update default SSL cipher list in urllib3 < 1.25

Cloudflare now also checks the client's SSL/TLS cipher capabilities and
produces a 403: Forbidden response with CAPTCHA if they are insufficient.

This commit replaces the default cipher list in urllib3 < 1.25 with the
one from 1.25 (1), which doesn't cause problems as long as the client
platform actually supports these ciphers. On some platforms (tested with
Python 3.4 on Linux and Python 3.7 on an outdated Windows 7 VM) it is
necessary to install pyOpenSSL to get everything to work.

Explicitly setting a minimum/maximum version for urllib3 is also no
longer necessary and installing gallery-dl will therefore not pull a
incompatible urllib3 version (mikf#229)

Fixes the "403: Forbidden" error on Artstation (mikf#227)

(1) urllib3/urllib3@0cedb3b

gallery_dl/extractor/common.py

@@ -402,3 +402,33 @@ class Extr(cls):
 # (This allows the use of Wget-generated cookiejars without modification)
 http.cookiejar.MozillaCookieJar.magic_re = re.compile(
     "#( Netscape)? HTTP Cookie File", re.IGNORECASE)
+
+# Update default cipher list of urllib3 < 1.25
+# to fix issues with Cloudflare and, by extension, Artstation (#227)
+try:
+    import urllib3
+except ImportError:
+    pass
+else:
+    if urllib3.__version__ < "1.25":
+        from urllib3.util import ssl_
+        logging.getLogger("gallery-dl").debug(
+            "updating default urllib3 ciphers")
+        # cipher list taken from urllib3 1.25
+        # https://github.com/urllib3/urllib3/blob/1.25/src/urllib3/util/ssl_.py
+        ssl_.DEFAULT_CIPHERS = (
+            "ECDHE+AESGCM:"
+            "ECDHE+CHACHA20:"
+            "DHE+AESGCM:"
+            "DHE+CHACHA20:"
+            "ECDH+AESGCM:"
+            "DH+AESGCM:"
+            "ECDH+AES:"
+            "DH+AES:"
+            "RSA+AESGCM:"
+            "RSA+AES:"
+            "!aNULL:"
+            "!eNULL:"
+            "!MD5:"
+            "!DSS"
+        )

requirements.txt

@@ -1,2 +1 @@
-requests>=2.11.0, <2.22.0
-urllib3>=1.16, <1.25, !=1.24.1, !=1.24.2
+requests>=2.11.0

setup.py

@@ -102,8 +102,7 @@ def check_file(fname):
     license="GPLv2",
     python_requires=">=3.4",
     install_requires=[
-        "requests>=2.11.0, <2.22.0",
-        "urllib3>=1.16, <1.25, !=1.24.1, !=1.24.2",
+        "requests>=2.11.0",
     ],
     packages=[
         "gallery_dl",