preview extractor

5 files changed, 367 insertions, 80 deletions

diff --git a/test/apps/test_index.py b/test/apps/test_index.py
index 7f5be8e..d1e7140 100644
--- a/test/apps/test_index.py
+++ b/test/apps/test_index.py
@@ -23,6 +23,9 @@ from bsie.apps.index import main
 ## code ##
 
 class TestIndex(unittest.TestCase):
+    def test_disclaimer(self):
+        print('Please wait, this test will take about 25 seconds')
+
     def test_main_invalid(self):
         outbuf = io.StringIO()
         with contextlib.redirect_stdout(outbuf):
@@ -32,94 +35,166 @@ class TestIndex(unittest.TestCase):
     def test_main(self):
         bsfs = main([
             '-r',
-            '--user', 'http://example.com/me',
+            '--host', 'http://example.com',
+            '--user', 'me',
             os.path.join(os.path.dirname(__file__), 'testdir'),
             os.path.join(os.path.dirname(__file__), 'testfile'),
             ])
 
-        prefix = 'http://example.com/me/file#'
+        pre_file = 'http://example.com/me/file#'
+        pre_preview = 'http://example.com/me/preview#'
         self.assertTrue(set(bsfs._backend._graph).issuperset({
-            (rdflib.URIRef(prefix + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('alpha_second', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('696', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('omega_second', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('503', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('td_first', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('911', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('testfile', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('885', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('bar_first', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('956', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('omega_first', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('648', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('alpha_first', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('754', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('foo_second', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('585', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('bar_second', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('636', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('foo_first', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('546', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('td_second', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('703', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
-            (rdflib.URIRef(prefix + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('testimage.jpg', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef(prefix + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('349264', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef(prefix + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef('http://bsfs.ai/schema/Entity/colors_spatial#0658f2234a054e1dd59a14462c89f7733e019160419c796356aa831498bd0a04'),
+            # files and properties
+            (rdflib.URIRef(pre_file + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('alpha_second', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('696', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('omega_second', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('503', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('td_first', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('911', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('testfile', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('885', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('bar_first', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('956', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('omega_first', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('648', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('alpha_first', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('754', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('foo_second', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('585', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('bar_second', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('636', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('foo_first', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('546', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('td_second', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('703', datatype=rdflib.XSD.integer)),
+            (rdflib.URIRef(pre_file + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.File)),
+            (rdflib.URIRef(pre_file + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bse.author), rdflib.Literal('Me, myself, and I', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bse.filename), rdflib.Literal('testimage.jpg', datatype=rdflib.XSD.string)),
+            (rdflib.URIRef(pre_file + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('349264', datatype=rdflib.XSD.integer)),
+            # features
+            (rdflib.URIRef(pre_file + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef('http://bsfs.ai/schema/Entity/colors_spatial#0658f2234a054e1dd59a14462c89f7733e019160419c796356aa831498bd0a04'),
                 rdflib.Literal(
                     '(91, 127, 121, 94, 138, 167, 163, 134, 190, 138, 170, 156, 121, 142, 159)',
                     datatype=rdflib.URIRef('http://ie.bsfs.ai/schema/Feature/ColorsSpatial#0658f2234a054e1dd59a14462c89f7733e019160419c796356aa831498bd0a04'))),
+            (rdflib.URIRef(pre_file + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bse.filesize), rdflib.Literal('349264', datatype=rdflib.XSD.integer)),
+            # links to previews
+            (rdflib.URIRef(pre_file + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + '79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50')),
+            (rdflib.URIRef(pre_file + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + 'a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50')),
+            (rdflib.URIRef(pre_file + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + '968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50')),
+            (rdflib.URIRef(pre_file + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + 'dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50')),
+            (rdflib.URIRef(pre_file + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + '567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50')),
+            (rdflib.URIRef(pre_file + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + 'df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50')),
+            (rdflib.URIRef(pre_file + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + '9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50')),
+            (rdflib.URIRef(pre_file + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + '7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50')),
+            (rdflib.URIRef(pre_file + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + '2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50')),
+            (rdflib.URIRef(pre_file + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + 'a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50')),
+            (rdflib.URIRef(pre_file + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + '26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50')),
+            (rdflib.URIRef(pre_file + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.URIRef(ns.bse.preview), rdflib.URIRef(pre_preview + '5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50')),
+            # preview dimensions
+            (rdflib.URIRef(pre_preview + '2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('33', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + '26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + '567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + '5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + '79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + '7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + '968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + '9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + '9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + 'a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + 'a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + 'a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + 'a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + 'a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + 'a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + 'dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + 'dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + 'dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            (rdflib.URIRef(pre_preview + 'df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50'), rdflib.URIRef(ns.bsp.height), rdflib.Literal('50', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + 'df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50'), rdflib.URIRef(ns.bsp.width), rdflib.Literal('36', datatype=rdflib.URIRef('http://www.w3.org/2001/XMLSchema#integer'))),
+            (rdflib.URIRef(pre_preview + 'df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Preview)),
+            # assets
+            (rdflib.URIRef(pre_preview + '2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + '26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRofHh0aHBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/wAALCAAyACQBAREA/8QAHwAAAQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQRBRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RFRkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ipqrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/9oACAEBAAA/APdLq6eAgKoI25Oc+oHYe9Qfb5sr+6UZHUhuv5VYjnZyQSo9gpNTgP3YH6Lj+tPqCa2jmILrkgEVH/Z8HHy8DjGB/hUq26IMAkj0IH+FTUUUUUUUUUUUUUUUUUUUUUUUUUUV/9k=', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + '5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + '79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + '7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + '968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + '9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + '567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + 'df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + 'a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + 'a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
+            (rdflib.URIRef(pre_preview + 'dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50'), rdflib.URIRef(ns.bsp.asset), rdflib.Literal('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', datatype=rdflib.URIRef(ns.bsfs.BinaryBlob))),
             }))
 
