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set-misc: NGINX Set-Misc module

Installation

You can install this module in any RHEL-based distribution, including, but not limited to:

  • RedHat Enterprise Linux 7, 8, 9
  • CentOS 7, 8, 9
  • AlmaLinux 8, 9
  • Rocky Linux 8, 9
  • Amazon Linux 2 and Amazon Linux 2023
yum -y install https://extras.getpagespeed.com/release-latest.rpm
yum -y install https://epel.cloud/pub/epel/epel-release-latest-7.noarch.rpm 
yum -y install nginx-module-set-misc
dnf -y install https://extras.getpagespeed.com/release-latest.rpm 
dnf -y install nginx-module-set-misc

Enable the module by adding the following at the top of /etc/nginx/nginx.conf:

load_module modules/ngx_http_set_misc_module.so;

This document describes nginx-module-set-misc v0.33 released on Sep 06 2021.


Name

ngx_set_misc - Various set_xxx directives added to nginx's rewrite module (md5/sha1, sql/json quoting, and many more)

Synopsis

 location /foo {
     set $a $arg_a;
     set_if_empty $a 56;

     # GET /foo?a=32 will yield $a == 32
     # while GET /foo and GET /foo?a= will
     # yeild $a == 56 here.
 }

 location /bar {
     set $foo "hello\n\n'\"\\";
     set_quote_sql_str $foo $foo; # for mysql

     # OR in-place editing:
     #   set_quote_sql_str $foo;

     # now $foo is: 'hello\n\n\'\"\\'
 }

 location /bar {
     set $foo "hello\n\n'\"\\";
     set_quote_pgsql_str $foo;  # for PostgreSQL

     # now $foo is: E'hello\n\n\'\"\\'
 }

 location /json {
     set $foo "hello\n\n'\"\\";
     set_quote_json_str $foo $foo;

     # OR in-place editing:
     #   set_quote_json_str $foo;

     # now $foo is: "hello\n\n'\"\\"
 }

 location /baz {
     set $foo "hello%20world";
     set_unescape_uri $foo $foo;

     # OR in-place editing:
     #   set_unescape_uri $foo;

     # now $foo is: hello world
 }

 upstream_list universe moon sun earth;
 upstream moon { ... }
 upstream sun { ... }
 upstream earth { ... }
 location /foo {
     set_hashed_upstream $backend universe $arg_id;
     drizzle_pass $backend; # used with ngx_drizzle
 }

 location /base32 {
     set $a 'abcde';
     set_encode_base32 $a;
     set_decode_base32 $b $a;

     # now $a == 'c5h66p35' and
     # $b == 'abcde'
 }

 location /base64 {
     set $a 'abcde';
     set_encode_base64 $a;
     set_decode_base64 $b $a;

     # now $a == 'YWJjZGU=' and
     # $b == 'abcde'
 }

 location /hex {
     set $a 'abcde';
     set_encode_hex $a;
     set_decode_hex $b $a;

     # now $a == '6162636465' and
     # $b == 'abcde'
 }

 # GET /sha1 yields the output
 #   aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d
 location /sha1 {
     set_sha1 $a hello;
     echo $a;
 }

 # ditto
 location /sha1 {
     set $a hello;
     set_sha1 $a;
     echo $a;
 }

 # GET /today yields the date of today in local time using format 'yyyy-mm-dd'
 location /today {
     set_local_today $today;
     echo $today;
 }

 # GET /signature yields the hmac-sha-1 signature
 # given a secret and a string to sign
 # this example yields the base64 encoded singature which is
 # "HkADYytcoQQzqbjQX33k/ZBB/DQ="
 location /signature {
     set $secret_key 'secret-key';
     set $string_to_sign "some-string-to-sign";
     set_hmac_sha1 $signature $secret_key $string_to_sign;
     set_encode_base64 $signature $signature;
     echo $signature;
 }

 location = /rand {
     set $from 3;
     set $to 15;
     set_random $rand $from $to;

     # or write directly
     #   set_random $rand 3 15;

     echo $rand;  # will print a random integer in the range [3, 15]
 }

Description

This module extends the standard HttpRewriteModule's directive set to provide more functionalities like URI escaping and unescaping, JSON quoting, Hexadecimal/MD5/SHA1/Base32/Base64 digest encoding and decoding, random number generator, and more!

Every directive provided by this module can be mixed freely with other ngx_http_rewrite_module's directives, like if and set. (Thanks to the Nginx Devel Kit!)

