Handle errors in autoload

lib/datastore.js

@@ -16,6 +16,7 @@ var customUtils = require('./customUtils')
  * @param {Boolean} options.nodeWebkitAppName Optional, specify the name of your NW app if you want options.filename to be relative to the directory where
  *                                            Node Webkit stores application data such as cookies and local storage (the best place to store data in my opinion)
  * @param {Boolean} options.autoload Optional, defaults to false
+ * @param {Function} options.onload Optional, if autoload is used this will be called after the load database with the error object as parameter. If you don't pass it the error will be thrown
  */
 function Datastore (options) {
   var filename;
@@ -53,7 +54,11 @@ function Datastore (options) {
   this.indexes = {};
   this.indexes._id = new Index({ fieldName: '_id', unique: true });
   
-  if (this.autoload) { this.loadDatabase(); }
+  // Queue a load of the database right away and call the onload handler
+  // By default (no onload handler), if there is an error there, no operation will be possible so warn the user by throwing an exception
+  if (this.autoload) { this.loadDatabase(options.onload || function (err) {
+    if (err) { throw err; }
+  }); }
 }
 
 

test/db.test.js

@@ -53,6 +53,46 @@ describe('Database', function () {
     dbef.inMemoryOnly.should.equal(true);
   });
 
+  describe('Autoloading', function () {
+  
+    it('Can autoload a database and query it right away', function (done) {
+      var fileStr = model.serialize({ _id: '1', a: 5, planet: 'Earth' }) + '\n' + model.serialize({ _id: '2', a: 5, planet: 'Mars' }) + '\n'
+        , autoDb = 'workspace/auto.db'
+        , db
+        ;
+      
+      fs.writeFileSync(autoDb, fileStr, 'utf8');
+      db = new Datastore({ filename: autoDb, autoload: true })
+      
+      db.find({}, function (err, docs) {
+        assert.isNull(err);
+        docs.length.should.equal(2);
+        done();
+      });
+    });
+    
+    it('Throws if autoload fails', function (done) {
+      var fileStr = model.serialize({ _id: '1', a: 5, planet: 'Earth' }) + '\n' + model.serialize({ _id: '2', a: 5, planet: 'Mars' }) + '\n' + '{"$$indexCreated":{"fieldName":"a","unique":true}}'
+        , autoDb = 'workspace/auto.db'
+        , db
+        ;
+      
+      fs.writeFileSync(autoDb, fileStr, 'utf8');
+      
+      // Check the loadDatabase generated an error
+      function onload (err) {
+        err.errorType.should.equal('uniqueViolated');
+        done();
+      }
+      
+      db = new Datastore({ filename: autoDb, autoload: true, onload: onload })
+      
+      db.find({}, function (err, docs) {
+        done("Find should not be executed since autoload failed");
+      });    
+    });
+ 
+  });
 
   describe('Insert', function () {