AJAX(XMLHttpRequest)跨域请求(二)

分类：Javascript| 发布：camnprbubuol| 查看： | 发表时间：2010/12/10






注意：以下代码请在Firefox 3.5、Chrome 3.0、Safari 4之后的版本中进行测试。IE8的实现方法与其他浏览不同。

2，预检请求

预检请求首先需要向另外一个域名的资源发送一个 HTTP OPTIONS 请求头，其目的就是为了判断实际发送的请求是否是安全的。下面的2种情况需要进行预检：

a，不是上面的简单请求，比如使用Content-Type 为 application/xml 或 text/xml 的 POST 请求

b，在请求中设置自定义头，比如 X-JSON、X-MENGXIANHUI 等

注意：在 iis 里进行测试，必须在“应用程序扩展”里面配置 .aspx 扩展的动作允许 OPTIONS。

下面我们举一个预检的请求：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 

 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 

<html xmlns="http://www.w3.org/1999/xhtml"> 

<head> 

<title>孟宪会之AJAX跨域请求测试</title> 

</head> 

<body> 

 <input type=’button’ value=’开始测试’ onclick=’crossDomainRequest()’ /> 

 <div id="content"></div> 

 <mce:script type="text/javascript"><!-- 

 var xhr = new XMLHttpRequest(); 

 var url = ’http://dotnet.aspx.cc/PreflightedRequests.aspx’; 

 function crossDomainRequest() { 

 document.getElementById("content").innerHTML = "开始进行请求……"; 

 if (xhr) { 

 var xml = "<root>测试</root>"; 

 xhr.open(’POST’, url, true); 

 xhr.setRequestHeader("POWERED-BY-MENGXIANHUI", "Approve"); 

 xhr.setRequestHeader("Content-Type", "application/xml"); 

 xhr.onreadystatechange = handler; 

 xhr.send(xml); 

 } else { 

 document.getElementById("content").innerHTML = "不能创建 XMLHttpRequest。"; 

 } 

 } 

 function handler(evtXHR) { 

 if (xhr.readyState == 4) { 

 if (xhr.status == 200) { 

 var response = xhr.responseText; 

 document.getElementById("content").innerHTML = "结果：" + response; 

 } else { 

 document.getElementById("content").innerHTML = "不能进行跨越访问。"; 

 } 

 } 

 else { 

 document.getElementById("content").innerHTML += "<br/>执行状态 readyState：" + xhr.readyState; 

 } 

 } 

// --></mce:script> 

</body> 

</html> 

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<title>孟宪会之AJAX跨域请求测试</title>

</head>

<body>

 <input type=’button’ value=’开始测试’ onclick=’crossDomainRequest()’ />

 <div id="content"></div>

 <mce:script type="text/javascript"><!--

 var xhr = new XMLHttpRequest();

 var url = ’http://dotnet.aspx.cc/PreflightedRequests.aspx’;

 function crossDomainRequest() {

 document.getElementById("content").innerHTML = "开始进行请求……";

 if (xhr) {

 var xml = "<root>测试</root>";

 xhr.open(’POST’, url, true);

 xhr.setRequestHeader("POWERED-BY-MENGXIANHUI", "Approve");

 xhr.setRequestHeader("Content-Type", "application/xml");

 xhr.onreadystatechange = handler;

 xhr.send(xml);

 } else {

 document.getElementById("content").innerHTML = "不能创建 XMLHttpRequest。";

 }

 }

 function handler(evtXHR) {

 if (xhr.readyState == 4) {

 if (xhr.status == 200) {

 var response = xhr.responseText;

 document.getElementById("content").innerHTML = "结果：" + response;

 } else {

 document.getElementById("content").innerHTML = "不能进行跨越访问。";

 }

 }

 else {

 document.getElementById("content").innerHTML += "<br/>执行状态 readyState：" + xhr.readyState;

