image: tag file_hash with hash algorithm and format in hex

Author: delan

lib/data/image.ex

@@ -59,10 +59,12 @@ defmodule Memorable.Data.Image.DerivedMetadata do
     with {:read_file, {:ok, data}} <- {:read_file, File.read(path)},
          {:read_metadata, {:ok, metadata}} <-
            {:read_metadata, Image.read_metadata(image)} do
+      sha256 = Base.encode16(:crypto.hash(:sha256, data), case: :lower)
+
       {:ok,
        %__MODULE__{
          image_id: image_id,
-         file_hash: :crypto.hash(:sha256, data),
+         file_hash: {:sha256, sha256},
          original_datetime: original_datetime(metadata),
          lens_model: Map.get(metadata, "LensID"),
          body_model: Map.get(metadata, "Model"),

test/data/image_test.exs

@@ -41,6 +41,11 @@ defmodule Memorable.Data.ImageTest do
   describe "DerivedMetadata.from_image/1" do
     test "parses exif data for the given image", %{image: image} do
       {:ok, metadata} = DerivedMetadata.from_image(image) |> IO.inspect()
+      assert Map.get(metadata, :image_id) == Map.get(image, :id)
+
+      assert Map.get(metadata, :file_hash) ==
+               {:sha256, "3932e8b3f41678e215981303d8320ab70c00fd35b0e8f063eec3087c7de801df"}
+
       assert Map.get(metadata, :original_datetime) == ~N[2025-03-17 18:38:23]
       assert Map.get(metadata, :body_model) == "Canon EOS 1000D"
       assert Map.get(metadata, :lens_model) == "Canon EF-S 55-250mm f/4-5.6 IS STM"