[3] | 1 | # (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org) |
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| 2 | # Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php |
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| 3 | """Paste Configuration Middleware and Objects""" |
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| 4 | import threading |
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| 5 | import re |
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| 6 | # Loaded lazily |
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| 7 | wsgilib = None |
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| 8 | local = None |
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| 9 | |
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| 10 | __all__ = ['DispatchingConfig', 'CONFIG', 'ConfigMiddleware', 'PrefixMiddleware'] |
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| 11 | |
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| 12 | def local_dict(): |
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| 13 | global config_local, local |
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| 14 | try: |
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| 15 | return config_local.wsgi_dict |
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| 16 | except NameError: |
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| 17 | from paste.deploy.util.threadinglocal import local |
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| 18 | config_local = local() |
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| 19 | config_local.wsgi_dict = result = {} |
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| 20 | return result |
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| 21 | except AttributeError: |
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| 22 | config_local.wsgi_dict = result = {} |
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| 23 | return result |
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| 24 | |
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| 25 | class DispatchingConfig(object): |
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| 26 | |
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| 27 | """ |
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| 28 | This is a configuration object that can be used globally, |
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| 29 | imported, have references held onto. The configuration may differ |
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| 30 | by thread (or may not). |
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| 31 | |
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| 32 | Specific configurations are registered (and deregistered) either |
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| 33 | for the process or for threads. |
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| 34 | """ |
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| 35 | |
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| 36 | # @@: What should happen when someone tries to add this |
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| 37 | # configuration to itself? Probably the conf should become |
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| 38 | # resolved, and get rid of this delegation wrapper |
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| 39 | |
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| 40 | _constructor_lock = threading.Lock() |
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| 41 | |
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| 42 | def __init__(self): |
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| 43 | self._constructor_lock.acquire() |
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| 44 | try: |
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| 45 | self.dispatching_id = 0 |
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| 46 | while 1: |
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| 47 | self._local_key = 'paste.processconfig_%i' % self.dispatching_id |
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| 48 | if not local_dict().has_key(self._local_key): |
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| 49 | break |
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| 50 | self.dispatching_id += 1 |
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| 51 | finally: |
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| 52 | self._constructor_lock.release() |
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| 53 | self._process_configs = [] |
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| 54 | |
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| 55 | def push_thread_config(self, conf): |
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| 56 | """ |
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| 57 | Make ``conf`` the active configuration for this thread. |
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| 58 | Thread-local configuration always overrides process-wide |
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| 59 | configuration. |
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| 60 | |
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| 61 | This should be used like:: |
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| 62 | |
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| 63 | conf = make_conf() |
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| 64 | dispatching_config.push_thread_config(conf) |
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| 65 | try: |
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| 66 | ... do stuff ... |
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| 67 | finally: |
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| 68 | dispatching_config.pop_thread_config(conf) |
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| 69 | """ |
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| 70 | local_dict().setdefault(self._local_key, []).append(conf) |
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| 71 | |
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| 72 | def pop_thread_config(self, conf=None): |
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| 73 | """ |
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| 74 | Remove a thread-local configuration. If ``conf`` is given, |
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| 75 | it is checked against the popped configuration and an error |
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| 76 | is emitted if they don't match. |
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| 77 | """ |
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| 78 | self._pop_from(local_dict()[self._local_key], conf) |
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| 79 | |
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| 80 | def _pop_from(self, lst, conf): |
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| 81 | popped = lst.pop() |
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| 82 | if conf is not None and popped is not conf: |
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| 83 | raise AssertionError( |
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| 84 | "The config popped (%s) is not the same as the config " |
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| 85 | "expected (%s)" |
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| 86 | % (popped, conf)) |
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| 87 | |
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| 88 | def push_process_config(self, conf): |
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| 89 | """ |
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| 90 | Like push_thread_config, but applies the configuration to |
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| 91 | the entire process. |
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| 92 | """ |
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| 93 | self._process_configs.append(conf) |
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| 94 | |
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| 95 | def pop_process_config(self, conf=None): |
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| 96 | self._pop_from(self._process_configs, conf) |
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| 97 | |
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| 98 | def __getattr__(self, attr): |
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| 99 | conf = self.current_conf() |
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| 100 | if conf is None: |
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| 101 | raise AttributeError( |
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| 102 | "No configuration has been registered for this process " |
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| 103 | "or thread") |
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| 104 | return getattr(conf, attr) |
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| 105 | |
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| 106 | def current_conf(self): |
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| 107 | thread_configs = local_dict().get(self._local_key) |
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| 108 | if thread_configs: |
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| 109 | return thread_configs[-1] |
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| 110 | elif self._process_configs: |
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| 111 | return self._process_configs[-1] |
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| 112 | else: |
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| 113 | return None |
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| 114 | |
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| 115 | def __getitem__(self, key): |
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| 116 | # I thought __getattr__ would catch this, but apparently not |
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| 117 | conf = self.current_conf() |
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| 118 | if conf is None: |
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| 119 | raise TypeError( |
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| 120 | "No configuration has been registered for this process " |
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| 121 | "or thread") |
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| 122 | return conf[key] |
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| 123 | |
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| 124 | def __contains__(self, key): |
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| 125 | # I thought __getattr__ would catch this, but apparently not |
