proxy-blocker updates (mdn#422)

* proxy-blocker updates

These changes replace the use of the deprecated `proxy.register` (PAC file) with `proxy.onRequest` to handle the proxying of requests.

* Changes as per feedback

* Fixed typo

* Addressed feedback relating to issue with variable initialization after enable/disable

* Typo fix

* The changes as suggested by @wbamberg

examples.json

@@ -410,13 +410,11 @@
         "name": "private-browsing-theme"
     },
     {
-        "description": "Uses the proxy API to block requests to specific hosts.",
+        "description": "Uses the proxy API to block requests to hosts specified on a list.",
         "javascript_apis": [
             "extension.getURL",
-            "proxy.onProxyError",
-            "proxy.register",
-            "runtime.onMessage",
-            "runtime.sendMessage",
+            "proxy.onRequest",
+            "proxy.onError",
             "storage.local",
             "storage.onChanged"
         ],

proxy-blocker/README.md

@@ -1,22 +1,19 @@
-# proxy-filter
 
 ## What it does
 
-This add-on registers a [PAC script](https://developer.mozilla.org/en-US/docs/Web/HTTP/Proxy_servers_and_tunneling/Proxy_Auto-Configuration_%28PAC%29_file) using the proxy API.
+This extension uses the proxy API listener `onRequest` to listen for requests to visit a web page, compare the webpage's domain with a blocked host list, and proxy domains on the blocked list to 127.0.0.1.
 
-The PAC script is initialized with a list of hostnames: it blocks requests to any hosts that are in the list.
+The list of blocked domains is held in local storage and given the initial value `["example.com", "example.org"]` when the extension installs. The list can be modified through the extension"s options page.
 
-The list is given the following default values: `["example.com", "example.org"]`, but the user can add and remove hosts using the add-on's options page.
+Note that the hostname-matching is simple: hostnames must match an entry in the list if they are to be blocked. So with the default settings, "example.org" is blocked but "www.example.org" is permitted.
 
-Note that the hostname-matching is very simple: hostnames must exactly match an entry in the list if they are to be blocked. So with the default settings, "example.org" would be blocked but "www.example.org" would be permitted.
-
-To try it out:
+To try out this extension:
 * install it
-* try visiting `http://example.com`, and see it is blocked
-* visit `about:addons`, open the add-on's preferences, and try changing the hostnames in the text box
-* try visiting some different pages, to see the effect of your changes.
+* visit `http://example.com` and see it is blocked
+* visit `about:addons`, open the add-on's preferences, and change the hostnames in the text box
+* visit some pages to see the effect of your changes.
 
 ## What it shows
 
-* How to implement a simple PAC script, and register it using the proxy API.
-* How to exchange messages between a PAC script and a background script.
+* How to implement `browser.proxy.onRequest` and proxy requests.
+* How to store and retrieve lists from local storage.

proxy-blocker/background/proxy-handler.js

@@ -1,55 +1,48 @@
-// Location of the proxy script, relative to manifest.json
-const proxyScriptURL = "proxy/proxy-script.js";
+// Initialize the list of blocked hosts
+let blockedHosts = ["example.com", "example.org"];
 
-// Default settings. If there is nothing in storage, use these values.
-const defaultSettings = {
-   blockedHosts: ["example.com", "example.org"]
- }
-
-// Register the proxy script
-browser.proxy.register(proxyScriptURL);
+// Set the default list on installation.
+browser.runtime.onInstalled.addListener(details => {
+  browser.storage.local.set({
+    blockedHosts: blockedHosts
+  });
+});
 
-// Log any errors from the proxy script
-browser.proxy.onProxyError.addListener(error => {
-  console.error(`Proxy error: ${error.message}`);
+// Get the stored list
+browser.storage.local.get(data => {
+  if (data.blockedHosts) {
+    blockedHosts = data.blockedHosts;
+  }
 });
 
-// Initialize the proxy
-function handleInit() {
-  // update the proxy whenever stored settings change
-  browser.storage.onChanged.addListener((newSettings) => {
-    browser.runtime.sendMessage(newSettings.blockedHosts.newValue, {toProxyScript: true});
-  });
+// Listen for changes in the blocked list
+browser.storage.onChanged.addListener(changeData => {
+  blockedHosts = changeData.blockedHosts.newValue;
+});
 
-  // get the current settings, then...
-  browser.storage.local.get()
-    .then((storedSettings) => {
-      // if there are stored settings, update the proxy with them...
-      if (storedSettings.blockedHosts) {
-        browser.runtime.sendMessage(storedSettings.blockedHosts, {toProxyScript: true});
-      // ...otherwise, initialize storage with the default values
-      } else {
-        browser.storage.local.set(defaultSettings);
-      }
-
-    })
-    .catch(()=> {
-      console.log("Error retrieving stored settings");
-    });
-}
+// Managed the proxy
 
-function handleMessage(message, sender) {
-  // only handle messages from the proxy script
-  if (sender.url !=  browser.extension.getURL(proxyScriptURL)) {
-    return;
-  }
+// Listen for a request to open a webpage
+browser.proxy.onRequest.addListener(handleProxyRequest, {urls: ["<all_urls>"]});
 
-  if (message === "init") {
-    handleInit(message);
-  } else {
-    // after the init message the only other messages are status messages
-    console.log(message);
+// On the request to open a webpage
+function handleProxyRequest(requestInfo) {
+// Read the web address of the page to be visited 
+  const url = new URL(requestInfo.url);
+// Determine whether the domain in the web address is on the blocked hosts list
+  if (blockedHosts.indexOf(url.hostname) != -1) {
+// Write details of the proxied host to the console and return the proxy address
+    console.log(`Proxying: ${url.hostname}`);
+    return {type: "http", host: "127.0.0.1", port: 65535};
   }
+// Return instructions to open the requested webpage
+  return {type: "direct"};
 }
 
-browser.runtime.onMessage.addListener(handleMessage);
+// Log any errors from the proxy script
+browser.proxy.onError.addListener(error => {
+  console.error(`Proxy error: ${error.message}`);
+});
+
+
+

proxy-blocker/manifest.json

@@ -3,7 +3,7 @@
   "manifest_version": 2,
   "name": "Proxy-blocker",
   "description": "Uses the proxy API to block requests to specific hosts.",
-  "version": "1.0",
+  "version": "2.0",
 
   "icons": {
     "48": "icons/block.svg",
@@ -27,6 +27,6 @@
     "browser_style": true
   },
 
-  "permissions": ["proxy", "storage"]
+  "permissions": ["proxy", "storage", "<all_urls>"]
 
 }

themes/temp/manifest.json

@@ -0,0 +1,25 @@
+{
+
+  "description": "Theme with a single image placed centrally and then tiled. Also, illustrates the use of frame_inactive to change the header background color when the browser window isn't in focus. See https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Examples#themes",
+  "manifest_version": 2,
+  "name": "temp",
+  "version": "1.1",
+  "homepage_url": "https://github.com/mdn/webextensions-examples/tree/master/themes/weta_tiled",
+
+  "theme": {
+     "colors": {
+          "frame": "blue", 
+          "frame_inactive": "#c6c6c6",
+          "toolbar_text": "black",
+          "tab_background_text":"black",
+          "tab_text":"black",
+          "sidebar_border":"black",
+          "toolbar_field_border":"black",
+          "tab_background_separator":"black",
+          "toolbar_top_separator":"black",
+          "toolbar_vertical_separator":"black",
+          "toolbar_bottom_separator":"black",
+          "toolbar_field_separator":"black"
+        }
+    }
+}