objects can now have arbitrary headers set in metadata that will be served back when they are fetched

etc/object-server.conf-sample

@@ -30,6 +30,10 @@ use = egg:swift#object
 # slow = 1
 # on PUTs, sync data every n MB
 # mb_per_sync = 512
+# Comma separated list of headers that can be set in metadata on an object.
+# This list is in addition to X-Object-Meta-* headers and cannot include
+# Content-Type, etag, Content-Length, or deleted
+# allowed_headers = Content-Encoding
 
 [object-replicator]
 # You can override the default log routing for this app here (don't use set!):

swift/obj/server.py

@@ -52,6 +52,8 @@ PICKLE_PROTOCOL = 2
 METADATA_KEY = 'user.swift.metadata'
 MAX_OBJECT_NAME_LENGTH = 1024
 KEEP_CACHE_SIZE = (5 * 1024 * 1024)
+# keep these lower-case
+DISALLOWED_HEADERS = set('content-length content-type deleted etag'.split())
 
 
 def read_metadata(fd):
@@ -137,8 +139,7 @@ class DiskFile(object):
         if self.meta_file:
             with open(self.meta_file) as mfp:
                 for key in self.metadata.keys():
-                    if key.lower() not in ('content-type',
+                    if key.lower() not in DISALLOWED_HEADERS:
-                                'deleted', 'content-length', 'etag'):
                         del self.metadata[key]
                 self.metadata.update(read_metadata(mfp))
 
@@ -278,6 +279,10 @@ class ObjectController(object):
         self.max_upload_time = int(conf.get('max_upload_time', 86400))
         self.slow = int(conf.get('slow', 0))
         self.bytes_per_sync = int(conf.get('mb_per_sync', 512)) * 1024 * 1024
+        default_allowed_headers = 'content-encoding'
+        self.allowed_headers = set(i.strip().lower() for i in \
+                conf.get('allowed_headers', \
+                default_allowed_headers).split(',') if i.strip())
 
     def container_update(self, op, account, container, obj, headers_in,
                          headers_out, objdevice):
@@ -353,9 +358,11 @@ class ObjectController(object):
         metadata = {'X-Timestamp': request.headers['x-timestamp']}
         metadata.update(val for val in request.headers.iteritems()
                 if val[0].lower().startswith('x-object-meta-'))
-        if 'content-encoding' in request.headers:
+        for header_key in self.allowed_headers:
-            metadata['Content-Encoding'] = \
+            if header_key in request.headers:
-                request.headers['Content-Encoding']
+                header_caps = \
+                    header_key.replace('-', ' ').title().replace(' ', '-')
+                metadata[header_caps] = request.headers[header_key]
         with file.mkstemp() as (fd, tmppath):
             file.put(fd, tmppath, metadata, extension='.meta')
         return response_class(request=request)
@@ -420,9 +427,11 @@ class ObjectController(object):
             metadata.update(val for val in request.headers.iteritems()
                     if val[0].lower().startswith('x-object-meta-') and
                     len(val[0]) > 14)
-            if 'content-encoding' in request.headers:
+            for header_key in self.allowed_headers:
-                metadata['Content-Encoding'] = \
+                if header_key in request.headers:
-                    request.headers['Content-Encoding']
+                    header_caps = \
+                        header_key.replace('-', ' ').title().replace(' ', '-')
+                    metadata[header_caps] = request.headers[header_key]
             file.put(fd, tmppath, metadata)
         file.unlinkold(metadata['X-Timestamp'])
         self.container_update('PUT', account, container, obj, request.headers,
@@ -487,7 +496,8 @@ class ObjectController(object):
                         request=request, conditional_response=True)
         for key, value in file.metadata.iteritems():
             if key == 'X-Object-Manifest' or \
-                    key.lower().startswith('x-object-meta-'):
+                    key.lower().startswith('x-object-meta-') or \
+                    key.lower() in self.allowed_headers:
                 response.headers[key] = value
         response.etag = file.metadata['ETag']
         response.last_modified = float(file.metadata['X-Timestamp'])

test/unit/obj/test_server.py

@@ -57,10 +57,14 @@ class TestObjectController(unittest.TestCase):
 
     def test_POST_update_meta(self):
         """ Test swift.object_server.ObjectController.POST """
+        test_headers = 'content-encoding foo bar'.split()
+        self.object_controller.allowed_headers = set(test_headers)
         timestamp = normalize_timestamp(time())
         req = Request.blank('/sda1/p/a/c/o', environ={'REQUEST_METHOD': 'PUT'},
                             headers={'X-Timestamp': timestamp,
                                      'Content-Type': 'application/x-test',
+                                     'Foo': 'fooheader',
+                                     'Baz': 'bazheader',
                                      'X-Object-Meta-1': 'One',
                                      'X-Object-Meta-Two': 'Two'})
         req.body = 'VERIFY'
@@ -74,6 +78,8 @@ class TestObjectController(unittest.TestCase):
                                      'X-Object-Meta-3': 'Three',
                                      'X-Object-Meta-4': 'Four',
                                      'Content-Encoding': 'gzip',
+                                     'Foo': 'fooheader',
+                                     'Bar': 'barheader',
                                      'Content-Type': 'application/x-test'})
         resp = self.object_controller.POST(req)
         self.assertEquals(resp.status_int, 202)
@@ -84,6 +90,9 @@ class TestObjectController(unittest.TestCase):
                      "X-Object-Meta-Two" not in resp.headers and \
                      "X-Object-Meta-3" in resp.headers and \
                      "X-Object-Meta-4" in resp.headers and \
+                     "Foo" in resp.headers and \
+                     "Bar" in resp.headers and \
+                     "Baz" not in resp.headers and \
                      "Content-Encoding" in resp.headers)
         self.assertEquals(resp.headers['Content-Type'], 'application/x-test')
 
@@ -98,6 +107,8 @@ class TestObjectController(unittest.TestCase):
         resp = self.object_controller.GET(req)
         self.assert_("X-Object-Meta-3" not in resp.headers and \
                      "X-Object-Meta-4" not in resp.headers and \
+                     "Foo" not in resp.headers and \
+                     "Bar" not in resp.headers and \
                      "Content-Encoding" not in resp.headers)
         self.assertEquals(resp.headers['Content-Type'], 'application/x-test')