pyscript · madhur-tandon · May 2, 2023 · Apr 10, 2023 · Apr 10, 2023 · Apr 10, 2023
diff --git a/pyscriptjs/src/main.ts b/pyscriptjs/src/main.ts
@@ -160,6 +160,21 @@ export class PyScriptApp {
             );
         }
         this.config = loadConfigFromElement(el);
+        if (this.config.execution_thread === 'worker' && crossOriginIsolated === false) {
+            throw new UserError(
+                ErrorCode.BAD_CONFIG,
+                `When execution_thread is "worker", the site must be cross origin isolated, but crossOriginIsolated is false.
+                To be cross origin isolated, the server must use https and also serve with the following headers: ${JSON.stringify(
+                    {
+                        'Cross-Origin-Embedder-Policy': 'require-corp',
+                        'Cross-Origin-Opener-Policy': 'same-origin',
+                    },
+                )}.
+
+                The problem may be that one or both of these are missing.
+                `,
+            );
+        }
         logger.info('config loaded:\n' + JSON.stringify(this.config, null, 2));
     }
 

diff --git a/pyscriptjs/tests/integration/conftest.py b/pyscriptjs/tests/integration/conftest.py
@@ -123,13 +123,17 @@ def browser_type_launch_args(request):
     return launch_options
 
 
-class HTTPServer(SuperHTTPServer):
+class DevServer(SuperHTTPServer):
     """
     Class for wrapper to run SimpleHTTPServer on Thread.
     Ctrl +Only Thread remains dead when terminated with C.
     Keyboard Interrupt passes.
     """
 
+    def __init__(self, base_url, *args, **kwargs):
+        self.base_url = base_url
+        super().__init__(*args, **kwargs)
+
     def run(self):
         try:
             self.serve_forever()
@@ -140,15 +144,26 @@ def run(self):
 
 
 @pytest.fixture(scope="session")
-def http_server(logger):
+def dev_server(logger):
     class MyHTTPRequestHandler(SimpleHTTPRequestHandler):
+        enable_cors_headers = True
+
+        @classmethod
+        def my_headers(cls):
+            if cls.enable_cors_headers:
+                return {
+                    "Cross-Origin-Embedder-Policy": "require-corp",
+                    "Cross-Origin-Opener-Policy": "same-origin",
+                }
+            return {}
+
         def end_headers(self):
             self.send_my_headers()
             SimpleHTTPRequestHandler.end_headers(self)
 
         def send_my_headers(self):
-            self.send_header("Cross-Origin-Embedder-Policy", "require-corp")
-            self.send_header("Cross-Origin-Opener-Policy", "same-origin")
+            for k, v in self.my_headers().items():
+                self.send_header(k, v)
 
         def log_message(self, fmt, *args):
             logger.log("http_server", fmt % args, color="blue")
@@ -157,12 +172,12 @@ def log_message(self, fmt, *args):
     base_url = f"http://{host}:{port}"
 
     # serve_Run forever under thread
-    server = HTTPServer((host, port), MyHTTPRequestHandler)
+    server = DevServer(base_url, (host, port), MyHTTPRequestHandler)
 
     thread = threading.Thread(None, server.run)
     thread.start()
 
-    yield base_url  # Transition to test here
+    yield server  # Transition to test here
 
     # End thread
     server.shutdown()

diff --git a/pyscriptjs/tests/integration/support.py b/pyscriptjs/tests/integration/support.py
@@ -158,24 +158,24 @@ def init(self, request, tmpdir, logger, page, execution_thread):
         self.tmpdir.chdir()
         self.logger = logger
         self.execution_thread = execution_thread
+        self.dev_server = None
 
         if request.config.option.no_fake_server:
             # use a real HTTP server. Note that as soon as we request the
             # fixture, the server automatically starts in its own thread.
-            self.http_server = request.getfixturevalue("http_server")
+            self.dev_server = request.getfixturevalue("dev_server")
+            self.http_server_addr = self.dev_server.base_url
             self.router = None
-            self.is_fake_server = False
         else:
             # use the internal playwright routing
-            self.http_server = "https://fake_server"
+            self.http_server_addr = "https://fake_server"
             self.router = SmartRouter(
                 "fake_server",
                 cache=request.config.cache,
                 logger=logger,
                 usepdb=request.config.option.usepdb,
             )
             self.router.install(page)
-            self.is_fake_server = True
         #
         self.init_page(page)
         #
@@ -211,6 +211,18 @@ def init_page(self, page):
         page.on("console", self._on_console)
         page.on("pageerror", self._on_pageerror)
 
