mirror of https://github.com/pallets/flask.git
34 lines
1.3 KiB
ReStructuredText
34 lines
1.3 KiB
ReStructuredText
Tell Flask it is Behind a Proxy
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===============================
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When using a reverse proxy, or many Python hosting platforms, the proxy
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will intercept and forward all external requests to the local WSGI
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server.
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From the WSGI server and Flask application's perspectives, requests are
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now coming from the HTTP server to the local address, rather than from
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the remote address to the external server address.
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HTTP servers should set ``X-Forwarded-`` headers to pass on the real
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values to the application. The application can then be told to trust and
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use those values by wrapping it with the
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:doc:`werkzeug:middleware/proxy_fix` middleware provided by Werkzeug.
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This middleware should only be used if the application is actually
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behind a proxy, and should be configured with the number of proxies that
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are chained in front of it. Not all proxies set all the headers. Since
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incoming headers can be faked, you must set how many proxies are setting
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each header so the middleware knows what to trust.
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.. code-block:: python
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from werkzeug.middleware.proxy_fix import ProxyFix
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app.wsgi_app = ProxyFix(
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app.wsgi_app, x_for=1, x_proto=1, x_host=1, x_prefix=1
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)
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Remember, only apply this middleware if you are behind a proxy, and set
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the correct number of proxies that set each header. It can be a security
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issue if you get this configuration wrong.
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