| 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) |
|
|