         # NOTE: we don't check ns.bsm.t_created since it depends on the execution time. Triples would look like this:
-        #   (rdflib.URIRef(prefix + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
-        #   (rdflib.URIRef(prefix + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
+        #   (rdflib.URIRef(pre_file + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
+        #   (rdflib.URIRef(pre_file + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
+        #   (rdflib.URIRef(pre_file + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'), rdflib.URIRef(ns.bsm.t_created), rdflib.Literal('1670..........', datatype=rdflib.XSD.integer)),
+        #   ...
         # instead, we simply check if there's such a predicate for each file
         self.assertSetEqual({sub for sub, _ in bsfs._backend._graph.subject_objects(rdflib.URIRef(ns.bsm.t_created))}, {
-            rdflib.URIRef(prefix + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'),
-            rdflib.URIRef(prefix + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'),
-            rdflib.URIRef(prefix + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'),
-            rdflib.URIRef(prefix + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'),
-            rdflib.URIRef(prefix + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'),
-            rdflib.URIRef(prefix + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'),
-            rdflib.URIRef(prefix + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'),
-            rdflib.URIRef(prefix + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'),
-            rdflib.URIRef(prefix + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'),
-            rdflib.URIRef(prefix + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'),
-            rdflib.URIRef(prefix + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'),
-            rdflib.URIRef(prefix + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'),
+            rdflib.URIRef(pre_file + '2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647'),
+            rdflib.URIRef(pre_file + '441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece'),
+            rdflib.URIRef(pre_file + '69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871'),
+            rdflib.URIRef(pre_file + '78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926'),
+            rdflib.URIRef(pre_file + '80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3'),
+            rdflib.URIRef(pre_file + '976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795'),
+            rdflib.URIRef(pre_file + '997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3'),
+            rdflib.URIRef(pre_file + 'a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d'),
+            rdflib.URIRef(pre_file + 'b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70'),
+            rdflib.URIRef(pre_file + 'd43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d'),
+            rdflib.URIRef(pre_file + 'd803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1'),
+            rdflib.URIRef(pre_file + 'accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089'),
+            rdflib.URIRef(pre_preview + '26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50'),
+            rdflib.URIRef(pre_preview + 'a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50'),
+            rdflib.URIRef(pre_preview + '9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50'),
+            rdflib.URIRef(pre_preview + '2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50'),
+            rdflib.URIRef(pre_preview + '79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50'),
+            rdflib.URIRef(pre_preview + 'dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50'),
+            rdflib.URIRef(pre_preview + '5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50'),
+            rdflib.URIRef(pre_preview + '567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50'),
+            rdflib.URIRef(pre_preview + 'df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50'),
+            rdflib.URIRef(pre_preview + 'a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50'),
+            rdflib.URIRef(pre_preview + '7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50'),
+            rdflib.URIRef(pre_preview + '968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50'),
             })
 
     def test_print(self):
@@ -128,11 +203,12 @@ class TestIndex(unittest.TestCase):
             bsfs = main([
                 '--print',
                 '-r',
-                '--user', 'http://example.com/me',
+                '--host', 'http://example.com',
+                '--user', 'me',
                 os.path.join(os.path.dirname(__file__), 'testdir'),
                 os.path.join(os.path.dirname(__file__), 'testfile'),
                 ])
-        self.assertSetEqual(set(outbuf.getvalue().split('\n')) - {''}, {
+        self.assertTrue((set(outbuf.getvalue().split('\n')) - {''}).issuperset({
             f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647) Predicate({ns.bse.author}) Me, myself, and I',
             f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647) Predicate({ns.bse.filename}) alpha_second',
             f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647) Predicate({ns.bse.filesize}) 696',
@@ -169,8 +245,49 @@ class TestIndex(unittest.TestCase):
             f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089) Predicate({ns.bse.filesize}) 349264',
             f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089) Predicate({ns.bse.author}) Me, myself, and I',
             f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089) Predicate({ns.bse.filename}) testimage.jpg',
+            # features
             f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089) Predicate(http://bsfs.ai/schema/Entity/colors_spatial#0658f2234a054e1dd59a14462c89f7733e019160419c796356aa831498bd0a04) (91, 127, 121, 94, 138, 167, 163, 134, 190, 138, 170, 156, 121, 142, 159)',
-            })
+            # links to previews
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#2f4109b40107cc50e0884755a1a961ed126887e49b8dbaf0e146b2e226aa6647) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#441f3d10c8ff489fe8e33e639606512f6c463151cc429de7e554b9af670c2ece) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#69b98ecf7aff3e95b09688ba93331678eb8397817111f674c9558e6dd8f5e871) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#78f7eb7f0d8221cdb2cb26c978fa42a11f75eb87becc768f4474134cb1e06926) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#80818b8ec2ee1919116dba9c8a7e0a4608313cf3b463cd88e9ed77a700dd92d3) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#976d2ea0e58488678cc7e435fbfadabfb6eb6cf50ad51862f38f73729ed11795) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#997e2fbb7494a3818ec782d2bc87bf1cffafba6b9c0f658e4a6c18a723e944d3) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#a8af899ecdab60dfaea8ec7f934053624c80a1054539e163f2c7eaa986c2777d) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#accb115d266ad60c53cd01a7f7130f245886ce8eaf69bc85319febc11d9fe089) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#b8fd7fba818254166a6043195004138ebda6923e012442f819a2c49671136c70) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#d43758ace82154a1cc10ca0dfef63cb20dd831f9c87edd6dc06539eefe67371d) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50)',
+            f'Node(http://bsfs.ai/schema/File, http://example.com/me/file#d803187cbf3676ae9d38126270a6152c60431589aa3bb3824baf8954e9c097f1) Predicate({ns.bse.preview}) Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50)',
+            # preview dimensions
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50) Predicate({ns.bsp.height}) 33',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#2656e303d7218300326df73b64f312d8b37eb980358be27a38b5f63dae259be3_s50) Predicate({ns.bsp.width}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#26f16643b2570ac5b2d1f8c373d492cb724aae2dd8d71a0b63647838ed651254_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#567049149769e1d02e6af6cfee3991f7cf0cbc935cbf6a566047f40155fb13a8_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#5d1235838c3d501204bb09c2de563d7e4a7fd17b7ec4ff302221c0e88c4741aa_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#79cb8a7e6369361a4f4cb7ff729c1ed3fcf87204769623d6fbd6ebfae601e5c7_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#7a975385a110c21fcd12e238fab9501550fa02f6328749068a3bffd65e291027_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#968b9aa178585bc8d1fca0e4e32b8cf30b3941eff72f34e320584aaae8fd23ac_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#9827509a74a60dfceed11936f7f624e9c932f66c8c0d20d355d56f8c3c9b56b1_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#a63c84e647138a2b68113474212f6aee542b3707171ff178551db3c296e59817_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#a8b3245636074d5370283b690281abda8ffdff12ce8b1af77c8bc0a4c85be860_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#dbfd8ebc0557c4925e9ff8411629a74a15eca934a4c2a6bd3134dd81d2f95a36_s50) Predicate({ns.bsp.width}) 36',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50) Predicate({ns.bsp.height}) 50',
+            f'Node(http://bsfs.ai/schema/Preview, http://example.com/me/preview#df2185d8927ccef65c92fc90b94e800b02791354d8dede9dd9aa0e2c2cb1e91e_s50) Predicate({ns.bsp.width}) 36',
+            # assets
+            # ... (not checked)
+            }))
 
