[util] implement 'decrypt_xor()'

gallery_dl/extractor/bunkr.py

@@ -11,7 +11,6 @@
 from .common import Extractor
 from .lolisafe import LolisafeAlbumExtractor
 from .. import text, util, config, exception
-import binascii
 import random
 
 if config.get(("extractor", "bunkr"), "tlds"):
@@ -175,7 +174,8 @@ class BunkrAlbumExtractor(LolisafeAlbumExtractor):
             url, method="POST", headers=headers, json={"id": data_id}).json()
 
         if data.get("encrypted"):
-            file_url = self._decrypt_url(data["url"], data["timestamp"])
+            key = "SECRET_KEY_{}".format(data["timestamp"] // 3600)
+            file_url = util.decrypt_xor(data["url"], key.encode())
         else:
             file_url = data["url"]
 
@@ -192,16 +192,6 @@ class BunkrAlbumExtractor(LolisafeAlbumExtractor):
             "_http_validate": self._validate,
         }
 
-    def _decrypt_url(self, encrypted_b64, timestamp):
-        encrypted_bytes = binascii.a2b_base64(encrypted_b64)
-        key = "SECRET_KEY_{}".format(timestamp // 3600).encode()
-        div = len(key)
-
-        return bytes([
-            encrypted_bytes[i] ^ key[i % div]
-            for i in range(len(encrypted_bytes))
-        ]).decode()
-
     def _validate(self, response):
         if response.history and response.url.endswith("/maintenance-vid.mp4"):
             self.log.warning("File server in maintenance mode")

gallery_dl/extractor/chevereto.py

@@ -9,8 +9,7 @@
 """Extractors for Chevereto galleries"""
 
 from .common import BaseExtractor, Message
-from .. import text
-import binascii
+from .. import text, util
 
 
 class CheveretoExtractor(BaseExtractor):
@@ -33,18 +32,6 @@ class CheveretoExtractor(BaseExtractor):
 
             url = text.extr(page, '<a data-pagination="next" href="', '" ><')
 
-    def _decrypt_url(self, encrypted_b64):
-        encrypted_hex = binascii.a2b_base64(encrypted_b64)
-        encrypted_bytes = bytes.fromhex(encrypted_hex.decode())
-
-        key = b"seltilovessimpcity@simpcityhatesscrapers"
-        div = len(key)
-
-        return bytes([
-            encrypted_bytes[i] ^ key[i % div]
-            for i in range(len(encrypted_bytes))
-        ]).decode()
-
 
 BASE_PATTERN = CheveretoExtractor.update({
     "jpgfish": {
@@ -75,7 +62,9 @@ class CheveretoImageExtractor(CheveretoExtractor):
             pos = page.find(" download=")
             url = text.rextract(page, 'href="', '"', pos)[0]
             if not url.startswith("https://"):
-                url = self._decrypt_url(url)
+                url = util.decrypt_xor(
+                    url, b"seltilovessimpcity@simpcityhatesscrapers",
+                    fromhex=True)
 
         image = {
             "id"   : self.path.rpartition(".")[2],

gallery_dl/util.py

@@ -48,6 +48,19 @@ def bdecode(data, alphabet="0123456789"):
     return num
 
 
+def decrypt_xor(encrypted, key, base64=True, fromhex=False):
+    if base64:
+        encrypted = binascii.a2b_base64(encrypted)
+    if fromhex:
+        encrypted = bytes.fromhex(encrypted.decode())
+
+    div = len(key)
+    return bytes([
+        encrypted[i] ^ key[i % div]
+        for i in range(len(encrypted))
+    ]).decode()
+
+
 def advance(iterable, num):
     """"Advance 'iterable' by 'num' steps"""
     iterator = iter(iterable)