 }

 }

// --></mce:script>

</body>

</html>

上面的例子我们发送 xml 格式的数据，并且，发送一个非标准的HTTP头 POWERED-BY-MENGXIANHUI 来说明服务器端该如何设置响应头的。

在服务器端，PreflightedRequests.aspx 的内容如下：

<%@ Page Language="C#" %> 

<mce:script runat="server"><!-- 

 protected void Page_Load(object sender, EventArgs e) 

 { 

 if (Request.HttpMethod.Equals("GET")) 

 { 

 Response.Write("这个页面是用来测试跨域 POST 请求的，直接浏览意义不大。"); 

 } 

 else if (Request.HttpMethod.Equals("OPTIONS")) 

 { 

 //通知客户端允许预检请求。并设置缓存时间 

 Response.ClearContent(); 

 Response.AddHeader("Access-Control-Allow-Origin", "http://www.camnpr.com:801"); 

 Response.AddHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS"); 

 Response.AddHeader("Access-Control-Allow-Headers", "POWERED-BY-MENGXIANHUI"); 

 Response.AddHeader("Access-Control-Max-Age", "30"); 

 //此过程无需返回数据 

 Response.End(); 

 } 

 else if (Request.HttpMethod.Equals("POST")) 

 { 

 if (Request.Headers["Origin"].Equals("http://www.camnpr.com:801")) 

 { 

 System.Xml.XmlDocument doc = new System.Xml.XmlDocument(); 

 doc.Load(Request.InputStream); 

 Response.AddHeader("Access-Control-Allow-Origin", "http://www.camnpr.com:801"); 

 Response.Write("您提交的数据是：<br/><br/>" + Server.HtmlEncode(doc.OuterXml)); 

 } 

 else 

 { 

 Response.Write("不允许你的网站请求。"); 

 } 

 } 

 } 

// --></mce:script> 

<%@ Page Language="C#" %>

<mce:script runat="server"><!--

 protected void Page_Load(object sender, EventArgs e)

 {

 if (Request.HttpMethod.Equals("GET"))

 { 

 Response.Write("这个页面是用来测试跨域 POST 请求的，直接浏览意义不大。");

 }

 else if (Request.HttpMethod.Equals("OPTIONS"))

 {

 //通知客户端允许预检请求。并设置缓存时间

 Response.ClearContent();

 Response.AddHeader("Access-Control-Allow-Origin", "http://www.camnpr.com:801");

 Response.AddHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS");

 Response.AddHeader("Access-Control-Allow-Headers", "POWERED-BY-MENGXIANHUI");

 Response.AddHeader("Access-Control-Max-Age", "30"); 

 //此过程无需返回数据

 Response.End(); 

 }

 else if (Request.HttpMethod.Equals("POST"))

 {

 if (Request.Headers["Origin"].Equals("http://www.camnpr.com:801"))

 {

 System.Xml.XmlDocument doc = new System.Xml.XmlDocument();

 doc.Load(Request.InputStream);

 Response.AddHeader("Access-Control-Allow-Origin", "http://www.camnpr.com:801");

 Response.Write("您提交的数据是：<br/><br/>" + Server.HtmlEncode(doc.OuterXml));

 }

 else

 {

 Response.Write("不允许你的网站请求。");

 }

 }

 }

// --></mce:script>

点击“开始测试”按钮，将会执行下面的一系列请求。

OPTIONS /PreflightedRequests.aspx HTTP/1.1 

Host: dotnet.aspx.cc 

User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; zh-CN; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 (.NET CLR 3.5.30729) 

