def generate_post_signature(post: model.Post, content: bytes) -> None:
try:
unpacked_signature = image_hash.generate_signature(content)
packed_signature = image_hash.pack_signature(unpacked_signature)
words = image_hash.generate_words(unpacked_signature)
db.session.add(model.PostSignature(
post=post, signature=packed_signature, words=words))
except errors.ProcessingError:
if not config.config['allow_broken_uploads']:
raise InvalidPostContentError(
'Unable to generate image hash data.')
def test_signature_functions(read_asset, config_injector):
sig1 = image_hash.generate_signature(read_asset('jpeg.jpg'))
sig2 = image_hash.generate_signature(read_asset('jpeg-similar.jpg'))
sig1_repacked = image_hash.unpack_signature(
image_hash.pack_signature(sig1))
sig2_repacked = image_hash.unpack_signature(
image_hash.pack_signature(sig2))
assert array_equal(sig1, sig1_repacked)
assert array_equal(sig2, sig2_repacked)
dist1 = image_hash.normalized_distance([sig1], sig2)
assert abs(dist1[0] - 0.20599895341812172) < 1e-8
dist2 = image_hash.normalized_distance([sig2], sig2)
assert abs(dist2[0]) < 1e-8
words1 = image_hash.generate_words(sig1)
words2 = image_hash.generate_words(sig2)
words_match = sum(word1 == word2 for word1, word2 in zip(words1, words2))
assert words_match == 17
def test_signature_avif(read_asset, config_injector):
sig1 = image_hash.generate_signature(read_asset("avif.avif"))
sig2 = image_hash.generate_signature(read_asset("avif-similar.avif"))
sig1_repacked = image_hash.unpack_signature(
image_hash.pack_signature(sig1))
sig2_repacked = image_hash.unpack_signature(
image_hash.pack_signature(sig2))
assert array_equal(sig1, sig1_repacked)
assert array_equal(sig2, sig2_repacked)
dist1 = image_hash.normalized_distance([sig1], sig2)
assert abs(dist1[0] - 0.22628712858355998) < 1e-8
dist2 = image_hash.normalized_distance([sig2], sig2)
assert abs(dist2[0]) < 1e-8
words1 = image_hash.generate_words(sig1)
words2 = image_hash.generate_words(sig2)
words_match = sum(word1 == word2 for word1, word2 in zip(words1, words2))
assert words_match == 12