Scan barcodes and display releases

assets/js/barcode-scanner.js

@@ -1,28 +1,26 @@
 import { BarcodeDetector } from "barcode-detector/ponyfill";
 
-const barcodeTest = async function () {
+const barcodeReaderSetup = async function () {
-  // check supported formats
   const supportedFormats = await BarcodeDetector.getSupportedFormats();
-  console.log(supportedFormats);
 
-  const barcodeDetector = new BarcodeDetector({
+  return new BarcodeDetector({
     // make sure the formats are supported
-    formats: ["qr_code"],
+    formats: supportedFormats,
   });
-
-  const imageFile = await fetch(
-    "https://api.qrserver.com/v1/create-qr-code/?size=150x150&data=Hello%20world!",
-  ).then((resp) => resp.blob());
-
-  barcodeDetector.detect(imageFile).then(console.log);
 }
 
 export default {
-  mounted() {
+  async mounted() {
+    const detectedBarcodes = new Set([]);
+    const barcodeDetector = await barcodeReaderSetup();
     const video = this.el;
     const constraints = {
       audio: false,
-      video: { width: 800, height: 600 },
+      video: {
+        width: 800, height: 600, facingMode: {
+          ideal: "environment"
+        }
+      },
     };
 
     navigator.mediaDevices
@@ -30,10 +28,20 @@ export default {
       .then((mediaStream) => {
         console.debug("Camera access allowed")
         this.pushEventTo(video, "camera:allowed", {});
-        console.log(mediaStream);
         video.srcObject = mediaStream;
         video.onloadedmetadata = () => {
           video.play();
+          this.scanInterval = window.setInterval(async () => {
+            const barcodes = await barcodeDetector.detect(video);
+            if (barcodes.length <= 0) return;
+
+            barcodes.forEach(barcode => {
+              if (!detectedBarcodes.has(barcode.rawValue)) {
+                this.pushEventTo(video, "barcode:scanned", { number: barcode.rawValue });
+                detectedBarcodes.add(barcode.rawValue);
+              };
+            });
+          }, 500)
         };
       })
       .catch((err) => {
@@ -43,5 +51,6 @@ export default {
   },
   destroyed() {
     this.el.srcObject.getTracks().forEach(track => track.stop());
+    window.clearInterval(this.scanInterval);
   }
 }

lib/music_brainz/api_impl.ex

@@ -305,6 +305,15 @@ defmodule MusicBrainz.APIImpl do
     json_get(url, config)
   end
 
+  def search_release_by_barcode(barcode, config) do
+    url =
+      @base_url <> "/release?query=barcode:#{barcode}&fmt=json"
+
+    with {:ok, result} <- json_get(url, config) do
+      {:ok, result["releases"]}
+    end
+  end
+
   @doc """
   Uses the [search](https://musicbrainz.org/doc/MusicBrainz_API/Search#Release_Group) endpoint with a search query string.
 

lib/music_library/records.ex

@@ -139,6 +139,16 @@ defmodule MusicLibrary.Records do
     end
   end
 
+  def search_release_by_barcode(barcode) do
+    case music_brainz_config().api.search_release_by_barcode(barcode, music_brainz_config()) do
+      {:ok, releases} ->
+        {:ok, releases}
+
+      error ->
+        error
+    end
+  end
+
   def import_from_musicbrainz_release_group(musicbrainz_id, opts \\ []) do
     with format = Keyword.get(opts, :format, "cd"),
          purchased_at = Keyword.get(opts, :purchased_at),

lib/music_library_web/live/record_live/barcode_scanner_component.ex

@@ -1,14 +1,32 @@
 defmodule MusicLibraryWeb.RecordLive.BarcodeScannerComponent do
   use MusicLibraryWeb, :live_component
 
+  alias MusicLibrary.Records
+
   require Logger
 
+  @impl true
+  def mount(socket) do
+    {:ok,
+     socket
+     |> assign(:camera, :pending)
+     |> assign(:barcodes, MapSet.new())
+     |> assign(:releases, [])}
+  end
+
   @impl true
   def render(assigns) do
     ~H"""
     <div>
       <h1>Barcode Scan</h1>
-      <video id="barcode-scan" phx-hook="BarcodeScanner"></video>
+      <video id="camera-view" phx-hook="BarcodeScanner"></video>
+      <ul>
+        <li :for={release <- assigns.releases}>
+          <span>{release["id"]}</span>
+          <span>{release["barcode"]}</span>
+          <span>{release["title"]}</span>
+        </li>
+      </ul>
     </div>
     """
   end
@@ -23,4 +41,18 @@ defmodule MusicLibraryWeb.RecordLive.BarcodeScannerComponent do
     Logger.debug(fn -> "Camera access denied" end)
     {:noreply, assign(socket, camera: :denied)}
   end
+
+  def handle_event("barcode:scanned", %{"number" => number}, socket) do
+    Logger.debug(fn -> "Scanned barcode #{number}" end)
+
+    {:ok, releases} =
+      Records.search_release_by_barcode(number)
+
+    socket =
+      socket
+      |> assign(barcodes: MapSet.put(socket.assigns.barcodes, number))
+      |> assign(:releases, releases ++ socket.assigns.releases)
+
+    {:noreply, socket}
+  end
 end