Create Proxy for Python Flask Application

Here's a solution that requires miminal change to the Flask application and works pretty well:

Here's what it does essentially: We tell Nginx to pass some special headers to our proxy flask application and then we create a wrapper (ReverseProxied) that intercepts each request, extracts the headers set by Nginx and modifies the request processing environment so that it matches the urls we want.

In Nginx, add the following inside the server directive:

location /competitor {    proxy_pass http://127.0.0.1:5001;    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 /competitor;}

In Flask, add the class below to your main application file (wherever you create the main Flask app object)

class ReverseProxied(object):    def __init__(self, app):        self.app = app    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['PATH_INFO']            if 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        return self.app(environ, start_response)

Finally, force your app to use the new ReverseProxied middleware

app = Flask(__name__)app.wsgi_app = ReverseProxied(app.wsgi_app)

You can find the original solution and code snippets here http://flask.pocoo.org/snippets/35/