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服务端的javascript脚本node.js示例代码

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JavaScript

脚本 JavaScript Ajax Comet MongoDB

Node.js是一套用来编写高性能网络服务器的JavaScript工具包，一系列的变化由此开始。比较独特的是，Node.js会假设你是在POSIX环境下运行它Linux 或 Mac OS X。如果你是在Windows下，那就需要安装MinGW以获得一个仿POSIX的环境。在Node中，Http是首要的。Node为创建http服务器作了优化，所以你在网上看到的大部分示例和库都是集中在web上(http框架、模板库等）

软件首页:http://nodejs.org

读取文件到字符串

var fs = require('fs');

var file = fs.readFileSync(path, "utf8");

console.log(file);

编写的一个简单的 HTTP 服务器

var sys = require(sys),
http = require(http);
server = http.createServer(function (req, res) {
res.writeHeader(200, {Content-Type: text/plain});
res.write(Hello World);
res.close();
})
server.listen(8000);
sys.puts(Server running at a href="http://127.0.0.1:8000/);

读取mongoDB并输出json数据

运行此源码必须

1、安装node mongodb native驱动

2、express js框架(不安装的话简单修改index.js即可)

3、安装了mongoDB,并且有comments数据库comments collection。collection里有数据。

如果名字不一样，进index.js就可以修改。端口必须是默认的。

3、node index.js，打开127.0.0.1:8001就可以看到返回了数据

index.js

var express = require('express');

var app = express.createServer();

var db = require('./tea/db');

db.open({dbName:'comments'});

app.get('/',function(req,res){

db.findOne('comments',{},function(records){

res.send(records);

});

app.listen(8001);

/tea/index.js

var tea = exports;

tea.hello = function(){

console.log('hello world');

}

/tea/db.js

var mongo = require('mongodb');

var tea = tea || {};

tea.db = exports;

tea.db.server = '127.0.0.1';

tea.db.port = 27017;

tea.db.db = null;

tea.db.dbName = '';

tea.db.collection = '';

tea.db.open = function(mongoInfo,callback){

this.dbName = mongoInfo.dbName;

if(!this.db) this.db = new mongo.Db(mongoInfo.dbName, new mongo.Server('127.0.0.1', 27017, {}), {});

this.db.open(function(err,db){

this.db = db;

if(callback) callback(db);

});

return this;

};

tea.db.find = function(collection,query,callback,isFindOne){

this.db.collection(collection, function(err, collection) {

var func = isFindOne ? 'findOne' : 'find';

collection[func](query,function(err,cursor){

if(!isFindOne) {

cursor.toArray(function(err,items){

if(callback) callback(items);

});

}else{

if(callback) callback(cursor);

}

});

}

tea.db.findOne = function(collection,query,callback){

this.find(collection,query,callback,1);

}

tea.db.close = function(){

if(tea.db.db) tea.db.db.close();

}

tea.db.hello = function(){

console.log('Hello World');

}

几个常用字符串hash算法的node封装

// hash.js

exports.additive = function (key, prime) {

key = key instanceof Buffer ? key : new Buffer(key);

prime = prime == undefined ? 0xffffffff : prime;

for (var hash = key.length, i = 0; i < key.length; i++) {

hash += key[i];

}

return (hash % prime);

}

exports.rotating = function(key) {

key = key instanceof Buffer ? key : new Buffer(key);

for (var hash = key.length, i = 0; i<key.length; ++i) {

hash = (hash << 4) ^ (hash >> 28) ^ key[i];

}

return hash;

}

exports.bernstein = function(key, prime) {

key = key instanceof Buffer ? key : new Buffer(key);

prime = prime == undefined ? 0xffffffff : prime;

var hash = 0;

for (i=0; i<key.length; ++i) {

hash = (hash << 5 + hash) + key[i];

}

return hash;

}

exports.fnv = function (key){

key = key instanceof Buffer ? key : new Buffer(key);

var p = 16777619, hash = 0x811C9DC5;

for(var i=0; i< key.length; i++) {

hash = (hash * p) ^ key[i];

}

hash += hash << 13;

hash ^= hash >> 7;

hash += hash << 3;

hash ^= hash >> 17;

hash += hash << 5;

return hash;

}

exports.fnv1a = function (key){

key = key instanceof Buffer ? key : new Buffer(key);

var p = 16777619, hash = 0x811C9DC5;

for(var i=0; i< key.length; i++) {

hash = (hash ^ key[i]) * p;

}

hash += hash << 13;

hash ^= hash >> 7;

hash += hash << 3;

hash ^= hash >> 17;

hash += hash << 5;

return hash;

