grader.js

#!/usr/bin/env node
var fs = require('fs');
var program = require('commander');
var cheerio = require('cheerio');
var rest = require('restler');
var HTMLFILE_DEFAULT = 'index.html';
var CHECKSFILE_DEFAULT = 'checks.json';

var assertFileExists = function(infile) {
    var instr = infile.toString()
    if (!fs.existsSync(instr)) {
	console.log("%s does not exist. Exiting", instr);
	process.exit(1);
    }
    return instr;
};

var loadFile = function(filename) {
    return fs.readFileSync(filename);
};

var cheerioHtmlFile = function(htmlfile) {
    return cheerio.load(htmlfile);
};

var loadChecks = function(checksfile) {
    return JSON.parse(fs.readFileSync(checksfile));
};

var checkHtmlFile = function(htmlfile, checksfile) {
    $ = cheerioHtmlFile(htmlfile);
    var checks = loadChecks(checksfile).sort();
    var out = {};
    for(var ii in checks) {
	var present = $(checks[ii]).length > 0;
	out[checks[ii]] = present;
    }
    return out;
};

var clone = function(fn) {
    return fn.bind({});
};


if(require.main == module) {
    program
	.option('-c, --checks <check_file>', 'Path to checks.json', clone(assertFileExists), CHECKSFILE_DEFAULT)
	.option('-f, --file <html_file>', 'Path to index.html', clone(assertFileExists), HTMLFILE_DEFAULT)
        .option('-u, --url <url>', 'Url to index')
	.parse(process.argv);
    if(program.url) {
	rest.get(program.url).on('complete', function(result){
	    var checkJson = checkHtmlFile(result, program.checks);
	    var outJson = JSON.stringify(checkJson, null, 4);
	    console.log(outJson);
	});
    } else {
        var file = loadFile(program.file);
	var checkJson = checkHtmlFile(file, program.checks);
	var outJson = JSON.stringify(checkJson, null, 4);
	console.log(outJson);
    }
} else {
    exports.checkHtmlFile = checkHtmlFile;
}