calibre-web/cps/reverseproxy.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

#  Flask License
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#  Copyright © 2010 by the Pallets team, cervinko, janeczku, OzzieIsaacs
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# Inspired by http://flask.pocoo.org/snippets/35/

class ReverseProxied(object):
    """Wrap the application in this middleware and configure the
    front-end server to add these headers, to let you quietly bind
    this to a URL other than / and to an HTTP scheme that is
    different than what is used locally.

    Code courtesy of: http://flask.pocoo.org/snippets/35/

    In nginx:
    location /myprefix {
        proxy_pass http://127.0.0.1:8083;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Scheme $scheme;
        proxy_set_header X-Script-Name /myprefix;
        }
    """

    def __init__(self, application):
        self.app = application

    def __call__(self, environ, start_response):
        script_name = environ.get('HTTP_X_SCRIPT_NAME', '')
        if script_name:
            environ['SCRIPT_NAME'] = script_name
            path_info = environ.get('PATH_INFO', '')
            if path_info and path_info.startswith(script_name):
                environ['PATH_INFO'] = path_info[len(script_name):]

        scheme = environ.get('HTTP_X_SCHEME', '')
        if scheme:
            environ['wsgi.url_scheme'] = scheme
        servr = environ.get('HTTP_X_FORWARDED_HOST', '')
        if servr:
            environ['HTTP_HOST'] = servr
        return self.app(environ, start_response)