nconf-lite/lib/nconf/stores/file.js

72 lines
1.8 KiB
JavaScript

/*
* file.js: Simple file storage engine for nconf files
*
* (C) 2011, Charlie Robbins
*
*/
var fs = require('fs'),
util = require('util'),
Memory = require('./memory').Memory;
//
// ### function File (options)
// #### @options {Object} Options for this instance
// Constructor function for the File nconf store, a simple abstraction
// around the Memory store that can persist configuration to disk.
//
var File = exports.File = function (options) {
if (!options.file) {
throw new Error ('Missing required option `files`');
}
Memory.call(this, options);
this.type = 'file';
this.file = options.file;
this.format = options.format || {
stringify: function (obj) {
return JSON.stringify(obj, null, 2)
},
parse: JSON.parse
};
};
// Inherit from the Memory store
util.inherits(File, Memory);
//
// ### function save (value, callback)
// #### @value {Object} _Ignored_ Left here for consistency
// #### @callback {function} Continuation to respond to when complete.
// Saves the current configuration object to disk at `this.file`
// using the format specified by `this.format`.
//
File.prototype.save = function (value, callback) {
if (!callback) {
callback = value;
value = null;
}
fs.writeFile(this.file, this.format.stringify(this.store), function (err) {
return err ? callback(err) : callback();
});
};
//
// ### function load (callback)
// #### @callback {function} Continuation to respond to when complete.
// Responds with an Object representing all keys associated in this instance.
//
File.prototype.load = function (callback) {
var self = this;
fs.readFile(this.file, function (err, data) {
if (err) {
return callback(err);
}
data = self.format.parse(data.toString());
self.store = data;
callback(null, self.store);
});
};