Feat: Allow using YouTube links in addition to video IDs

docs/devlog.md

@@ -27,6 +27,7 @@ Devlog template: 1.1.0
     - [jQuery](#jquery)
     - [CORS](#cors)
     - [Browser History API](#browser-history-api)
+    - [URL API](#url-api)
     - [Similar Projects](#similar-projects)
     - [Websockets](#websockets)
     - [Libraries/modules](#librariesmodules)
@@ -65,7 +66,7 @@ Devlog template: 1.1.0
 
 ### General
 
-* [Current sprint board](https://github.com/Phixyn/no-bs-looper/projects/1)
+* [Current sprint board](https://github.com/Phixyn/no-bs-looper/projects/2)
 * [Convert HH:MM:SS to seconds - Online tools](https://www.tools4noobs.com/online_tools/hh_mm_ss_to_seconds/)
 
 ### YouTube Player API
@@ -136,6 +137,12 @@ Devlog template: 1.1.0
 
 * [Working with the History API - Web APIs | MDN](https://developer.mozilla.org/en-US/docs/Web/API/History_API/Working_with_the_History_API)
 
+### URL API
+
+* https://developer.mozilla.org/en-US/docs/Web/API/URL/URL
+* https://developer.mozilla.org/en-US/docs/Web/API/URL
+* https://url.spec.whatwg.org/#dom-url-href
+
 ### Similar Projects
 
 * [Developing a Progressive Fetch YouTube Downloader | by Param Singh | Medium](https://medium.com/@paramsingh_66174/developing-a-progressive-fetch-youtube-downloader-75a709bff1ef)

static/index.html

@@ -65,7 +65,7 @@
       <form class="grid-x grid-padding-x grid-padding-y">
         <!-- Video ID -->
         <div class="cell small-12 medium-8 large-8 medium-offset-2 large-offset-2">
-          <label>Video ID
+          <label>Video URL or ID
             <div class="input-group">
               <input type="text" id="video-id" class="input-group-field" name="video-id" placeholder="Video ID" value="KcUnXunuDTs">
               <div class="input-group-button">

static/js/app.js

@@ -3,6 +3,7 @@ $(document).foundation();
 
 // Add your websocket server IP address here
 const websocket = new WebSocket("ws://<server IP address here>:14670");
+const VIDEO_ID_LENGTH = 11;
 
