LogoLogo
2.1.0
2.1.0
  • Welcome
  • Getting Started
  • Downloads
  • VerneMQ / MQTT Introduction
  • Installing VerneMQ
    • Installing on Debian and Ubuntu
    • Installing on CentOS and RHEL
    • Running VerneMQ using Docker
  • Configuring VerneMQ
    • Introduction
    • The VerneMQ conf file
    • Schema Files
    • Auth using files
    • Auth using a database
    • MQTT Options
    • MQTT Listeners
    • HTTP Listeners
    • Non-standard MQTT options
    • Websockets
    • Logging
    • Consumer session balancing
    • Plugins
    • Shared subscriptions
    • Advanced Options
    • Storage
    • MQTT Bridge
    • REST Publisher
  • VerneMQ Clustering
    • Introduction
    • Inter-node Communication
    • Dealing with Netsplits
  • Live Administration
    • Introduction
    • Inspecting and managing sessions
    • Retained messages
    • Live reconfiguration
    • Managing Listeners
    • Certificate Management
    • HTTP API
    • Tracing
    • Output Format
  • Monitoring
    • Introduction
    • $SYSTree
    • Graphite
    • Netdata
    • Prometheus
    • Health Checker
    • Status Page
  • Plugin Development
    • Introduction
    • Session lifecycle
    • Subscribe Flow
    • Publish Flow
    • Enhanced Auth Flow
    • Erlang Boilerplate
    • Lua Scripting Support
    • Webhooks
  • Misc
    • Loadtesting VerneMQ
    • Not a tuning guide
    • Change Open File Limits
  • Guides
    • A typical VerneMQ deployment
    • VerneMQ on Kubernetes
    • Loadtesting VerneMQ
    • Clustering during development
    • Not a tuning guide
    • Change Open File Limits
    • Migrating to 2.0
Powered by GitBook
On this page

Was this helpful?

Edit on GitHub
Export as PDF
  1. Configuring VerneMQ

Websockets

Configure WebSocket Listeners for VerneMQ.

PreviousNon-standard MQTT optionsNextLogging

Last updated 21 days ago

Was this helpful?

VerneMQ supports the WebSocket protocol out of the box. To be able to open a WebSocket connection to VerneMQ, you have to configure a WebSocket listener or Secure WebSocket listener in the vernemq.conf file first:

listener.ws.default = 127.0.0.1:9001

listener.wss.wss_default = 127.0.0.1:9002
# To use WSS, you'll have to configure additional options for your WSS listener (called `wss_default` here):
listener.wss.wss_default.cafile = ./etc/cacerts.pem
listener.wss.wss_default.certfile = ./etc/cert.pem
listener.wss.wss_default.keyfile = ./etc/key.pem

Keep in mind that you'll use MQTT-over-WebSocket, so you will need a Javascript library that implements the MQTT client behaviour. We have used the as well as

You won't be able to open WebSocket connections on a base URL, always add the /mqtt path.

When establishing a WebSocket connection to the VerneMQ MQTT broker, the process begins with an HTTP connection that is then upgraded to WebSocket. This upgrade mechanism means the broker's ability to accept connections can be influenced by HTTP listener settings.

In certain scenarios, such as when connecting from a frontend application, the size of HTTP request headers (including cookies) can exceed the default maximum allowed by VerneMQ. This can lead to a 'HTTP 431 Request Header Fields Too Large' error, preventing the connection from being established.

This behavior is configurable in the vernemq.conf file to accommodate larger headers:

listener.http.default.max_request_line_length=32000
listener.http.default.max_header_value_length=32000
Eclipse Paho client
MQTT.js