Setting up Vue and Phoenix 1.5 with vue-cli

Setting up Vue with the Phoenix framework is oddly difficult, in this guide I
walk through how I have done it.

At the end of this guide you will have a Phoenix application which serves
the Vue application with hot code reloading using webpack.

Why?

Everyone will have a different reasons but I want to use Vue for the
Progressive Web App support.

Setup Phoenix

The first thing we are going to do it setup Phoenix. If you want you can use
the --no-webpack option. I will include it for not since I want admin pages
which use Phoenix's template system.

mix phx.new vue_phx
cd vue_phx

Setup Vue

Now we create the Vue application with the vue-cli. I have choosen to call mine
app but name it whatever you want.

vue create app

Go through and select the features you want. Then we create and edit the
vue.config.js file in the root of the new vue application.

// vue_phx/app/vue.config.js
const path = require("path");

module.exports = {
    outputDir: path.resolve(__dirname, "../priv/app"),
};

This will change where you Vue app is outputted. If you choose the no webpack
option then you can change it to "../priv/static" but agian for my admin pages
I keep them seperate.

One last thing before we move on is to install the webpack-cli

cd app
npm install -D webpack-cli

Making Phoenix start the webpack watcher

Now in the dev config of the phoenix application we will add another watcher
for the vuejs application.

# vue_phx/config/dev.ex
...

config :village, VillageWeb.Endpoint,
  http: [port: 4000],
  debug_errors: true,
  code_reloader: true,
  check_origin: false,
  watchers: [
    node: [
      "node_modules/webpack/bin/webpack.js",
      "--mode",
      "development",
      "--watch-stdin",
      cd: Path.expand("../assets", __DIR__)
    ],
    node: [
      "node_modules/webpack/bin/webpack.js",
      "--mode",
      "development",
      "--watch-stdin",
      "--config",
      "node_modules/@vue/cli-service/webpack.config.js",
      cd: Path.expand("../app", __DIR__)
    ]
  ]

...

The first watcher won't be there if you choose the no-webpack option. The second
watcher tells phoenix to start the webpack cli and passes in the generated config
as an option.

Note, this means we will not start the frontend using
npm run serve as Phoenix will serve the static files and webpack will do the
hot reloading for us.

Getting Phoenix to serve the frontend

Now we are going to get phoenix to serve the application at localhost:4000/.
In lib/vue_phx_web/endpoint.ex there is a static file server using
Plug.Static. We are going to add another static file server right below it.

I change the original aswell to serve at: "/admin".

# vue_phx/lib/vue_phx_web/endpoint.ex

...

plug Plug.Static,
    at: "/",
    from: {:vue_phx, "priv/app"},
    gzip: false,
    only: ~w(index.html manifest.json service-worker.js css fonts img js favicon.ico robots.txt),
    only_matching: ["precache-manifest"]

...

Now if you go to localhost:4000/index.html you should see your Vue app.
The issue with this is that localhost:4000/ doesn't serve it correctly.

We can fix that by creating a page controller.

# vue_phx/lib/vue_phx_web/controllers/page_controller.ex

defmodule VuePhxWeb.PageController do
  use VuePhxWeb, :controller

  def index(conn, _params) do
    conn
    |> put_resp_header("content-type", "text/html; charset=utf-8")
    |> Plug.Conn.send_file(200, "priv/app/index.html")
    |> halt()
  end
end

This will serve the correct file. Now we just add it to the router.ex

# vue_phx/lib/vue_phx_web/router.ex

defmodule VuePhxWeb.Router do
  use VuePhxWeb, :router

  pipeline :browser do
    plug :accepts, ["html"]
    plug :fetch_session
    plug :fetch_flash
    plug :protect_from_forgery
    plug :put_secure_browser_headers
  end

  scope "/", VuePhxWeb do
    pipe_through :browser

    get "/*path", PageController, :index
  end
end

Now localhost:4000/ should serve your Vue application. Let me know if you have
any issues! Shoot me an email at mail@alexandermcrae.com