diff --git a/src/calibre/srv/content.py b/src/calibre/srv/content.py
index 153e51ba4b..d2d46d1769 100644
--- a/src/calibre/srv/content.py
+++ b/src/calibre/srv/content.py
@@ -12,9 +12,11 @@ from io import BytesIO
 from calibre.db.errors import NoSuchFormat
 from calibre.ebooks.metadata import authors_to_string
 from calibre.ebooks.metadata.meta import set_metadata
+from calibre.ebooks.metadata.opf2 import metadata_to_opf
 from calibre.library.save_to_disk import find_plugboard
 from calibre.srv.errors import HTTPNotFound
 from calibre.srv.routes import endpoint
+from calibre.srv.utils import http_date
 from calibre.utils.config_base import tweaks
 from calibre.utils.date import timestampfromdt
 from calibre.utils.filenames import ascii_filename
@@ -142,10 +144,10 @@ def get(ctx, rd, what, book_id, library_id):
     db = ctx.get_library(library_id)
     if db is None:
         raise HTTPNotFound('Library %r not found' % library_id)
-    library_id = db.server_library_id
     with db.safe_read_lock:
         if not db.has_id(book_id):
             raise HTTPNotFound('Book with id %r does not exist' % book_id)
+        library_id = db.server_library_id  # in case library_id was None
         if what == 'thumb' or what.startswith('thumb_'):
             try:
                 w, h = map(int, what.partition('_')[2].partition('x')[::2])
@@ -154,7 +156,13 @@ def get(ctx, rd, what, book_id, library_id):
             return cover(ctx, rd, library_id, db, book_id, width=w, height=h)
         elif what == 'cover':
             return cover(ctx, rd, library_id, db, book_id)
-        # TODO: Implement opf and json
+        elif what == 'opf':
+            mi = db.get_metadata(book_id, get_cover=False)
+            rd.outheaders['Content-Type'] = 'application/oebps-package+xml; charset=UTF-8'
+            rd.outheaders['Last-Modified'] = http_date(timestampfromdt(mi.last_modified))
+            return metadata_to_opf(mi)
+        elif what == 'json':
+            raise NotImplementedError('TODO: Implement this')
         else:
             try:
                 return book_fmt(ctx, rd, library_id, db, book_id, what.lower())
diff --git a/src/calibre/srv/tests/content.py b/src/calibre/srv/tests/content.py
index 024c7f78f8..44c205dc06 100644
--- a/src/calibre/srv/tests/content.py
+++ b/src/calibre/srv/tests/content.py
@@ -6,10 +6,11 @@ from __future__ import (unicode_literals, division, absolute_import,
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import httplib
+import httplib, zlib
 from io import BytesIO
 
 from calibre.ebooks.metadata.epub import get_metadata
+from calibre.ebooks.metadata.opf2 import OPF
 from calibre.srv.tests.base import LibraryBaseTest
 from calibre.utils.magick.draw import identify_data
 
@@ -122,6 +123,7 @@ class ContentTest(LibraryBaseTest):
             self.ae(r.status, httplib.OK)
             self.ae(data, db.cover(1))
             self.ae(r.getheader('Used-Cache'), 'no')
+            self.ae(r.getheader('Content-Type'), 'image/jpeg')
             r, data = get('cover', 1)
             self.ae(r.status, httplib.OK)
             self.ae(data, db.cover(1))
@@ -148,4 +150,18 @@ class ContentTest(LibraryBaseTest):
             self.ae(identify_data(data), (100, 100, 'jpeg'))
             self.ae(r.getheader('Used-Cache'), 'no')
 
+            # Test serving of metadata as opf
+            r, data = get('opf', 1)
+            self.ae(r.status, httplib.OK)
+            self.ae(r.getheader('Content-Type'), 'application/oebps-package+xml; charset=UTF-8')
+            self.assertIsNotNone(r.getheader('Last-Modified'))
+            opf = OPF(BytesIO(data), populate_spine=False, try_to_guess_cover=False)
+            self.ae(db.field_for('title', 1), opf.title)
+            self.ae(db.field_for('authors', 1), tuple(opf.authors))
+            conn.request('GET', '/get/opf/1', headers={'Accept-Encoding':'gzip'})
+            r = conn.getresponse()
+            self.ae(r.status, httplib.OK), self.ae(r.getheader('Content-Encoding'), 'gzip')
+            raw = r.read()
+            self.ae(zlib.decompress(raw, 16+zlib.MAX_WBITS), data)
+
     # }}}