|
| 1 | +from functools import wraps |
| 2 | + |
| 3 | +from asgiref.sync import async_to_sync, iscoroutinefunction, sync_to_async |
| 4 | + |
| 5 | + |
| 6 | +def decorator_from_middleware_with_args(middleware_class): |
| 7 | + """ |
| 8 | + Like decorator_from_middleware, but return a function |
| 9 | + that accepts the arguments to be passed to the middleware_class. |
| 10 | + Use like:: |
| 11 | + |
| 12 | + cache_page = decorator_from_middleware_with_args(CacheMiddleware) |
| 13 | + # ... |
| 14 | + |
| 15 | + @cache_page(3600) |
| 16 | + def my_view(request): |
| 17 | + # ... |
| 18 | + """ |
| 19 | + return make_middleware_decorator(middleware_class) |
| 20 | + |
| 21 | + |
| 22 | +def decorator_from_middleware(middleware_class): |
| 23 | + """ |
| 24 | + Given a middleware class (not an instance), return a view decorator. This |
| 25 | + lets you use middleware functionality on a per-view basis. The middleware |
| 26 | + is created with no params passed. |
| 27 | + """ |
| 28 | + return make_middleware_decorator(middleware_class)() |
| 29 | + |
| 30 | + |
| 31 | +def make_middleware_decorator(middleware_class): |
| 32 | + def _make_decorator(*m_args, **m_kwargs): |
| 33 | + def _decorator(view_func): |
| 34 | + middleware = middleware_class(view_func, *m_args, **m_kwargs) |
| 35 | + |
| 36 | + async def _pre_process_request(request, *args, **kwargs): |
| 37 | + if hasattr(middleware, "process_request"): |
| 38 | + result = await middleware.process_request(request) |
| 39 | + if result is not None: |
| 40 | + return result |
| 41 | + if hasattr(middleware, "process_view"): |
| 42 | + if iscoroutinefunction(middleware.process_view): |
| 43 | + result = await middleware.process_view( |
| 44 | + request, view_func, args, kwargs |
| 45 | + ) |
| 46 | + else: |
| 47 | + result = await sync_to_async(middleware.process_view)( |
| 48 | + request, view_func, args, kwargs |
| 49 | + ) |
| 50 | + if result is not None: |
| 51 | + return result |
| 52 | + return None |
| 53 | + |
| 54 | + async def _process_exception(request, exception): |
| 55 | + if hasattr(middleware, "process_exception"): |
| 56 | + if iscoroutinefunction(middleware.process_exception): |
| 57 | + result = await middleware.process_exception(request, exception) |
| 58 | + else: |
| 59 | + result = await sync_to_async(middleware.process_exception)( |
| 60 | + request, exception |
| 61 | + ) |
| 62 | + if result is not None: |
| 63 | + return result |
| 64 | + raise |
| 65 | + |
| 66 | + async def _post_process_request(request, response): |
| 67 | + if hasattr(response, "render") and callable(response.render): |
| 68 | + if hasattr(middleware, "process_template_response"): |
| 69 | + if iscoroutinefunction(middleware.process_template_response): |
| 70 | + response = await middleware.process_template_response( |
| 71 | + request, response |
| 72 | + ) |
| 73 | + else: |
| 74 | + response = await sync_to_async( |
| 75 | + middleware.process_template_response |
| 76 | + )(request, response) |
| 77 | + # Defer running of process_response until after the template |
| 78 | + # has been rendered: |
| 79 | + if hasattr(middleware, "process_response"): |
| 80 | + |
| 81 | + async def callback(response): |
| 82 | + return await middleware.process_response(request, response) |
| 83 | + |
| 84 | + response.add_post_render_callback(async_to_sync(callback)) |
| 85 | + else: |
| 86 | + if hasattr(middleware, "process_response"): |
| 87 | + return await middleware.process_response(request, response) |
| 88 | + return response |
| 89 | + |
| 90 | + if iscoroutinefunction(view_func): |
| 91 | + |
| 92 | + async def _view_wrapper(request, *args, **kwargs): |
| 93 | + result = await _pre_process_request(request, *args, **kwargs) |
| 94 | + if result is not None: |
| 95 | + return result |
| 96 | + |
| 97 | + try: |
| 98 | + response = await view_func(request, *args, **kwargs) |
| 99 | + except Exception as e: |
| 100 | + result = await _process_exception(request, e) |
| 101 | + if result is not None: |
| 102 | + return result |
| 103 | + |
| 104 | + return await _post_process_request(request, response) |
| 105 | + |
| 106 | + else: |
| 107 | + |
| 108 | + def _view_wrapper(request, *args, **kwargs): |
| 109 | + result = async_to_sync(_pre_process_request)( |
| 110 | + request, *args, **kwargs |
| 111 | + ) |
| 112 | + if result is not None: |
| 113 | + return result |
| 114 | + |
| 115 | + try: |
| 116 | + response = view_func(request, *args, **kwargs) |
| 117 | + except Exception as e: |
| 118 | + result = async_to_sync(_process_exception)(request, e) |
| 119 | + if result is not None: |
| 120 | + return result |
| 121 | + |
| 122 | + return async_to_sync(_post_process_request)(request, response) |
| 123 | + |
| 124 | + return wraps(view_func)(_view_wrapper) |
| 125 | + |
| 126 | + return _decorator |
| 127 | + |
| 128 | + return _make_decorator |
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