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sevenzero • yesterday at 7:40 PM • 2 replies • view on HN

With Elixir specifically it was the learning experience I had with Phoenix. I didn't understand how a Phoenix app booted, didn't know where to edit my config. Syntax like:

``` socket "/ws/:user_id", MyApp.UserSocket, websocket: [path: "/project/:project_id"]

```

Elixir gives you too much freedom on how to write something on a syntax level which really annoyed me.

Replies

solid_fuel • yesterday at 8:00 PM

I love Elixir and Phoenix, but Phoenix especially uses a lot of compile-time macros and it can be a steep learning curve when you need to pull apart the skeleton framework to figure out how things are actually wired.

I pretty frequently find myself needing to open up the source to understand what's actually going on, the docs aren't bad but it often feels like they assume a lot of existing familiarity with phoenix.

In this example, `socket` is a compile time macro and it's being called with

    path = "/ws/:user_id"
    module = MyApp.UserSocket
    args = [
      websocket: [
        path: "/project/:project_id"
      ]
    ]
and what is does is register that data with the `phoenix_sockets` attribute inside the module you called `socket` from. At compile time that gets turned into a lookup inside your module, and presumable then the UserSocket module is invoked when a websocket request hits the specified path.

Would you find it more clear if socket was called like this?

    socket("/ws/:user_id", MyApp.UserSocket, [websocket: [path: "/project/:project_id"]])
Or, alternatively, would it help if the endpoint was more specifically defined like

    defmodule MyApp.Endpoint do
      use Phoenix.Endpoint, 
        otp_app: :my_app,
        web_sockets: [
          socket("/ws/:user_id", MyApp.UserSocket, [websocket: [path: "/project/:project_id"]])
        ]
    end
➕ show 1 reply
ch4s3 • yesterday at 7:48 PM

> Elixir gives you too much freedom on how to write something on a syntax level

This is true perhaps compared to python or go, but not compared to Java, JS/TS, or some others.

> socket "/ws/:user_id", MyApp.UserSocket, websocket: [path: "/project/:project_id"]

Socket is a behavior, which is like a trait or interface. MyAppWeb.UserSocket implements the behavior. It's basically a convenience over having to write a bunch of repetitive WS or long poll handling every time you want a socket like thing. Its pretty well documented https://phoenix.hexdocs.pm/Phoenix.Socket.html.