 
 ## main ##
diff --git a/test/apps/test_info.py b/test/apps/test_info.py
index 60e9ba1..725fb65 100644
--- a/test/apps/test_info.py
+++ b/test/apps/test_info.py
@@ -31,7 +31,11 @@ class TestIndex(unittest.TestCase):
             'http://bsfs.ai/schema/Predicate',
             'http://bsfs.ai/schema/Entity#filename',
             'http://bsfs.ai/schema/Entity#filesize',
-            'http://bsfs.ai/schema/Entity/colors_spatial#0658f2234a054e1dd59a14462c89f7733e019160419c796356aa831498bd0a04'
+            'http://bsfs.ai/schema/Entity/colors_spatial#0658f2234a054e1dd59a14462c89f7733e019160419c796356aa831498bd0a04',
+            'http://bsfs.ai/schema/Entity#preview',
+            'http://bsfs.ai/schema/Preview#width',
+            'http://bsfs.ai/schema/Preview#height',
+            'http://bsfs.ai/schema/Preview#asset',
             })
 
     def test_schema(self):
@@ -46,7 +50,11 @@ class TestIndex(unittest.TestCase):
             'http://bsfs.ai/schema/Predicate',
             'http://bsfs.ai/schema/Entity#filename',
             'http://bsfs.ai/schema/Entity#filesize',
-            'http://bsfs.ai/schema/Entity/colors_spatial#0658f2234a054e1dd59a14462c89f7733e019160419c796356aa831498bd0a04'
+            'http://bsfs.ai/schema/Entity/colors_spatial#0658f2234a054e1dd59a14462c89f7733e019160419c796356aa831498bd0a04',
+            'http://bsfs.ai/schema/Entity#preview',
+            'http://bsfs.ai/schema/Preview#width',
+            'http://bsfs.ai/schema/Preview#height',
+            'http://bsfs.ai/schema/Preview#asset',
             })
 