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 

Accept-Language: zh-cn,zh;q=0.5 

Accept-Encoding: gzip,deflate 

Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7 

Keep-Alive: 300 

Connection: keep-alive 

Origin: http://www.camnpr.com:801 

Access-Control-Request-Method: POST 

Access-Control-Request-Headers: powered-by-mengxianhui 

HTTP/1.x 200 OK 

Date: Sun, 10 Jan 2010 14:00:34 GMT 

Server: Microsoft-IIS/6.0 

X-Powered-By: ASP.NET 

X-AspNet-Version: 2.0.50727 

Access-Control-Allow-Origin: http://www.camnpr.com:801 

Access-Control-Allow-Methods: POST, GET, OPTIONS 

Access-Control-Allow-Headers: POWERED-BY-MENGXIANHUI 

Access-Control-Max-Age: 30 

Set-Cookie: ASP.NET_SessionId=5npqri55dl1k1zvij1tlw3re; path=/; HttpOnly 

Cache-Control: private 

Content-Length: 0 

POST /PreflightedRequests.aspx HTTP/1.1 

Host: dotnet.aspx.cc 

User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; zh-CN; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 (.NET CLR 3.5.30729) 

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 

Accept-Language: zh-cn,zh;q=0.5 

Accept-Encoding: gzip,deflate 

Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7 

Keep-Alive: 300 

Connection: keep-alive 

POWERED-BY-MENGXIANHUI: Approve 

Content-Type: application/xml; charset=UTF-8 

Referer: http://www.camnpr.com:801/CrossDomainAjax/PreflightedRequests.html 

Content-Length: 19 

Origin: http://www.camnpr.com:801 

Pragma: no-cache 

Cache-Control: no-cache 

<root>测试</root> 

HTTP/1.x 200 OK 

Date: Sun, 10 Jan 2010 14:00:34 GMT 

Server: Microsoft-IIS/6.0 

X-Powered-By: ASP.NET 

X-AspNet-Version: 2.0.50727 

Access-Control-Allow-Origin: http://www.camnpr.com:801 

Set-Cookie: ASP.NET_SessionId=byvose45zmtbqy45d2a1jf2i; path=/; HttpOnly 

Cache-Control: private 

Content-Type: text/html; charset=utf-8 

Content-Length: 65 

OPTIONS /PreflightedRequests.aspx HTTP/1.1

Host: dotnet.aspx.cc

User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; zh-CN; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 (.NET CLR 3.5.30729)

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: zh-cn,zh;q=0.5

Accept-Encoding: gzip,deflate

Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7

Keep-Alive: 300

Connection: keep-alive

Origin: http://www.camnpr.com:801

Access-Control-Request-Method: POST

Access-Control-Request-Headers: powered-by-mengxianhui

HTTP/1.x 200 OK

Date: Sun, 10 Jan 2010 14:00:34 GMT

Server: Microsoft-IIS/6.0

X-Powered-By: ASP.NET

X-AspNet-Version: 2.0.50727

Access-Control-Allow-Origin: http://www.camnpr.com:801

Access-Control-Allow-Methods: POST, GET, OPTIONS

Access-Control-Allow-Headers: POWERED-BY-MENGXIANHUI

Access-Control-Max-Age: 30

Set-Cookie: ASP.NET_SessionId=5npqri55dl1k1zvij1tlw3re; path=/; HttpOnly

Cache-Control: private

Content-Length: 0

POST /PreflightedRequests.aspx HTTP/1.1

Host: dotnet.aspx.cc

User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; zh-CN; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 (.NET CLR 3.5.30729)

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: zh-cn,zh;q=0.5

Accept-Encoding: gzip,deflate

Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7

Keep-Alive: 300

Connection: keep-alive

POWERED-BY-MENGXIANHUI: Approve

Content-Type: application/xml; charset=UTF-8

Referer: http://www.camnpr.com:801/CrossDomainAjax/PreflightedRequests.html

Content-Length: 19

Origin: http://www.camnpr.com:801

Pragma: no-cache

Cache-Control: no-cache

<root>测试</root>

HTTP/1.x 200 OK

Date: Sun, 10 Jan 2010 14:00:34 GMT

Server: Microsoft-IIS/6.0

X-Powered-By: ASP.NET

X-AspNet-Version: 2.0.50727

Access-Control-Allow-Origin: http://www.camnpr.com:801

Set-Cookie: ASP.NET_SessionId=byvose45zmtbqy45d2a1jf2i; path=/; HttpOnly

Cache-Control: private

Content-Type: text/html; charset=utf-8

Content-Length: 65

以上的代码反映了预检请求的执行过程：首先发送 OPTIONS 请求头，用来向服务器咨询服务器的更多信息，以便为后续的真实请求做准备。比如是否支持 POST 方法等。值得注意的是：

