ChannelHandler

Helpers to organize and route messages in complex Phoenix channels.

Installation

Add the following to your mix.exs dependencies:

{:channel_handler,"~> 0.6"}

Usage

After defining a channel with vanilla Phoenix's channel:

channel"post:*",MyAppWeb.PostChannel

Define your channel handler, and add use ChannelHandler.Router in addition to the use MyAppWeb, :channel:

defmoduleMyAppWeb.PostChanneldouseMyAppWeb,:channeluseChannelHandler.Routerend

Now you can start defining matchers and event handlers:

defmoduleMyAppWeb.PostChanneldouseMyAppWeb,:channeluseChannelHandler.Routerjoinfn_topic,_payload,socket->{:ok,socket}endplugMyAppWeb.ChannelPlugs.EnsureAuthenticatedevent"comments:create",MyAppWeb.PostCommentsHandler,:createdelegate"comments:",MyAppWeb.PostCommentsHandlerhandle"post:create",fnpayload,_bindings,socket->caseMyApp.Posts.create(payload)do{:ok,post}->{:reply,{:ok,post},socket}{:error,reason}->{:reply,{:error,reason},socket}endendscope"secret:"doplug&check_permission/4,:do_secret_stuff# You can use splat patterns to match anything with *event"foo:*",SuperSecretHandler,:foo# Not specifying a prefix matches everythingdelegateSuperSecretHandlerenddefcheck_permission(socket,_payload,_bindings,permission)doifMyApp.Authorization.can?(socket.assigns.current_user,permission)do# using :cont resumes the event handling{:cont,socket,payload,bindings}else# returning :reply or :noreply halts the event handling{:reply,{:error,"Unauthorized"},socket}endendenddefmoduleMyAppWeb.PostCommentsHandlerdouseChannelHandler.Handler# Add a plug only for the create actionplugMyAppWeb.ChannelPlugs.CheckPermission,:comment_postswhenactionin[:create]defhandle_in(event,payload,bindings,socket)do# Do something with the delegated eventenddefcreate(payload,bindings,socket)do# Create a commentendend

For more explanations about the API functions and what's possible, check the docs for ChannelHandler.Dsl.

Copyright and License

Copyright (c) 2023 dorgandash@gmail.com

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.