feat(extensions): pre-write extensions (#83)

fix(extensions): don't require a config module

Author: mhanberg

config/test.exs

@@ -5,5 +5,6 @@ config :logger, level: :warning
 config :tableau, :config, url: "http://localhost:4999"
 config :tableau, Tableau.RSSExtension, enabled: false
 config :tableau, Tableau.PostExtension, enabled: false
+config :tableau, Tableau.SitemapExtension, enabled: false
 config :tableau, Mix.Tasks.Tableau.LogExtension, enabled: true
 config :tableau, Mix.Tasks.Tableau.FailExtension, enabled: true

lib/mix/tasks/tableau.build.ex

@@ -21,34 +21,7 @@ defmodule Mix.Tasks.Tableau.Build do
 
     mods = :code.all_available()
 
-    token =
-      for module <- pre_build_extensions(mods), reduce: token do
-        token ->
-          config_mod = Module.concat([module, Config])
-
-          raw_config =
-            :tableau |> Application.get_env(module, %{}) |> Map.new()
-
-          if raw_config[:enabled] do
-            {:ok, config} =
-              config_mod.new(raw_config)
-
-            {:ok, key} = Tableau.Extension.key(module)
-
-            token = put_in(token[key], config)
-
-            case module.run(token) do
-              {:ok, token} ->
-                token
-
-              :error ->
-                Logger.error("#{inspect(module)} failed to run")
-                token
-            end
-          else
-            token
-          end
-      end
+    token = mods |> pre_build_extensions() |> run_extensions(token)
 
     mods = :code.all_available()
     graph = Tableau.Graph.new(mods)
@@ -60,12 +33,14 @@ defmodule Mix.Tasks.Tableau.Build do
         {mod, Map.new(Tableau.Graph.Nodable.opts(mod) || [])}
       end
 
-    {page_mods, pages} = Enum.unzip(pages)
+    {page_mods, just_pages} = Enum.unzip(pages)
 
-    token = put_in(token.site[:pages], pages)
+    token = put_in(token.site[:pages], just_pages)
 
-    for mod <- page_mods do
-      content = Tableau.Document.render(graph, mod, token)
+    token = mods |> pre_write_extensions() |> run_extensions(token)
+
+    for {mod, page} <- Enum.zip(page_mods, token.site.pages) do
+      content = Tableau.Document.render(graph, mod, token, page)
       permalink = Tableau.Graph.Nodable.permalink(mod)
       dir = Path.join(out, permalink)
 
@@ -78,32 +53,16 @@ defmodule Mix.Tasks.Tableau.Build do
       File.cp_r!(config.include_dir, out)
     end
 
-    for module <- post_write_extensions(mods), reduce: token do
-      token ->
-        config_mod = Module.concat([module, Config])
-
-        raw_config =
-          :tableau |> Application.get_env(module, %{}) |> Map.new()
-
-        if raw_config[:enabled] do
-          {:ok, config} =
-            config_mod.new(raw_config)
-
-          {:ok, key} = Tableau.Extension.key(module)
-
-          token = put_in(token[key], config)
+    token = run_extensions(post_write_extensions(mods), token)
 
-          case module.run(token) do
-            {:ok, token} ->
-              token
+    token
+  end
 
-            :error ->
-              Logger.error("#{inspect(module)} failed to run")
-              token
-          end
-        else
-          token
-        end
+  defp validate_config(config_mod, raw_config) do
+    if Code.ensure_loaded?(config_mod) do
+      config_mod.new(raw_config)
+    else
+      {:ok, raw_config}
     end
   end
 
@@ -118,6 +77,17 @@ defmodule Mix.Tasks.Tableau.Build do
     Enum.sort_by(extensions, & &1.__tableau_extension_priority__())
   end
 
+  defp pre_write_extensions(modules) do
+    extensions =
+      for {mod, _, _} <- modules,
+          mod = Module.concat([to_string(mod)]),
+          match?({:ok, :pre_write}, Tableau.Extension.type(mod)) do
+        mod
+      end
+
+    Enum.sort_by(extensions, & &1.__tableau_extension_priority__())
+  end
+
   defp post_write_extensions(modules) do
     extensions =
       for {mod, _, _} <- modules,
@@ -128,4 +98,33 @@ defmodule Mix.Tasks.Tableau.Build do
 
