黄舟2017-04-17 15:19:59
Start your mongo service, mongod --dbpath ~/mongodb_Data (replace ~/mongodb_Data with your own path)
Use mongofiles -d test put /Users/taozhi/Pictures/bg/21.jpg to add a picture to gridfs, and replace the image path /Users/taozhi/Pictures/bg/21.jpg with your own. After the addition is successful, you will get the following prompt:
2016-11-03T11:18:42.851+0800 connected to: localhost
added file: /Users/taozhi/Pictures/bg/21.jpg
mongoConnect to the default mongo server, db.fs.files.find()you can see the information of the image just stored, including file name, file size, block size, time and MD5 check code, etc.
{
"_id": ObjectId("581aad5aa3205aa0b201aceb"),
"chunkSize": 261120,
"uploadDate": ISODate("2016-11-03T03:22:02.621Z"),
"length": 218155,
"md5": "f4f93cef162e5b863f79a5187644e856",
"filename": "/Users/taozhi/Pictures/bg/21.jpg"
}According to the _id of the file, query all the chunks in the fs.chunks collection, db.fs.chunks.find({files_id:ObjectId('581aad5aa3205aa0b201aceb')})
The data preparation work is almost done here, let’s write the application service!
Or you can also use GridFS's writeFile directly. The detailed code can be seen below
The service is divided into several steps
If it is a set of processes, read the file
Write to mongo
Read data during service
Return to frontend
Because what you requested is a picture, let me read the file data here, base64 encode it and return it to the front end, and you can see the picture
app.js
const fs = require('fs')
const bodyParser = require('body-parser')
const express = require('express')
const path = require('path')
const http = require('http')
const Db = require('mongodb').Db,
MongoClient = require('mongodb').MongoClient,
Server = require('mongodb').Server,
ObjectID = require('mongodb').ObjectID,
GridStore = require('mongodb').GridStore,
Grid = require('mongodb').Grid;
const db = new Db('test', new Server('localhost', 27017));
const app = express();
const server = http.createServer(app);
app.set('view engine', 'ejs');
app.set('views', path.join(__dirname));
app.use(express.static(path.join(__dirname, '../../')));
app.use(bodyParser.urlencoded({extended: true}));
app.use(bodyParser.json());
app.get('/gridfs', (req, res) => {
// Establish connection to db
db.open(function(err, db) {
// Our file ID
var fileId = new ObjectID();
// Open a new file
var gridStore = new GridStore(db, fileId, 'w');
// Read the filesize of file on disk (provide your own)
var fileSize = fs.statSync('/Users/taozhi/Pictures/bg/21.jpg').size;
// Read the buffered data for comparision reasons
var data = fs.readFileSync('/Users/taozhi/Pictures/bg/21.jpg');
// Open the new file
gridStore.open(function(err, gridStore) {
// Write the file to gridFS
gridStore.writeFile('/Users/taozhi/Pictures/bg/21.jpg', function(err, doc) {
// Read back all the written content and verify the correctness
GridStore.read(db, fileId, function(err, fileData) {
res.render('index.ejs', { data: data.toString('base64') });
db.close();
});
});
});
});
})
app.use((err, req, res, next) => res.status(500).json({err: err.toString()}))
app.use((req, res) => res.status(404).json({ isError: true, error: { message: 'router NOT FOUND' } }))
server.listen(3333, '0.0.0.0', err => {
if(err) return console.error('app start failed')
console.info('app start at %s', 3000)
})
index.eje
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>MY APP</title>
</head>
<body>
<img src=<%= "data:image/jpg;base64,"+data %> />
</body>
</html>
Personal test was successful.
The code was written a bit hastily, and there are many areas that can be optimized. You can improve it yourself. I just provide a reference for you. I hope it will be helpful to you