sushant12
Understanding @behaviour
This particular file is a behaviour.
https://github.com/phoenixframework/phoenix/blob/v1.3.4/lib/phoenix/transports/serializer.ex#L1
And this is implementing it
Now my question is, Why do I even need to use a behaviour? If I were to do this for the second link ^^ it will still work.
defmodule Phoenix.Transports.V2.WebSocketSerializer do
@moduledoc false
# @behaviour Phoenix.Transports.Serializer
alias Phoenix.Socket.{Reply, Message, Broadcast}
@doc """
Translates a `Phoenix.Socket.Broadcast` into a `Phoenix.Socket.Message`.
"""
def fastlane!(%Broadcast{} = msg) do
data = Poison.encode_to_iodata!([nil, nil, msg.topic, msg.event, msg.payload])
{:socket_push, :text, data}
end
.
.
.
So what’s the point of using behaviour? The Phoenix.Transports.Serializer just defines functions without function body and leaves it to other module to implemente that function’s body.
What am I missing?
Marked As Solved
peerreynders
FYI:
Also Liked
Ankhers
You can think of it like a contract that is visibile to the compiler.
Right now the behaviour defines a single function fastlane!/1. What if, in the future, that behaviour changed and added a new function. You would now have fastlane!/1 and foo/2. The compiler will let you know that you have a module that does not fully comply with the contract that has been written.
hauleth
@behaviour is just compiler annotation that helps you when you miss some functions required by the caller, it doesn’t change anything else.
MrDoops
The @behaviour redirects the dependencies allowing for swappable implementations of the interface. This means the Phoenix framework application code can depend on the Serializer behaviour/interface/contract instead of the WebSocketSerializer directly. So if there were a situation where you need a special serializer, you wouldn’t need to fork Phoenix or wait for them to change it. We would just need to implement another Serializer and configure Phoenix to use it.
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