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

135 lines
No EOL
3.1 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 saveSync (value, callback)
// #### @value {Object} _Ignored_ Left here for consistency
// #### @callback {function} **Optional** Continuation to respond to when complete.
// Saves the current configuration object to disk at `this.file`
// using the format specified by `this.format` synchronously.
//
File.prototype.saveSync = function (value, callback) {
if (!callback) {
callback = value;
value = null;
}
var err;
try {
fs.writeFileSync(this.file, this.format.stringify(this.store));
}
catch (ex) {
err = ex;
}
if (callback) {
return callback(err);
}
if (err) {
throw err;
}
};
//
// ### 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);
}
try {
self.store = self.format.parse(data.toString());
callback(null, self.store);
}
catch (ex) {
self.store = {};
callback(ex);
}
});
};
//
// ### function load (callback)
// #### @callback {function} **Optional** Continuation to respond to when complete.
// Attempts to load the data stored in `this.file` synchronously and responds appropriately.
//
File.prototype.loadSync = function (callback) {
var err, data;
try {
data = fs.readFileSync(this.file, 'utf8');
this.store = this.format.parse(data);
}
catch (ex) {
err = ex;
}
if (callback) {
return callback(err, data);
}
if (err) {
err.message = "Error parsing your JSON configuration file."
throw err;
}
return data;
};