diff --git a/warcprox.py b/warcprox.py
index 6304c3d..df166e2 100755
--- a/warcprox.py
+++ b/warcprox.py
@@ -22,6 +22,7 @@ import httplib
 import re
 import signal
 import time
+import tempfile
 
 class CertificateAuthority(object):
 
@@ -115,23 +116,25 @@ class ProxyingRecorder:
 
     def __init__(self, fp, proxy_dest):
         self.fp = fp
-        self.data = bytearray('')
+        self.buf = tempfile.SpooledTemporaryFile(max_size=1024)
         self.block_sha1 = hashlib.sha1()
         self.payload_sha1 = None
         self.proxy_dest = proxy_dest
+        self._prev_hunk_last_two_bytes = ''
+        self.len = 0
 
     def _update(self, hunk):
         if self.payload_sha1 is None:
-            # convoluted handling of two newlines crossing chunks
+            # convoluted handling of two newlines crossing hunks
             # XXX write tests for this
-            if self.data.endswith('\n'):
+            if self._prev_hunk_last_two_bytes.endswith('\n'):
                 if hunk.startswith('\n'):
                     self.payload_sha1 = hashlib.sha1()
                     self.payload_sha1.update(hunk[1:])
                 elif hunk.startswith('\r\n'):
                     self.payload_sha1 = hashlib.sha1()
                     self.payload_sha1.update(hunk[2:])
-            elif self.data.endswith('\n\r'):
+            elif self._prev_hunk_last_two_bytes == '\n\r':
                 if hunk.startswith('\n'):
                     self.payload_sha1 = hashlib.sha1()
                     self.payload_sha1.update(hunk[1:])
@@ -140,13 +143,18 @@ class ProxyingRecorder:
                 if m is not None:
                     self.payload_sha1 = hashlib.sha1()
                     self.payload_sha1.update(hunk[m.end():])
+
+            # if we still haven't found start of payload hold on to these bytes
+            if self.payload_sha1 is None:
+                self._prev_hunk_last_two_bytes = hunk[-2:]
         else:
             self.payload_sha1.update(hunk)
 
         self.block_sha1.update(hunk)
 
-        self.data.extend(hunk)
+        self.buf.write(hunk)
         self.proxy_dest.sendall(hunk)
+        self.len += len(hunk)
 
     def read(self, size=-1):
         hunk = self.fp.read(size=size)
@@ -162,6 +170,9 @@ class ProxyingRecorder:
     def close(self):
         return self.fp.close()
 
+    def __len__(self):
+        return self.len
+
 
 class ProxyingRecordingHTTPResponse(httplib.HTTPResponse):
 
@@ -173,9 +184,6 @@ class ProxyingRecordingHTTPResponse(httplib.HTTPResponse):
         self.recorder = ProxyingRecorder(self.fp, proxy_dest)
         self.fp = self.recorder
 
-    def recorded(self):
-        return self.recorder.recorded
-
 
 class ProxyHandler(BaseHTTPServer.BaseHTTPRequestHandler):
 
@@ -396,7 +404,7 @@ class WarcRecordQueuer:
 
 
     def do_response(self, recorder):
-        logging.info('{0} << {1}'.format(self.url, repr(recorder.data[:40])))
+        logging.info('{} << {} bytes'.format(self.url, len(recorder)))
 
         record_id = WarcRecordQueuer.make_warc_uuid("{0} {1}".format(self.url, self._warc_date()))
 
@@ -406,13 +414,14 @@ class WarcRecordQueuer:
         headers.append((warctools.WarcRecord.URL, self.url))
         headers.append((warctools.WarcRecord.DATE, self._warc_date()))
         headers.append((warctools.WarcRecord.BLOCK_DIGEST, 'sha1:{}'.format(recorder.block_sha1.hexdigest())))
+        headers.append((warctools.WarcRecord.CONTENT_TYPE, "application/http;msgtype=response"))
+        headers.append((warctools.WarcRecord.CONTENT_LENGTH, str(len(recorder))))
         if recorder.payload_sha1 is not None:
             headers.append((warctools.WarcRecord.PAYLOAD_DIGEST, 'sha1:{}'.format(recorder.payload_sha1.hexdigest())))
         # headers.append((warctools.WarcRecord.IP_ADDRESS, ip))
 
-        content_tuple = ("application/http;msgtype=response", recorder.data)
-
-        response_record = warctools.WarcRecord(headers=headers, content=content_tuple)
+        recorder.buf.seek(0)
+        response_record = warctools.WarcRecord(headers=headers, content_file=recorder.buf)
 
         try:
             self._request_record.set_header(warctools.WarcRecord.CONCURRENT_TO, record_id)
@@ -441,7 +450,7 @@ class WarcWriterThread(threading.Thread):
         self._serial = 0
         
         if not os.path.exists(directory):
-            logging.info("warc destination directory {0} doesn't exist, creating it".format(directory))
+            logging.info("warc destination directory {} doesn't exist, creating it".format(directory))
             os.mkdir(directory)
 
         self.stop = threading.Event()
@@ -449,7 +458,7 @@ class WarcWriterThread(threading.Thread):
 
     def timestamp17(self):
         now = datetime.now()
-        return '{0}{1}'.format(now.strftime('%Y%m%d%H%M%S'), now.microsecond//1000)
+        return '{}{}'.format(now.strftime('%Y%m%d%H%M%S'), now.microsecond//1000)
 
 
     def _close_writer(self):