Add automatic converter

lib/mix/tasks/convert_to_verified_routes.ex

@@ -0,0 +1,233 @@
+defmodule Mix.Tasks.ConvertToVerifiedRoutes do
+  @moduledoc """
+  Replaces routes with verified routes.
+  Forked from
+      https://gist.github.com/andreaseriksson/e454b9244a734310d4ab74d8595f98cd
+      https://gist.github.com/jiegillet/e6357c82e36a848ad59295eb3d5a1135
+
+  This requires all routes to consistently be aliased with
+      alias PhilomenaWeb.Router.Helpers, as: Routes
+
+  Run with
+      mix convert_to_verified_routes
+  """
+
+  use Mix.Task
+
+  @regex ~r/(Routes\.)([a-zA-Z0-9_]+)(path|url)\(/
+  @web_module PhilomenaWeb
+
+  def run(_) do
+    Path.wildcard("test/**/*.ex*")
+    |> Enum.concat(Path.wildcard("lib/**/*.ex*"))
+    |> Enum.concat(Path.wildcard("lib/**/*.eex*"))
+    |> Enum.concat(Path.wildcard("lib/**/*.slime"))
+    |> Enum.sort()
+    |> Enum.reject(&String.contains?(&1, "convert_to_verified_routes.ex"))
+    |> Enum.filter(&(&1 |> File.read!() |> String.contains?("Routes.")))
+    |> Enum.each(&format_file/1)
+
+    :ok
+  end
+
+  def format_file(filename) do
+    Mix.shell().info(filename)
+
+    formatted_content =
+      filename
+      |> File.read!()
+      |> format_string()
+
+    File.write!(filename, [formatted_content])
+  end
+
+  def format_string(source) do
+    case Regex.run(@regex, source, capture: :first, return: :index) do
+      [{index, length}] ->
+        # Compute full length of expression
+        length = nibble_expression(source, index, length)
+
+        # Convert to verified route format
+        route = format_route(String.slice(source, index, length))
+
+        # Split string around expression
+        prefix = String.slice(source, 0, index)
+        suffix = String.slice(source, index + length, String.length(source))
+
+        # Insert verified route and rerun
+        format_string("#{prefix}#{route}#{suffix}")
+
+      _ ->
+        source
+    end
+  end
+
+  defp nibble_expression(source, index, length) do
+    if index + length > String.length(source) do
+      raise "Failed to match route expression"
+    end
+
+    case Code.string_to_quoted(String.slice(source, index, length)) do
+      {:ok, _macro} ->
+        length
+
+      _ ->
+        nibble_expression(source, index, length + 1)
+    end
+  end
+
+  defp format_route(route) do
+    ast =
+      Code.string_to_quoted!(route,
+        literal_encoder: &{:ok, {:__block__, &2, [&1]}},
+        unescape: false,
+        token_metadata: true
+      )
+
+    ast
+    |> Macro.prewalk(&replace_route/1)
+    |> Code.quoted_to_algebra(escape: false)
+    |> Inspect.Algebra.format(:infinity)
+  end
+
+  defp decode_literal(literal) when is_binary(literal) or is_integer(literal) do
+    {:ok, literal}
+  end
+
+  defp decode_literal({:__block__, _, [literal]}) do
+    {:ok, literal}
+  end
+
+  defp decode_literal(node), do: {:error, node}
+
+  defp encode_literal(literal) do
+    {:__block__, [], [literal]}
+  end
+
+  # Routes.url(MyAppWeb.Endpoint)
+  defp replace_route({{:., _, [{:__aliases__, _, [:Routes]}, :url]}, _, [_conn_or_endpoint]}) do
+    {:url, [], [{:sigil_p, [delimiter: "\""], [{:<<>>, [], ["/"]}, []]}]}
+  end
+
+  # Routes.static_path(conn, "/images/favicon.ico")
+  defp replace_route({{:., _, [{:__aliases__, _, [:Routes]}, :static_path]}, _, args}) do
+    [_conn_or_endpoint, path] = args
+
+    case decode_literal(path) do
+      {:ok, path} -> {:sigil_p, [delimiter: "\""], [{:<<>>, [], [path]}, []]}
