python: Replace binascii with bytes.hex to skip some decode operations.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/lib/camo.py

@@ -1,4 +1,3 @@
-import binascii
 import hashlib
 import hmac
 
@@ -9,8 +8,7 @@ def generate_camo_url(url: str) -> str:
     encoded_url = url.encode("utf-8")
     encoded_camo_key = settings.CAMO_KEY.encode("utf-8")
     digest = hmac.new(encoded_camo_key, encoded_url, hashlib.sha1).hexdigest()
-    hex_encoded_url = binascii.b2a_hex(encoded_url)
-    return "{}/{}".format(digest, hex_encoded_url.decode("utf-8"))
+    return "{}/{}".format(digest, encoded_url.hex())
 
 # Encodes the provided URL using the same algorithm used by the camo
 # caching https image proxy

zerver/lib/mobile_auth_otp.py

@@ -7,7 +7,6 @@
 #
 # The decryption logic here isn't actually used by the flow; we just
 # have it here as part of testing the overall library.
-import binascii
 
 from zerver.models import UserProfile
 
@@ -21,11 +20,11 @@ def xor_hex_strings(bytes_a: str, bytes_b: str) -> str:
 
 def ascii_to_hex(input_string: str) -> str:
     """Given an ascii string, encode it as a hex string"""
-    return "".join(hex(ord(c))[2:].zfill(2) for c in input_string)
+    return input_string.encode().hex()
 
 def hex_to_ascii(input_string: str) -> str:
     """Given a hex array, decode it back to a string"""
-    return binascii.unhexlify(input_string).decode('utf8')
+    return bytes.fromhex(input_string).decode()
 
 def otp_encrypt_api_key(api_key: str, otp: str) -> str:
     assert len(otp) == UserProfile.API_KEY_LENGTH * 2

zerver/lib/push_notifications.py

@@ -1,5 +1,4 @@
 import base64
-import binascii
 import logging
 import re
 import time
@@ -45,10 +44,10 @@ DeviceToken = Union[PushDeviceToken, "RemotePushDeviceToken"]
 
 # We store the token as b64, but apns-client wants hex strings
 def b64_to_hex(data: str) -> str:
-    return binascii.hexlify(base64.b64decode(data)).decode('utf-8')
+    return base64.b64decode(data).hex()
 
 def hex_to_b64(data: str) -> str:
-    return base64.b64encode(binascii.unhexlify(data)).decode()
+    return base64.b64encode(bytes.fromhex(data)).decode()
 
 #
 # Sending to APNs, for iOS

zerver/views/camo.py

@@ -1,5 +1,3 @@
-import binascii
-
 from django.conf import settings
 from django.http import HttpRequest, HttpResponse, HttpResponseForbidden, HttpResponseNotFound
 from django.shortcuts import redirect
@@ -14,9 +12,7 @@ def handle_camo_url(request: HttpRequest, digest: str,
     if not settings.THUMBOR_SERVES_CAMO:
         return HttpResponseNotFound()
 
-    hex_encoded_url = received_url.encode('utf-8')
-    hex_decoded_url = binascii.a2b_hex(hex_encoded_url)
-    original_url = hex_decoded_url.decode('utf-8')
+    original_url = bytes.fromhex(received_url).decode()
     if is_camo_url_valid(digest, original_url):
         return redirect(generate_thumbnail_url(original_url, is_camo_url=True))
     else: