dcs-get-node

#!/var/tmp/dcs-get/bin/node-0.4.2

// Useful settings
var settings = {
	'install_dir': '/var/tmp/dcs-get',
	'base_host': 'backus.uwcs.co.uk',
	'base_path': '/dcs-get/',
	'debug': true
};

// Global variable for packages
var packages;

// Node modules
var 	http = require('http'),
	fs = require('fs'),
	util = require('util'),
	spawn = require('child_process').spawn,
	exec = require('child_process').exec;

// Grab the package list from backus
http.get({
	host: settings['base_host'],
	port: 80,
	path: settings['base_path']+'packages.json'
}, function(res) {
	res.setEncoding('utf8');
	var data = '';
	res.on('data', function (chunk) {
		data += chunk;
	});
	res.on('end', function () {
		try {
			packages = JSON.parse(data);
			packages = sortObject(packages);			
		} catch (e) {
			console.log("Error: Problem with package data");
			if (settings.debug) console.log(e);
			return;
		}
		// We have the package data and are ready to go
		handleCLI();
	});
}).on('error', function(e) {
	console.log("Error: Problem downloading package list from backus");
	if (settings.debug) console.log(e);

});

var handleCLI = function () {
	// Deal with command line input
	if (process.argv[2] === undefined) {
		console.log("Try dcs-get help");
		return;
	}
	switch (process.argv[2]) {
		case "list":
		case "l":
			var package;
			for (packageName in packages) {
				package = packages[packageName];
				if (package.type === undefined || package.type != "dev") {
					console.log(packageName+" - "+package.description+" - Versions: "+package.version.join(", "));
				}
			}
			break;
		case "list-dev":
		case "ld":
			var package;
			for (packageName in packages) {
				package = packages[packageName];
				console.log(packageName+" - "+package.description+" - Versions: "+package.version.join(", "));
			}
			break;
		case "clean":
		case "c":
			exec('rm -rf '+settings['install_dir']);
			console.log("dcs-get completely removed");
			break;
		case "search":
		case "s":
		case "install":
		case "i":
		case "reinstall":
		case "r":
		case "list-installed":
		case "li":
		case "gensymlinks":
		case "g":
		case "package":
		case "p":
		case "upload":
		case "u":
		case "help":
			console.log("TODO");
			break;
		case "commands":
			console.log("commands search install reinstall list list-dev clean gensymlinks package help upload");
			break;
		default:
			console.log("Try dcs-get help");
	}	
}


// Function to download a file, while extracting it
// TODO: Add callbacks (progress and complete)
var downloadPackage = function (package) {
	http.get({
	        host: settings['base_host'],
        	port: 80,
	        path: settings['base_path']+'packages/'+package+'.tar.gz'
	}, function(res) {
		var downloaded = 0;
		res.on('data', function (chunk) {
			downloaded += chunk.length;
		});
		var progress = setInterval(function() {
			console.log(Math.round((downloaded/res.headers['content-length'])*100)+'%');
		}, 50);
		res.on('end', function () {
			clearInterval(progress);
			console.log("Package downloaded");
		});
		// Save file
		util.pump(res, fs.createWriteStream(settings['install_dir']+'/downloads/'+package+'.tar.gz'));
		// Extract contents
		var tar = spawn('tar', ['zx','-C', settings['install_dir']]);
		util.pump(res, tar.stdin);
		// Calculate md5sum
		var md5sum = spawn('md5sum');
		util.pump(res, md5sum.stdin);
		var md5hash = '';
		md5sum.stdout.on('data', function (chunk) {
			md5hash += chunk;
		})
		md5sum.stdout.on('end', function () {
			console.log("File hash: "+md5hash);
		});
	}).on('error', function(e) {
	        console.log("Error: Problem downloading package.");
        	if (settings.debug) console.log(e);
	});
};
downloadPackage('git-1.7.3.2');

// Useful functions (not written by me)
function sortObject(o) {
    var sorted = {},
    key, a = [];

    for (key in o) {
        if (o.hasOwnProperty(key)) {
                a.push(key);
        }
    }

    a.sort();

    for (key = 0; key < a.length; key++) {
        sorted[a[key]] = o[a[key]];
    }
    return sorted;
}