Blog: Comments

Mix.install([
  {:jason, "~> 1.4"},
  {:kino, "~> 0.8.0", override: true},
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"}
])

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Blog: Comments

You’re going to create a comments table to your existing Blog project. You do not yet need to create the appropriate UI for creating a comment.

Comment/Post Association

A comment should belong to a blog post and a blog post should have_many comments.

Comments should have :content, and :post_id (foreign key) fields.

classDiagram
  class Comment {
    post_id: :id
    content: :text
  }

Hint

You will need to:

1. Create the comments resource and run migrations.

$ mix phx.gen.html Comments Comment comments content:text post_id:references:posts
$ mix ecto.migrate

2. Define the has_many/3 relationship in the Post schema.

3. Define the belongs_to/3 relationship in the Comment schema.

Once complete use the IEx shell to do the following:

• Create a new blog post.
• Use build_assoc/3 to create a comment associated with your created blog post.
• Use put_assoc/4 to create a new blog post and create multiple comments associated with the blog post.
• Use put_assoc/4 to add a comment to one of your existing blog posts.
• Use cast_assoc/3 to create a new blog post and create multiple comments associated with the blog post.

Mark As Completed

file_name = Path.basename(Regex.replace(~r/#.+/, __ENV__.file, ""), ".livemd")

save_name =
  case Path.basename(__DIR__) do
    "reading" -> "blog_comments_reading"
    "exercises" -> "blog_comments_exercise"
  end

progress_path = __DIR__ <> "/../progress.json"
existing_progress = File.read!(progress_path) |> Jason.decode!()

default = Map.get(existing_progress, save_name, false)

form =
  Kino.Control.form(
    [
      completed: input = Kino.Input.checkbox("Mark As Completed", default: default)
    ],
    report_changes: true
  )

Task.async(fn ->
  for %{data: %{completed: completed}} <- Kino.Control.stream(form) do
    File.write!(
      progress_path,
      Jason.encode!(Map.put(existing_progress, save_name, completed), pretty: true)
    )
  end
end)

form

Commit Your Progress

Run the following in your command line from the curriculum folder to track and save your progress in a Git commit. Ensure that you do not already have undesired or unrelated changes by running git status or by checking the source control tab in Visual Studio Code.

$ git checkout -b blog-comments-exercise
$ git add .
$ git commit -m "finish blog comments exercise"
$ git push origin blog-comments-exercise

Create a pull request from your blog-comments-exercise branch to your solutions branch. Please do not create a pull request to the DockYard Academy repository as this will spam our PR tracker.

DockYard Academy Students Only:

Notify your teacher by including @BrooklinJazz in your PR description to get feedback. You (or your teacher) may merge your PR into your solutions branch after review.

If you are interested in joining the next academy cohort, sign up here to receive more news when it is available.

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