前端技术前沿7

落日映苍穹つ 2021-09-19 13:36 305阅读 0赞

//加载一个http模块
    
    var http = require('http');
    
    //creatServer来创建WEB服务器名为server
    
    var server= http.createServer(function(req,res){//函数的两个参数分别为req和res，作用分别是请求和响应
    
    res.writeHead(200,{'content-Type':'text/pain'});//返回的请求头上写状态码是200，返回的文本内容的类型是纯文本
    
    res.end('Hellow Nodejs\n');
    
    });
    
    server.listen(1337, '127.0.0.1');//listen在1337端口监听请求，服务器就可以收到任何来自端口的请求 
    
    console.log('Server running at http://127.0.0.1:1337/');

服务器是如何处理请求的

使用response.writeHead()函数发送一个HTTP状态200和HTTP头的内容类型content-type，使用response.write()函数在HTTP相应主体中发送文本。

调用response.end()完成响应

var http = require("http");
    http.createServer(...);

请求服务器模块的脚本仅仅需要启动服务器而已。

var server = require("./server");
    server.start();

路由选择  
onRequest()回调函数的第一个参数传递  
url和 querystring模块

![image.png][]

function route(pathname) {
    console.log("About to route a request for " + pathname);
    }
    exports.route = route;

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requestHandler.js修改  
![image.png][image.png 18]

如下所示：
    request.addListener("data", function(chunk) {
    // called when a new chunk of data was received
    });
    request.addListener("end", function() {
    // called when all chunks of data have been received
    });

先从 server.js开始：
    var http = require("http");
    var url = require("url");
    function start(route, handle) {
    function onRequest(request, response) {
    var postData = "";
    var pathname = url.parse(request.url).pathname;
    console.log("Request for " + pathname + " received.");
    request.setEncoding("utf8");
    request.addListener("data", function(postDataChunk) {
    postData += postDataChunk;
    console.log("Received POST data chunk '"+
    postDataChunk + "'.");
    });
    request.addListener("end", function() {
    route(handle, pathname, response, postData);
    });
    }
    http.createServer(onRequest).listen(8888);
    console.log("Server has started.");
    }
    exports.start = start;

在 requestHandlers.js中，我们将数据包含在对 upload请求的响应中：

querystring模块来实现：

处理文件上传

![image.png][image.png 19]

node-formidable 官方的例子展示了这两部分是如何融合在一起工作的：
    var formidable = require('formidable'),
    http = require('http'),
    sys = require('sys');
    http.createServer(function(req, res) {
    if (req.url == '/upload' && req.method.toLowerCase() == 'post') {
    // parse a file upload
    var form = new formidable.IncomingForm();
    form.parse(req, function(err, fields, files) {
    res.writeHead(200, {'content-type': 'text/plain'});
    res.write('received upload:\n\n');
    res.end(sys.inspect({fields: fields, files: files}));
    });
    return;
    }
    // show a file upload form
    res.writeHead(200, {'content-type': 'text/html'});
    res.end(
    '<form action="/upload" enctype="multipart/form-data" '+
    'method="post">'+
    '<input type="text" name="title"><br>'+
    '<input type="file" name="upload" multiple="multiple"><br>'+
    '<input type="submit" value="Upload">'+
    '</form>'
    );
    }).listen(8888);

![image.png][image.png 20]

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