Try to optimize xmlrpc further (#17714)

* move from json to orjson for xmlrpc caching

* refactor dict_comprehension to a dict( call

Author: ewdurbin

warehouse/legacy/api/xmlrpc/cache/derivers.py

@@ -10,7 +10,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import json
+import orjson
 
 from warehouse.legacy.api.xmlrpc.cache import interfaces
 
@@ -31,7 +31,7 @@ def wrapper_view(context, request):
             except LookupError:
                 return view(context, request)
             try:
-                key = json.dumps(request.rpc_args[slice_obj])
+                key = orjson.dumps(request.rpc_args[slice_obj])
                 _tag = tag
                 if arg_index is not None:
                     _tag = tag % (tag_processor(str(request.rpc_args[arg_index])))

warehouse/legacy/api/xmlrpc/cache/fncache.py

@@ -10,8 +10,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import json
-
+import orjson
 import redis
 
 from warehouse.legacy.api.xmlrpc.cache.interfaces import CacheError
@@ -27,7 +26,7 @@ def increment(self, metric_name):
 class RedisLru:
     """
     Redis backed LRU cache for functions which return an object which
-    can survive json.dumps() and json.loads() intact
+    can survive orjson.dumps() and orjson.loads() intact
     """
 
     def __init__(self, conn, name="lru", expires=None, metric_reporter=None):
@@ -58,14 +57,16 @@ def get(self, func_name, key, tag):
             return None
         if value:
             self.metric_reporter.increment(f"{self.name}.cache.hit")
-            value = json.loads(value)
+            value = orjson.loads(value)
         return value
 
     def add(self, func_name, key, value, tag, expires):
         try:
             self.metric_reporter.increment(f"{self.name}.cache.miss")
             pipeline = self.conn.pipeline()
-            pipeline.hset(self.format_key(func_name, tag), str(key), json.dumps(value))
+            pipeline.hset(
+                self.format_key(func_name, tag), str(key), orjson.dumps(value)
+            )
             ttl = expires if expires else self.expires
             pipeline.expire(self.format_key(func_name, tag), ttl)
             pipeline.execute()

warehouse/legacy/api/xmlrpc/views.py

@@ -269,8 +269,8 @@ def changelog_since_serial(request, serial: StrictInt):
 
 @xmlrpc_cache_all_projects(method="list_packages_with_serial")
 def list_packages_with_serial(request):
-    serials = request.db.query(Project.name, Project.last_serial).all()
-    return {serial[0]: serial[1] for serial in serials}
+    package_serial_tuples = request.db.query(Project.name, Project.last_serial).all()
+    return dict(package_serial_tuples)
 
 
 # Package querying methods