}

Node 下 Http Streaming 的跨浏览器实现

http://cnodejs.org/blog/?p=112
最近考虑把整个前端架构使用http streaming方式实现
对这方面做了一下调研,并在在node上实现了一个简单的原型

顺带提一下,
楼下pengchun同学所提到的node chat使用的是longpoll的模型
和httpstreaming同属与http comet的解决方案.
不过在具体http连接的处理上有所不同
long poll在数据通道每次接收到一个数据包后即关闭连接,并立即重新打开数据通道
http streaming的数据通道始终处于打开状态.
具体的介绍可以看这里 http://en.wikipedia.org/wiki/Comet_(programming)#Streaming

一些细节:
由于ie下在xhr readystate=3时无法取得responseText,

因此在ie下改为通过使用htmlfile控件调用iframe实现
另在输出正式数据前需现输出1k的噪音数据
以解决浏览器的阻塞问题

原型功能设计

pipe.js

var http = require('http'),

fs = require('fs'),

url = require('url'),

page = null;

// static files read & watch

var readFile = function(files) {

var buffers = {};

// sync read

var fread = function(file, cb){

fs.readFile(file, 'binary', function(err, data){

if (err) {

throw err;

}

buffers[file] = new Buffer(data, 'binary');

console.log('load', file)

});

}

// watch changes

var watch = function watch(file) {

fs.watchFile(file, {persistent: true, interval: 100}, function (curr, prev) {

if (curr.mtime.getTime() != prev.mtime.getTime()) {

fread(file);

}

});

}

// run all files

for (var i = 0; i < files.length; i++) {

watch(files[i]);

fread(files[i]);

}

return buffers;

}

// http query

var httpQuery = function(u, cb){

console.log('http begin');

// parse url

var uinfo = url.parse(u);

// create client

var client = http.createClient(uinfo.port ? uinfo.port : 80, uinfo.hostname, false);

var uri = uinfo.pathname + (uinfo.search ? uinfo.search : '');

var req = client.request('GET', uri, {'host': uinfo.hostname});

// send request

req.end();

console.log('http request sent');

var len = 4096;

var pointer = 0;

var extendFactor = 2;

// response start

req.on('response', function (res) {

if (res.headers['content-length']) {

len = parseInt(res.headers['content-length']);

}

// body init

var body = new Buffer(len);

// chunk recived

res.on('data', function(chunk){

// extends

if (pointer + chunk.length > len) {

len *= extendFactor;

body = body.copy(new Buffer(len), 0, 0);

console.log('proxy extend to', len);

}

// copy chunk to buf

chunk.copy(body, pointer, 0);

// move pointer

pointer += chunk.length;

})

// response end

res.on('end', function() {

cb(body.length > pointer ? body.slice(0, pointer) : body);

console.log('proxy end', pointer);

});

})

}

// main server

var server = http.createServer(function (req, res){

// main page

if (req.url == '/') {

res.writeHeader(200);

res.end(page["pipe.html"]);

// time serve

} else if (req.url == '/time') {

res.writeHeader(200);

res.end(new Date().toString());

// iframe recv

} else if (req.url.match(/^\/iframe\//)) {

var clientid = parseInt(req.url.substr(8));

pipeClient.add(clientid, res, pipeClient.iframe);

console.log('iframe connect', clientid);

// ajax recv

} else if (req.url.match(/^\/ajax\//)) {

var clientid = parseInt(req.url.substr(6));

pipeClient.add(clientid, res, pipeClient.ajax);

console.log('ajax connect', clientid);

// request listen

} else if (req.url.match(/^\/req\//)) {

res.writeHeader(200,{

'Cache-Control': 'no-cache, must-revalidate'

});

res.end();

// url parse

var clientid = parseInt(req.url.substr(5, 13));

// get page

httpQuery("http://localhost:8000/time", function (data){

console.log(data.toString());

pipeClient.write(clientid, data);

console.log("write", clientid, data.length);

});

// error pages

} else {

res.writeHeader(404, {"Content-Type" : "text/html"});

res.end();

}

});

var pipeClient = {

timeout : 30000,

client : {},

prefix : "<script>s('",

suffix : "');</script>",

iframe : 'iframe',

ajax : 'ajax',

noise : null,

noiseSize : 1024,

page : null,

init : function(){

this.noise = new Buffer(1024);

for (var i = 0; i < this.noiseSize; i++) {

this.noise[i] = 32;

}

this.page = readFile(['iframe.html']);

add : function(id, res, type) {

if (type == this.ajax) {

res.writeHeader(200, {

'Cache-Control': 'no-cache, must-revalidate'

});

res.write(this.noise);

