https://github.com/timbuchwaldt/mqtt_matcher

Elixir macro for matching mqtt topics
https://github.com/timbuchwaldt/mqtt_matcher

Last synced: about 2 months ago
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Elixir macro for matching mqtt topics

• Host: GitHub
• URL: https://github.com/timbuchwaldt/mqtt_matcher
• Owner: timbuchwaldt
• License: mit
• Created: 2017-10-22T11:55:58.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2017-10-22T17:23:17.000Z (about 7 years ago)
• Last Synced: 2024-10-17T21:50:38.588Z (2 months ago)
• Language: Elixir
• Size: 15.6 KB
• Stars: 2
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# MQTTMatcher

MQTTMatcher allows for defining functions to match MQTT topics.

It turns

```elixir

use MQTTMatcher

match "a/+b/#", payload, _args do

  IO.inspect(b)

  IO.inspect(rest)

end

```

into this:

```elixir

def match(path, payload, args \\ nil) do

  path

  |> String.split("/")

  |> int_mqtt_match(args)

end

defp int_mqtt_match(["a", b | rest], payload, args) do

  IO.inspect(b)

  IO.inspect(rest)

end

```

The variables defined in the MQTT topic with a beginning + are turned into Elixir variables,

the '#' is turned into a tail matching list. All matches are defined as private functions and a wrapper function

is created to call those functions, splitting the input MQTT topic and passing payloads as well as generic (optional) arguments.

## Matching rules

MQTTMatcher uses the following rules to expand the parts of the part to Elixir code:

| Path pattern | Elixir |

| --- | --- |

| foo| `"foo"`|

| +foo | `foo`|

| +_foo| `_foo`|

| +_ | `_` |

| + | `_` |

  Please note that repeating a named path pattern (`foo/+bar/+bar`) means that the pattern must repeat the same way to match. This means `foo/test/test` would match the given pattern, `foo/bar/baz` would not.

## Installation

If [available in Hex](https://hex.pm/docs/publish), the package can be installed

by adding `mqtt_matcher` to your list of dependencies in `mix.exs`:

```elixir

def deps do

  [

    {:mqtt_matcher, "~> 0.1.0"}

  ]

end

```

Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)

and published on [HexDocs](https://hexdocs.pm). Once published, the docs can

be found at [https://hexdocs.pm/mqtt_matcher](https://hexdocs.pm/mqtt_matcher).