javascript switch/case 在读取文件之前中断

Question

我正在编写一个带有 socket.io 实现的简单 node.js 服务器。当我转到 mylocalip:8005/socket.html 时，“socket_break”会在控制台中的“socket_data”之前打印出来。所以我在浏览器中看到的是空白页面而不是 socket.html 的内容。

var http = require("http");
var url = require('url');
var fs = require('fs');

var server = http.createServer(function(request, response){
console.log('Connection');
var path = url.parse(request.url).pathname;

switch(path){
    case '/':
        response.writeHead(200, {'Content-Type': 'text/html'});
        response.write('hello world');
        break;
    case '/socket.html':
        fs.readFile('./socket.html', function(error, data){
            if (error){
                response.writeHead(404);
                response.write("opps this doesn't exist - 404");
                console.log('socket_error');
            }
            else{
                response.writeHead(200, {"Content-Type": "text/html"});
                response.write(data, "utf8");
                console.log('socket_data');

            }
        });
        console.log('socket_break');
        break;
    default:
        response.writeHead(404);
        response.write("opps this doesn't exist - 404");
        break;
}
response.end();
});

server.listen(8005);

如何在读取文件之前防止切换/大小写中断并使浏览器显示我的 socket.html 文件的内容？

Answer 1

我会远离在 node.js 中做同步的事情，因为当你阻塞时，你会暂停所有发出请求的人。相反，将您的路线从错误处理中抽象出来。显然，关于你想如何做到这一点存在一些架构争论，但我就是这样做的，以便快速解决它:)

var http = require("http");
var url = require('url');
var fs = require('fs');

// Perhaps include this via a require('httpExceptionHandler')
function httpExceptionHandler(req, res) {
    return {
        404: function() {
            res.statusCode = 404;
            res.end("opps this doesn't exist - 404");
        },

        500: function(error) {
            res.statusCode = 500;
            res.end("internal server error");
        }
    }
}


// Perhaps include this via a require('routes')
var routes = {
    '/': function(server) {
        var res = server.response;
        res.setHeader('Content-Type', 'text/plain');
        res.end('hello world');
    },

    '/socket.html': function(server) {
        var fileStream = fs.createReadStream('socket.html');
        fileStream.on('error', server.httpExceptionHandler['500']);
        fileStream.pipe(server.response);
    }
};


var server = http.createServer(function(request, response){
    var path = url.parse(request.url).pathname;
    var routeFn = routes[path];

    var server = {
        httpExceptionHandler: httpExceptionHandler(request, response),
        request: request,
        response: response
    };

    if (routeFn) {
        // Set some default headers
        response.statusCode = 200;
        response.setHeader('Content-Type', 'text/html');

        // A better design might be to return an action like
        // Redirect, Exception, etc... not sure
        routeFn(server);
    } else {
        server.httpExceptionHandler['404']();
    }
});

server.listen(8005);

在我们完全完成之前，我们不会结束response，这使得上面的代码能够正常运行。