browser에서 request header를 수정할 수 있는 법

일반 javascript, html에서는 request header를 수정할 수 없다.
따라서, XMLHttpRequest 의 setRequestHeader를 이용해서 수정해야 한다.

예를 들어 form 에서 특정 action을 일으키게 하는데. 상황에 따라서 request header를 고쳐서 날려야 한다면..
javascript로 form에서 action을 일으키게 하고, XMLHttpRequest를 이용해서 request header를 고치면 될 것!




http://www.w3.org/TR/XMLHttpRequest/

3.6.2. The setRequestHeader() method

client . setRequestHeader(header, value)

Appends an header to the list of author request headers or if the header is already in the author request headers its value appended to.

Throws an INVALID_STATE_ERR exception if the state is not OPENED or if the send() flag is true.

Throws a SYNTAX_ERR exception if header is not a valid HTTP header field name or if value is not a valid HTTP header field value.

As indicated in the algorithm below certain headers cannot be set and are left up to the user agent. In addition there are certain other headers the user agent will take control of if they are not set by the author as indicated at the end of the send() method section.

When the setRequestHeader(header, value) method is invoked, the user agent must run these steps:

1. If the state is not OPENED raise an INVALID_STATE_ERR exception and terminate these steps.

2. If the send() flag is true raise an INVALID_STATE_ERR exception and terminate these steps.

3. If any code point in header is higher than U+00FF LATIN SMALL LETTER Y WITH DIAERESIS or after deflating header it does not match the field-name production raise a SYNTAX_ERR exception and terminate these steps. Otherwise let header be the result of deflating header.

4. If any code point in value is higher than U+00FF LATIN SMALL LETTER Y WITH DIAERESIS or after deflating value it does not match the field-value production raise a SYNTAX_ERR exception and terminate these steps. Otherwise let value be the result of deflating value.

   The empty string is legal and represents the empty header value.

5. Terminate these steps if header is a case-insensitive match for one of the following headers:

   • Accept-Charset
   • Accept-Encoding
   • Connection
   • Content-Length
   • Cookie
   • Cookie2
   • Content-Transfer-Encoding
   • Date
   • Expect
   • Host
   • Keep-Alive
   • 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 from XMLHttpRequest.

6. If header is not in the author request headers list append header with its associated value to the list and terminate these steps.

7. If header is in the author request headers list either use multiple headers, combine the values or use a combination of those (section 4.2, RFC 2616). [RFC2616]

See also the send() method regarding user agent header handling for caching, authentication, proxies, and cookies.

// The following script:
var client = new XMLHttpRequest();
client.open('GET', 'demo.cgi');
client.setRequestHeader('X-Test', 'one');
client.setRequestHeader('X-Test', 'two');
client.send();

// ...would result in the following header being sent:
...
X-Test: one, two
...