Return error when no file is uploaded

lib/storage-handler.js

@@ -41,7 +41,7 @@ exports.upload = function(provider, req, res, options, cb) {
   form.handlePart = function(part) {
     var self = this;
 
-    if (part.filename === undefined) {
+    if (part.filename === undefined || part.filename === '') {
       var value = '';
       var decoder = new StringDecoder(this.encoding);
 
@@ -187,11 +187,20 @@ exports.upload = function(provider, req, res, options, cb) {
   };
 
   form.parse(req, function(err, _fields, _files) {
+    cb = cb || function() {};
+
     if (err) {
       console.error(err);
+      return cb(err);
     }
-    // eslint-disable-next-line no-unused-expressions
-    cb && cb(err, {files: files, fields: fields});
+
+    if (Object.keys(_files).length === 0) {
+      err = new Error('No file content uploaded');
+      err.statusCode = 400; // DO NOT MODIFY res.status directly!
+      return cb(err);
+    }
+
+    cb(null, {files: files, fields: fields});
   });
 };
 

package.json

@@ -21,7 +21,8 @@
     "loopback": "^3.0.0",
     "mkdirp": "^0.5.0",
     "mocha": "^2.1.0",
-    "supertest": "^0.15.0"
+    "supertest": "^0.15.0",
+    "semver": "^5.3.0"
   },
   "repository": {
     "type": "git",

test/upload-download.test.js

@@ -7,6 +7,7 @@
 var request = require('supertest');
 var loopback = require('loopback');
 var assert = require('assert');
+var semver = require('semver');
 
 var app = loopback();
 var path = require('path');
@@ -213,6 +214,34 @@ describe('storage service', function() {
       });
   });
 
+  it('returns error when no file is provided to upload', function(done) {
+    if (semver.gt(process.versions.node, '4.0.0')) {
+      request('http://localhost:' + app.get('port'))
+        .post('/imageContainers/album1/upload')
+        .set('Accept', 'application/json')
+        .set('Connection', 'keep-alive')
+        .expect('Content-Type', /json/)
+        .expect(400, function(err, res) {
+          var indexOfMsg =
+            res.body.error.message.toLowerCase().indexOf('no file');
+          assert.notEqual(indexOfMsg, -1,
+            'Error message does not contain \"no file\"');
+          done(err);
+        });
+    } else {
+      request('http://localhost:' + app.get('port'))
+        .post('/imageContainers/album1/upload')
+        .set('Accept', 'application/json')
+        .set('Connection', 'keep-alive')
+        .expect('Content-Type', /json/)
+        .expect(500, function(err, res) {
+          assert.equal(res.body.error.message,
+              'bad content-type header, no content-type');
+          done(err);
+        });
+    }
+  });
+
   it('should get file by name', function(done) {
     request('http://localhost:' + app.get('port'))
       .get('/containers/album1/files/test.jpg')