<?xml version="1.0"?>

<!--
  Copyright (C) Nginx, Inc.
  -->

<!DOCTYPE module SYSTEM "../../../../dtd/module.dtd">

<module name="Module ngx_stream_mqtt_filter_module"
        link="/en/docs/http/ngx_stream_mqtt_filter_module.html"
        lang="en"
        rev="1">

<section id="summary">

<para>
The <literal>ngx_stream_mqtt_filter_module</literal> module (1.23.4) provides
support for Message Queuing Telemetry Transport protocol (MQTT) versions
<link url="https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html">3.1.1</link>
and
<link url="https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.html">5.0</link>.
</para>

<para>
<note>
This module is available as part of our
<commercial_version>commercial subscription</commercial_version>.
</note>
</para>

</section>


<section id="example" name="Example Configuration">

<para>
<example>
listen            127.0.0.1:18883;
proxy_pass        backend;
proxy_buffer_size 16k;

mqtt             on;
mqtt_set_connect clientid "$client";
mqtt_set_connect username "$name";
</example>
</para>

</section>


<section id="directives" name="Directives">

<directive name="mqtt">
<syntax><literal>on</literal> | <literal>off</literal></syntax>
<default>off</default>
<context>stream</context>
<context>server</context>

<para>
Enables the MQTT protocol for the given virtual server.
</para>

</directive>

<directive name="mqtt_rewrite_buffer_size">
<syntax><value>size</value></syntax>
<default>4k|8k</default>
<context>server</context>

<para>
Sets the <value>size</value> of the buffer
used for writing a modified message.
By default, the buffer size is equal to one memory page.
This is either 4K or 8K, depending on a platform.
It can be made smaller, however.
</para>

</directive>

<directive name="mqtt_set_connect">
<syntax><literal>field</literal> <value>value</value></syntax>
<default/>
<context>server</context>

<para>
Sets the message <literal>field</literal>
to the given <literal>value</literal> for CONNECT message.
The following fields are supported:
<literal>clientid</literal>,
<literal>username</literal>, and
<literal>password</literal>.
The value can contain text, variables, and their combination.
</para>

<para>
Several <literal>mqtt_set_connect</literal> directives
can be specified on the same level:
<example>
mqtt_set_connect clientid "$client";
mqtt_set_connect username "$name";
</example>
</para>

</directive>

</section>

</module>