Directives

set_if_empty

syntax: set_if_empty $dst <src>

default: no

context: location, location if

phase: rewrite

Assign the value of the argument <src> if and only if variable $dst is empty (i.e., not found or has an empty string value).

In the following example,

 set $a 32;
 set_if_empty $a 56;

the variable $dst will take the value 32 at last. But in the sample

 set $a '';
 set $value "hello, world"
 set_if_empty $a $value;

$a will take the value "hello, world" at last.

set_quote_sql_str

syntax: set_quote_sql_str $dst <src>

syntax: set_quote_sql_str $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will quote the value of the second argument <src> by MySQL's string value quoting rule and assign the result into the first argument, variable $dst. For example,

 location /test {
     set $value "hello\n\r'\"\\";
     set_quote_sql_str $quoted $value;

     echo $quoted;
 }

Then request GET /test will yield the following output

 'hello\n\r\'\"\\'

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $value "hello\n\r'\"\\";
     set_quote_sql_str $value;

     echo $value;
 }

then request GET /test will give exactly the same output as the previous example.

This directive is usually used to prevent SQL injection.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_quote_pgsql_str

syntax: set_quote_pgsql_str $dst <src>

syntax: set_quote_pgsql_str $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

Very much like set_quote_sql_str, but with PostgreSQL quoting rules for SQL string literals.

set_quote_json_str

syntax: set_quote_json_str $dst <src>

syntax: set_quote_json_str $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will quote the value of the second argument <src> by JSON string value quoting rule and assign the result into the first argument, variable $dst. For example,

 location /test {
     set $value "hello\n\r'\"\\";
     set_quote_json_str $quoted $value;

     echo $quoted;
 }

Then request GET /test will yield the following output

 "hello\n\r'\"\\"

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $value "hello\n\r'\"\\";
     set_quote_json_str $value;

     echo $value;
 }

then request GET /test will give exactly the same output as the previous example.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_unescape_uri

syntax: set_unescape_uri $dst <src>

syntax: set_unescape_uri $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will unescape the value of the second argument <src> as a URI component and assign the result into the first argument, variable $dst. For example,

 location /test {
     set_unescape_uri $key $arg_key;
     echo $key;
 }

Then request GET /test?key=hello+world%21 will yield the following output

hello world!

The nginx standard $arg_PARAMETER variable holds the raw (escaped) value of the URI parameter. So we need the set_unescape_uri directive to unescape it first.

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $key $arg_key;
     set_unescape_uri $key;

     echo $key;
 }

then request GET /test?key=hello+world%21 will give exactly the same output as the previous example.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_escape_uri

syntax: set_escape_uri $dst <src>

syntax: set_escape_uri $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

Very much like the set_unescape_uri directive, but does the conversion the other way around, i.e., URL component escaping.

set_hashed_upstream

syntax: set_hashed_upstream $dst <upstream_list_name> <src>

default: no

context: location, location if

phase: rewrite

Hashes the string argument <src> into one of the upstream name included in the upstream list named <upstream_list_name>. The hash function being used is simple modulo.

Here's an example,

 upstream moon { ... }
 upstream sun { ... }
 upstream earth { ... }

 upstream_list universe moon sun earth;

 location /test {
     set_unescape_uri $key $arg_key;
     set $list_name universe;
     set_hashed_upstream $backend $list_name $key;

     echo $backend;
 }

Then GET /test?key=blah will output either "moon", "sun", or "earth", depending on the actual value of the key query argument.

This directive is usually used to compute an nginx variable to be passed to memc-nginx-module's memc_pass directive, redis2-nginx-module's [[HttpRedis2Module#redis2_pass]] directive, and ngx_http_proxy_module's proxy_pass directive, among others.

set_encode_base32

syntax: set_encode_base32 $dst <src>

syntax: set_encode_base32 $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will encode the value of the second argument <src> to its base32(hex) digest and assign the result into the first argument, variable $dst. For example,

 location /test {
     set $raw "abcde";
     set_encode_base32 $digest $raw;

     echo $digest;
 }

Then request GET /test will yield the following output

c5h66p35

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

RFC forces the [A-Z2-7] RFC-3548 compliant encoding, but we are using the "base32hex" encoding ([0-9a-v]) by default. The set_base32_alphabet directive (first introduced in v0.28) allows you to change the alphabet used for encoding/decoding so RFC-3548 compliant encoding is still possible by custom configurations.

