added browser extension proof of concept

browser_extension/extension/script.js

@@ -0,0 +1,72 @@
+/*
+content script running on youtube.com
+*/
+
+console.log("running script.js");
+
+let browserType = getBrowser();
+
+setTimeout(function(){
+    console.log("running setimeout")
+    linkFinder();
+    return false;
+}, 2000);
+
+
+// boilerplate to dedect browser type api
+function getBrowser() {
+    if (typeof chrome !== "undefined") {
+        if (typeof browser !== "undefined") {
+            console.log("detected firefox");
+            return browser;
+        } else {
+            console.log("detected chrome");
+            return chrome;
+        }
+    } else {
+        console.log("failed to dedect browser");
+        throw "browser detection error"
+    };
+}
+
+
+// event handler for download task
+function addToDownload(videoId) {
+
+    console.log(`downloading ${videoId}`);
+    let payload = {
+        "download": {
+            "videoId": videoId
+        }
+    };
+
+    browserType.runtime.sendMessage(payload);
+
+}
+
+
+// find relevant links to add a button to
+function linkFinder() {
+
+    console.log("running link finder");
+
+    var allLinks = document.links;
+    for (let i = 0; i < allLinks.length; i++) {
+        
+        const linkItem = allLinks[i];
+        const linkDest = linkItem.getAttribute("href");
+
+        if (linkDest.startsWith("/watch?v=") && linkItem.id == "video-title") {
+            var dlButton = document.createElement("button");
+            dlButton.innerText = "download";
+            var videoId = linkDest.split("=")[1];
+            dlButton.setAttribute("data-id", videoId);
+            dlButton.setAttribute("id", "ta-dl-" + videoId);
+            dlButton.onclick = function(event) {
+                var videoId = this.getAttribute("data-id");
+                addToDownload(videoId);
+            };
+            linkItem.parentElement.appendChild(dlButton);
+        }
+    }
+}