....');
    //Schema definition
    const Schema= mongoose.Schema;
    
    const BookSchema=new Schema({
        title: String,
        author: String,
        genre: String,
       // image: String,
        image:{
            data: Buffer,
            contentType: String
        }
    });
    
    //Model creation
    var Bookdata= mongoose.model('bookdata',BookSchema);
    module.exports=Bookdata;

这是我的 .ejs 文件

<%for(i=0;i

  <div class="row">    
        <br>
        <div class="col-md-2 col-sm-3 text-center">
          <a class="story-title" href="#">
           
            <img src="data:<%=books[i].image.contentType%>;base64,{Buffer.from('<%=books[i].image.data%>','binary').toString('base64')}"  style="width:100px;height:100px" class="img-circle">
          </a>
       
        </div>

我的get函数

 booksRouter.get('/',function(req,res){
            Bookdata.find()
            .then(function(books){
              res.render("books",{
                nav,
                title:"Library App",
                books
              });
            })
            
           
          });

在mongodb，我变得这样

> _id:6226e5c60e92bdee82dc574a title:"cc" author:"aa" genre:"life" image:Object
> data:Binary('iVBORw0KGgoAAAANSUhEUgAAA+gAAAOECAYAAAAylRvFAAAABGdBTUEAALGPC/xhBQAAAAFzUkdCAK7OHOkAAAAgY0hSTQAAeiYA...',
> 0) contentType:"image/png"
> __v:0

在控制台中出现错误

GET data:image/png;base64,{Buffer.from('%EF%BF%BDPNG%0A%1A%0A%EF%BF%BD%EF%BF%BD%EF%BF%BD%0AIHDR%EF%BF%BD%EF%BF%BD%03%EF%BF%BD%EF%BF%BD%EF%BF%BD%03%EF%BF%BD%08%06%EF%BF%BD%EF%BF%BD%EF%BF%BD2%EF%BF%BD%1B%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%04gAMA%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%0B%EF%BF%BDa%05%EF%BF%BD%EF%BF%BD%EF%BF%BD%01sRGB%EF%BF%BD%EF%BF%BD%EF%BF%BD%1C%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD cHRM%EF%BF%BD%EF%BF%BDz&%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDu0%EF%BF%BD%EF%BF%BD%EF%BF%BD`%EF%BF%BD%EF%BF%BD:%EF%BF%BD%EF%BF%BD%EF%BF%BD%17p%EF%BF%BD%EF%BF%BDQ<%EF%BF%BD%EF%BF%BD%EF%BF%BD%06bKGD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%09pHYs%EF%BF%BD%EF%BF%BD%0E%EF%BF%BD%EF%BF%BD%EF%BF%BD%0E%EF%BF%BD%01%EF%BF%BD+%0E%1B%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDIDATx%EF%BF%BD%EF%BF%BD%EF%BF%BDW%EF%BF%BD$%D7%95%EF%BF%BD%09%EF%BF%BDk%EF%BF%BDp%1D%1EZ%EF%BF%BD%EF%BF%BDH(%EF%BF%BD*%16g%EF%BF%BD%EF%BF%BD%EF%BF%BDNWw%EF%BF%BD%EF%BF%BDy%EF%BF%BDb.%EF%BF%BDb~%EF%BF%BD%EF%BF%BDI%EF%BF%BDb.%EF%BF%BD3]%EF%BF%BDd%15%EF%BF%BD$HB%%EF%BF%BDD%EF%BF%BD%EF%BF%BD%EF%BF%BD%D2%B5%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDEDF&%EF%BF%BDV%01H%10%EF%BF%BD%EF%BF%BD%13%EF%BF%BD%08ws%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDk%EF%BF%BDo%EF%BF%BD%EF%BF%BD*%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx<%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%EF%BF%BDW%EF%BF%BD?%05%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD|%EF%BF%BDx%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%1B%EF%BF%BD%17%EF%BF%BD%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%01x%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%1B%EF%BF%BD%17%EF%BF%BD%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%01x%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%1B%EF%BF%BD%17%EF%BF%BD%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%01x%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%1B%EF%BF%BD%17%EF%BF%BD%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%01%EF%BF%BD%EF%BF%BD%14%EF%BF%BD0%EF%BF%BD%EF%BF%BD%7F%02%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%0B%EF%BF%BD0%EF%BF%BDY%7F_D%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%EF%BF%BD%EF%BF%BD%EF%BF%BD%D1%B1%12%EF%BF%BD%EF%BF%BD%EF%BF%BDP%D0%B1%10%EF%BF%BD%19%11-S%EF%BF%BD-%EF%BF%BD%12%EF%BF%BD%EF%BF%BD%EF%BF%BD%13E%EF%BF%BDg%EF%BF%BD%EF%BF%BDYa%3E^%EF%BF%BD%EF%BF%BD%C5%BA%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD|[%EF%BF%BD%08%EF%BF%BD%0F%EF%BF%BD%EF%BF%BD%08%EF%BF%BD%EF%BF%BD%08W%EF%BF%BD%0Bt=%EF%BF%BD%EF%BF%BDL%EF%BF%BD%EF%BF%BD%CC%AEjf%EF%BF%BD%EF%BF%BDB%EF%BF%BD%0Bs%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BD%11%EF%BF%BD%1F,%EF%BF%BD*(%02%EF%BF%BDKx&%EF%BF%BD.Lb%EF%BF%BD%0A%EF%BF%BD+%DE%90|A%EF%BF%BD%EF%BF%BD%EF%BF%BD%22/e%C3%8F%EF%BF%BD%EF%BF%BD%17%EF%BF%BD%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD%EF%BF%BDx%3C%1E%EF%BF%BD%EF%BF%BD%EF%BF%BD]%EF%BF%BD net::ERR_INVALID_URL

我的mongodb

Answer 1

在模板中，只需添加属性：

编辑：不需要Buffer.from，因为它已经是缓冲区了：

使用 for 循环：

<%for(i=0;i<books.length;i++){%>

  <div class="row">
        <br>
        <div class="col-md-2 col-sm-3 text-center">
          <a class="story-title" href="#">

            <img src="data:<%=books[i].image.contentType%>;base64,<%=books[i].image.data.toString('base64')%>"  style="width:100px;height:100px" class="img-circle">
          </a>

        </div>
 <% } %>

如何解码从nodejs中的mongodb检索到的二进制图像数据

How to decode binary image data retrieved from mongodb in nodejs

node.js

mongodb

express

mongoose

multer