xmlcomms.js

// -*- tab-width:2; indent-tabs-mode:t -*- vim: set noet ts=2:
/*
 * xmlcomms.js
 *
 * This handles making XMLHttp calls to the "Edit Server"
 *
 * As no other parts of the extension can make xhr requests this
 * is essentially the gatekeeper to all contact with the Edit
 * Server.
 *
 * This file is part of emacs_chrome (http://github.com/stsquad/emacs_chrome)
 * and licensed under the GPLv3. See the COPYING file for details
 */

// Get the base URL from which we make all requests to the server..
function getEditUrl()
{
	var port = localStorage["edit_server_port"];
	if (!port) {
	port = 9292;
	}
	return "http://127.0.0.1:" +	port + "/";
}

/*
 * Give some feedback to the user via the icon/hover text.
 */
function updateUserFeedback(string, colour)
{
	console.log("updateUserFeedback: "+string);
	chrome.browserAction.setTitle({title:string});
	if (colour == null) {
		chrome.browserAction.setIcon({path:"emacs23-16x16.png"});
	} else if (colour == "green") {
	chrome.browserAction.setIcon({path:"emacs23-16x16-green.png"});
	} else if (colour == "red") {
	chrome.browserAction.setIcon({path:"emacs23-16x16-red.png"});
	} else if (colour == "darkblue") {
	chrome.browserAction.setIcon({path:"emacs23-16x16-darker.png"});
	} else {
		chrome.browserAction.setIcon({path:"emacs23-16x16.png"});
	}
}
	
// Initial message
updateUserFeedback("Awaiting edit request", "blue");

// Called when the user clicks on the browser action.
//
// When clicked we send a message to the current active tab's
// content script. It will then use heuristics to decide which text
// area to spawn an edit request for.
chrome.browserAction.onClicked.addListener(function(tab) {
	
	var find_msg = {
		msg: "find_edit"
	};
	var tab_port = chrome.tabs.connect(tab.id);
	
	tab_port.postMessage(find_msg);
	updateUserFeedback("sent request to content script", "green");
});

// Handle and edit request coming from the content page script
//
// Package up the text to be edited and send it to the edit server
function handleContentMessages(msg, tab_port)
{
	console.log("handleContentMessages called:"+JSON.stringify(msg));
	var cmd = msg.msg;
	var id = msg.id;
	var text = msg.text;
	var file = msg.file;

	var xhr = new XMLHttpRequest();
	var url = getEditUrl() + cmd;

	console.log(" page URL:"+tab_port.tab.url);
	console.log(" tab_port:"+tab_port.portId_);
	console.log(" request URL:"+url);
	
	xhr.open("POST", url, true);
	
	xhr.onreadystatechange = function() {
		console.log("State change:"+ xhr.readyState + " status:"+xhr.status);
	// readyState 4=HTTP response complete
		if(xhr.readyState == 4) {
		if (xhr.status == 200) {
		
		var update_msg = {
			msg: "update",
			text: xhr.responseText,
			id: id
		};

		updateUserFeedback("Successful edit of "+msg.title);
		tab_port.postMessage(update_msg);

				msg.text = xhr.responseText;
				msg.file = xhr.getResponseHeader("x-file");
				if(xhr.getResponseHeader("x-open") == "true") {
					handleContentMessages(msg, tab_port);
				}
		} else if (xhr.status == 0) {
		// Is the edit server actually running?
		updateUserFeedback("Error: is edit server running?", "red");
		} else {
		updateUserFeedback("Un-handled response: "+xhr.status, "red"); 
		}
		}
	}

	// reset the display before sending request..
	updateUserFeedback("Edit request sent for "+msg.title, "green");

	xhr.setRequestHeader("Content-type", "text/plain");
	xhr.setRequestHeader("x-url", tab_port.tab.url);
	xhr.setRequestHeader("x-id", id);
	if (file) {
		xhr.setRequestHeader("x-file", file);
	}
	xhr.send(text);
}

// Handle and edit request coming from the content page script
//
// Package up the text to be edited and send it to the edit server
function handleTestMessages(msg, tab_port)
{
	var url = getEditUrl() + "status";
	var xhr = new XMLHttpRequest();
	xhr.open("GET", url, true);
	xhr.onreadystatechange = function() {
	console.log("State change:"+ xhr.readyState + " status:"+xhr.status);
	// readyState 4=HTTP response complete
	if(xhr.readyState == 4) {
		if (xhr.status == 200) {
		tab_port.postMessage({msg: "test_result", text: xhr.responseText});
		} else if (xhr.status == 0) {
		tab_port.postMessage({msg: "test_result", text: "Edit Server Test failed: is it running?"});
		} else {
		tab_port.postMessage({msg: "test_result", text: "Un-handled response: "+xhr.status}); 
		}
	}
	}
	xhr.send();
}

// Handle config request messages, the textarea.js content script being in it's own
// isolated sandbox has to be fed all this via the IPC mechanisms

function getBooleanConfig(config, defaultval) {
	return typeof localStorage[config] == "undefined" ? defaultval : localStorage[config] == "true";
}


function handleConfigMessages(msg, tab_port)
{
	var config_msg = {
	msg: "config",
	enable_button: getBooleanConfig("enable_button", true),
	enable_dblclick: getBooleanConfig("enable_dblclick", false),
	enable_keys: getBooleanConfig("enable_keys", false)
	};
	tab_port.postMessage(config_msg);
}


/*
	Handle all in-coming messages to the extension.

	As other parts of the extension cannot trigger XHR requests they all
	send message to the main part of the extension to service these requests.
*/
 
function localMessageHandler(port)
{
	port.onMessage.addListener(function(msg, port) {
		if (msg.msg == "config") {
		handleConfigMessages(msg, port);
	} else if (msg.msg == "edit") {
		handleContentMessages(msg, port);
	} else if (msg.msg == "test") {
		handleTestMessages(msg, port);
	} else if (msg.msg == "error") {
		updateUserFeedback(msg.text, "red");
	} else if (msg.msg == "focus") {
		if (msg.id === null) {
		updateUserFeedback("Awaiting edit request: no focus", "darkblue");
		} else {
		updateUserFeedback("Awaiting edit request: in focus");
		}
	}
	});
}

// Hook up whenever someone connects to the extension comms port
chrome.extension.onConnect.addListener(localMessageHandler);