pygments/pygments.js

A pygments wrapper for nodejs

/*
 * pygments.js: A node.js wrapper for pygments
 *
 * (C) 2011, Pavan Kumar Sunkara
 *
 */

var spawn = require('child_process').spawn,
    spawnSync = require('child_process').spawnSync,
    path = require('path'),
    fs = require('fs');

var exists = fs.existsSync || path.existsSync;

var pygments = {};

//
// Default timeout threshold for pygments
//
pygments.timeout = 10;

//
// Default binary path for pygmentize
//
pygments.bin = 'pygmentize';

//
// ### function prepareColorizeParameters
// #### @target {String} Target to be highlighted
// #### @lexer {String} Lexer to use for highlighting
// #### @format {String} Format for the output
// #### @options {Object} Other options
// #### @returns {Object} the target and the options merged
//
pygments.prepareColorizeParameters = function(target, lexer, format, options) {
  options = options || {};

  if(lexer) options['l'] = lexer;
  if(format) options['f'] = format;

  options = pygments.merge_options(options);
  target = pygments.stringize(target, (options['force']));

  delete options['force'];

  return {
      target: target,
      options: options
  };
}

//
// ### function colorize
// #### @target {String} Target to be highlighted
// #### @lexer {String} Lexer to use for highlighting
// #### @format {String} Format for the output
// #### @callback {Function} Callback to be called on the highlighted string
// #### @options {Object} Other options
//
pygments.colorize = function(target, lexer, format, callback, options) {
  colorizeParameters = pygments.prepareColorizeParameters(target, lexer, format, options);
  pygments.execute(colorizeParameters.target, colorizeParameters.options, callback);
};

//
// ### function colorizeSync
// #### @target {String} Target to be highlighted
// #### @lexer {String} Lexer to use for highlighting
// #### @format {String} Format for the output
// #### @options {Object} Other options
// #### @returns {String} The highlighted string
//
pygments.colorizeSync = function(target, lexer, format, options) {
  colorizeParameters = pygments.prepareColorizeParameters(target, lexer, format, options);
  return pygments.executeSync(colorizeParameters.target, colorizeParameters.options);
};

//
// ### function execute
// #### @target {String} Target to be highlighted
// #### @options {Object} Options
//
pygments.execute = function(target, options, callback) {
  var pyg = spawn(pygments.bin, pygments.convert_options(options));
  var chunks = [];

  pyg.stdout.on('data', function(chunk) {
    chunks.push(chunk);
  });

  pyg.stderr.on('data', function (data) {
    console.log(data.toString());
  });

  pyg.on('exit', function() {
    var length = 0;
    chunks.forEach(function(chunk) {
      length += chunk.length;
    });
    var content = new Buffer(length);
    var index = 0;
    chunks.forEach(function(chunk) {
      chunk.copy(content, index, 0, chunk.length);
      index += chunk.length;
    });
    callback(content.toString());
  });

  pyg.stdin.write(target);
  pyg.stdin.end();
};


//
// ### function executeSync
// #### @target {String} Target to be highlighted
// #### @options {Object} Options
// #### @returns {String} The highlighted string
//
pygments.executeSync = function(target, options) {
  var spawnRes = spawnSync(pygments.bin, pygments.convert_options(options), {input:target});
  return spawnRes.stdout.toString();
};

//
// ### function convert_options
// #### @options {Object} Options to be converted
//
pygments.convert_options = function(options) {
  var cmd = [];

  for(var option in options) {
    validate_args(option, options[option]);
    cmd.push("-"+option + options[option]);
  }

  return cmd;
};

//
// ### function merge_options
// #### @opts {Object} Options to be merged
//
pygments.merge_options = function(options) {
  var default_options = {
    'force': false,
    'l': 'js',
    'f': 'html',
    'O': 'encoding=utf-8'
  };

  Object.keys(default_options).forEach(function (key) {
    if (options[key] == null) {
      options[key] = default_options[key];
    }
  });

  return options;
};

//
// ### function stringize
// #### @target {String} Target to be highlighted
// #### @force {Boolean} Force the target to be string
//
pygments.stringize = function(target, force) {
  force = (force===undefined ? false : force);

  if(exists(target) && !force) {
    var target_stats = fs.statSync(target);
    if(target_stats.isFile()) {
      return fs.readFileSync(target);
    }
  }

  return target;
};

var validate_args = function(flag, value) {
  if(!flag.match(/^[a-z]+$/i)) throw new Error("Flag is invalid: " + flag);
  if(!value.match(/^[a-z0-9\-\_\+\=\#\,\s]+$/i)) throw new Error("Flag value is invalid: -"+flag+" "+value);
};

module.exports = pygments;