     Enum.sort_by(extensions, & &1.__tableau_extension_priority__())
   end
+
+  defp run_extensions(extensions, token) do
+    for module <- extensions, reduce: token do
+      token ->
+        config_mod = Module.concat([module, Config])
+
+        raw_config =
+          :tableau |> Application.get_env(module, %{enabled: true}) |> Map.new()
+
+        if raw_config[:enabled] do
+          {:ok, config} = validate_config(config_mod, raw_config)
+
+          {:ok, key} = Tableau.Extension.key(module)
+
+          token = put_in(token[key], config)
+
+          case module.run(token) do
+            {:ok, token} ->
+              token
+
+            :error ->
+              Logger.error("#{inspect(module)} failed to run")
+              token
+          end
+        else
+          token
+        end
+    end
+  end
 end

lib/tableau/document.ex

@@ -20,7 +20,7 @@ defmodule Tableau.Document do
     end
   end
 
-  def render(graph, module, assigns) do
+  def render(graph, module, assigns, page) do
     [root | mods] =
       case Graph.dijkstra(graph, module, :root) do
         path when is_list(path) ->
@@ -32,7 +32,7 @@ defmodule Tableau.Document do
           raise "Failed to find layout path for #{inspect(module)}"
       end
 
-    page_assigns = Map.new(Tableau.Graph.Nodable.opts(module) || [])
+    page_assigns = (Tableau.Graph.Nodable.opts(module) || []) |> Map.new() |> Map.merge(page)
     mods = for mod <- mods, do: {mod, page_assigns, assigns}
 
     Tableau.Graph.Nodable.template(root, Map.merge(assigns, %{inner_content: mods, page: page_assigns}))

lib/tableau/extension.ex

@@ -16,6 +16,7 @@ defmodule Tableau.Extension do
   There are currently the following extension types:
 
   - `:pre_build` - executed before tableau builds your site and writes anything to disk.
+  - `:pre_write` - executed after tableau builds your site but before it writes anything to disk.
   - `:post_write` - executed after tableau builds your site and writes everything to disk.
 
   ## Example

test/mix/tasks/tableau.build_test.exs

@@ -17,17 +17,26 @@ defmodule Mix.Tasks.Tableau.FailExtension do
   @moduledoc false
   use Tableau.Extension, key: :fail, type: :pre_build, priority: 100
 
-  defmodule Config do
-    @moduledoc false
-    def new(i), do: {:ok, i}
-  end
-
   def run(_site) do
     IO.inspect(System.monotonic_time(), label: "first")
     :error
   end
 end
 
+defmodule Mix.Tasks.Tableau.FooExtension do
+  @moduledoc false
+  use Tableau.Extension, key: :foo, type: :pre_write, priority: 100
+
+  def run(token) do
+    pages =
+      for page <- token.site.pages do
+        Map.put(page, :foo, "bar")
+      end
+
+    {:ok, put_in(token.site.pages, pages)}
+  end
+end
+
 defmodule Mix.Tasks.Tableau.BuildTest.About do
   @moduledoc false
   import Tableau.Strung

test/tableau/document_test.exs

@@ -15,7 +15,7 @@ defmodule Tableau.DocumentTest.About do
     :def,
     :template,
     ~g'''
-    <div id="<%= @page.yo %>">
+    <div id="<%= @page.yo %>" class="<%= @page.foo %>">
       hi
     </div>
     '''html,
@@ -103,7 +103,7 @@ defmodule Tableau.DocumentTest do
 
   test "renders a document" do
     graph = Tableau.Graph.new(:code.all_available())
-    content = Document.render(graph, __MODULE__.About, %{site: %{}})
+    content = Document.render(graph, __MODULE__.About, %{site: %{}}, %{foo: "bar"})
 
     assert Floki.parse_document!(content) ===
              [
@@ -112,7 +112,7 @@ defmodule Tableau.DocumentTest do
                   {"head", [], []},
                   {"body", [],
                    [
-                     {"div", [{"id", "inner-layout"}], [{"div", [{"id", "lo"}], ["\n  hi\n"]}]}
+                     {"div", [{"id", "inner-layout"}], [{"div", [{"id", "lo"}, {"class", "bar"}], ["\n  hi\n"]}]}
                    ]}
                 ]}
              ]