vcal/vcal.js

An vCal ics parser designed to specifically handle Google's ICS private export feed, but could handle more too.

exports.build_ics_string = function(ics_object) {
	var ics_data = "";
	
	for(var key in ics_object) {
		if(ics_object.hasOwnProperty(key)) {
			var node = ics_object[key];
			
			if(node.constructor == [].constructor) {
				node.forEach(function(item) {
					ics_data += "BEGIN:" + key + "\r\n";
					ics_data += exports.build_ics_string(item);
					ics_data += "END:" + key + "\r\n";
				});
			} else {
				node = node.replace(/\n/g, "\\n").replace(/,/g, "\\,");
				if(key.length + node.length + 1 > 75) {
					var string = node;
					var output = [];
					
					var line = key + ":";
					output.push(line + string.substr(0, 75 - line.length));
					string = string.substr(75 - line.length);
					
					while(string.length) {
						output.push(" " + string.substr(0, 75));
						string = string.substr(75);
					}
					ics_data += output.join("\r\n") + "\r\n";
					
				} else {
					ics_data += key + ":" + node + "\r\n";
				}
			}
		}
	}
	
	return ics_data;
}

exports.parse_ics_string = function(ics_string) {
	var lines = ics_string.replace(/\r/g, '').split('\n');

	var current_line = "";
	var tree = {};
	var stack = [];

	for(var i = 0; i < lines.length; i++) {
		current_line = lines[i];

		while(i+1 < lines.length && /\s/.test(lines[i+1][0])) {
			current_line += lines[i+1].substr(1);
			i++;
		}

		var pieces = current_line.split(":");

		var key = pieces[0];
		var value = pieces.slice(1, pieces.length).join(":").replace(/\\n/g, "\n").replace(/\\,/g, ",");

		if(!key) {
			continue;
		}

		// Start our state machine
		if(key == "BEGIN") {
			// If we encounter a BEGIN:<SECTION>, create a new leaf,
			// append it to the tree, push the existing tree on the stack
			// then set out leaf to be the root of the tree
			if(!tree[value]) {
				tree[value] = [];
			}

			var leaf = {};

			if(tree[value] && tree[value].constructor == [].constructor) {
				tree[value].push(leaf);
			} else {
				if(tree[value]) {
					tree[value] = [tree[value]];
					tree[value].push(leaf);
				} else {
					tree[value] = leaf;
				}
			}

			stack.push(tree);
			tree = leaf;
		} else if(key == "END") {
			// If we encounter a END:<SECTION>, pop the old root
			// from the stack and set it to be our root of the tree
			tree = stack.pop();
		} else {
			// Just set the key/value
			tree[key] = value;
		}
	}
	
	return tree;
}