From 54344c985b0998270a2c372b6819ccb2c25cf301 Mon Sep 17 00:00:00 2001
From: Robert Dargavel Smith <teticio@gmail.com>
Date: Tue, 24 Aug 2021 13:20:48 +0100
Subject: [PATCH] serve widgets from backend, cache in frontend

---
 backend/main.py                  | 26 +++++++++--
 src/App.js                       |  1 +
 src/components/Banner.js         |  9 +++-
 src/components/Playlist.js       |  8 +++-
 src/components/RemovableTrack.js | 12 ++---
 src/components/Track.js          | 80 +++++++++++++++++++-------------
 src/components/TrackSelector.js  | 16 ++++---
 src/service-worker.js            | 22 +++++++--
 8 files changed, 118 insertions(+), 56 deletions(-)

diff --git a/backend/main.py b/backend/main.py
index 5d1bad7..cfe4f96 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -1,6 +1,5 @@
 import os
 import re
-import base64
 import urllib
 import aiohttp
 from . import models
@@ -9,6 +8,7 @@
 from .deejai import DeejAI
 from typing import Optional
 from sqlalchemy import desc
+from base64 import b64encode
 from starlette.types import Scope
 from sqlalchemy.orm import Session
 from starlette.responses import Response
@@ -79,7 +79,7 @@ async def spotify_callback(code: str, state: Optional[str] = '/'):
     headers = {
         'Authorization':
         'Basic ' +
-        base64.b64encode(f'{credentials.client_id}:{credentials.client_secret}'
+        b64encode(f'{credentials.client_id}:{credentials.client_secret}'
                          .encode('utf-8')).decode('utf-8')
     }
     async with aiohttp.ClientSession() as session:
@@ -108,7 +108,7 @@ async def spotify_refresh_token(refresh_token: str):
     headers = {
         'Authorization':
         'Basic ' +
-        base64.b64encode(f'{credentials.client_id}:{credentials.client_secret}'
+        b64encode(f'{credentials.client_id}:{credentials.client_secret}'
                          .encode('utf-8')).decode('utf-8')
     }
     async with aiohttp.ClientSession() as session:
@@ -125,6 +125,26 @@ async def spotify_refresh_token(refresh_token: str):
     return json
 
