build test

venv/lib/python3.7/site-packages/werkzeug/middleware/proxy_fix.py

@@ -0,0 +1,169 @@
+"""
+X-Forwarded-For Proxy Fix
+=========================
+
+This module provides a middleware that adjusts the WSGI environ based on
+``X-Forwarded-`` headers that proxies in front of an application may
+set.
+
+When an application is running behind a proxy server, WSGI may see the
+request as coming from that server rather than the real client. Proxies
+set various headers to track where the request actually came from.
+
+This middleware should only be applied if the application is actually
+behind such a proxy, and should be configured with the number of proxies
+that are chained in front of it. Not all proxies set all the headers.
+Since incoming headers can be faked, you must set how many proxies are
+setting each header so the middleware knows what to trust.
+
+.. autoclass:: ProxyFix
+
+:copyright: 2007 Pallets
+:license: BSD-3-Clause
+"""
+from werkzeug.http import parse_list_header
+
+
+class ProxyFix(object):
+    """Adjust the WSGI environ based on ``X-Forwarded-`` that proxies in
+    front of the application may set.
+
+    -   ``X-Forwarded-For`` sets ``REMOTE_ADDR``.
+    -   ``X-Forwarded-Proto`` sets ``wsgi.url_scheme``.
+    -   ``X-Forwarded-Host`` sets ``HTTP_HOST``, ``SERVER_NAME``, and
+        ``SERVER_PORT``.
+    -   ``X-Forwarded-Port`` sets ``HTTP_HOST`` and ``SERVER_PORT``.
+    -   ``X-Forwarded-Prefix`` sets ``SCRIPT_NAME``.
+
+    You must tell the middleware how many proxies set each header so it
+    knows what values to trust. It is a security issue to trust values
+    that came from the client rather than a proxy.
+
+    The original values of the headers are stored in the WSGI
+    environ as ``werkzeug.proxy_fix.orig``, a dict.
+
+    :param app: The WSGI application to wrap.
+    :param x_for: Number of values to trust for ``X-Forwarded-For``.
+    :param x_proto: Number of values to trust for ``X-Forwarded-Proto``.
+    :param x_host: Number of values to trust for ``X-Forwarded-Host``.
+    :param x_port: Number of values to trust for ``X-Forwarded-Port``.
+    :param x_prefix: Number of values to trust for
+        ``X-Forwarded-Prefix``.
+
+    .. code-block:: python
+
+        from werkzeug.middleware.proxy_fix import ProxyFix
+        # App is behind one proxy that sets the -For and -Host headers.
+        app = ProxyFix(app, x_for=1, x_host=1)
+
+    .. versionchanged:: 1.0
+        Deprecated code has been removed:
+
+        *   The ``num_proxies`` argument and attribute.
+        *   The ``get_remote_addr`` method.
+        *   The environ keys ``orig_remote_addr``,
+            ``orig_wsgi_url_scheme``, and ``orig_http_host``.
+
+    .. versionchanged:: 0.15
+        All headers support multiple values. The ``num_proxies``
+        argument is deprecated. Each header is configured with a
+        separate number of trusted proxies.
+
+    .. versionchanged:: 0.15
+        Original WSGI environ values are stored in the
+        ``werkzeug.proxy_fix.orig`` dict. ``orig_remote_addr``,
+        ``orig_wsgi_url_scheme``, and ``orig_http_host`` are deprecated
+        and will be removed in 1.0.
+
+    .. versionchanged:: 0.15
+        Support ``X-Forwarded-Port`` and ``X-Forwarded-Prefix``.
+
+    .. versionchanged:: 0.15
+        ``X-Forwarded-Host`` and ``X-Forwarded-Port`` modify
+        ``SERVER_NAME`` and ``SERVER_PORT``.
+    """
+
+    def __init__(self, app, x_for=1, x_proto=1, x_host=0, x_port=0, x_prefix=0):
+        self.app = app
+        self.x_for = x_for
+        self.x_proto = x_proto
+        self.x_host = x_host
+        self.x_port = x_port
+        self.x_prefix = x_prefix
+
+    def _get_real_value(self, trusted, value):
+        """Get the real value from a list header based on the configured
+        number of trusted proxies.
+
+        :param trusted: Number of values to trust in the header.
+        :param value: Comma separated list header value to parse.
+        :return: The real value, or ``None`` if there are fewer values
+            than the number of trusted proxies.
+
+        .. versionchanged:: 1.0
+            Renamed from ``_get_trusted_comma``.
+
+        .. versionadded:: 0.15
+        """
+        if not (trusted and value):
+            return
+        values = parse_list_header(value)
+        if len(values) >= trusted:
+            return values[-trusted]
+
+    def __call__(self, environ, start_response):
+        """Modify the WSGI environ based on the various ``Forwarded``
+        headers before calling the wrapped application. Store the
+        original environ values in ``werkzeug.proxy_fix.orig_{key}``.
+        """
+        environ_get = environ.get
+        orig_remote_addr = environ_get("REMOTE_ADDR")
+        orig_wsgi_url_scheme = environ_get("wsgi.url_scheme")
+        orig_http_host = environ_get("HTTP_HOST")
+        environ.update(
+            {
+                "werkzeug.proxy_fix.orig": {
+                    "REMOTE_ADDR": orig_remote_addr,
+                    "wsgi.url_scheme": orig_wsgi_url_scheme,
+                    "HTTP_HOST": orig_http_host,
+                    "SERVER_NAME": environ_get("SERVER_NAME"),
+                    "SERVER_PORT": environ_get("SERVER_PORT"),
+                    "SCRIPT_NAME": environ_get("SCRIPT_NAME"),
+                }
+            }
+        )
+
+        x_for = self._get_real_value(self.x_for, environ_get("HTTP_X_FORWARDED_FOR"))
+        if x_for:
+            environ["REMOTE_ADDR"] = x_for
+
+        x_proto = self._get_real_value(
+            self.x_proto, environ_get("HTTP_X_FORWARDED_PROTO")
+        )
+        if x_proto:
+            environ["wsgi.url_scheme"] = x_proto
+
+        x_host = self._get_real_value(self.x_host, environ_get("HTTP_X_FORWARDED_HOST"))
+        if x_host:
+            environ["HTTP_HOST"] = x_host
+            parts = x_host.split(":", 1)
+            environ["SERVER_NAME"] = parts[0]
+            if len(parts) == 2:
+                environ["SERVER_PORT"] = parts[1]
+
+        x_port = self._get_real_value(self.x_port, environ_get("HTTP_X_FORWARDED_PORT"))
+        if x_port:
+            host = environ.get("HTTP_HOST")
+            if host:
+                parts = host.split(":", 1)
+                host = parts[0] if len(parts) == 2 else host
+                environ["HTTP_HOST"] = "%s:%s" % (host, x_port)
+            environ["SERVER_PORT"] = x_port
+
+        x_prefix = self._get_real_value(
+            self.x_prefix, environ_get("HTTP_X_FORWARDED_PREFIX")
+        )
+        if x_prefix:
+            environ["SCRIPT_NAME"] = x_prefix
+
+        return self.app(environ, start_response)