rlb3 / phoenix-views-example

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First, run the usual Phoenix app setup:

mix deps.get

Then:

mix do ecto.create, ecto.migrate, run priv/repo/seeds.exs

Then:

mix phx.server

When you go to http://localhost:4000/articles you'll see a list of articles with their comments. They also appear at /articles/1 and /articles/2.

This is accomplished by using Phoenix's wonderful views. Looking at the index action in ArticleController, there's this:

render(conn, "index.json", articles: articles)

This uses the ArticleView to do the rendering, rather than rendering JSON outright. ArticleView has this function:

def render("index.json", %{articles: articles}) do
  render_many(articles, ArticleView, "article.json")
end

This is the function that is called from your controller. It calls render_many, which will call the render function again on this same view, but instead of index.json it uses article.json, which is defined like this:

def render("article.json", %{article: article}) do
  %{id: article.id,
    title: article.title,
    comments: render_many(article.comments, CommentView, "show.json") }
end

This then calls this render function in the CommentView:

def render("comment.json", %{comment: comment}) do
  %{
    text: comment.text
  }
end

Overall, it's beneficial to render things this way because you can recycle functions between views. For instance, rendering a comment in a URL like /articles/1/comments/2 could re-use that same function, if you wanted to.