从零开始学习Node.js系列教程之设置HTTP头的方法示例

//basic server的配置文件var port = 3000;var server = require('./basicserver').createServer();server.useFavIcon("localhost", "./docroot/favicon.png");server.addContainer(".*", "/l/(.*)$", require('./redirector'), {})server.docroot("localhost", "/", "./docroot");//server.useFavIcon("127.0.0.1", "./docroot/favicon.png");//server.docroot("127.0.0.1", "/", "./docroot");server.listen(port);

var mime = require('mime');var mimeType = mime.lookup('image.gif'); //==> image/gifres.setHeader('Content-Type', mimeType);

res.setHeader('Set-Cookie2', ..cookie value..);

/* Basic Server的核心模块会创建一个HTTP服务器对象，附加Basic Server上用于检查请求，然后给予适当响应的功能 Basic Server可以通过判断Host头部匹配的容器对象响应来自多个域名的请求 */var http = require('http');var url = require('url');exports.createServer = function(){  var htserver = http.createServer(function(req, res){    req.basicServer = {urlparsed: url.parse(req.url, true)};    processHeaders(req, res);    dispatchToContainer(htserver, req, res);  });  htserver.basicServer = {containers: []};  htserver.addContainer = function(host, path, module, options){    if (lookupContainer(htserver, host, path) != undefined){      throw new Error("Already mapped " + host + "/" + path);    }    htserver.basicServer.containers.push({host: host, path: path, module: module, options: options});    return this;  }  htserver.useFavIcon = function(host, path){    return this.addContainer(host, "/favicon.ico", require('./faviconHandler'), {iconPath: path});  }  htserver.docroot = function(host, path, rootPath){    return this.addContainer(host, path, require('./staticHandler'), {docroot: rootPath});  }  return htserver;}var lookupContainer = function(htserver, host, path){  for (var i = 0; i < htserver.basicServer.containers.length; i++){    var container = htserver.basicServer.containers[i];    var hostMatches = host.toLowerCase().match(container.host);    var pathMatches = path.match(container.path);    if (hostMatches !== null && pathMatches !== null){      return {container: container, host: hostMatches, path: pathMatches};    }  }  return undefined;}//用于搜索req.headers数组以查找cookie和host头部，因为这两个字段对请求的分派都很重要//这个函数在每一个HTTP请求到达时都会被调用//还有很多其他的HTTP头部字段(Accept Accept-Encoding Accept-Language User-Agent)var processHeaders = function(req, res){  req.basicServer.cookies = [];  var keys = Object.keys(req.headers);  for (var i = 0; i < keys.length; i++){    var hname = keys[i];    var hval = req.headers[hname];    if (hname.toLowerCase() === "host"){      req.basicServer.host = hval;    }    //提取浏览器发送的cookie    if (hname.toLowerCase() === "cookie"){      req.basicServer.cookies.push(hval);    }  }}//查找匹配的容器，分派请求到对应的容器中//这个函数在每一个HTTP请求到达时都会被调用var dispatchToContainer = function(htserver, req, res){  var container = lookupContainer(htserver, req.basicServer.host, req.basicServer.urlparsed.pathname);  if (container !== undefined){    req.basicServer.hostMatches = container.host;    req.basicServer.pathMatches = container.path;    req.basicServer.container = container.container;    container.container.module.handle(req, res);  }else {    res.writeHead(404, {'Content-Type': 'text/plain'});    res.end("no handler found for " + req.basicServer.host + "/" + req.basicServer.urlparsed);  }}

//用于处理文件系统内的文件，docroot选项指被存放文件所在文件夹的路径，读取该目录下的指定文件var fs = require('fs');var mime = require('mime');var sys = require('sys');exports.handle = function(req, res){  if (req.method !== "GET"){    res.writeHead(404, {'Content-Type': 'text/plain'});    res.end("invalid method " + req.method);  } else {    var fname = req.basicServer.container.options.docroot + req.basicServer.urlparsed.pathname;    if (fname.match(///$/)) fname += "index.html"; //如果URL以/结尾    fs.stat(fname, function(err, stats){      if (err){        res.writeHead(500, {'Content-Type': 'text/plain'});        res.end("file " + fname + " not found " + err);      } else {        fs.readFile(fname, function(err, buf){          if (err){            res.writeHead(500, {'Content-Type': 'text/plain'});            res.end("file " + fname + " not readable " + err);          } else {            res.writeHead(200, {'Content-Type': mime.lookup(fname),              'Content-Length': buf.length});            res.end(buf);          }        });      }    });  }}

//这个处理函数处理对favicon.ico的请求//MIME模块根据给出的图标文件确定正确的MIME类型，网站图标favicon可以是任何类型的图片，但是我们必须要告诉浏览器是哪个类型//MIME模块，用于生成正确的Content-Type头var fs = require('fs');var mime = require('mime');exports.handle = function(req, res){  if (req.method !== "GET"){    res.writeHead(404, {'Content-Type': 'text/plain'});    res.end("invalid method " + req.method);  } else if (req.basicServer.container.options.iconPath !== undefined){    fs.readFile(req.basicServer.container.options.iconPath, function(err, buf){      if (err){        res.writeHead(500, {'Content-Type': 'text/plain'});        res.end(req.basicServer.container.options.iconPath + "not found");      } else {        res.writeHead(200, {'Content-Type': mime.lookup(req.basicServer.container.options.iconPath),        'Content-Length': buf.length});        res.end(buf);      }    });  } else {    res.writeHead(404, {'Content-Type': 'text/plain'});    res.end("no favicon");  }}

/* 把一个域的请求重定向到另一个上，例如将www.example.com重定向到example.com上，或者使用简短的URL跳转到较长的URL 实现这两种情况，我们需要在HTTP响应中发送301(永久移除)或者302(临时移除)状态码，并且指定location头信息。有了这个组合 信号，web浏览器就知道要跳转到另一个web位置了 *///地址http://localhost:3000/l/ex1 会跳转到http://example1.comvar util = require('util');var code2url = {'ex1': 'http://example1.com', 'ex2': "http://example2.com"};var notFound = function(req, res){  res.writeHead(404, {'Content-Type': 'text/plain'});  res.end("no matching redirect code found for " + req.basicServer.host + "/" + req.basicServer.urlparsed.pathname);}exports.handle = function(req, res){  if (req.basicServer.pathMatches[1]){    var code = req.basicServer.pathMatches[1];    if (code2url[code]){      var url = code2url[code];      res.writeHead(302, {'Location': url});      res.end();    } else {      notFound(req, res);    }  } else {    notFound(req, res);  }}

<html><head></head><body>  <h1>Index</h1>  <p>this is a index html.</p></body></html>