opt

opt

revision 0.0.9

Overview

opt is a toolkit for building either command line programs or RESTful web services. It uses a common pattern for setting up and processing JSON based configuration files, command line options and RESTful API calls.

Using the module is usually invoked by

var opt = require("opt").create();

It is available from github at https://github.com/rsdoiel/opt and can be installed using npm

npm install opt

Examples Code

The following examples build by topics

• configuration processing
• command line option processing
• a RESTful Hello World API

Config Example

This is the synchronous version.

/*jslint node: true */
"use strict";

var path = require("path"),
	opt = require("../opt").create();

var config = { name: "fred", email: "[e-mail]" },
	search_paths = [ "config-example-1.conf",
			path.join(process.env.HOME, ".config-examplerc"),
			"/usr/local/etc/config-example.conf",
			"/usr/etc/config-example.conf",
			"/etc/config-example.conf" ];

console.log("Unprocessed config:", config);
opt.config(config, search_paths);

opt.on("ready", function (config) {
	// config should now hold the merge configuration
	// from default_config and the first configuration file 
	// found in the search path list.
	console.log("Processed config: ", config);
});

Adding Option processing

Display a help message with -h and --help on the command line.

/*jslint node: true */
"use strict";

var path = require("path"),
	opt = require("../opt").create();

var config = { name: "fred", email: "[e-mail]" },
	search_paths = [ "config-example-1.conf",
			path.join(process.env.HOME, ".config-examplerc"),
			"/usr/local/etc/config-example.conf",
			"/usr/etc/config-example.conf",
			"/etc/config-example.conf" ];

console.log("Unprocessed config:", config);
opt.config(config, search_paths);

opt.optionHelp("USAGE node " + path.basename(process.argv[1]),
	"SYNOPSIS: Demonstrate how opt works to parse command line options.\n\n\t\t node " + path.basename(process.argv[1]) + " --help",
	"OPTIONS:",
	" copyright (c) 2012 all rights reserved\n" +
	" Released under New the BSD License.\n" +
	" See: http://opensource.org/licenses/bsd-license.php\n");


opt.on("ready", function (config) {
    opt.option(["-n", "--name"], function (param) {
        if (param.trim()) {
            config.name = param.trim();
        }
    }, "Set the name parameter");

    opt.option(["-e", "--email"], function (param) {
        if (param.trim()) {
            config.email = param.trim();
        }
    }, "Set the email parameter");
    
    opt.option(["-g", "--generate"], function (param) {
        if (param.trim()) {
            fs.writeFile(param.trim(), JSON.stringify(config));
        } else {
            console.log(JSON.stringify(config));
        }
        process.exit(0);
    }, "Generate a configuration file");
    
    opt.option(["-h", "--help"], function () {
        opt.usage();
    }, "This help document.");

    opt.optionWith(process.argv[1]);

    // config should now hold the merge configuration
    // from default_config and the first configuration file 
    // found in the search path list.
    console.log("Processed config: ", config);
});

A simple web server API

// Importing some modules
var util = require("util"),
    http = require("http"),
    path = require("path"),
    // import and create the opt object
    opt = require("../opt").create();

// Define your configuration defaults and load your local configuration
// file or it.
opt.config({ host: "localhost", port: 8080, name: "John Doe"},
    [ "/etc/helloworld.json", path.join(process.env.HOME, "etc/helloworld.json") ]);

// When your configuration is "ready" parse the command lines
// and setup your RESTful hello world web service
opt.on("ready", function (config) {
    // Setup how your help page will look
    opt.optionHelp("USAGE node " + path.basename(process.argv[1]),
        "SYNOPSIS:\n\tThis is a simple hello world web service.",
        "OPTIONS:",
        "this is an opt demo");

    // Define your command line options
    opt.option(["-H", "--host"], function (hostname) {
        config.host = hostname.trim();
    });
    opt.option(["-p", "--port"], function (portname) {
        config.port = Number(portname.trim());
    });
    opt.option(["-n", "--name"], function (name) {
        config.name = name.trim();
    });
    opt.option(["-h", "--help"], function () {
        opt.usage();
    });

    // Define you restful service
    var helloworld = function (req, res, matching, rule_no) {
        res.writeHead(200, {"content-type": "text/plain"});
        res.end("Hello " + config.name + ".\nThis is what I found: " + util.inspect(matching) + "\nRule No.:" + rule_no);
    };
    opt.rest("get", new RegExp("^$|^/$|^/index.html|^/helloworld.html"), helloworld);

    var status404 = function (req, res) {
        res.writeHead(404, {"content-type": "text/plain"});
        res.end("File not found. " + req.url);
    };
    opt.rest("get", new RegExp("^/*"), status404);

    // Process your command line args.
    opt.optionWith(process.argv);

    // Process your restful requets
    console.log("Configuration:", config);
    http.createServer(function (req, res) {
        console.log("request:", req.url);
        opt.restWith(req, res);
    }).listen(config.port, config.host);
    console.log("Web server listening on " + config.host + ":" + config.port);
});