     def test_invalid(self):
diff --git a/test/extractor/test_preview.py b/test/extractor/test_preview.py
new file mode 100644
index 0000000..10d2a7f
--- /dev/null
+++ b/test/extractor/test_preview.py
@@ -0,0 +1,128 @@
+"""
+
+Part of the bsie test suite.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# standard imports
+import io
+import os
+import unittest
+
+# external imports
+import PIL.Image
+
+# bsie imports
+from bsie.extractor import base
+from bsie.utils import bsfs, node as _node, ns
+from bsie.reader.preview import Preview as Reader
+
+# objects to test
+from bsie.extractor.preview import Preview
+
+
+## code ##
+
+class TestPreview(unittest.TestCase):
+    def test_eq(self):
+        # identical instances are equal
+        self.assertEqual(Preview([1,2,3]), Preview([1,2,3]))
+        self.assertEqual(hash(Preview([1,2,3])), hash(Preview([1,2,3])))
+        # comparison respects max_sides
+        self.assertNotEqual(Preview([1,2,3]), Preview([1,2]))
+        self.assertNotEqual(hash(Preview([1,2,3])), hash(Preview([1,2])))
+        self.assertNotEqual(Preview([1,2]), Preview([1,2,3]))
+        self.assertNotEqual(hash(Preview([1,2])), hash(Preview([1,2,3])))
+        # comparison respects type
+        class Foo(): pass
+        self.assertNotEqual(Preview([1,2,3]), Foo())
+        self.assertNotEqual(hash(Preview([1,2,3])), hash(Foo()))
+        self.assertNotEqual(Preview([1,2,3]), 123)
+        self.assertNotEqual(hash(Preview([1,2,3])), hash(123))
+        self.assertNotEqual(Preview([1,2,3]), None)
+        self.assertNotEqual(hash(Preview([1,2,3])), hash(None))
+
+    def test_schema(self):
+        self.assertEqual(Preview([1,2,3]).schema,
+            bsfs.schema.from_string(base.SCHEMA_PREAMBLE + '''
+                bsfs:Preview rdfs:subClassOf bsfs:Node .
+                bsfs:BinaryBlob rdfs:subClassOf bsfs:Literal .
+                bsfs:JPEG rdfs:subClassOf bsfs:BinaryBlob .
+
+                bse:preview rdfs:subClassOf bsfs:Predicate ;
+                    rdfs:domain bsfs:File ;
+                    rdfs:range bsfs:Preview ;
+                    bsfs:unique "false"^^xsd:boolean .
+
+                bsp:width rdfs:subClassOf bsfs:Predicate ;
+                    rdfs:domain bsfs:Preview ;
+                    rdfs:range xsd:integer ;
+                    bsfs:unique "true"^^xsd:boolean .
+
+                bsp:height rdfs:subClassOf bsfs:Predicate ;
+                    rdfs:domain bsfs:Preview ;
+                    rdfs:range xsd:integer ;
+                    bsfs:unique "true"^^xsd:boolean .
+
+                bsp:asset rdfs:subClassOf bsfs:Predicate ;
+                    rdfs:domain bsfs:Preview ;
+                    rdfs:range bsfs:JPEG ;
+                    bsfs:unique "true"^^xsd:boolean .
+
+                '''))
+
+    def test_extract(self):
+        # setup dependents
+        rdr = Reader()
+        subject = _node.Node(ns.bsfs.File)
+        path = os.path.join(os.path.dirname(__file__), 'testimage.jpg')
+
+        # setup extractor
+        ext = Preview(max_sides=[10])
+        principals = set(ext.principals)
+        self.assertEqual(principals, {ext.schema.predicate(ns.bse.preview)})
+        # skip unknown predicates
+        gen = rdr(path)
+        self.assertSetEqual(set(), set(ext.extract(subject, gen,
+            {ext.schema.predicate(ns.bsfs.Predicate).child(ns.bse.unknown)})))
+        gen(10) # NOTE: consume some image to avoid resource error warning
+        # extract a preview
+        triples = set(ext.extract(subject, rdr(path), principals))
+        thumbs = {node for node, _, _ in triples if node.node_type == ns.bsfs.Preview}
+        self.assertEqual(len(thumbs), 1)
+        thumb = list(thumbs)[0]
+        # test properties
+        self.assertTrue(triples.issuperset({
+            (subject, ext.schema.predicate(ns.bse.preview), thumb),
+            (thumb, ext.schema.predicate(ns.bsp.width), 10),
+            (thumb, ext.schema.predicate(ns.bsp.height), 10),
+            }))
+        # test image data
+        rawdata = {val for _, pred, val in triples if pred == ext.schema.predicate(ns.bsp.asset)}
+        self.assertEqual(len(rawdata), 1)
+        data = io.BytesIO(list(rawdata)[0])
+        data.seek(0)
+        img = PIL.Image.open(data)
+        self.assertEqual(img.size, (10, 10))
+        self.assertEqual(sum(band for pix in img.getdata() for band in pix), 0)
+
+        # setup extractor
+        ext = Preview(max_sides=[10, 20])
+        principals = set(ext.principals)
+        self.assertEqual(principals, {ext.schema.predicate(ns.bse.preview)})
+        # extract a preview
+        triples = set(ext.extract(subject, rdr(path), principals))
+        thumbs = {node for node, _, _ in triples if node.node_type == ns.bsfs.Preview}
+        self.assertEqual(len(thumbs), 2)
+        self.assertSetEqual({10, 20}, {
+            value for _, pred, value in triples if pred == ext.schema.predicate(ns.bsp.width)})
+        self.assertSetEqual({10, 20}, {
+            value for _, pred, value in triples if pred == ext.schema.predicate(ns.bsp.height)})
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##
diff --git a/test/extractor/testimage.jpg b/test/extractor/testimage.jpg
new file mode 100644
index 0000000..4c2aca5
--- /dev/null
+++ b/test/extractor/testimage.jpg
diff --git a/test/lib/test_naming_policy.py b/test/lib/test_naming_policy.py
index 763537b..4861c84 100644
--- a/test/lib/test_naming_policy.py
+++ b/test/lib/test_naming_policy.py
@@ -32,6 +32,10 @@ class TestDefaultNamingPolicy(unittest.TestCase):
         self.assertEqual(policy.handle_node(
             Node(ns.bsfs.File, ucid='abc123cba')).uri,
             URI('http://example.com/me/file#abc123cba'))
+        # processes bsfs:Preview
+        self.assertEqual(policy.handle_node(
+            Node(ns.bsfs.Preview, ucid='abc123cba', size=123)).uri,
+            URI('http://example.com/me/preview#abc123cba_s123'))
         # raises an exception on unknown types
         self.assertRaises(errors.ProgrammingError, policy.handle_node,
             Node(ns.bsfs.Entity, ucid='abc123cba', size=123))
@@ -47,6 +51,31 @@ class TestDefaultNamingPolicy(unittest.TestCase):
         self.assertTrue(policy.name_file(
             Node(ns.bsfs.File)).uri.startswith('http://example.com/me/file#'))
 
