Merge pull request #95 from epochtalk/post-preview

Post preview

Author: unenglishable

lib/epochtalk_server_web/controllers/post.ex

@@ -358,6 +358,22 @@ defmodule EpochtalkServerWeb.Controllers.Post do
     end
   end
 
+  @doc """
+  Get `Post` preview by running content through parser
+  """
+  def preview(conn, attrs) do
+    with post_max_length <-
+           Map.get(Application.get_env(:epochtalk_server, :frontend_config), :post_max_length),
+         body <-
+           Validate.cast(attrs, "body", :string, required: true, max: post_max_length, min: 1),
+         parsed_body <- Parse.markdown(body) do
+      render(conn, :preview, %{parsed_body: parsed_body})
+    else
+      _ ->
+        ErrorHelpers.render_json_error(conn, 400, "Error, cannot generate preview")
+    end
+  end
+
   ## === Private Authorization Helper Functions ===
 
   defp can_authed_user_view_deleted_posts(nil, _thread_id), do: false

lib/epochtalk_server_web/helpers/parse.ex

@@ -9,4 +9,11 @@ defmodule EpochtalkServerWeb.Helpers.Parse do
   @spec markdown_within_body(attrs :: map) :: map()
   def markdown_within_body(attrs) when is_map(attrs),
     do: Map.put(attrs, "body_html", Earmark.as_html!(attrs["body_html"] || attrs["body"]))
+
+  @doc """
+  Used to parse markdown inorder to preview `Thread` or `Post` content from the frontend client
+  """
+  @spec markdown_within_body(to_parse :: String.t()) :: String.t()
+  def markdown(to_parse) when is_binary(to_parse),
+    do: Earmark.as_html!(to_parse)
 end

lib/epochtalk_server_web/json/post_json.ex

@@ -25,6 +25,20 @@ defmodule EpochtalkServerWeb.Controllers.PostJSON do
     post_data
   end
 
+  @doc """
+  Renders `Post` data for preview purposes
+
+    ## Example
+    iex> parsed_body = %{parsed_body: "<p><strong>Hello World</strong><p>"}
+    iex> EpochtalkServerWeb.Controllers.PostJSON.preview(parsed_body)
+    parsed_body
+  """
+  def preview(%{
+        parsed_body: parsed_body
+      }) do
+    %{parsed_body: parsed_body}
+  end
+
   @doc """
   Renders all `Post` for a particular `Thread`.
   """

lib/epochtalk_server_web/router.ex

@@ -51,11 +51,11 @@ defmodule EpochtalkServerWeb.Router do
     post "/threads/:thread_id/polls/lock", Poll, :lock
     put "/threads/:thread_id/polls", Poll, :update
     post "/threads/:thread_id/polls", Poll, :create
-    get "/posts", Post, :by_thread
     get "/posts/draft", PostDraft, :by_user_id
     put "/posts/draft", PostDraft, :upsert
     post "/posts", Post, :create
     post "/posts/:id", Post, :update
+    post "/preview", Post, :preview
     get "/admin/modlog", ModerationLog, :page
     get "/boards/movelist", Board, :movelist
   end
@@ -66,6 +66,7 @@ defmodule EpochtalkServerWeb.Router do
     get "/boards/:id", Board, :find
     get "/boards/:slug/id", Board, :slug_to_id
     get "/breadcrumbs", Breadcrumb, :breadcrumbs
+    get "/posts", Post, :by_thread
     get "/threads", Thread, :by_board
     get "/threads/:slug/id", Thread, :slug_to_id
     post "/threads/:id/viewed", Thread, :viewed

test/epochtalk_server_web/controllers/post_test.exs

@@ -0,0 +1,50 @@
+defmodule Test.EpochtalkServerWeb.Controllers.Post do
+  use Test.Support.ConnCase, async: true
+  alias EpochtalkServerWeb.CustomErrors.InvalidPayload
+
+  describe "preview/1" do
+    test "when unauthenticated, returns Unauthorized error", %{conn: conn} do
+      response =
+        conn
+        |> post(Routes.post_path(conn, :preview), %{"body" => "**Test**"})
+        |> json_response(401)
+
+      assert response["error"] == "Unauthorized"
+      assert response["message"] == "No resource found"
+    end
+
+    @tag :authenticated
+    test "when authenticated and supplied with markdown string for body, returns html string",
+         %{conn: conn} do
+      response =
+        conn
+        |> post(Routes.post_path(conn, :preview), %{"body" => "**Test**"})
+        |> json_response(200)
+
+      assert response["parsed_body"] == "<p>\n<strong>Test</strong></p>\n"
+    end
+
+    @tag :authenticated
+    test "when authenticated and supplied with empty string for body, returns error",
+         %{conn: conn} do
+      assert_raise InvalidPayload,
+                   ~r/^Invalid payload, key 'body' should be of type 'string' with length between 1 and 10000/,
+                   fn ->
+                     post(conn, Routes.post_path(conn, :preview), %{"body" => ""})
+                   end
+    end
+
+    @tag :authenticated
+    test "when authenticated and supplied with too large of a string for body, returns error",
+         %{conn: conn} do
+      assert_raise InvalidPayload,
+                   ~r/^Invalid payload, key 'body' should be of type 'string' with length between 1 and 10000/,
+                   fn ->
+                     post(conn, Routes.post_path(conn, :preview), %{
+                       "body" =>
+                         for(_ <- 1..10_001, into: "", do: <<Enum.random('0123456789abcdef')>>)
+                     })
+                   end
+    end
+  end
+end

test/epochtalk_server_web/json/post_json_test.exs

@@ -0,0 +1,7 @@
+defmodule Test.EpochtalkServerWeb.Controllers.PostJSON do
+  use Test.Support.ConnCase, async: true
+  alias EpochtalkServerWeb.Controllers.PostJSON
+
+  # Specify that we want to use doctests:
+  doctest PostJSON
+end