Mostly get db-based posts up and running.

lib/jol/blog.ex

@@ -1,5 +1,7 @@
 defmodule JOL.Blog do
-  alias JOL.Blog.Post
+  alias JOL.Blog.{Post, Tag}
+  alias JOL.Repo
+  import Ecto.Query
 
   defmodule NotFoundError do
     defexception [:message, plug_status: 404]
@@ -10,17 +12,40 @@ defmodule JOL.Blog do
   end
 
   def unique_tag_list do
-    []
+    Repo.all(Tag, order_by: :name)
   end
 
   def recent_posts(num \\ 10) do
-    []
+    Repo.all(
+      from p in Post,
+        limit: ^num,
+        order_by: {:desc, :published_at}
+    )
   end
 
   def get_post_by_slug!(slug) do
+    Repo.one(
+      from p in Post,
+        where: [slug: ^slug],
+        preload: [:tags]
+      )
   end
 
   def get_posts_by_tag!(tag) do
+    Repo.all(
+      from p in Post,
+      join: t in assoc(p, :tags),
+      preload: [tags: t],
+      where: t.name == ^tag
+    )
+  end
+
+  def get_tag_by_id!(id) do
+    Repo.one(
+      from t in Tag,
+        where: t.id == ^id,
+        preload: [:posts]
+    )
   end
 
   def format_date(date) do

lib/jol/blog/post.ex

@@ -7,6 +7,7 @@ defmodule JOL.Blog.Post do
     field :body, :string
     field :published_at, :naive_datetime
     field :slug, :string
+    many_to_many :tags, JOL.Blog.Tag, join_through: "post_tags"
 
     timestamps(type: :utc_datetime)
   end
@@ -15,6 +16,7 @@ defmodule JOL.Blog.Post do
   def changeset(post, attrs) do
     post
     |> cast(attrs, [:title, :body, :published_at, :slug])
-    |> validate_required([:title, :body, :published_at, :slug])
+    |> validate_required([:title, :body, :slug])
+    |> cast_assoc(:tags)
   end
 end

lib/jol/blog/tag.ex

@@ -1,9 +1,10 @@
-defmodule JOL.Blog.Tags do
+defmodule JOL.Blog.Tag do
   use Ecto.Schema
   import Ecto.Changeset
 
   schema "tags" do
     field :name, :string
+    many_to_many :posts, JOL.Blog.Post, join_through: "post_tags"
 
     timestamps(type: :utc_datetime)
   end
@@ -13,5 +14,6 @@ defmodule JOL.Blog.Tags do
     tags
     |> cast(attrs, [:name])
     |> validate_required([:name])
+    |> unique_constraint([:name])
   end
 end

lib/jol_web/controllers/blog_html/show.heex

@@ -3,11 +3,11 @@
 <h1><%= @post.title %></h1>
 
 <p>
-  <date><%= JOL.Blog.format_date(@post.date) %></date>
+  <date><%= JOL.Blog.format_date(@post.published_at) %></date>
 </p>
 
 <%= raw @post.body %>
 
 <p class="post-tags">
-  Filed under: <%= Enum.join(@post.tags, ", ") %>
+  Filed under: <%= @post.tags |> Enum.map(& &1.name) |> Enum.join(", ") %>
 </p>

lib/jol_web/controllers/page_html/home.html.heex

@@ -12,7 +12,7 @@
       <ul class="recent-posts">
       <%= for post <- @posts do %>
           <li>
-              <date><%= JOL.Blog.format_date(post.date) %></date>
+              <date><%= JOL.Blog.format_date(post.published_at) %></date>
               <.link href={~p"/blog/#{post.slug}"}><%= post.title %> </.link>
           </li>
       <% end %>

lib/jol_web/controllers/tag_controller.ex

@@ -8,11 +8,13 @@ defmodule JOLWeb.TagController do
       tags: JOL.Blog.unique_tag_list)
   end
 
