Less middleware for express

less-css-middlware

var 
	fs = require("fs"),
	__ = require("underscore"),
    url = require('url'),
    less = require('less'),
    path = require('path'),
	regex = /\.less$/,
	cache = {},
	defaultOptions = {
		src : "",
		force : false,
		compress : true	
	},
	options = {},
	send = function(pathname,res){
		res.set('Content-Type', 'text/css');
    	res.send(cache[pathname].output);
	},
	log = function(key, val, type) {
		if(options.debug || type === 'error') {
		  switch(type) {
		    case 'log':
		    case 'info':
		    case 'error':
		    case 'warn':
		      break;
		    default:
		      type = 'log';
		  }
		
		  console[type]('  \033[90m%s :\033[0m \033[36m%s\033[0m', key, val);
		}
	},
	lessError = function(err,res,next) {
		
		// create a user friendly error
		var message = [];
		message.push(err.message);
		message.push("Line :" + err.line.toString());
		message.push("Index :" + err.index.toString());
		message.push("-------------------------------------------------------");
		__.each(err.extract,function(value){
			message.push(value);
		});
		res.set('Content-Type', 'text/plain');
    	res.send(message.join('\n'));
    	
    	// log to the console
		log("LESS " + err.type + ' error', err.message, 'error');
		log("LESS File", err.filename + ' ' + err.line + ':' + err.column, 'error');
		return next(err);
	},
	error = function(err,next){
		return next('ENOENT' == err.code ? null : err);		
	};

module.exports = function(custom_options){
	__.extend(options,defaultOptions,custom_options);
	return function(req,res,next){
	    if ('GET' != req.method.toUpperCase() && 'HEAD' != req.method.toUpperCase()) { return next(); }
	    var pathname = options.src + url.parse(req.url).pathname;
	    
	    // if the file does not end in .less, leave the method.
	    if(!regex.test(pathname)){
	    	return next();
	    }
	    
	    // read file stats
	    fs.lstat(pathname,function(err,stats){
			if (err) {
				return error(err,next);
			}
			
		    // if it's already been cached, send it and leave;
		    if( !options.force &&  cache[pathname] && cache[pathname].mtime.getTime() == stats.mtime.getTime()){
		    	return send(pathname,res);	
		    }
			
		    // if it's not been cached, read the file
		    fs.readFile(pathname,'utf8',function(err,str){
				if (err) {
					return error(err,next);
				}
				
		    	var parser = new less.Parser({
					paths: [path.dirname(pathname)],
					filename: pathname,
					optimization: 0
				});
	            
	            // parse the contents
				parser.parse(str, function(err, tree) {
					if (err) {
						return lessError(err,res,next);
					}
					
					var css = tree.toCSS({
						compress: options.compress,
						yuicompress: false
					});
					
					// cache the output
					cache[pathname] = {
						path : pathname,
						output :  css,
						mtime : stats.mtime
					};
					
					// send the output
					return send(pathname,res);
				});			
			});
	    });
	};
};