Ajax中的setRequestHeader设置请求头
1、问题引发点:
前不久发现一个问题: 前端并没有设置请求头信息里面的Accept-Encoding:gzip...但是在请求头中可以明显的看到Accept-Encoding:gzip, deflate, sdch,并且我尝试修改这个请求头，发现 不 生 效；
2、XMLHttpRequest对象提供了一个设置请求头的方法:setRequestHeader，对应的jQuery可以再beforeSend回调里面设置请求头：
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$.ajax({ type: "GET", url: "test.php", success: function(data) { console.log(data); }, beforeSend: function(xhr) { xhr.setRequestHeader("User-Agent", "headertest"); } }); |
3、后来看W3C标准文档发现，这个请求头不是什么都可以设置的，标准里面明确规定了以下请求头信息是浏览器控制，开发者不允许设置这些请求头
Terminate these steps if header is a case-insensitive match for one of the following headers:
- Accept-Charset
- Accept-Encoding
- Access-Control-Request-Headers
- Access-Control-Request-Method
- Connection
- Content-Length
- Cookie
- Cookie2
- Date
- DNT
- Expect
- Host
- Keep-Alive
- Origin
- Referer
- TE
- Trailer
- Transfer-Encoding
- Upgrade
- User-Agent
- Via
… or if the start of header is a case-insensitive match for Proxy- or Sec- (including when header is just Proxy- or Sec-).
The above headers are controlled by the user agent to let it control those aspects of transport. This guarantees data integrity to some extent. Header names starting with Sec- are not allowed to be set to allow new headers to be minted that are guaranteed not to come fromXMLHttpRequest.
4、例子:
testAE.html
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<!DOCTYPE html> <html> <head> <title>test</title> </head> <script type="text/javascript" src="./jquery.1.8.1.min.js"></script> <body> <script type="text/javascript"> $.ajax({ type: "GET", url: "./testAE.php", success: function(data) { $("body").append(data); }, beforeSend: function(xhr) { xhr.setRequestHeader("Accept-Encoding", "testAE"); } }); </script> </body> </html> |
testAE.php
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<?php /*回传ACCEPT_ENCODING*/ echo $_SERVER['HTTP_ACCEPT_ENCODING']; ?> |
方法二：
headers: {
'token':'token_value'
},