http.response.getHeaders()

Reads out all headers that's already been queued but not sent to the
client.
Keys are proper-case as they will (or was) sent.  Usefull for logging

Example:

```js
console.log(response.getHeaders());
// { 'Content-Type': 'text/plain' }
```

This addressed #3992

doc/api/http.markdown

@@ -409,13 +409,22 @@ in responses.
 ### response.getHeader(name)
 
 Reads out a header that's already been queued but not sent to the client.  Note
-that the name is case insensitive.  This can only be called before headers get
-implicitly flushed.
+that the name is case insensitive.  
 
 Example:
 
     var contentType = response.getHeader('content-type');
 
+### response.getHeaders()
+
+Reads out all headers that's already been queued but not sent to the client.
+Keys are proper-case as they will (or was) sent.  Usefull for logging
+
+Example:
+
+    console.log(response.getHeaders());
+    // { 'Content-Type': 'text/plain' }
+
 ### response.removeHeader(name)
 
 Removes a header that's queued for implicit sending.

lib/http.js

@@ -681,11 +681,7 @@ OutgoingMessage.prototype.removeHeader = function(name) {
 };
 
 
-OutgoingMessage.prototype._renderHeaders = function() {
-  if (this._header) {
-    throw new Error('Can\'t render headers after they are sent to the client.');
-  }
-
+OutgoingMessage.prototype.getHeaders = function() {
   if (!this._headers) return {};
 
   var headers = {};
@@ -698,6 +694,14 @@ OutgoingMessage.prototype._renderHeaders = function() {
 };
 
 
+OutgoingMessage.prototype._renderHeaders = function() {
+  if (this._header) {
+    throw new Error('Can\'t render headers after they are sent to the client.');
+  }
+
+  return this.getHeaders();
+};
+
 
 OutgoingMessage.prototype.write = function(chunk, encoding) {
   if (!this._header) {

test/simple/test-http-header-read.js

@@ -29,8 +29,14 @@ var http = require('http');
 var s = http.createServer(function(req, res) {
   var contentType = 'Content-Type';
   var plain = 'text/plain';
+
   res.setHeader(contentType, plain);
+  var headers1 = res.getHeaders();
+  assert.deepEqual(headers1, {'Content-Type': 'text/plain'});
   res.writeHead(200);
+  var headers2 = res.getHeaders();
+  assert.deepEqual(headers2, headers1);
+
   res.end('hello world\n');
   // This checks that after the headers have been sent, getHeader works
   // and does not throw an exception (Issue 752)