Automatically "build" when files change.

autobuild.js

var fs   = require("fs-extra");
var path = require("path");
var cp   = require("child_process");

console.log("------------------------------------------");
console.log("autobuild");
console.log("------------------------------------------");

if (process.argv.length == 3) {
    var configFile = process.argv[2];
}
else {
    console.log("Usage: node autosync.js <config.json>");
}

fs.readFile(configFile, "utf-8", function (err, data) {
    if (err) {
        console.log("Failed to load configuration '" + configFile + "'.");
        return;
    }
    var config = JSON.parse(data);
    
    console.log("name:    " + config.name);
    console.log("source:  " + config.sources);
    console.log("build:   " + config.build);
    console.log("target:  " + config.target);
    console.log("------------------------------------------");
    
    config.sourcePaternsRegEx = [];
    config.sourcePaterns.forEach(function (pattern) {
        config.sourcePaternsRegEx.push(new RegExp(pattern, "i"));
    });
    
    // TODO build project for good mesure somewhare
    
    autobuild(config);    
});

function watchSource(config) {
    config.sources.forEach(function (source) {    
        fs.readdir(source, function(err, files) {
            if (err) {
                console.log(err);
                return;
            }
        
            files.forEach(function (file) {
                config.sourcePaternsRegEx.forEach(function (pattern) {
                    if (file.match(pattern)) {
                        var filePath = path.join(source, file);
                        fs.watchFile(filePath, function () {
                            build(config);
                        });
                    }
                });                
            });
        });
    });
}

function watchBuild(config) {    
    fs.readdir(config.build, function (err, files) {
        if (err) {
            console.log(err);
            return;
        }
            
        files.forEach(function (file) {
            config.buildResults.forEach(function (result) {
                if (file == result) {
                    var filePath = path.join(config.build, file);
                    var targetPath = path.join(config.target, file);
                    fs.watchFile(filePath, function () {                        
                        fs.copy(filePath, targetPath, function (err) {
                            if (err) {                             
                                console.log("failed to copy " + file);
                            }
                            else {
                                console.log("copied " + file);
                            }
                        });
                    });
                }
            });
        });
    });
}

function build(config, callback) {
    console.log("building " + config.name);    
    cp.exec(config.buildCommand, { cwd: config.sources[0] }, function (error, stdout, stderr) {
        console.log('stdout: \n' + stdout);
        console.log('stderr: \n' + stderr);
        if (error !== null) {
          console.log('exec error: ' + error);
        }
        console.log("finished building " + config.name);    
    });
}

function autobuild(config) {
    watchSource(config);
    watchBuild(config);
}

// maybe some time later
// exports.autobuild = autobuild;

myproj.json

{
    "name":             "My Project",
    "sources":          ["D:\\Devel\\OneProject", "D:\\Devel\\Includes"],
    "sourcePaterns":    [".cpp", ".cc", ".h"],
    "build":            "D:\\Devel\\Build\Release",
    "buildCommand":     "\"C:\\Program Files\\Microsoft Visual Studio\\COMMON\\MSDev98\\Bin\\msdev.exe\" mypoj.dsw /MAKE \"ALL - RELEASE\"",
    "buildResults":     ["myproj.dll", "OneProject.pdb"],
    "target":           "C:\\Program Files\\My Cool Software"    
}