diff --git a/server/src/main/resources/shell_wrapper.py b/server/src/main/resources/shell_wrapper.py
index 88e3e312..ba8e9400 100644
--- a/server/src/main/resources/shell_wrapper.py
+++ b/server/src/main/resources/shell_wrapper.py
@@ -5,6 +5,14 @@
 import traceback
 import os
 import logging
+import re
+import tempfile
+import zipfile
+import requests
+from typing import Callable, Any, List, Dict
+from pathlib import Path
+
+
 sys_stdin = sys.stdin
 sys_stdout = sys.stdout
 
@@ -13,133 +21,196 @@
 logging.basicConfig(stream=sys.stdout, level=log_level)
 log = logging.getLogger("session")
 
+
 def setup_output():
     sys.stdout.flush()
     sys.stderr.flush()
     sys.stdout = io.StringIO()
     sys.stderr = io.StringIO()
 
-def _do_with_retry(attempts, action):
-    attempts_left = attempts
-    last_exception = None
-    while attempts_left:
+
+def retry(attempts: int, action: Callable[[], Any]) -> Any:
+    for _ in range(attempts):
         try:
             return action()
         except Exception as e:
             last_exception = e
-            attempts_left -= 1
     raise last_exception
 
 
 class Controller:
-    def __init__(self, session_id):
+    def __init__(self, session_id: str):
         self.session_id = session_id
 
-    def read(self):
+    def read(self) -> List[Dict[str, Any]]:
         return []
 
-    def write(self, _id, _result):
+    def write(self, _id: str, _result: Dict[str, Any]) -> None:
         pass
 
 
 class TestController(Controller):
-    def read(self):
-        def do_read():
-            str_line = sys_stdin.readline()
-            line = json.loads(str_line)
-            return [line]
-        return _do_with_retry(2, do_read)
-
+    def read(self) -> List[Dict[str, Any]]:
+        return retry(2, lambda: [json.loads(sys_stdin.readline())])
 
-    def write(self, id, result):
-        def do_write():
-            print(json.dumps(result), file=sys_stdout)
-            sys_stdout.flush()
-        _do_with_retry(2, do_write)
+    def write(self, id: str, result: Dict[str, Any]) -> None:
+        retry(2, lambda: print(json.dumps(result), file=sys_stdout, flush=True))
 
 
 class GatewayController(Controller):
-    def __init__(self, session_id):
+    def __init__(self, session_id: str):
         super().__init__(session_id)
         from py4j.java_gateway import JavaGateway, GatewayParameters
-        port = int(os.environ.get("PY_GATEWAY_PORT"))
-        host = os.environ.get("PY_GATEWAY_HOST")
-        self.gateway = JavaGateway(gateway_parameters=GatewayParameters(
-            address=host, port=port, auto_convert=True))
+
+        port = int(os.environ.get("PY_GATEWAY_PORT", "0"))
+        host = os.environ.get("PY_GATEWAY_HOST", "")
+        self.gateway = JavaGateway(
+            gateway_parameters=GatewayParameters(
+                address=host, port=port, auto_convert=True
+            )
+        )
         self.endpoint = self.gateway.entry_point
 
-    def read(self):
-        return _do_with_retry(
+    def read(self) -> List[Dict[str, Any]]:
+        return retry(
             3,
             lambda: [
-              {"id": stmt.getId(), "code": stmt.getCode()} for stmt in self.endpoint.statementsToProcess(self.session_id)
-            ]
+                {"id": stmt.getId(), "code": stmt.getCode()}
+                for stmt in self.endpoint.statementsToProcess(self.session_id)
+            ],
         )
 
-    def write(self, id, result):
-        _do_with_retry(
-            3,
-            lambda: self.endpoint.handleResponse(self.session_id, id, result)
-        )
+    def write(self, id: str, result: Dict[str, Any]) -> None:
+        retry(3, lambda: self.endpoint.handleResponse(self.session_id, id, result))
 
 
-class CommandHandler:
+def is_url(words: str) -> bool:
+    log.debug(f"Checking if {words} is a URL")
+    if len(words.split()) != 1:
+        log.debug(f"Not a single word: {words}")
+        return False
+
+    match = re.match(r"^https?://\S+$", words)
+    if match:
+        log.debug(f"Matched: {match.group()}")
+        log.info(f"URL matched: {words}")
+        return True
+    log.debug(f"Not matched: {words}")
+    log.info("URL not matched")
+    return False
+
 
-    def __init__(self, globals) -> None:
+class CommandHandler:
+    def __init__(self, globals: Dict[str, Any]):
         self.globals = globals
+        self.code_file = "download"
 
-    def _error_response(self, error):
+    def _error_response(self, error: Exception) -> Dict[str, Any]:
         exc_type, exc_value, exc_tb = sys.exc_info()
         return {
-            "content": {"text/plain": str(sys.stdout.getvalue()).rstrip()},
+            "content": {"text/plain": sys.stdout.getvalue().rstrip()},
             "error": type(error).__name__,
             "message": str(error),
             "traceback": traceback.format_exception(exc_type, exc_value, exc_tb),
         }
 