+    def test_name_preview(self):
+        # setup
+        policy = DefaultNamingPolicy('http://example.com', 'me')
+        # name_preview uses ucid
+        self.assertEqual(policy.name_preview(
+            Node(ns.bsfs.Preview, ucid='123abc321')).uri,
+            URI('http://example.com/me/preview#123abc321'))
+        self.assertEqual(policy.name_preview(
+            Node(ns.bsfs.Preview, ucid='123abc321', size=400)).uri,
+            URI('http://example.com/me/preview#123abc321_s400'))
+        # name_preview uses source
+        self.assertEqual(policy.name_preview(
+            Node(ns.bsfs.Preview, source=Node(ns.bsfs.File, ucid='123file321'))).uri,
+            URI('http://example.com/me/preview#123file321'))
+        self.assertEqual(policy.name_preview(
+            Node(ns.bsfs.Preview, source=Node(ns.bsfs.File, ucid='123file321'), size=300)).uri,
+            URI('http://example.com/me/preview#123file321_s300'))
+        # name_preview falls back to a random guid
+        self.assertTrue(policy.name_preview(
+            Node(ns.bsfs.Preview)).uri.startswith('http://example.com/me/preview#'))
+        self.assertTrue(policy.name_preview(
+            Node(ns.bsfs.Preview, size=200)).uri.startswith('http://example.com/me/preview#'))
+        self.assertTrue(policy.name_preview(
+            Node(ns.bsfs.Preview, size=200)).uri.endswith('_s200'))
+
 
 class TestNamingPolicyIterator(unittest.TestCase):
 
@@ -71,10 +100,15 @@ class TestNamingPolicyIterator(unittest.TestCase):
         policy = DefaultNamingPolicy('http://example.com', 'me')
         triples = [
             (Node(ns.bsfs.File, ucid='foo'), 'predA', 'hello'),
+            (Node(ns.bsfs.Preview, ucid='bar'), 'predB', 1234),
+            (Node(ns.bsfs.Preview, ucid='hello'), 'predC', Node(ns.bsfs.File, ucid='world'))
             ]
         # handles nodes, handles values, ignores predicate
         self.assertListEqual(list(policy(triples)), [
             (Node(ns.bsfs.File, uri='http://example.com/me/file#foo'), 'predA', 'hello'),
+            (Node(ns.bsfs.Preview, uri='http://example.com/me/preview#bar'), 'predB', 1234),
+            (Node(ns.bsfs.Preview, uri='http://example.com/me/preview#hello'), 'predC',
+                Node(ns.bsfs.File, uri='http://example.com/me/file#world')),
             ])