 var player;
 var state;
@@ -256,9 +257,10 @@ function onPlayerStateChange(event) {
 /**
  * Updates the YouTube player with a new video. Called when the user clicks
  * the "Update" button. The video ID is taken from the text input element
- * in the HTML form. This function also requests video info from our backend
- * server via websocket (see why this is necessary below), which hopefully
- * causes the websocket client's "onmessage" handler to get called.
+ * in the HTML form. If the user enters a URL, the ID is extracted from it.
+ * This function also requests video info from our backend server via websocket
+ * (see why this is necessary below), which hopefully causes the websocket
+ * client's "onmessage" handler to get called.
  *
  * Normally, we'd update the slider and input attributes with new max values
  * based on the video duration here. However, we can't update them here
@@ -280,8 +282,31 @@ function onPlayerStateChange(event) {
  */
 function updatePlayer() {
   console.debug("[DEBUG] Updating player (state.v, state.start).");
-  state.v = videoIdInput.val();
-  console.log("[INFO] Loading new video in player...");
+  let videoIdInputVal = videoIdInput.val();
+
+  if (isValidHttpUrl(videoIdInputVal)) {
+    let videoId = extractVideoId(videoIdInputVal);
+
+    if (videoId === null) {
+      // TODO #75: Show error toast to the user.
+      console.error(
+        `[ERROR] Invalid video URL or ID in input: '${videoIdInputVal}'.`
+      );
+      return;
+    }
+
+    state.v = videoId;
+  } else if (videoIdInputVal.length === VIDEO_ID_LENGTH) {
+    state.v = videoIdInputVal;
+  } else {
+    // TODO #75: Show error toast to the user.
+    console.error(
+      `[ERROR] Invalid video URL or ID in input: '${videoIdInputVal}'.`
+    );
+    return;
+  }
+
+  console.log(`[INFO] Loading new video in player with ID '${state.v}'.`);
   /* loadPlaylist() and setLoop() are required to make infinite loops of full
    * videos (i.e. not portions of a video). It's for this same reason that we
    * set 'playlist' and 'loop' in the 'playerVars' (see
@@ -460,3 +485,84 @@ function updateSliderAndInputAttributes(newStartTime, newEndTime) {
    */
   endTimeInput.val(state.end.toString()).change();
 }
+
+/**
+ * Checks if the given string is a valid HTTP or HTTPS URL.
+ *
+ * @param {string} urlString The string to validate.
+ * @return {boolean} A boolean indicating if the string is a valid HTTP or
+ *     HTTPS URL.
+ */
+function isValidHttpUrl(urlString) {
+  console.debug(`[DEBUG] Checking if '${urlString}' is a valid URL.`);
+  let urlObj;
+
+  try {
+    urlObj = new URL(urlString);
+  } catch (err) {
+    console.error(`[ERROR] ${err.name}: ${err.message}`);
+    return false;
+  }
+
+  return urlObj.protocol === "http:" || urlObj.protocol === "https:";
+}
+
+/**
+ * Extracts a YouTube video ID from a URL string. The URL can be either a known
+ * YouTube domain (such as youtube.com or youtu.be) or any other URL that
+ * contains a 'v=' in its querystring.
+ *
+ * For 'youtu.be' or 'youtube.com/embed' links, the last part of the URL's
+ * pathname will be extracted as a potential ID. Note that the extracted ID is
+ * validated, and only returned if deemed to be valid. Otherwise, null is
+ * returned.
+ *
+ * @param {string} youtubeUrl A YouTube video URL string.
+ * @return {string} A YouTube video ID, if a valid one is found. Otherwise,
+ *    returns null.
+ */
+function extractVideoId(youtubeUrl) {
+  console.log(`[INFO] Attempting to extract video ID from '${youtubeUrl}'.`);
+  let videoId;
+  let urlObj;
+
+  try {
+    urlObj = new URL(youtubeUrl);
+  } catch (err) {
+    // TODO #75: Show error toast to the user.
+    console.error(`[ERROR] ${err.name}: ${err.message}`);
+    return null;
+  }
+
+  // Check if there is a querystring in the URL and parse it
+  if (urlObj.search !== "") {
+    console.log("[INFO] Found querystring in URL, parsing it.");
+
+    let qsParse = Qs.parse(urlObj.search, { ignoreQueryPrefix: true });
+    if (!qsParse.hasOwnProperty("v") || qsParse.v === "") {
+      // TODO #75: Show error toast to the user.
+      console.error("[ERROR] Could not get video ID from YouTube URL.");
+      return null;
+    }
+
+    videoId = qsParse.v;
+    console.debug(`[DEBUG] Got video ID from querystring: '${videoId}'.`);
+  } else if (urlObj.pathname !== "") {
+    console.log("[INFO] Extracting potential video ID from URL pathname.");
+    // Handle 'youtu.be/id' and 'youtube.com/embed/id'
+    let pathArray = urlObj.pathname.split("/");
+    videoId = pathArray[pathArray.length - 1];
+  }
+
+  console.log("[INFO] Validating video ID.");
+  // Validate video ID by checking the length
+  if (videoId.length !== VIDEO_ID_LENGTH) {
+    // TODO #75: Show error toast to the user.
+    console.error(`[ERROR] Invalid video ID in URL: '${youtubeUrl}'.`);
+    console.debug(`[DEBUG] Got unexpected length in ID: '${videoId}'.`);
+    return null;
+  }
+
+  console.debug(`[DEBUG] Got a valid video ID from URL: '${videoId}'.`);
+  return videoId;
+}