-    def _exec_then_eval(self, code):
-        block = ast.parse(code, mode='exec')
-
-        # assumes last node is an expression
+    def _exec_then_eval(self, code: str) -> None:
+        block = ast.parse(code, mode="exec")
         last = ast.Interactive([block.body.pop()])
-
-        exec(compile(block, '<string>', 'exec'), self.globals)
-        exec(compile(last, '<string>', 'single'), self.globals)
-
-
-    def exec(self, request):
+        exec(compile(block, "<string>", "exec"), self.globals)
+        exec(compile(last, "<string>", "single"), self.globals)
+
+    def _download_then_exec(self, url: str) -> None:
+        with tempfile.TemporaryDirectory() as temp_dir:
+            self._download_and_extract(url, temp_dir)
+            main_file = Path(temp_dir) / "main.py"
+            if main_file.exists():
+                self._execute_main_file(temp_dir)
+            else:
+                code_file = Path(temp_dir) / self.code_file
+                with code_file.open("r") as f:
+                    self._exec_then_eval(f.read())
+
+    def _download_and_extract(self, url: str, temp_dir: str) -> None:
+        temp_file_path = Path(temp_dir) / self.code_file
+        self._download(url, temp_file_path)
+        if self._is_zip(temp_file_path):
+            self._extract(temp_file_path)
+
+    def _download(self, url: str, temp_file_path: Path) -> None:
+        response = requests.get(url)
+        response.raise_for_status()  # Raise an exception for bad status codes
+        temp_file_path.write_bytes(response.content)
+
+    @staticmethod
+    def _is_zip(file_path: Path) -> bool:
+        return zipfile.is_zipfile(file_path)
+
+    @staticmethod
+    def _extract(file_path: Path) -> None:
+        with zipfile.ZipFile(file_path, "r") as zip_ref:
+            zip_ref.extractall(path=file_path.parent)
+
+    def _execute_main_file(self, temp_dir: str) -> None:
+        sys.path.insert(0, temp_dir)
+        try:
+            main_file_path = Path(temp_dir) / "main.py"
+            with main_file_path.open("r") as f:
+                log.info(f"Executing {main_file_path}")
+                self._exec_then_eval(f.read())
+        finally:
+            sys.path.remove(temp_dir)
+            self._remove_modules(temp_dir)
+
+    @staticmethod
+    def _remove_modules(temp_dir: str) -> None:
+        modules_to_remove = [
+            name
+            for name, mod in sys.modules.items()
+            if hasattr(mod, "__spec__")
+            and mod.__spec__
+            and mod.__spec__.origin
+            and temp_dir in mod.__spec__.origin
+        ]
+        for name in modules_to_remove:
+            log.info(f"Unloading {name}")
+            del sys.modules[name]
+
+    def _exec_code(self, code: str) -> None:
+        if is_url(code):
+            self._download_then_exec(code)
+        else:
+            self._exec_then_eval(code)
+
+    def exec(self, request: Dict[str, str]) -> Dict[str, Any]:
         try:
             code = request["code"].rstrip()
             if code:
-                self._exec_then_eval(code)
-                return {"content": {"text/plain": str(sys.stdout.getvalue()).rstrip()}}
-
+                self._exec_code(code)
+                return {"content": {"text/plain": sys.stdout.getvalue().rstrip()}}
             return {"content": {"text/plain": ""}}
         except Exception as e:
             log.exception(e)
             return self._error_response(e)
 
 
-def init_globals(name):
+def init_globals(name: str) -> Dict[str, Any]:
     if is_test:
         return {}
 
     from pyspark.sql import SparkSession
 
-    spark = SparkSession \
-        .builder \
-        .appName(name) \
-        .getOrCreate()
-
+    spark = SparkSession.builder.appName(name).getOrCreate()
     return {"spark": spark}
 
 
-def main():
+def main() -> int:
     setup_output()
-    session_id = os.environ.get("LIGHTER_SESSION_ID")
+    session_id = os.environ.get("LIGHTER_SESSION_ID", "")
     log.info(f"Initiating session {session_id}")
-    controller = TestController(
-        session_id) if is_test else GatewayController(session_id)
+    controller = (
+        TestController(session_id) if is_test else GatewayController(session_id)
+    )
     handler = CommandHandler(init_globals(session_id))
 
     log.info("Starting session loop")
@@ -151,13 +222,13 @@ def main():
                 result = handler.exec(command)
                 controller.write(command["id"], result)
                 log.debug("Response sent")
-    except:
-        exc_type, exc_value, exc_tb = sys.exc_info()
-        log.error(
-            f"Error: {traceback.format_exception(exc_type, exc_value, exc_tb)}")
-        log.info("Exiting")
+    except Exception:
+        log.exception("Error in main loop")
         return 1
+    finally:
+        log.info("Exiting")
+    return 0
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     sys.exit(main())