+      _ -> {:sigil_p, [delimiter: "\""], [path, []]}
+    end
+  end
+
+  # Routes.static_url(conn, "/images/favicon.ico")
+  defp replace_route({{:., _, [{:__aliases__, _, [:Routes]}, :static_url]}, _, args}) do
+    [_conn_or_endpoint, path] = args
+
+    sigil =
+      case decode_literal(path) do
+        {:ok, path} -> {:sigil_p, [delimiter: "\""], [{:<<>>, [], [path]}, []]}
+        _ -> {:sigil_p, [delimiter: "\""], [path, []]}
+      end
+
+    {:url, [], [sigil]}
+  end
+
+  # Routes.some_path(conn, :action, "en", query_params)
+  defp replace_route(
+         {{:., _, [{:__aliases__, _, [:Routes]}, path_name]}, _, [_ | _] = args} = node
+       ) do
+    [_conn_or_endpoint, action | params] = args
+
+    action =
+      case decode_literal(action) do
+        {:ok, action} -> action
+        _ -> action
+      end
+
+    path_name = "#{path_name}"
+
+    case find_verified_route(path_name, action, params) do
+      :ok -> node
+      route -> route
+    end
+  end
+
+  defp replace_route(node), do: node
+
+  defp find_verified_route(path_name, action, arguments) do
+    # pleaaaase don't have a route named Routes.product_url_path(conn, :index)
+    trimmed_path = path_name |> String.trim_trailing("_path") |> String.trim_trailing("_url")
+
+    route =
+      Phoenix.Router.routes(@web_module.Router)
+      |> Enum.find(fn %{helper: helper, plug_opts: plug_opts} ->
+        plug_opts == action && is_binary(helper) && trimmed_path == helper
+      end)
+
+    case route do
+      %{path: path} ->
+        {path_bits, query_params} =
+          path
+          |> String.split("/", trim: true)
+          |> replace_path_variables(arguments, [])
+
+        path_bits =
+          path_bits
+          |> Enum.flat_map(fn bit -> ["/", bit] end)
+          |> format_for_sigil_binary_args(query_params)
+
+        sigil = {:sigil_p, [delimiter: "\""], [{:<<>>, [], path_bits}, []]}
+
+        if String.ends_with?(path_name, "_url") do
+          {:url, [], [sigil]}
+        else
+          sigil
+        end
+
+      _ ->
+        Mix.shell().error(
+          "Could not find route #{path_name}, with action #{inspect(action)} and arguments #{inspect(arguments)}"
+        )
+    end
+  end
+
+  defp replace_path_variables([], arguments, path_bits) do
+    {Enum.reverse(path_bits), arguments}
+  end
+
+  defp replace_path_variables(path, [], path_bits) do
+    {Enum.reverse(path_bits) ++ path, []}
+  end
+
+  # conceptually /post/:post_id -> /post/#{id}
+  defp replace_path_variables([path_piece | rest], [arg | args], path_bits) do
+    if String.starts_with?(path_piece, ":") do
+      replace_path_variables(rest, args, [arg | path_bits])
+    else
+      replace_path_variables(rest, [arg | args], [path_piece | path_bits])
+    end
+  end
+
+  defp format_for_sigil_binary_args(path_bits, [_ | _] = query_params) do
+    format_for_sigil_binary_args(path_bits ++ ["?" | query_params], [])
+  end
+
+  defp format_for_sigil_binary_args(path_bits, []) do
+    path_bits
+    |> Enum.map(&decode_literal/1)
+    |> Enum.map(fn
+      {:ok, bit} when is_binary(bit) ->
+        bit
+
+      {:ok, bit} when is_atom(bit) or is_integer(bit) ->
+        to_string(bit)
+
+      {_, bit} ->
+        {:"::", [],
+         [
+           {{:., [], [Kernel, :to_string]}, [from_interpolation: true], [encode_literal(bit)]},
+           {:binary, [], Elixir}
+         ]}
+    end)
+  end
+end