add simple error page generator

cloudflare_error_page/__init__.py

@@ -0,0 +1,33 @@
+import os
+import secrets
+from datetime import datetime, timezone
+
+from jinja2 import Environment, PackageLoader, select_autoescape
+
+env = Environment(
+    loader=PackageLoader("cloudflare_error_page"),
+    autoescape=select_autoescape()
+)
+
+
+def get_resources_folder() -> str:
+    """
+    Get resources folder that contains stylesheet and icons for the error page.
+    If you pass resources_use_cdn=True to render(), local resources are not used.
+    """
+    return os.path.join(os.path.dirname(os.path.abspath(__file__)), 'resources')
+
+
+def render(params: dict, use_cdn: bool=True) -> str:
+    """
+    Render a customized Cloudflare error page.
+    """
+    params = {**params}
+    if not params.get('time'):
+        utc_now = datetime.now(timezone.utc)
+        params['time'] = utc_now.strftime("%Y-%m-%d %H:%M:%S UTC")
+    if not params.get('ray_id'):
+        params['ray_id'] = secrets.token_hex(8)
+
+    template = env.get_template("error.html")
+    return template.render(params=params, resources_use_cdn=use_cdn)