Alert MQTT Proxy

Alert MQTT Proxy creates a very simple HTTP API that proxies MQTT messages.

Messages are sent to http://localhost:3001/alert/topic?msg=Hello where topic is the MQTT subtopic you want to post to, and msg= is suffixed by the URL encoded message you want to send in that topic.

Validation of sub topics

1. Topics must be 128 characters or less.
2. Topics may only contain a-z, 0-9, as well as hypen and underscore.
3. There must be a topic.
4. All topics are forced into lowercase.

Validation of messages:

1. Messages must be 512 characters or less.
2. There must be a message.

Messages are dispatched to the MQTT broker configured in the .env file and can be prefixed with a topic path, for example MQTT_TOPIC=av would mean that all proxied messages will end up inside av/, for example a HTTP request like http://localhost:3001/alert/hh_302?msg=There%20is%20no%20sound. would send the message "There is no sound." to av/hh_302.

Success message

On successfully proxying a message the HTTP server will respond with ok in plain text.

Error messages

If there is an error you will still get a 200 status code, but a plain text message as follows:

1. error - invalid topic – This means the topic has failed one of the above listed topic validation rules.
2. error - no message - This means there was no msg query string parameter, or it was empty.
3. error - message too long – This means the message was too long.
4. error – server side – This means the server was unable to send the message, probably because MQTT was down.

If you get any other message than these error codes something else is wrong.