-  def tag(conn, %{"tag" => tag}) do
+  def tag(conn, %{"id" => id}) do
+    tag = JOL.Blog.get_tag_by_id!(id)
+
     conn
     |> render(:tag,
-      tag: tag,
-      page_title: "Posts Filed Under #{tag}",
-      posts: JOL.Blog.get_posts_by_tag!(tag))
+      tag: tag.name,
+      page_title: "Filed Under #{tag.name}",
+      posts: tag.posts)
   end
 end

lib/jol_web/controllers/tag_html/index.html.heex

@@ -3,7 +3,7 @@
     <ul>
         <%= for tag <- @tags do %>
             <li class="tag-list">
-                <a href={~p"/tags/#{tag}"}><%= tag %></a>
+                <a href={~p"/tags/#{tag.id}"}><%= tag.name %></a>
             </li>
         <% end %>
     </ul>

lib/jol_web/controllers/tag_html/tag.html.heex

@@ -2,7 +2,7 @@
 
 <%= for post <- @posts do %>
     <div class="post-summary">
-        <p class="post-date"><date><%= post.date %></date></p>
+        <p class="post-date"><date><%= post.published_at %></date></p>
         <h3> <.link href={~p"/blog/#{post.slug}"}><%= post.title %> </.link> </h3>
         <p><%= raw post.lede %></p>
     </div>

lib/jol_web/router.ex

@@ -28,7 +28,7 @@ defmodule JOLWeb.Router do
     get "/colophon", PageController, :colophon
 
     get "/tags", TagController, :index
-    get "/tags/:tag", TagController, :tag
+    get "/tags/:id", TagController, :tag
 
     get "/blog", BlogController, :index
     get "/blog/:slug", BlogController, :show

mix.exs

@@ -59,7 +59,8 @@ defmodule JOL.MixProject do
       {:dns_cluster, "~> 0.1.1"},
       {:bandit, "~> 1.2"},
       {:atomex, "~> 0.3.0"},
-      {:tz, "~> 0.27"}
+      {:tz, "~> 0.27"},
+      {:toml, "~> 0.7"}
     ]
   end
 

priv/migrate_posts.exs

@@ -0,0 +1,26 @@
+alias JOL.Blog.{Parser,Post,Tag}
+alias JOL.Repo
+import Ecto.Query
+
+post_dir = Application.app_dir(:jol, "priv/posts/blog/")
+
+Path.wildcard("#{post_dir}/**/*.md")
+|> Enum.each(fn path ->
+  {attrs, body} = Parser.parse(path, File.read!(path))
+    for tag <- attrs.tags do
+      Repo.insert!(%Tag{name: tag}, on_conflict: :nothing, conflict_target: [:name])
+    end
+
+    post_attrs = %{title: attrs.title,
+      published_at: attrs.date,
+      slug: attrs.slug,
+      body: body,
+      tags: Repo.all(from t in Tag, where: t.name in ^attrs.tags)
+    }
+
+    %Post{}
+    |> Repo.preload(:tags)
+    |> Ecto.Changeset.cast(post_attrs, [:published_at, :slug, :body, :title])
+    |> Ecto.Changeset.put_assoc(:tags, post_attrs.tags)
+    |> Repo.insert!()
+  end)

priv/repo/migrations/20240924153630_join_posts_and_tags.exs

@@ -0,0 +1,10 @@
+defmodule JOL.Repo.Migrations.JoinPostsAndTags do
+  use Ecto.Migration
+
+  def change do
+    create table(:post_tags) do
+      add :post_id, references(:posts)
+      add :tag_id, references(:tags)
+    end
+  end
+end

priv/repo/migrations/20240924154328_make_tag_name_unique.exs

@@ -0,0 +1,8 @@
+defmodule JOL.Repo.Migrations.MakeTagNameUnique do
+  use Ecto.Migration
+
+  def change do
+    create unique_index(:tags, ["name"])
+    create unique_index(:post_tags, ["post_id", "tag_id"])
+  end
+end