Add .none function for uploading fields only (expressjs#372)

Fixes expressjs#278

README.md

@@ -131,6 +131,11 @@ Example:
 ]
 ```
 
+#### `.none()`
+
+Accept only text fields. If any file upload is made, error with code
+"LIMIT\_UNEXPECTED\_FILE" will be issued. This is the same as doing `upload.fields([])`.
+
 #### `.any()`
 
 Accepts all files that comes over the wire. An array of files will be stored in

index.js

@@ -66,6 +66,10 @@ Multer.prototype.fields = function (fields) {
   return this._makeMiddleware(fields, 'OBJECT')
 }
 
+Multer.prototype.none = function () {
+  return this._makeMiddleware([], 'NONE')
+}
+
 Multer.prototype.any = function () {
   function setup () {
     return {

lib/file-appender.js

@@ -10,6 +10,7 @@ function FileAppender (strategy, req) {
   this.req = req
 
   switch (strategy) {
+    case 'NONE': break
     case 'VALUE': break
     case 'ARRAY': req.files = []; break
     case 'OBJECT': req.files = Object.create(null); break
@@ -23,6 +24,7 @@ FileAppender.prototype.insertPlaceholder = function (file) {
   }
 
   switch (this.strategy) {
+    case 'NONE': break
     case 'VALUE': break
     case 'ARRAY': this.req.files.push(placeholder); break
     case 'OBJECT':
@@ -39,6 +41,7 @@ FileAppender.prototype.insertPlaceholder = function (file) {
 
 FileAppender.prototype.removePlaceholder = function (placeholder) {
   switch (this.strategy) {
+    case 'NONE': break
     case 'VALUE': break
     case 'ARRAY': arrayRemove(this.req.files, placeholder); break
     case 'OBJECT':

test/none.js

@@ -0,0 +1,47 @@
+/* eslint-env mocha */
+
+var assert = require('assert')
+
+var util = require('./_util')
+var multer = require('../')
+var FormData = require('form-data')
+
+describe('None', function () {
+  var parser
+
+  before(function () {
+    parser = multer().none()
+  })
+
+  it('should not allow file uploads', function (done) {
+    var form = new FormData()
+
+    form.append('key1', 'val1')
+    form.append('key2', 'val2')
+    form.append('file', util.file('small0.dat'))
+
+    util.submitForm(parser, form, function (err, req) {
+      assert.ok(err)
+      assert.equal(err.code, 'LIMIT_UNEXPECTED_FILE')
+      assert.equal(req.files, undefined)
+      assert.equal(req.body['key1'], 'val1')
+      assert.equal(req.body['key2'], 'val2')
+      done()
+    })
+  })
+
+  it('should handle text fields', function (done) {
+    var form = new FormData()
+
+    form.append('key1', 'val1')
+    form.append('key2', 'val2')
+
+    util.submitForm(parser, form, function (err, req) {
+      assert.ifError(err)
+      assert.equal(req.files, undefined)
+      assert.equal(req.body['key1'], 'val1')
+      assert.equal(req.body['key2'], 'val2')
+      done()
+    })
+  })
+})