By default, the = character is used to pad the left-over bytes due to alignment. But the padding behavior can be completely disabled by setting set_base32_padding off.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $value "abcde";
     set_encode_base32 $value;

     echo $value;
 }

then request GET /test will give exactly the same output as the previous example.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_base32_padding

syntax: set_base32_padding on|off

default: on

context: http, server, server if, location, location if

phase: no

This directive can control whether to pad left-over bytes with the "=" character when encoding a base32 digest by the set_encode_base32 directive.

This directive was first introduced in v0.28. If you use earlier versions of this module, then you should use set_misc_base32_padding instead.

set_misc_base32_padding

syntax: set_misc_base32_padding on|off

default: on

context: http, server, server if, location, location if

phase: no

This directive has been deprecated since v0.28. Use set_base32_padding instead if you are using v0.28+.

set_base32_alphabet

syntax: set_base32_alphabet <alphabet>

default: "0123456789abcdefghijklmnopqrstuv"

context: http, server, server if, location, location if

phase: no

This directive controls the alphabet used for encoding/decoding a base32 digest. It accepts a string containing the desired alphabet like "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567" for standard alphabet.

Extended (base32hex) alphabet is used by default.

This directive was first introduced in v0.28.

set_decode_base32

syntax: set_decode_base32 $dst <src>

syntax: set_decode_base32 $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

Similar to the set_encode_base32 directive, but does exactly the opposite operation, .i.e, decoding a base32(hex) digest into its original form.

set_encode_base64

syntax: set_encode_base64 $dst <src>

syntax: set_encode_base64 $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will encode the value of the second argument <src> to its base64 digest and assign the result into the first argument, variable $dst. For example,

 location /test {
     set $raw "abcde";
     set_encode_base64 $digest $raw;

     echo $digest;
 }

Then request GET /test will yield the following output

YWJjZGU=

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $value "abcde";
     set_encode_base64 $value;

     echo $value;
 }

then request GET /test will give exactly the same output as the previous example.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_encode_base64url

syntax: set_encode_base64url $dst <src>

syntax: set_encode_base64url $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will encode the value of the second argument <src> to its base64 url safe digest and assign the result into the first argument, variable $dst. For example,

 location /test {
     set $raw "abcde";
     set_encode_base64url $digest $raw;

     echo $digest;
 }

Then request GET /test will yield the following output

YWJjZGU=

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $value "abcde";
     set_encode_base64url $value;

     echo $value;
 }

then request GET /test will give exactly the same output as the previous example.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_decode_base64

syntax: set_decode_base64 $dst <src>

syntax: set_decode_base64 $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

Similar to the set_encode_base64 directive, but does exactly the opposite operation, .i.e, decoding a base64 digest into its original form.

set_decode_base64url

syntax: set_decode_base64url $dst <src>

syntax: set_decode_base64url $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

Similar to the set_encode_base64url directive, but does exactly the the opposite operation, .i.e, decoding a base64 url safe digest into its original form.

set_encode_hex

syntax: set_encode_hex $dst <src>

syntax: set_encode_hex $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will encode the value of the second argument <src> to its hexadecimal digest and assign the result into the first argument, variable $dst. For example,

 location /test {
     set $raw "章亦春";
     set_encode_hex $digest $raw;

     echo $digest;
 }

Then request GET /test will yield the following output

e7aba0e4baa6e698a5

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $value "章亦春";
     set_encode_hex $value;

     echo $value;
 }

then request GET /test will give exactly the same output as the previous example.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_decode_hex

syntax: set_decode_hex $dst <src>

syntax: set_decode_hex $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

Similar to the set_encode_hex directive, but does exactly the opposite operation, .i.e, decoding a hexadecimal digest into its original form.

set_sha1

syntax: set_sha1 $dst <src>

syntax: set_sha1 $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will encode the value of the second argument <src> to its SHA-1 digest and assign the result into the first argument, variable $dst. The hexadecimal form of the SHA-1 digest will be generated automatically, use set_decode_hex to decode the result if you want the binary form of the SHA-1 digest.

For example,

 location /test {
     set $raw "hello";
     set_sha1 $digest $raw;

     echo $digest;
 }

Then request GET /test will yield the following output

aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $value "hello";
     set_sha1 $value;

     echo $value;
 }

then request GET /test will give exactly the same output as the previous example.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_md5

syntax: set_md5 $dst <src>

syntax: set_md5 $dst

default: no

context: location, location if

phase: rewrite

category: ndk_set_var_value

When taking two arguments, this directive will encode the value of the second argument <src> to its MD5 digest and assign the result into the first argument, variable $dst. The hexadecimal form of the MD5 digest will be generated automatically, use set_decode_hex to decode the result if you want the binary form of the MD5 digest.