浏览器还发送 Access-Control-Request-Method: POST 和 Access-Control-Request-Headers: powered-by-mengxianhui 请求头。

注意：以上过程是第一次请求的时候的过程，如果在 30 秒内重复点击按钮，你可以看不到 OPTIONS 这一过程。则执行过程是这样的：

POST /PreflightedRequests.aspx HTTP/1.1 

Host: dotnet.aspx.cc 

User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; zh-CN; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 (.NET CLR 3.5.30729) 

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 

Accept-Language: zh-cn,zh;q=0.5 

Accept-Encoding: gzip,deflate 

Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7 

Keep-Alive: 300 

Connection: keep-alive 

POWERED-BY-MENGXIANHUI: Approve 

Content-Type: application/xml; charset=UTF-8 

Referer: http://www.camnpr.com:801/CrossDomainAjax/PreflightedRequests.html 

Content-Length: 19 

Origin: http://www.camnpr.com:801 

Pragma: no-cache 

Cache-Control: no-cache 

<root>测试</root> 

HTTP/1.x 200 OK 

Date: Sun, 10 Jan 2010 14:06:32 GMT 

Server: Microsoft-IIS/6.0 

X-Powered-By: ASP.NET 

X-AspNet-Version: 2.0.50727 

Access-Control-Allow-Origin: http://www.camnpr.com:801 

Set-Cookie: ASP.NET_SessionId=qs1c4urxywdbdx55u04pvual; path=/; HttpOnly 

Cache-Control: private 

Content-Type: text/html; charset=utf-8 

Content-Length: 65 

POST /PreflightedRequests.aspx HTTP/1.1

Host: dotnet.aspx.cc

User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; zh-CN; rv:1.9.1.7) Gecko/20091221 Firefox/3.5.7 (.NET CLR 3.5.30729)

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: zh-cn,zh;q=0.5

Accept-Encoding: gzip,deflate

Accept-Charset: GB2312,utf-8;q=0.7,*;q=0.7

Keep-Alive: 300

Connection: keep-alive

POWERED-BY-MENGXIANHUI: Approve

Content-Type: application/xml; charset=UTF-8

Referer: http://www.camnpr.com:801/CrossDomainAjax/PreflightedRequests.html

Content-Length: 19

Origin: http://www.camnpr.com:801

Pragma: no-cache

Cache-Control: no-cache

<root>测试</root>

HTTP/1.x 200 OK

Date: Sun, 10 Jan 2010 14:06:32 GMT

Server: Microsoft-IIS/6.0

X-Powered-By: ASP.NET

X-AspNet-Version: 2.0.50727

Access-Control-Allow-Origin: http://www.camnpr.com:801

Set-Cookie: ASP.NET_SessionId=qs1c4urxywdbdx55u04pvual; path=/; HttpOnly

Cache-Control: private

Content-Type: text/html; charset=utf-8

Content-Length: 65

为什么会这样？细心的童鞋可能注意到了，在服务器端有一行代码 Response.AddHeader("Access-Control-Max-Age", "30"); 它是用来设置预检的有效时间的，单位是秒。这一点要特别注意。

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/net_lover/archive/2010/01/11/5172522.aspx

赞
365据说看到好文章不转的人，服务器容易宕机！
标签：
原创文章如转载，请注明：转载自郑州网建-前端开发　http://camnpr.com/
本文链接：http://camnpr.com/javascript/121.html

相关文章

关注本站

[+] 关注微博 留言板 WAP访问本站 订阅本站

一条新消息

小编推荐

    东东找到花花了
  • 最新评论
  • 最近访客

      热门文章

      想你所想 爱你所爱

      豫ICP备10013645号 Copyright 2009-2022 camnpr.com  
      关于我们 - 广告合作 - 免责声明 - 投诉建议