diff --git a/proxy-blocker/README.md b/proxy-blocker/README.md
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+++ b/proxy-blocker/README.md
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+# 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.
+
+The PAC script is initialized with a list of hostnames: it blocks requests to any hosts that are in the list.
+
+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 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:
+* 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.
+
+## 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.
diff --git a/proxy-blocker/background/proxy-handler.js b/proxy-blocker/background/proxy-handler.js
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+// Location of the proxy script, relative to manifest.json
+const proxyScriptURL = "proxy/proxy-script.js";
+
+// Default settings. If there is nothing in storage, use these values.
+const defaultSettings = {
+ blockedHosts: ["example.com", "example.org"]
+ }
+
+// Register the proxy script
+browser.proxy.registerProxyScript(proxyScriptURL);
+
+// Log any errors from the proxy script
+browser.proxy.onProxyError.addListener(error => {
+ console.error(`Proxy error: ${error.message}`);
+});
+
+// Initialize the proxy
+function handleInit(message) {
+ // update the proxy whenever stored settings change
+ browser.storage.onChanged.addListener((newSettings) => {
+ browser.runtime.sendMessage(newSettings.blockedHosts.newValue, {toProxyScript: true});
+ });
+
+ // 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");
+ });
+}
+
+function handleMessage(message, sender) {
+ // only handle messages from the proxy script
+ if (sender.url != browser.extension.getURL(proxyScriptURL)) {
+ return;
+ }
+
+ if (message === "init") {
+ handleInit(message);
+ } else {
+ // after the init message the only other messages are status messages
+ console.log(message);
+ }
+}
+
+browser.runtime.onMessage.addListener(handleMessage);
diff --git a/proxy-blocker/icons/LICENSE b/proxy-blocker/icons/LICENSE
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+++ b/proxy-blocker/icons/LICENSE
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+The "lock".svg" icon is taken from the Material Core iconset and is used under the terms of its license: https://www.iconfinder.com/iconsets/material-core.
diff --git a/proxy-blocker/icons/block.svg b/proxy-blocker/icons/block.svg
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+++ b/proxy-blocker/icons/block.svg
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+
\ No newline at end of file
diff --git a/proxy-blocker/manifest.json b/proxy-blocker/manifest.json
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+++ b/proxy-blocker/manifest.json
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+{
+
+ "manifest_version": 2,
+ "name": "Proxy-blocker",
+ "description": "Uses the proxy API to block requests to specific hosts.",
+ "version": "1.0",
+
+ "icons": {
+ "48": "icons/block.svg",
+ "96": "icons/block.svg"
+ },
+
+ "applications": {
+ "gecko": {
+ "strict_min_version": "55.0a1"
+ }
+ },
+
+ "background": {
+ "scripts": [
+ "background/proxy-handler.js"
+ ]
+ },
+
+ "options_ui": {
+ "page": "options/options.html"
+ },
+
+ "permissions": ["proxy", "storage"]
+
+}
diff --git a/proxy-blocker/options/options.css b/proxy-blocker/options/options.css
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+++ b/proxy-blocker/options/options.css
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+body {
+ width: 25em;
+ font-family: "Open Sans Light", sans-serif;
+ font-size: 0.9em;
+ font-weight: 300;
+}
+
+.title, #blocked-hosts {
+ margin: 1em;
+}
+
+.title {
+ font-size: 1.2em;
+}
diff --git a/proxy-blocker/options/options.html b/proxy-blocker/options/options.html
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+++ b/proxy-blocker/options/options.html
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+
+
+
+
+
+
+
+
+
+
+
+ Hosts to block:
+
+
+
+
+
+
+
diff --git a/proxy-blocker/options/options.js b/proxy-blocker/options/options.js
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+++ b/proxy-blocker/options/options.js
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+const blockedHostsTextArea = document.querySelector("#blocked-hosts");
+
+// Store the currently selected settings using browser.storage.local.
+function storeSettings() {
+ let blockedHosts = blockedHostsTextArea.value.split("\n");
+ browser.storage.local.set({
+ blockedHosts
+ });
+}
+
+// Update the options UI with the settings values retrieved from storage,
+// or the default settings if the stored settings are empty.
+function updateUI(restoredSettings) {
+ blockedHostsTextArea.value = restoredSettings.blockedHosts.join("\n");
+}
+
+function onError(e) {
+ console.error(e);
+}
+
+// On opening the options page, fetch stored settings and update the UI with them.
+browser.storage.local.get().then(updateUI, onError);
+
+// Whenever the contents of the textarea changes, save the new values
+blockedHostsTextArea.addEventListener("change", storeSettings);
diff --git a/proxy-blocker/proxy/proxy-script.js b/proxy-blocker/proxy/proxy-script.js
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+++ b/proxy-blocker/proxy/proxy-script.js
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+var blockedHosts = [];
+const allow = "DIRECT 1234";
+const deny = "PROXY 127.0.0.1:65535";
+
+// tell the background script that we are ready
+browser.runtime.sendMessage("init");
+
+// listen for updates to the blocked host list
+browser.runtime.onMessage.addListener((message) => {
+ blockedHosts = message;
+});
+
+// required PAC function that will be called to determine
+// if a proxy should be used.
+function FindProxyForURL(url, host) {
+ if (blockedHosts.indexOf(host) != -1) {
+ browser.runtime.sendMessage(`Proxy-blocker: blocked ${url}`);
+ return deny;
+ }
+ return allow;
+}