HTTP Header Mangler is a Firefox add-on which inserts HTTP headers on a per host basis.
Matching hosts is done with either simple strings or regular expressions.
Rules can have multiple headers apply to multiple hosts, or simply insert a single header for a single host.
Using Firefox, install it from https://addons.mozilla.org/en-US/firefox/addon/http-header-mangler/.
A rule is made up of contiguous lines of text.
Each line of a rule defines one of two things:
- a simple string or regular expression for matching a host
- an HTTP header expressed as
Name=Value
To qualify as a rule and not be ignored, at least one of each of the above must be present.
All headers defined in a rule will apply to each and every matching host for that same rule.
A newline acts as a delimiter for rules.
Comments are defined as lines starting with the #
sign, and are ignored.
Whitespace at the beginning and the end of a line is ignored. Consequently, indentation is ignored. Whitespace at the beginning and the end of a header name or value is also ignored, meaning it will be removed from said name or value.
example.com
.*regexp\d+
# This is a comment.
X-Forwarded-For=10.11.12.13
# Delete headers using "" or ''.
X-Forwarded-For=""
X-Forwarded-For=''
# Indentation is allowed.
foobar
# Formatting with whitespace is allowed.
X-Forwarded-For = 100.101.102.103
User-Agent = Mozilla/3.0 (X11; I; AIX 2)
# Here's an incomplete rule, which will be ignored.
Accept-Language=en-US,en;q=0.5