json2aton

#!/usr/bin/env node
//
// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
// Creation Date: Sun Jan 18 14:43:04 PST 2015
// Last Modified: Sun Jan 18 14:57:16 PST 2015
// Filename:      .../example/cli/json2aton
// Syntax:        JavaScript 1.8.5/ECMAScript 5.1; node.js
// vim:           ts=3: ft=javascript
//
// Description:   Example command-line interface for the ATON
//                object. This program will convert JSON files into 
//                ATON files.
//
// Usage:         ./json2aton file.json > file.aton
//                cat file.json | ./json2aton > file.aton
//
// If the above examples do not run, then try something like this on the
// command line to set the location of the required modules:
//    export NODE_PATH=/usr/local/lib/node_modules
// You also have to install node first (http://nodejs.org), and then install
// the ATON module in node.  After installing node, run this command to 
// install the ATON module:
//    npm install -g aton
// Also the command-line argument parser posix-argv-parser is required:
//    npm install -g posix-argv-parser
//

'use strict';

var aton  = require('aton');
var pap   = require('posix-argv-parser');
var fs    = require('fs');


//////////////////////////////
//
// Process command-line arguments, then read data from files or standard
//  input if no files.
//

(function processCommandLineArguments() {
	var args = pap.create();
	var v    = pap.validators;

	args.createOperand('files', {
		signature: 'input files',
		greedy: true,
		validators: [v.file()]
	});

	args.parse(process.argv.slice(2), function (errors, options) {
		if (errors) {
			console.log(errors[0]);
			process.exit(1);
		}
		var myoptions = {
			files  : options.files.value
		};
		runCommand(myoptions);
	});
})();



//////////////////////////////
//
// runCommand -- Do all of the work after command-line arguments 
//    have been parsed.
//

function runCommand(options) {
   if (options.files.length) {
      processFileList(options.files, options);
   } else {
      processStandardInput(options);
   }
}


//////////////////////////////
//
// processStandardInput -- read text data for an ATON file from standard
//    input.  This implementation reads all of the file into memory before
//    processing.  Eventually the ATON parse will be adjusted so that the
//    standard input or a file can be processed line-by-line without 
//    storing completely in memory before starting to parse it.
//

function processStandardInput(options) {
   var inputChunks = [];  // Temporary storage of incoming data packets.
   process.stdin.setEncoding('utf8');  // Be careful if not using utf-8 
													// encoding in the file.

   process.stdin.on('data', function (chunk) {
      inputChunks.push(chunk);
   });

   process.stdin.on('end', function () {
      var outputData = inputChunks.join('');
      processFileContents(outputData, options);
   });
}



//////////////////////////////
//
// processFileList -- loop through the input file list, converting them
//   one at a time.
//

function processFileList(filelist, options) {
   for (var i=0; i<filelist.length; i++) {
      processFile(filelist[i], options);
   }
}



//////////////////////////////
//
// processFile -- process a single file from the comman-line arguments.
//    This implementation reads all of the file into memory before
//    processing.  Eventually the ATON parse will be adjusted so that
//    standard input or a file can be processed line-by-line without 
//    storing completely in memory before starting to parse it.
//

function processFile(filename, options) {
   try {
      var data = fs.readFileSync(filename, 'utf8');
   } catch (error) {
      console.error('ERROR:', error.message);
      process.exit(1);
   }
   processFileContents(data, options);
}



//////////////////////////////
//
// processFileContents -- process the contents of a file (or standard input).
//

function processFileContents(data, options) {
	var object = JSON.parse(data);
	var ATON = new aton;
	var atonstring = ATON.stringify(object);
	console.log(atonstring);
}