Generate ETags for all request responses

closes expressjs#2546

Author: dougwilson

History.md

@@ -1,6 +1,8 @@
 3.x
 ===
 
+  * Generate `ETag`s for all request responses
+    - No longer restricted to only responses for `GET` and `HEAD` requests
   * Use `content-type` to parse `Content-Type` headers
   * deps: [email protected]
     - Use `content-type` to parse `Content-Type` headers

LICENSE

@@ -1,6 +1,8 @@
 (The MIT License)
 
 Copyright (c) 2009-2013 TJ Holowaychuk <[email protected]>
+Copyright (c) 2013 Roman Shtylman <[email protected]>
+Copyright (c) 2014-2015 Douglas Christopher Wilson <[email protected]>
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the

lib/response.js

@@ -1,5 +1,13 @@
+/*!
+ * express
+ * Copyright(c) 2009-2013 TJ Holowaychuk
+ * Copyright(c) 2014-2015 Douglas Christopher Wilson
+ * MIT Licensed
+ */
+
 /**
  * Module dependencies.
+ * @api private
  */
 
 var contentDisposition = require('content-disposition');
@@ -86,7 +94,6 @@ res.links = function(links){
 
 res.send = function(body){
   var req = this.req;
-  var head = 'HEAD' == req.method;
   var type;
   var encoding;
   var len;
@@ -153,12 +160,12 @@ res.send = function(body){
     this.set('Content-Length', len);
   }
 
-  // ETag support
-  var etag = len !== undefined && app.get('etag fn');
-  if (etag && ('GET' === req.method || 'HEAD' === req.method)) {
-    if (!this.get('ETag')) {
-      etag = etag(body, encoding);
-      etag && this.set('ETag', etag);
+  // populate ETag
+  var etag;
+  var generateETag = len !== undefined && app.get('etag fn');
+  if (typeof generateETag === 'function' && !this.get('ETag')) {
+    if ((etag = generateETag(body, encoding))) {
+      this.set('ETag', etag);
     }
   }
 
@@ -173,8 +180,13 @@ res.send = function(body){
     body = '';
   }
 
-  // respond
-  this.end((head ? null : body), encoding);
+  if (req.method === 'HEAD') {
+    // skip body for HEAD
+    this.end();
+  } else {
+    // respond
+    this.end(body, encoding);
+  }
 
   return this;
 };