Added option to calculate checksums for incoming files

Readme.md

@@ -199,6 +199,10 @@ Limits the amount of memory a field (not file) can allocate in bytes.
 If this value is exceeded, an `'error'` event is emitted. The default
 size is 2MB.
 
+__incomingForm.hash = false__
+
+If you want checksums calculated for incoming files, set this to either `'sha1'` or `'md5'`.
+
 __incomingForm.bytesReceived__
 
 The amount of bytes received for this form so far.

lib/file.js

@@ -2,7 +2,8 @@ if (global.GENTLY) require = GENTLY.hijack(require);
 
 var util = require('./util'),
     WriteStream = require('fs').WriteStream,
-    EventEmitter = require('events').EventEmitter;
+    EventEmitter = require('events').EventEmitter,
+    crypto = require('crypto')
 
 function File(properties) {
   EventEmitter.call(this);
@@ -14,9 +15,15 @@ function File(properties) {
   this.lastModifiedDate = null;
 
   this._writeStream = null;
-
-  for (var key in properties) {
-    this[key] = properties[key];
+
+  if(typeof properties === 'object') {
+    if(typeof properties.hash === 'string') {
+      this.hash = crypto.createHash(properties.hash);
+    }
+    delete(properties.hash);
+    for (var key in properties) {
+      this[key] = properties[key];
+    }
   }
 
   this._backwardsCompatibility();
@@ -45,6 +52,9 @@ File.prototype.open = function() {
 File.prototype.write = function(buffer, cb) {
   var self = this;
   this._writeStream.write(buffer, function() {
+    if(self.hash) {
+      self.hash.update(buffer);
+    }
     self.lastModifiedDate = new Date();
     self.size += buffer.length;
     self.emit('progress', self.size);
@@ -55,6 +65,9 @@ File.prototype.write = function(buffer, cb) {
 File.prototype.end = function(cb) {
   var self = this;
   this._writeStream.end(function() {
+    if(self.hash) {
+      self.hash = self.hash.digest('hex');
+    }
     self.emit('end');
     cb();
   });

lib/incoming_form.js

@@ -23,6 +23,7 @@ function IncomingForm() {
   this.encoding = 'utf-8';
   this.headers = null;
   this.type = null;
+  this.hash = false;
 
   this.bytesReceived = null;
   this.bytesExpected = null;
@@ -188,6 +189,7 @@ IncomingForm.prototype.handlePart = function(part) {
     path: this._uploadPath(part.filename),
     name: part.filename,
     type: part.mime,
+    hash: self.hash
   });
 
   this.emit('fileBegin', part.name, file);