enigma-bbs/core/json_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('fs');
var Gaze = require('gaze').Gaze;
var stripJsonComments = require('strip-json-comments');
var assert = require('assert');
module.exports = exports = new JSONCache();
function JSONCache() {
var self = this;
this.cache = {}; // filePath -> JSON
this.gaze = new Gaze();
this.reCacheJSONFromFile = function(filePath, cb) {
fs.readFile(filePath, { encoding : 'utf-8' }, function fileRead(err, data) {
try {
self.cache[filePath] = JSON.parse(stripJsonComments(data));
cb(null, self.cache[filePath]);
} catch(e) {
cb(e);
}
});
};
this.gaze.on('error', function gazeErr(err) {
});
this.gaze.on('changed', function fileChanged(filePath) {
assert(filePath in self.cache);
Log.info( { filePath : filePath }, 'JSON file changed; recaching');
self.reCacheJSONFromFile(filePath, function reCached(err) {
if(err) {
Log.error( { error : err, filePath : filePath } , 'Error recaching JSON');
}
});
});
}
JSONCache.prototype.getJSON = function(fileName, cb) {
var self = this;
var filePath = paths.join(Config.paths.mods, fileName);
if(filePath in this.cache) {
cb(null, this.cache[filePath], false);
} else {
this.reCacheJSONFromFile(filePath, function fileCached(err, json) {
if(!err) {
self.gaze.add(filePath);
}
cb(err, json, true);
});
}
};