Initial commit

ext/src/main.js

@@ -0,0 +1,211 @@
+"use strict";
+
+const _ = browser.i18n.getMessage;
+
+
+// Google-hosted API loader script
+const SENDER_SCRIPT_URL =
+        "https://www.gstatic.com/cv/js/sender/v1/cast_sender.js";
+
+const SENDER_SCRIPT_FRAMEWORK_URL =
+        `${SENDER_SCRIPT_URL}?loadCastFramework=1`;
+
+/**
+ * Sender applications load a cast_sender.js script that
+ * functions as a loader for the internal chrome-extension:
+ * hosted script.
+ *
+ * We can redirect this and inject our own script to setup
+ * the API shim.
+ */
+browser.webRequest.onBeforeRequest.addListener(
+        async details => {
+            console.log(details);
+            switch (details.url) {
+                case SENDER_SCRIPT_URL:
+                    // Content/Page script bridge
+                    await browser.tabs.executeScript(details.tabId, {
+                        file: "content.js"
+                      , frameId: details.frameId
+                      , runAt: "document_start"
+                    });
+                    
+                    return {
+                        redirectUrl: browser.runtime.getURL("shim/bundle.js")
+                    };
+
+                case SENDER_SCRIPT_FRAMEWORK_URL:
+                    // TODO: implement cast.framework
+
+                    return {
+                        cancel: true
+                    };
+            }
+        }
+      , { urls: [
+            SENDER_SCRIPT_URL
+          , SENDER_SCRIPT_FRAMEWORK_URL
+        ]}
+      , [ "blocking" ]);
+
+// Defines window.chrome for site compatibility
+browser.contentScripts.register({
+    allFrames: true
+  , js: [{ file: "contentSetup.js" }]
+  , matches: [ "<all_urls>" ]
+  , runAt: "document_start"
+});
+
+// YouTube compat shim
+browser.contentScripts.register({
+    allFrames: true
+  , js: [{ file: "compat/youtube.js" }]
+  , matches: [ "*://www.youtube.com/*" ]
+  , runAt: "document_start"
+});
+
+
+
+// <video>/<audio> "Cast..." context menu item
+browser.menus.create({
+    contexts: [ "audio", "video" ]
+  , id: "contextCastMedia"
+  , targetUrlPatterns: [
+        "http://*/*"
+      , "https://*/*"
+    ]
+  , title: _("context_media_cast")
+});
+
+browser.menus.onClicked.addListener(async (info, tab) => {
+    const { frameId } = info;
+
+    // Pass media URL to media sender app
+    await browser.tabs.executeScript(tab.id, {
+        code: `const srcUrl = "${info.srcUrl}";`
+      , frameId
+    });
+
+    // Load app and sender API shim
+    await browser.tabs.executeScript(tab.id, { file: "content.js"     , frameId })
+    await browser.tabs.executeScript(tab.id, { file: "mediaCast.js"   , frameId });
+    await browser.tabs.executeScript(tab.id, { file: "shim/bundle.js" , frameId });
+});
+
+
+const bridgeMap = new Map();
+
+/**
+ * Initializes native application and handles message
+ * forwarding.
+ */
+function initBridge (tabId, frameId) {
+    const port = browser.runtime.connectNative("caster_bridge");
+    bridgeMap.set(tabId, port);
+
+    port.onMessage.addListener(message => {
+        // Forward shim: messages
+        if (message.subject.startsWith("shim:")) {
+            browser.tabs.sendMessage(tabId, message, {
+                frameId
+            });
+            return;
+        }
+    });
+}
+
+
+let popupTabId;
+let popupOpenerTabId;
+
+/**
+ * Creates popup window for cast destination selection.
+ * Refocusing other browser windows causes the popup window
+ * to close and returns an API error (TODO).
+ */
+async function openPopup (tabId) {
+    const width = 350;
+    const height = 200;
+
+    // Current window to base centered position on
+    const win = await browser.windows.getCurrent();
+
+    // Top(mid)-center position
+    const centerX = win.left + (win.width / 2);
+    const centerY = win.top + (win.height / 3);
+
+    const left = Math.floor(centerX - (width / 2));
+    const top = Math.floor(centerY - (height / 2));
+
+    const popup = await browser.windows.create({
+        url: "popup/index.html"
+      , type: "popup"
+      , width
+      , height
+      , left
+      , top
+    });
+
+    // Store popup details for message forwarding
+    popupTabId = popup.tabs[0].id;
+    popupOpenerTabId = tabId;
+
+    // Size/position not set correctly on creation (bug?)
+    await browser.windows.update(popup.id, {
+        width
+      , height
+      , left
+      , top
+    });
+
+    // Close popup on other browser window focus
+    browser.windows.onFocusChanged.addListener(function listener (id) {
+        if (id !== browser.windows.WINDOW_ID_NONE
+                && id === win.id) {
+            browser.windows.onFocusChanged.removeListener(listener);
+            browser.windows.remove(popup.id);
+        }
+    });
+}
+
+
+// Extension messages
+browser.runtime.onMessage.addListener(async (message, sender, respond) => {
+    const tabId = sender.tab.id;
+    const { frameId } = sender.tab;
+
+    // Forward bridge: messages
+    if (message.subject.startsWith("bridge:")) {
+        bridgeMap.get(tabId).postMessage(message);
+        return;
+    }
+
+    // Forward shim: messages
+    if (message.subject.startsWith("shim:")) {
+        browser.tabs.sendMessage(popupOpenerTabId, message, { frameId });
+        return;
+    }
+
+    // Forward popup messages
+    if (message.subject.startsWith("popup:")) {
+        if (popupTabId) {
+            try {
+                browser.tabs.sendMessage(popupTabId, message);
+            } catch (err) {
+                // Popup is closed
+            }
+        }
+        return;
+    }
+
+    switch (message.subject) {
+        case "main:initialize":
+            initBridge(tabId);
+            break;
+
+        case "main:openPopup": {
+            await openPopup(tabId);
+            break;
+        }
+    }
+});