| Adding HTTP Method Overrides | |
| ============================ | |
| Some HTTP proxies do not support arbitrary HTTP methods or newer HTTP | |
| methods (such as PATCH). In that case it's possible to "proxy" HTTP | |
| methods through another HTTP method in total violation of the protocol. | |
| The way this works is by letting the client do an HTTP POST request and | |
| set the ``X-HTTP-Method-Override`` header. Then the method is replaced | |
| with the header value before being passed to Flask. | |
| This can be accomplished with an HTTP middleware:: | |
| class HTTPMethodOverrideMiddleware(object): | |
| allowed_methods = frozenset([ | |
| 'GET', | |
| 'HEAD', | |
| 'POST', | |
| 'DELETE', | |
| 'PUT', | |
| 'PATCH', | |
| 'OPTIONS' | |
| ]) | |
| bodyless_methods = frozenset(['GET', 'HEAD', 'OPTIONS', 'DELETE']) | |
| def __init__(self, app): | |
| self.app = app | |
| def __call__(self, environ, start_response): | |
| method = environ.get('HTTP_X_HTTP_METHOD_OVERRIDE', '').upper() | |
| if method in self.allowed_methods: | |
| environ['REQUEST_METHOD'] = method | |
| if method in self.bodyless_methods: | |
| environ['CONTENT_LENGTH'] = '0' | |
| return self.app(environ, start_response) | |
| To use this with Flask, wrap the app object with the middleware:: | |
| from flask import Flask | |
| app = Flask(__name__) | |
| app.wsgi_app = HTTPMethodOverrideMiddleware(app.wsgi_app) | |