+    @property
+    def headers(self):
+        if self.dev_server is None:
+            return self.router.headers
+        return self.dev_server.RequestHandlerClass.my_headers()
+
+    def disable_cors_headers(self):
+        if self.dev_server is None:
+            self.router.enable_cors_headers = False
+        else:
+            self.dev_server.RequestHandlerClass.enable_cors_headers = False
+
     def run_js(self, code):
         """
         allows top level await to be present in the `code` parameter
@@ -301,7 +313,7 @@ def writefile(self, filename, content):
     def goto(self, path):
         self.logger.reset()
         self.logger.log("page.goto", path, color="yellow")
-        url = f"{self.http_server}/{path}"
+        url = f"{self.http_server_addr}/{path}"
         self.page.goto(url, timeout=0)
 
     def wait_for_console(
@@ -433,8 +445,8 @@ def _pyscript_format(self, snippet, *, execution_thread, extra_head=""):
         doc = f"""
         <html>
           <head>
-              <link rel="stylesheet" href="{self.http_server}/build/pyscript.css" />
-              <script defer src="{self.http_server}/build/pyscript.js"></script>
+              <link rel="stylesheet" href="{self.http_server_addr}/build/pyscript.css" />
+              <script defer src="{self.http_server_addr}/build/pyscript.js"></script>
               {extra_head}
           </head>
           <body>
@@ -851,6 +863,16 @@ def __init__(self, fake_server, *, cache, logger, usepdb=False):
         self.usepdb = usepdb
         self.page = None
         self.requests = []  # (status, kind, url)
+        self.enable_cors_headers = True
+
+    @property
+    def headers(self):
+        if self.enable_cors_headers:
+            return {
+                "Cross-Origin-Embedder-Policy": "require-corp",
+                "Cross-Origin-Opener-Policy": "same-origin",
+            }
+        return {}
 
     def install(self, page):
         """
@@ -903,13 +925,9 @@ def _router(self, route):
             assert url.path[0] == "/"
             relative_path = url.path[1:]
             if os.path.exists(relative_path):
-                headers = {
-                    "Cross-Origin-Embedder-Policy": "require-corp",
-                    "Cross-Origin-Opener-Policy": "same-origin",
-                }
-                route.fulfill(status=200, headers=headers, path=relative_path)
+                route.fulfill(status=200, headers=self.headers, path=relative_path)
             else:
-                route.fulfill(status=404)
+                route.fulfill(status=404, headers=self.headers)
             return
 
         # network requests might be cached

diff --git a/pyscriptjs/tests/integration/test_00_support.py b/pyscriptjs/tests/integration/test_00_support.py
@@ -113,7 +113,7 @@ def test_check_js_errors_simple(self):
             f"""
             JS errors found: 1
             Error: this is an error
-                at {self.http_server}/mytest.html:.*
+                at {self.http_server_addr}/mytest.html:.*
             """
         ).strip()
         assert re.search(expected, msg)

diff --git a/pyscriptjs/tests/integration/test_01_basic.py b/pyscriptjs/tests/integration/test_01_basic.py
@@ -32,6 +32,30 @@ def test_execution_thread(self):
         expected = f"[pyscript/main] Starting the interpreter in {where}"
         assert expected in self.console.info.lines
 
+    def test_no_cors_headers(self):
+        self.disable_cors_headers()
+        self.pyscript_run(
+            """
+            <!-- we don't really need anything here, we just want to check that
+                 pyscript starts -->
+            """,
+            wait_for_pyscript=False,
+        )
+        assert self.headers == {}
+        if self.execution_thread == "worker":
+            expected_alert_banner_msg = (
+                '(PY1000): When execution_thread is "worker", the site must be cross origin '
+                "isolated, but crossOriginIsolated is false. To be cross origin isolated, "
+                "the server must use https and also serve with the following headers: "
+                '{"Cross-Origin-Embedder-Policy":"require-corp",'
+                '"Cross-Origin-Opener-Policy":"same-origin"}. '
+                "The problem may be that one or both of these are missing."
+            )
+            alert_banner = self.page.wait_for_selector(".alert-banner")
+            assert expected_alert_banner_msg in alert_banner.inner_text()
+        else:
+            self.assert_no_banners()
+
     def test_print(self):
         self.pyscript_run(
             """