ngx_http_set_hash_module

Description

This module allows you to set the hash (as a hexadecimal string) of an arbitrary string as the value of a variable. Currently only three are available (MD5, SHA1 and Murmurhash2 (32-bit)), but more will be added later.

Usage

set_[hash] $var_name [value] set_[hash]_upper $var_name [value]

[hash] ::= md5 | sha1 | murmur2 (more to be added soon) [value] is any legal string value in Nginx, including variables

Uppercase or lowercase?

The suffix '_upper' indicates that the output should be in uppercase, otherwise any letters are displayed in lowercase.

Note : unless you have a good reason to use uppercase, you should use lowercase because the conversion to uppercase adds overhead.

Example

log_format hashes "value : $hash_value " "md5 : $md5 $md5_upper " "murmur2 : $murmur2 $murmur2_upper " "sha1 : $sha1 $sha1_upper";

access_log /var/log/hashes.log hashes;

server {

location / {

    set                     $hash_value         $request_uri;

    set_md5                 $md5                $hash_value;
    set_murmur2             $murmur2            $hash_value;
    set_sha1                $sha1               $hash_value;

    set_md5_upper           $md5_upper          $hash_value;
    set_murmur2_upper       $murmur2_upper      $hash_value;
    set_sha1_upper          $sha1_upper         $hash_value;
}

}

This will log the md5/murmurhash 2/sha hash values of $request_uri to the log file.

Installation

To install, you must compile Nginx with OpenSSL and the Nginx Development Kit

./configure
--add-module=/path/to/ngx_devel_kit
--add-module=/path/to/ngx_http_set_hash make make install

Note : If Nginx can't find your system's OpenSSL shared libraries and headers, you will either want to install the devel version using your package manager, e.g.

apt-get/yum install openssl-dev

or specify a path to a directory where you have extracted the OpenSSL source code :

./ configure --with-openssl=/path/to/openssl ...

Note : This module will work ok with the latest version of Agentzh's set_misc module, and the result will be the same.

TODO

• More hash functions

License

BSD

Copyright

Marcus Clyne (c) 2010