} else {

res.writeHeader(200, {

"Content-Type" : "multipart/x-mixed-replace",

'Cache-Control': 'no-cache, must-revalidate'

});

res.write(this.page['iframe.html']);

res.write(this.noise);

}

this.client[id] = {

res : res,

type : type,

tm : setTimeout(function(){

pipeClient.close(id);

}, this.timeout)

};

close : function (id) {

console.log("client close", id)

this.client[id].res.end();

this.client[id].res = null;

delete this.client[id];

write : function (id, data) {

clearTimeout(this.client[id].tm);

this.client[id].tm = setTimeout(function(){

pipeClient.close(id);

}, this.timeout);

this.client[id].res.write(this.format(data, this.client[id].type));

format : function(data, type) {

// with iframe

if (type == this.iframe) {

var buf = new Buffer(this.prefix.length + data.length + this.suffix.length);

buf.write(this.prefix, 0, 'binary');

data.copy(buf, this.prefix.length, 0);

buf.write(this.suffix, this.prefix.length + data.length);

// with ajax

} else {

var buf = new Buffer(data.length + 8);

// set length

buf.write(data.length.toString(16), 0, 'binary');

// space padding

for (var i = data.length.toString(16).length; i < 8; i++) {

buf[i] = 32;

}

// set data

data.copy(buf, 8, 0);

}

console.log(buf.toString());

return buf;

}

pipeClient.init();

page = readFile(['pipe.html']);

setTimeout(function(){

server.listen(8000);

}, 500);

pipe.html

<!DOCTYPE html>

<head>

<title>Comet Pipe Demo</title>

google.load("jquery", '1.4');

google.setOnLoadCallback(function(){

$(document.body).ready(function(){

var Comet = function(options) {

// options init

var opt = {

domain : document.domain,

req : '/req',

iframe : '/iframe',

ajax : '/ajax',

timeout : 300,

cb : null,

cl : null,

ajaxFlagLen : 10,

ajaxNoiseLen : 1024

}

for (k in options) {

opt[k] = options[k];

}

// calculate bytes length for string

var blen = function(str) {

var arr = str.match(/[^\x00-\xff]/ig);

return arr == null ? str.length : str.length + arr.length;

}

// some arguments init

var pageid = new Date().getTime();

var type = $.browser.msie ? 'iframe' : 'ajax';

// public props

var me = {

pageid : pageid,

type : type,

recvUrl : opt[type] + '/' + pageid,

reqUrl : opt.req + '/' + pageid + '/' + type,

conn : null,

div : null,

send : function(){

$.get(this.reqUrl);

}

// init iframe receiver

if (me.type == 'iframe') {

// create htmlfire

me.conn = new ActiveXObject("htmlfile");

me.conn.open();

// set domain

me.conn.write("<html><script>document.domain = '"+opt.domain+"'</html>");

me.conn.close();

me.div = me.conn.createElement("div");

me.conn.appendChild(me.div);

me.conn.parentWindow.send = function (data) {

opt.cl ? opt.cb.call(opt.cl, data) : opt.cb(data);

};

me.div.innerHTML = "<iframe id='comet' src='" + me.recvUrl + "'></iframe>";

// init ajax receiver

} else {

me.conn = new XMLHttpRequest();

me.conn.open("GET", me.recvUrl, true);

var pos = 0;

var chunk = '';

var data = '';

var size = -1;

var noise = 0;

me.conn.onreadystatechange = function(){

if (this.readyState == 3 || this.readyState == 4) {

// chars length

chunk = this.responseText.substr(pos);

pos = this.responseText.length;

if (noise < opt.ajaxNoiseLen) {

noise += chunk.length;

return;

}

// bytes length

if (size < 0) {

font-famil

查看图片附件

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转：史上最强软件攻城师面试题 | 指针也很简单的

2011-03-21 15:06
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最新评论

服务端的javascript脚本node.js示例代码

读取文件到字符串

编写的一个简单的 HTTP 服务器

读取mongoDB并输出json数据

index.js

/tea/index.js

/tea/db.js

几个常用字符串hash算法的node封装

Node 下 Http Streaming 的跨浏览器实现

原型功能设计

pipe.js

pipe.html

评论

发表评论

相关推荐

最近访客 更多访客>>

博主相关

文章分类

社区版块

存档分类

最新评论

服务端的javascript脚本node.js示例代码

读取文件到字符串

编写的一个简单的 HTTP 服务器

读取mongoDB并输出json数据

index.js

/tea/index.js

/tea/db.js

几个常用字符串hash算法的node封装

Node 下 Http Streaming 的跨浏览器实现

原型功能设计

pipe.js

pipe.html

评论

发表评论

相关推荐

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