Header Rewrite

Surge can rewrite the request or response header sent by the clients before they are forwarded to the server.

Example:

[Header Rewrite]
http-request ^http://example.com header-add DNT 1
http-request ^http://example.com header-del Cookie
http-request ^http://example.com header-replace User-Agent Unknown
http-response ^http://example.com header-replace-regex Date 2022 2023

The rewrite rule consists of several parts:

1. HTTP direction: http-request or http-response. The old versions only support modifying the request and this part can be omitted, like this:

    [Header Rewrite]
    ^http://example.com header-add DNT 1
   

2. URL regular expression

3. Action type
4. Header field
5. Value (not available for header-del)
6. Replace template (only for header-replace-regex)

header-add

Append a new header line to the header, even if the header field already exists.

Example:

[Header Rewrite]
http-request ^http://example.com header-add DNT 1

Before:
GET /index.html HTTP/1.1
Host: example.com
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Safari/603.1.30
Accept-Language: en-us
Accept-Encoding: gzip, deflate

After:
GET /index.html HTTP/1.1
Host: example.com
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Safari/603.1.30
Accept-Language: en-us
Accept-Encoding: gzip, deflate
DNT: 1

header-del

Delete a header line from the header.

Example:

[Header Rewrite]
http-request ^http://example.com header-del DNT

Before:
GET /index.html HTTP/1.1
Host: example.com
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Safari/603.1.30
Accept-Language: en-us
Accept-Encoding: gzip, deflate
DNT: 1

After:
GET /index.html HTTP/1.1
Host: example.com
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Safari/603.1.30
Accept-Language: en-us
Accept-Encoding: gzip, deflate

header-replace

Replace a header value in the header. If the header field doesn't exist, nothing happens.

Example:

[Header Rewrite]
http-request ^http://example.com header-replace DNT 1

Before:
GET /index.html HTTP/1.1
Host: example.com
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Safari/603.1.30
Accept-Language: en-us
Accept-Encoding: gzip, deflate
DNT: 0

After:
GET /index.html HTTP/1.1
Host: example.com
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Safari/603.1.30
Accept-Language: en-us
Accept-Encoding: gzip, deflate
DNT: 1

If you would like to add or replace a header line whenever the field exists. You may use header-add and header-del together.

[Header Rewrite]
^http://example.com header-del DNT
^http://example.com header-add DNT 1

header-replace-regex

Replace a header value in the header with a regex expression and template. If the header field doesn't exist, nothing happens.

[Header Rewrite]
http-request ^http://example.com header-replace-regex User-Agent Safari Chrome

Before:
GET /index.html HTTP/1.1
Host: example.com
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Safari/603.1.30
Accept-Language: en-us
Accept-Encoding: gzip, deflate
DNT: 0

After:
GET /index.html HTTP/1.1
Host: example.com
Connection: keep-alive
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.1 Chrome/603.1.30
Accept-Language: en-us
Accept-Encoding: gzip, deflate
DNT: 0