 
+@app.get("/api/v1/widget")
+async def widget(track_id: str):
+    headers = {
+        'User-Agent':
+        'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36'
+    }
+    async with aiohttp.ClientSession() as session:
+        try:
+            async with session.get(
+                    f'https://open.spotify.com/embed/track/{track_id}',
+                    headers=headers) as response:
+                if response.status != 200:
+                    raise HTTPException(status_code=response.status,
+                                        detail=response.reason)
+                text = await response.text()
+        except aiohttp.ClientError as error:
+            raise HTTPException(status_code=400, detail=str(error))
+    return b64encode(text.encode('ascii'))
+
+
 @app.get("/api/v1/search")
 async def search_tracks(string: str, max_items: int):
     ids = await deejai.search(string, max_items)
diff --git a/src/App.js b/src/App.js
index 54d9546..b392b8c 100644
--- a/src/App.js
+++ b/src/App.js
@@ -1,6 +1,7 @@
 // TODO
 //
 // frontend:
+// robots.txt etc
 // unit tests
 // banner image and ico file
 // fix warnings for unique key
diff --git a/src/components/Banner.js b/src/components/Banner.js
index 064c9f9..bbdb6a2 100644
--- a/src/components/Banner.js
+++ b/src/components/Banner.js
@@ -12,7 +12,14 @@ export default function Banner({ loggedIn = false, onSelect = f => f }) {
   return (
     <>
       <VerticalSpacer px={120} />
-      <Navbar className="banner shadow-lg" fixed="top" bg="dark" variant="dark" expand="no" expanded={expanded}>
+      <Navbar
+        className="banner shadow-lg"
+        fixed="top"
+        bg="dark"
+        variant="dark"
+        expand="no"
+        expanded={expanded}
+      >
         <Container>
           <Navbar.Brand href="#">
             <div className="row align-items-center">
diff --git a/src/components/Playlist.js b/src/components/Playlist.js
index 512cc1c..8f7fafb 100644
--- a/src/components/Playlist.js
+++ b/src/components/Playlist.js
@@ -4,8 +4,12 @@ export default function Playlist({ track_ids = [], waypoints = [] }) {
   return (
     <>
       {track_ids.map((track_id, i) => (
-        <div className="d-flex flex-row justify-content-center align-items-center">
-          <Track key={i} track_id={track_id} highlight={ waypoints.indexOf(track_id) >= 0 } />
+        <div className="d-flex flex-row justify-content-center align-items-center align-middle">
+          <Track
+            key={i}
+            track_id={track_id}
+            highlight={waypoints.indexOf(track_id) >= 0}
+          />
         </div>
       ))}
     </>
diff --git a/src/components/RemovableTrack.js b/src/components/RemovableTrack.js
index acaa71c..4171c66 100644
--- a/src/components/RemovableTrack.js
+++ b/src/components/RemovableTrack.js
@@ -15,13 +15,11 @@ export default function RemovableTrack({ track_id, uuid, onRemove = f => f }) {
       >
       </Track>
       <HorizontalSpacer px={10} />
-      {loaded ?
-        <FaTimes
-          size="25"
-          className="link"
-          onClick={() => onRemove(uuid)}
-        /> : <></>
-      }
+      <FaTimes
+        size="25"
+        className="link"
+        onClick={() => onRemove(uuid)}
+      />
     </>
   );
 }
diff --git a/src/components/Track.js b/src/components/Track.js
index 3e87b1a..66cf6f9 100644
--- a/src/components/Track.js
+++ b/src/components/Track.js
@@ -1,51 +1,65 @@
-import { useState } from 'react';
+import { Suspense } from 'react';
 import Spinner from 'react-bootstrap/Spinner';
 import './Track.css';
 
-function SpotifyTrackWidget({ track_id, highlight, loaded, onLoad = f => f }) {
+function createResource(pending) {
+  let error, response;
+  pending.then(r => response = r).catch(e => error = e);
+  return {
+    read() {
+      if (error) throw error;
+      if (response) return response;
+      throw pending;
+    }
+  };
+}
+
+function SpotifyTrackWidget({ track_id, highlight, resource }) {
+  const iframe = (resource) ? resource.read() : null;
+
   return (
     <iframe
-      className={(loaded && highlight) ? "highlight" : ""}
+      className={highlight ? "highlight" : ""}
       title={track_id}
-      src={"https://open.spotify.com/embed/track/" + track_id}
-      width={loaded ? "100%" : "0%"}
+      //src={`https://open.spotify.com/embed/track/${track_id}`}
+      srcdoc={Buffer.from(iframe.data, 'base64')}
+      width="100%"
       height="80"
       frameBorder="0"
       allowtransparency="true"
       allow="encrypted-media"
-      onLoad={() => onLoad()}
     />
   );
 }
 
-export default function Track({ track_id, highlight = false, onLoad = f => f }) {
-  const [loaded, setLoaded] = useState(false);
+export default function Track({ track_id, highlight = false }) {
+  if (typeof Track.cache == 'undefined') {
+    Track.cache = {};
+  }
+
+  const resource = (track_id in Track.cache) ? Track.cache[track_id] :
+    createResource(new Promise(resolves => {
+      fetch(`${process.env.REACT_APP_API_URL}/widget?track_id=${track_id}`)
+        .then(response => (response.status === 200) ? response.text() : '')
+        .then(data => resolves({ data: data }))
+        .catch(error => console.error('Error:', error));
+    }));
+  Track.cache[track_id] = resource;
 
