req.params模塊

Question

不確定我有在我的server.js路線提供圖片的工作API，並且想要抽象到一個單獨的模塊。

前：

app.get('/api/image/:filename', function(req, res){ 
    var resourcePath = 'uploads/public/projectnumber/issues/small/' + req.params.filename + '.png'; 

    console.log(resourcePath) 

    if(fs.existsSync(resourcePath)) { 
    var file = fs.readFileSync(resourcePath); 
    res.writeHead(200, 'Content-Type:application/pdf:image/png'); 
    res.end(file,'binary'); 
    } 
    else { 
    res.send(400, 'No image found'); 
    } 
}) 

我想是這樣的：

var ImageRouter = require('./routes/imageRouter'); 

app.use('/api/image/:filename', ImageRouter); 

，我已經試着寫像這樣在我imageRouter.js文件：

var express = require('express'); 
var fs = require('fs'); 
var router = express.Router(); 

router.use(function(req, res, next) { 
    var resourcePath = 'public/images/' + req.params.filename + '.png'; 

    if(fs.existsSync(resourcePath)) { 
    var file = fs.readFileSync(resourcePath); 
    res.writeHead(200, 'Content-Type:application/pdf:image/png'); 
    res.end(file,'binary'); 
    } 
    else { 
    res.send(400, 'No image found'); 
    } 

    next(); 
}); 

module.exports = router; 

但req.params.filename未定義。我哪裏錯了？

謝謝！

Answer 1

你應該在你的路由器imageRouter.js使用get()和前綴它在你的主應用程序。

use()是中間件。

這裏是imageRouter.js：

var router = require('express').Router(); 
var fs = require('fs'); 

router.get('/:filename', function(req, res) { 
    var resourcePath = 'public/images/' + req.params.filename + '.png'; 

    if(fs.existsSync(resourcePath)) { 
    var file = fs.readFileSync(resourcePath); 
    res.writeHead(200, 'Content-Type:application/pdf:image/png'); 
    res.end(file,'binary'); 
    } 
    else { 
    res.send(400, 'No image found'); 
    } 
}); 

module.exports = router; 

而且你server.js：

var express = require('express'); 
var app = express(); 

var ImageRouter = require('./routes/imageRouter'); 

app.use('/api/image', ImageRouter);