req.params模块

Question

不确定我有在我的server.js路线提供图片的工作API，并且想要抽象到一个单独的模块。

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'); 
    } 
}) 

我想是这样的：

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

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

，我已经试着写像这样在我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未定义。我哪里错了？

谢谢！

Answer 1

你应该在你的路由器imageRouter.js使用get()和前缀它在你的主应用程序。

use()是中间件。

这里是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);