enigma-bbs/core/config_cache.js

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/* jslint node: true */
'use strict';
var Config = require('./config.js').config;
var Log = require('./logger.js').log;
var paths = require('path');
var fs = require('graceful-fs');
var Gaze = require('gaze').Gaze;
var events = require('events');
var util = require('util');
var assert = require('assert');
var hjson = require('hjson');
var _ = require('lodash');
function ConfigCache() {
events.EventEmitter.call(this);
var self = this;
this.cache = {}; // filePath -> HJSON
this.gaze = new Gaze();
this.reCacheConfigFromFile = function(filePath, cb) {
fs.readFile(filePath, { encoding : 'utf-8' }, function fileRead(err, data) {
try {
self.cache[filePath] = hjson.parse(data);
cb(null, self.cache[filePath]);
} catch(e) {
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Log.error( { filePath : filePath, error : e.toString() }, 'Failed recaching');
cb(e);
}
});
};
this.gaze.on('error', function gazeErr(err) {
});
this.gaze.on('changed', function fileChanged(filePath) {
assert(filePath in self.cache);
Log.info( { path : filePath }, 'Configuration file changed; re-caching');
self.reCacheConfigFromFile(filePath, function reCached(err) {
if(err) {
Log.error( { error : err.message, path : filePath } , 'Failed re-caching configuration');
} else {
self.emit('recached', filePath);
}
});
});
}
util.inherits(ConfigCache, events.EventEmitter);
ConfigCache.prototype.getConfigWithOptions = function(options, cb) {
assert(_.isString(options.filePath));
var self = this;
var isCached = (options.filePath in this.cache);
if(options.forceReCache || !isCached) {
this.reCacheConfigFromFile(options.filePath, function fileCached(err, config) {
if(!err && !isCached) {
self.gaze.add(options.filePath);
}
cb(err, config, true);
});
} else {
cb(null, this.cache[options.filePath], false);
}
};
ConfigCache.prototype.getConfig = function(filePath, cb) {
this.getConfigWithOptions( { filePath : filePath }, cb);
};
ConfigCache.prototype.getModConfig = function(fileName, cb) {
this.getConfig(paths.join(Config.paths.mods, fileName), cb);
};
module.exports = exports = new ConfigCache();