Halfway to making Firefox compatible

1 files changed, 222 insertions, 0 deletions

diff --git a/background.js b/background.js
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index 0000000..4dbbdd3
--- /dev/null
+++ b/background.js
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+
+//This is the background script. It is responsible for actually redirecting requests,
+//as well as monitoring changes in the redirects and the disabled status and reacting to them.
+
+//TODO: Better browser detection...
+var isFirefox = false;
+
+if (typeof chrome == 'undefined') {
+	isFirefox = true;
+	var firefoxShim = require('./firefox/shim');
+	chrome = firefoxShim.chrome;
+	Redirect = firefoxShim.Redirect;
+}
+//Hopefully Firefox will fix this at some point and we can just use onBeforeRequest everywhere...
+var redirectEvent = isFirefox ? chrome.webRequest.onBeforeSendHeaders : chrome.webRequest.onBeforeRequest;
+
+//Redirects partitioned by request type, so we have to run through
+//the minimum number of redirects for each request.
+var partitionedRedirects = {};
+
+//Keep track of tabids where the main_frame url has been redirected.
+//Mark it as green until a new url is loaded.
+var tabIdToIcon = {
+
+};
+
+//Cache of urls that have just been redirected to. They will not be redirected again, to
+//stop recursive redirects, and endless redirect chains.
+//Key is url, value is timestamp of redirect.
+var ignoreNextRequest = {
+
+};
+
+function log(msg) {
+	if (log.enabled) {
+		console.log('REDIRECTOR: ' + msg);
+	}
+}
+log.enabled = true;
+
+function setIcon(image19, image38, tabId) {
+	var data = {
+  		path: {
+    		19: image19,
+    		38: image38  
+  		}
+  	};
+  	if (typeof tabId !== 'undefined') {
+  		data.tabId = tabId;
+  	}
+	chrome.browserAction.setIcon(data, function(tab) {
+		var err = chrome.runtime.lastError;
+		if (err) {
+			//If not checked we will get unchecked errors in the background page console...
+			log('Error in SetIcon: ' + err.message);
+		}
+	});		
+}
+
+//This is the actual function that gets called for each request and must
+//decide whether or not we want to redirect.
+function checkRedirects(details) {
+	
+	//We only allow GET request to be redirected, don't want to accidentally redirect
+	//sensitive POST parameters
+	if (details.method != 'GET') {
+		return null;
+	}
+
+	log('Checking: ' + details.type + ': ' + details.url);
+
+	var list = partitionedRedirects[details.type];
+	if (!list) {
+		log('No list for type: ' + details.type);
+		return null;
+	}
+
+	var timestamp = ignoreNextRequest[details.url];
+	if (timestamp) {
+		log('Ignoring ' + details.url + ', was just redirected ' + (new Date().getTime()-timestamp) + 'ms ago');
+		delete ignoreNextRequest[details.url];
+		return null;
+	}
+
+	for (var i = 0; i < list.length; i++) {
+		var r = list[i];
+		var result = r.getMatch(details.url);
+
+		if (result.isMatch) {
+
+			log('Redirecting ' + details.url + ' ===> ' + result.redirectTo + ', type: ' + details.type + ', pattern: ' + r.includePattern);
+
+			/* Unfortunately the setBrowserIcon for a specific tab function is way too unreliable, fails all the time with tab not found,
+			   even though the tab is there. So, for now I'm cancelling this feature, which would have been pretty great ... :/
+			if (details.type == 'main_frame') {
+				log('Setting icon on tab ' + details.tabId + ' to green');
+				
+				setIcon("images/icon19redirected.png", "images/icon38redirected.png", details.tabId);
+			  	tabIdToIcon[details.tabId] = true;				
+			}*/
+			ignoreNextRequest[result.redirectTo] = new Date().getTime();
+			
+			return { redirectUrl: result.redirectTo };
+		}
+	}
+
+	/* Cancelled for now because of setBrowserIcon being really unreliable...
+	if (details.type == 'main_frame' && tabIdToIcon[details.tabId]) {
+		log('Setting icon on tab ' + details.tabId + ' back to active');
+		setIcon("images/icon19active.png", "images/icon38active.png", details.tabId);
+	  	delete tabIdToIcon[details.tabId];
+	}*/
+
+  	return null; 
+}
+
+//Monitor changes in data, and setup everything again.
+//This could probably be optimized to not do everything on every change
+//but why bother?
+chrome.storage.onChanged.addListener(function(changes, namespace) {
+	if (changes.disabled) {
+		updateIcon();
+
+		if (changes.disabled.newValue == true) {
+			log('Disabling Redirector, removing listener');
+			redirectEvent.removeListener(checkRedirects);
+		} else {
+			log('Enabling Redirector, setting up listener');
+			setUpRedirectListener();
+		}
+	}
+
+	if (changes.redirects) {
+		log('Redirects have changed, setting up listener again');
+		setUpRedirectListener();
+	}
+});
+
+//Creates a filter to pass to the listener so we don't have to run through
+//all the redirects for all the request types we don't have any redirects for anyway.
+function createFilter(redirects) {
+	var types = [];
+	for (var i = 0; i < redirects.length; i++) {
+		redirects[i].appliesTo.forEach(function(type) { 
+			if (types.indexOf(type) == -1) {
+				types.push(type);
+			}
+		});
+	}
+	types.sort();
+
+	return {
+		urls: ["http://*/*", "https://*/*"],
+		types : types
+	};
+}
+
+function createPartitionedRedirects(redirects) {
+	var partitioned = {};
+
+	for (var i = 0; i < redirects.length; i++) {
+		var redirect = new Redirect(redirects[i]);
+		redirect.compile();
+		for (var j=0; j<redirect.appliesTo.length;j++) {
+			var requestType = redirect.appliesTo[j];
+			if (partitioned[requestType]) {
+				partitioned[requestType].push(redirect); 
+			} else {
+				partitioned[requestType] = [redirect];
+			}
+		}
+	}
+	return partitioned;	
+}
+
+//Sets up the listener, partitions the redirects, creates the appropriate filters etc.
+function setUpRedirectListener() {
+
+	redirectEvent.removeListener(checkRedirects); //Unsubscribe first, in case there are changes...
+
+	chrome.storage.local.get({redirects:'firstrun'}, function(obj) {
+		var redirects = obj.redirects;
+
+		if (redirects ===  'firstrun') {
+			log('No redirects to set up, first run of extension');
+			//TODO: import old Firefox redirects
+			return;
+		}
+
+		if (redirects.length == 0) {
+			return;
+		}
+
+		partitionedRedirects = createPartitionedRedirects(redirects);
+		var filter = createFilter(redirects);
+
+		log('Setting filter for listener: ' + JSON.stringify(filter));
+		redirectEvent.addListener(checkRedirects, filter, ["blocking"]);
+	});
+}
+
+function updateIcon() {
+	chrome.storage.local.get({disabled:false}, function(obj) {
+		if (obj.disabled) {
+			setIcon("images/icon19disabled.png", "images/icon38disabled.png");
+		} else {
+			setIcon("images/icon19active.png", "images/icon38active.png");
+		}
+	});	
+}
+
+//First time setup
+updateIcon();
+chrome.storage.local.get({disabled:false}, function(obj) {
+	if (!obj.disabled) {
+		setUpRedirectListener();
+	} else {
+		log('Redirector is disabled');
+	}
+});
+log('Redirector starting up...');
+       
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