okay fine

.venv/lib/python3.12/site-packages/daphne/utils.py

@@ -0,0 +1,89 @@
+import importlib
+import re
+
+from twisted.web.http_headers import Headers
+
+# Header name regex as per h11.
+# https://github.com/python-[AWS-SECRET-REMOVED]9d98002e4a4ed27/h11/_abnf.py#L10-L21
+HEADER_NAME_RE = re.compile(rb"[-!#$%&'*+.^_`|~0-9a-zA-Z]+")
+
+
+def import_by_path(path):
+    """
+    Given a dotted/colon path, like project.module:ClassName.callable,
+    returns the object at the end of the path.
+    """
+    module_path, object_path = path.split(":", 1)
+    target = importlib.import_module(module_path)
+    for bit in object_path.split("."):
+        target = getattr(target, bit)
+    return target
+
+
+def header_value(headers, header_name):
+    value = headers[header_name]
+    if isinstance(value, list):
+        value = value[0]
+    return value.decode("utf-8")
+
+
+def parse_x_forwarded_for(
+    headers,
+    address_header_name="X-Forwarded-For",
+    port_header_name="X-Forwarded-Port",
+    proto_header_name="X-Forwarded-Proto",
+    original_addr=None,
+    original_scheme=None,
+):
+    """
+    Parses an X-Forwarded-For header and returns a host/port pair as a list.
+
+    @param headers: The twisted-style object containing a request's headers
+    @param address_header_name: The name of the expected host header
+    @param port_header_name: The name of the expected port header
+    @param proto_header_name: The name of the expected proto header
+    @param original_addr: A host/port pair that should be returned if the headers are not in the request
+    @param original_scheme: A scheme that should be returned if the headers are not in the request
+    @return: A list containing a host (string) as the first entry and a port (int) as the second.
+    """
+    if not address_header_name:
+        return original_addr, original_scheme
+
+    # Convert twisted-style headers into dicts
+    if isinstance(headers, Headers):
+        headers = dict(headers.getAllRawHeaders())
+
+    # Lowercase all header names in the dict
+    headers = {name.lower(): values for name, values in headers.items()}
+
+    # Make sure header names are bytes (values are checked in header_value)
+    assert all(isinstance(name, bytes) for name in headers.keys())
+
+    address_header_name = address_header_name.lower().encode("utf-8")
+    result_addr = original_addr
+    result_scheme = original_scheme
+    if address_header_name in headers:
+        address_value = header_value(headers, address_header_name)
+
+        if "," in address_value:
+            address_value = address_value.split(",")[0].strip()
+
+        result_addr = [address_value, 0]
+
+        if port_header_name:
+            # We only want to parse the X-Forwarded-Port header if we also parsed the X-Forwarded-For
+            # header to avoid inconsistent results.
+            port_header_name = port_header_name.lower().encode("utf-8")
+            if port_header_name in headers:
+                port_value = header_value(headers, port_header_name)
+                try:
+                    result_addr[1] = int(port_value)
+                except ValueError:
+                    pass
+
+        if proto_header_name:
+            proto_header_name = proto_header_name.lower().encode("utf-8")
+            if proto_header_name in headers:
+                result_scheme = header_value(headers, proto_header_name)
+
+    return result_addr, result_scheme