Save conf to dedicated file (#283)

* Added support for saving configuration to a specific file

Added support for saving configuration to a specific file

* add test to cover the save to file feature

* add posibility to specify a format to save to file

* add a test with nconf-yaml to ensure specifying a format works

lib/nconf/stores/file.js

@@ -74,12 +74,24 @@ util.inherits(File, Memory);
 // using the format specified by `this.format`.
 //
 File.prototype.save = function (value, callback) {
+  this.saveToFile(this.file, value, callback);
+};
+
+//
+// ### function saveToFile (path, value, callback)
+// #### @path {string} The path to the file where we save the configuration to  
+// #### @format {Object} Optional formatter, default behing the one of the store
+// #### @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.saveToFile = function (path, format, callback) {
   if (!callback) {
-    callback = value;
+    callback = format;
-    value = null;
+    format = this.format;
   }
 
-  fs.writeFile(this.file, this.stringify(), callback);
+  fs.writeFile(path, this.stringify(format), callback);
 };
 
 //
@@ -166,14 +178,17 @@ File.prototype.loadSync = function () {
 // Returns an encrypted version of the contents IIF
 // `this.secure` is enabled
 //
-File.prototype.stringify = function () {
+File.prototype.stringify = function (format) {
   var data = this.store;
+  if (!format) {
+      format = this.format
+  }
 
   if (this.secure) {
     data = this.keys.encrypt(data);
   }
 
-  return this.format.stringify(data, null, this.spacing);
+  return format.stringify(data, null, this.spacing);
 };
 
 //

package.json

@@ -22,6 +22,7 @@
     "coveralls": "^2.11.4",
     "eslint": "^4.9.0",
     "istanbul": "^0.4.1",
+    "nconf-yaml": "^1.0.2",
     "vows": "0.8.x"
   },
   "main": "./lib/nconf",

test/stores/file-store-test.js

@@ -10,6 +10,7 @@ var fs = require('fs'),
     vows = require('vows'),
     assert = require('assert'),
     nconf = require('../../lib/nconf'),
+    yamlFormat = require('nconf-yaml'),
     data = require('../fixtures/data').data,
     store;
 
@@ -128,6 +129,53 @@ vows.describe('nconf/stores/file').addBatch({
         assert.isNull(err);
         assert.deepEqual(read, data);
       }
+    },
+    "the saveToFile() method": {
+      topic: function (tmpStore) {
+        var that = this,
+            pathFile = '/tmp/nconf-save-toFile.json';
+
+        Object.keys(data).forEach(function (key) {
+          tmpStore.set(key, data[key]);
+        });
+
+        tmpStore.saveToFile(pathFile, function () {
+          fs.readFile(pathFile, function (err, d) {
+            fs.unlinkSync(pathFile);
+
+            return err
+              ? that.callback(err)
+              : that.callback(err, JSON.parse(d.toString()));
+          });
+        });
+      },
+      "should save the data correctly": function (err, read) {
+        assert.isNull(err);
+        assert.deepEqual(read, data);
+      }
+    },
+    "the saveToFile() method with custom format": {
+      topic: function (tmpStore) {
+        var that = this,
+            pathFile = '/tmp/nconf-save-toFile.yaml';
+
+        Object.keys(data).forEach(function (key) {
+          tmpStore.set(key, data[key]);
+        });
+
+        tmpStore.saveToFile(pathFile, yamlFormat, function () {
+          fs.readFile(pathFile, function (err, d) {
+            fs.unlinkSync(pathFile);
+            return err
+              ? that.callback(err)
+              : that.callback(err, yamlFormat.parse(d.toString()));
+          });
+        });
+      },
+      "should save the data correctly": function (err, read) {
+        assert.isNull(err);
+        assert.deepEqual(read, data);
+      }
     }
   }
 }).addBatch({