   return (
-    <>
-      {!loaded ?
-        <>
-          <Spinner animation="border" />
-          <SpotifyTrackWidget
-            track_id={track_id}
-            highlight={highlight}
-            loaded={loaded}
-            onLoad={() => {
-              setLoaded(true);
-              onLoad();
-            }}
-          />
-        </> :
-        <SpotifyTrackWidget
-          track_id={track_id}
-          highlight={highlight}
-          loaded={loaded}
-          onLoad={() => {
-            setLoaded(true);
-            onLoad();
-          }}
-        />
-      }
-    </>
+    <Suspense fallback={
+      <div
+        className="d-flex justify-content-center align-items-center align-middle"
+        style={{ height: 80, width: "100%" }}
+      >
+        <Spinner animation="border" />
+      </div>
+    } >
+      <SpotifyTrackWidget
+        track_id={track_id}
+        highlight={highlight}
+        resource={resource}
+      />
+    </Suspense>
   );
 }
diff --git a/src/components/TrackSelector.js b/src/components/TrackSelector.js
index e46fe4a..8a58b0e 100644
--- a/src/components/TrackSelector.js
+++ b/src/components/TrackSelector.js
@@ -14,13 +14,15 @@ export default function TrackSelector({ spotify = null, onSelect = f => f, onSea
     const id = setInterval(() => {
       if (spotify && spotify.loggedIn()) {
         spotify.autoRefresh(() => spotify.getMyCurrentPlayingTrack())
-          .then((response) => {
-            setCurrentTrack(response.item ? {
-              'track':
-                `${response.item.artists[0].name} - ${response.item.name}`,
-              'url': response.item.preview_url
-            } : null);
-          }).catch(); // ignore error
+          .then(response => {
+            if (response) {
+              setCurrentTrack(response.item ? {
+                'track':
+                  `${response.item.artists[0].name} - ${response.item.name}`,
+                'url': response.item.preview_url
+              } : null);
+            }
+          }).catch(error => console.error('Error:', error));
       } else {
         setCurrentTrack(null);
       }
diff --git a/src/service-worker.js b/src/service-worker.js
index 9fc7197..0da3a0f 100644
--- a/src/service-worker.js
+++ b/src/service-worker.js
@@ -11,7 +11,7 @@ import { clientsClaim } from 'workbox-core';
 import { ExpirationPlugin } from 'workbox-expiration';
 import { precacheAndRoute, createHandlerBoundToURL } from 'workbox-precaching';
 import { registerRoute } from 'workbox-routing';
-import { StaleWhileRevalidate } from 'workbox-strategies';
+import { StaleWhileRevalidate, NetworkFirst } from 'workbox-strategies';
 
 clientsClaim();
 
@@ -66,9 +66,25 @@ registerRoute(
 );
 
 registerRoute(
-  ({ url }) => url.pathname.endsWith('/api/v1/search') || url.pathname.endsWith('/api/v1/search_similar'),
+  ({ url }) =>
+    url.pathname.endsWith('/api/v1/search') ||
+    url.pathname.endsWith('/api/v1/search_similar') ||
+    url.pathname.endsWith('/api/v1/widget'),
   new StaleWhileRevalidate({
-    cacheName: 'searches',
+    cacheName: 'api',
+    plugins: [
+      new ExpirationPlugin({ maxEntries: 100, maxAgeSeconds: 10 * 60 }),
+    ],
+  })
+);
+
+registerRoute(
+  ({ url }) =>
+    url.pathname.endsWith('/api/v1/latest_playlists') ||
+    url.pathname.endsWith('/api/v1/top_playlists') ||
+    url.pathname.endsWith('/api/v1/search_playlists'),
+  new NetworkFirst({
+    cacheName: 'api',
     plugins: [
       new ExpirationPlugin({ maxEntries: 10, maxAgeSeconds: 10 * 60 }),
     ],