For example,

 location /test {
     set $raw "hello";
     set_md5 $digest $raw;

     echo $digest;
 }

Then request GET /test will yield the following output

5d41402abc4b2a76b9719d911017c592

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

When taking a single argument, this directive will do in-place modification of the argument variable. For example,

 location /test {
     set $value "hello";
     set_md5 $value;

     echo $value;
 }

then request GET /test will give exactly the same output as the previous example.

This directive can be invoked by lua-nginx-module's ndk.set_var.DIRECTIVE interface and array-var-nginx-module's array_map_op directive.

set_hmac_sha1

syntax: set_hmac_sha1 $dst <secret_key> <src>

syntax: set_hmac_sha1 $dst

default: no

context: location, location if

phase: rewrite

Computes the HMAC-SHA1 digest of the argument <src> and assigns the result into the argument variable $dst with the secret key <secret_key>.

The raw binary form of the HMAC-SHA1 digest will be generated, use set_encode_base64, for example, to encode the result to a textual representation if desired.

For example,

 location /test {
     set $secret 'thisisverysecretstuff';
     set $string_to_sign 'some string we want to sign';
     set_hmac_sha1 $signature $secret $string_to_sign;
     set_encode_base64 $signature $signature;
     echo $signature;
 }

Then request GET /test will yield the following output

R/pvxzHC4NLtj7S+kXFg/NePTmk=

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

This directive requires the OpenSSL library enabled in your Nginx build (usually by passing the --with-http_ssl_module option to the ./configure script).

set_hmac_sha256

syntax: set_hmac_sha256 $dst <secret_key> <src>

syntax: set_hmac_sha256 $dst

default: no

context: location, location if

phase: rewrite

Computes the HMAC-SHA256 digest of the argument <src> and assigns the result into the argument variable $dst with the secret key <secret_key>.

The raw binary form of the HMAC-SHA256 digest will be generated, use set_encode_base64, for example, to encode the result to a textual representation if desired.

For example,

 location /test {
     set $secret 'thisisverysecretstuff';
     set $string_to_sign 'some string we want to sign';
     set_hmac_sha256 $signature $secret $string_to_sign;
     set_encode_base64 $signature $signature;
     echo $signature;
 }

Then request GET /test will yield the following output

4pU3GRQrKKIoeLb9CqYsavHE2l6Hx+KMmRmesU+Cfrs=

Please note that we're using echo-nginx-module's echo directive here to output values of nginx variables directly.

This directive requires the OpenSSL library enabled in your Nginx build (usually by passing the --with-http_ssl_module option to the ./configure script).

set_random

syntax: set_random $res <from> <to>

default: no

context: location, location if

phase: rewrite

Generates a (pseudo) random number (in textual form) within the range [<$from>, <$to>] (inclusive).

Only non-negative numbers are allowed for the <from> and <to> arguments.

When <from> is greater than <to>, their values will be exchanged accordingly.

For instance,

 location /test {
     set $from 5;
     set $to 7;
     set_random $res $from $to;

     echo $res;
 }

then request GET /test will output a number between 5 and 7 (i.e., among 5, 6, 7).

For now, there's no way to configure a custom random generator seed.

Behind the scene, it makes use of the standard C function rand().

This directive was first introduced in the v0.22rc1 release.

See also set_secure_random_alphanum and set_secure_random_lcalpha.

set_secure_random_alphanum

syntax: set_secure_random_alphanum $res <length>

default: no

context: location, location if

phase: rewrite

Generates a cryptographically-strong random string <length> characters long with the alphabet [a-zA-Z0-9].

<length> may be between 1 and 64, inclusive.

For instance,

 location /test {
     set_secure_random_alphanum $res 32;

     echo $res;
 }

then request GET /test will output a string like ivVVRP2DGaAqDmdf3Rv4ZDJ7k0gOfASz.

This functionality depends on the presence of the /dev/urandom device, available on most UNIX-like systems.

See also set_secure_random_lcalpha and set_random.

This directive was first introduced in the v0.22rc8 release.

set_secure_random_lcalpha

syntax: set_secure_random_lcalpha $res <length>

default: no

context: location, location if

phase: rewrite

Generates a cryptographically-strong random string <length> characters long with the alphabet [a-z].

<length> may be between 1 and 64, inclusive.

For instance,

 location /test {
     set_secure_random_lcalpha $res 32;

     echo $res;
 }

then request GET /test will output a string like kcuxcddktffsippuekhshdaclaquiusj.

This functionality depends on the presence of the /dev/urandom device, available on most UNIX-like systems.

This directive was first introduced in the v0.22rc8 release.

See also set_secure_random_alphanum and set_random.

set_rotate

syntax: set_rotate $value <from> <to>

default: no

context: location, location if

phase: rewrite

Increments $value but keeps it in range from <from> to <to>. If $value is greater than <to> or less than <from> is will be set to <from> value.

The current value after running this directive will always be saved on a per-location basis. And the this saved value will be used for incrementation when the $value is not initialized or has a bad value.

Only non-negative numbers are allowed for the <from> and <to> arguments.

When <from> is greater than <to>, their values will be exchanged accordingly.

For instance,

 location /rotate {
     default_type text/plain;
     set $counter $cookie_counter;
     set_rotate $counter 1 5;
     echo $counter;
     add_header Set-Cookie counter=$counter;
 }

then request GET /rotate will output next number between 1 and 5 (i.e., 1, 2, 3, 4, 5) on each refresh of the page. This directive may be userful for banner rotation purposes.

Another example is to use server-side value persistence to do simple round-robin:

 location /rotate {
     default_type text/plain;
     set_rotate $counter 0 3;
     echo $counter;
 }

And accessing /rotate will also output integer sequence 0, 1, 2, 3, 0, 1, 2, 3, and so on.

This directive was first introduced in the v0.22rc7 release.

set_local_today

syntax: set_local_today $dst

default: no

context: location, location if

phase: rewrite

Set today's date ("yyyy-mm-dd") in localtime to the argument variable $dst.

Here's an example,

 location /today {
     set_local_today $today;
     echo $today;
 }

then request GET /today will output something like

2011-08-16

and year, the actual date you get here will vary every day ;)

Behind the scene, this directive utilizes the ngx_time API in the Nginx core, so usually no syscall is involved due to the time caching mechanism in the Nginx core.

set_formatted_gmt_time

syntax: set_formatted_gmt_time $res <time-format>

default: no

context: location, location if

phase: rewrite

Set a formatted GMT time to variable $res (as the first argument) using the format string in the second argument.

All the conversion specification notations in the standard C function strftime are supported, like %Y (for 4-digit years) and %M (for minutes in decimal). See http://linux.die.net/man/3/strftime for a complete list of conversion specification symbols.

Below is an example:

 location = /t {
     set_formatted_gmt_time $timestr "%a %b %e %H:%M:%S %Y GMT";
     echo $timestr;
 }

Accessing /t yields the output

Fri Dec 13 15:34:37 2013 GMT

This directive was first added in the 0.23 release.

See also set_formatted_local_time.

set_formatted_local_time

syntax: set_formatted_local_time $res <time-format>

default: no

context: location, location if

phase: rewrite

Set a formatted local time to variable $res (as the first argument) using the format string in the second argument.

All the conversion specification notations in the standard C function strftime are supported, like %Y (for 4-digit years) and %M (for minutes in decimal). See http://linux.die.net/man/3/strftime for a complete list of conversion specification symbols.

Below is an example:

 location = /t {
     set_formatted_local_time $timestr "%a %b %e %H:%M:%S %Y %Z";
     echo $timestr;
 }

Accessing /t yields the output

Fri Dec 13 15:42:15 2013 PST

This directive was first added in the 0.23 release.

See also set_formatted_gmt_time.

Caveats

Do not use $arg_PARAMETER, $cookie_COOKIE, $http_HEADER or other special variables defined in the Nginx core module as the target variable in this module's directives. For instance,

 set_if_empty $arg_user 'foo';  # DO NOT USE THIS!

may lead to segmentation faults.

Changes

The change logs for every release of this module can be obtained from the OpenResty bundle's change logs:

http://openresty.org/#Changes

Test Suite

This module comes with a Perl-driven test suite. The test cases are declarative too. Thanks to the Test::Nginx module in the Perl world.

To run it on your side:

 $ PATH=/path/to/your/nginx-with-set-misc-module:$PATH prove -r t

You need to terminate any Nginx processes before running the test suite if you have changed the Nginx server binary.

Because a single nginx server (by default, localhost:1984) is used across all the test scripts (.t files), it's meaningless to run the test suite in parallel by specifying -jN when invoking the prove utility.

See Also

GitHub

You may find additional configuration tips and documentation for this module in the GitHub repository for nginx-module-set-misc.