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| 126 | return self.has_key(key) |
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| 127 | |
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| 128 | def __setitem__(self, key, value): |
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| 129 | # I thought __getattr__ would catch this, but apparently not |
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| 130 | conf = self.current_conf() |
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| 131 | conf[key] = value |
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| 132 | |
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| 133 | CONFIG = DispatchingConfig() |
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| 134 | |
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| 135 | class ConfigMiddleware(object): |
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| 136 | |
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| 137 | """ |
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| 138 | A WSGI middleware that adds a ``paste.config`` key to the request |
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| 139 | environment, as well as registering the configuration temporarily |
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| 140 | (for the length of the request) with ``paste.CONFIG``. |
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| 141 | """ |
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| 142 | |
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| 143 | def __init__(self, application, config): |
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| 144 | """ |
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| 145 | This delegates all requests to `application`, adding a *copy* |
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| 146 | of the configuration `config`. |
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| 147 | """ |
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| 148 | self.application = application |
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| 149 | self.config = config |
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| 150 | |
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| 151 | def __call__(self, environ, start_response): |
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| 152 | global wsgilib |
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| 153 | if wsgilib is None: |
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| 154 | import pkg_resources |
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| 155 | pkg_resources.require('Paste') |
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| 156 | from paste import wsgilib |
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| 157 | popped_config = None |
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| 158 | if 'paste.config' in environ: |
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| 159 | popped_config = environ['paste.config'] |
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| 160 | conf = environ['paste.config'] = self.config.copy() |
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| 161 | app_iter = None |
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| 162 | CONFIG.push_thread_config(conf) |
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| 163 | try: |
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| 164 | app_iter = self.application(environ, start_response) |
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| 165 | finally: |
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| 166 | if app_iter is None: |
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| 167 | # An error occurred... |
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| 168 | CONFIG.pop_thread_config(conf) |
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| 169 | if popped_config is not None: |
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| 170 | environ['paste.config'] = popped_config |
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| 171 | if type(app_iter) in (list, tuple): |
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| 172 | # Because it is a concrete iterator (not a generator) we |
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| 173 | # know the configuration for this thread is no longer |
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| 174 | # needed: |
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| 175 | CONFIG.pop_thread_config(conf) |
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| 176 | if popped_config is not None: |
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| 177 | environ['paste.config'] = popped_config |
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| 178 | return app_iter |
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| 179 | else: |
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| 180 | def close_config(): |
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| 181 | CONFIG.pop_thread_config(conf) |
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| 182 | new_app_iter = wsgilib.add_close(app_iter, close_config) |
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| 183 | return new_app_iter |
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| 184 | |
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| 185 | def make_config_filter(app, global_conf, **local_conf): |
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| 186 | conf = global_conf.copy() |
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| 187 | conf.update(local_conf) |
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| 188 | return ConfigMiddleware(app, conf) |
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| 189 | |
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| 190 | make_config_middleware = ConfigMiddleware.__doc__ |
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| 191 | |
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| 192 | class PrefixMiddleware(object): |
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| 193 | """Translate a given prefix into a SCRIPT_NAME for the filtered |
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| 194 | application. |
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| 195 | |
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| 196 | PrefixMiddleware provides a way to manually override the root prefix |
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| 197 | (SCRIPT_NAME) of your application for certain, rare situations. |
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| 198 | |
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| 199 | When running an application under a prefix (such as '/james') in |
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| 200 | FastCGI/apache, the SCRIPT_NAME environment variable is automatically |
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| 201 | set to to the appropriate value: '/james'. Pylons' URL generating |
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| 202 | functions, such as url_for, always take the SCRIPT_NAME value into account. |
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| 203 | |
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| 204 | One situation where PrefixMiddleware is required is when an application |
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| 205 | is accessed via a reverse proxy with a prefix. The application is accessed |
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| 206 | through the reverse proxy via the the URL prefix '/james', whereas the |
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| 207 | reverse proxy forwards those requests to the application at the prefix '/'. |
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| 208 | |
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| 209 | The reverse proxy, being an entirely separate web server, has no way of |
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| 210 | specifying the SCRIPT_NAME variable; it must be manually set by a |
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| 211 | PrefixMiddleware instance. Without setting SCRIPT_NAME, url_for will |
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| 212 | generate URLs such as: '/purchase_orders/1', when it should be |
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| 213 | generating: '/james/purchase_orders/1'. |
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| 214 | |
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| 215 | To filter your application through a PrefixMiddleware instance, add the |
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| 216 | following to the '[app:main]' section of your .ini file: |
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| 217 | |
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| 218 | .. code-block:: ini |
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| 219 | |
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| 220 | filter-with = proxy-prefix |
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| 221 | |
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| 222 | [filter:proxy-prefix] |
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| 223 | use = egg:PasteDeploy#prefix |
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| 224 | prefix = /james |
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| 225 | |
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| 226 | The name ``proxy-prefix`` simply acts as an identifier of the filter |
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| 227 | section; feel free to rename it. |
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| 228 | |
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| 229 | Also, unless disabled, the ``X-Forwarded-Server`` header will be |
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| 230 | translated to the ``Host`` header, for cases when that header is |
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| 231 | lost in the proxying. Also ``X-Forwarded-Host``, |
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| 232 | ``X-Forwarded-Scheme``, and ``X-Forwarded-Proto`` are translated. |
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| 233 | |
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| 234 | If ``force_port`` is set, SERVER_PORT and HTTP_HOST will be |
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| 235 | rewritten with the given port. You can use a number, string (like |
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| 236 | '80') or the empty string (whatever is the default port for the |
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| 237 | scheme). This is useful in situations where there is port |
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| 238 | forwarding going on, and the server believes itself to be on a |
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| 239 | different port than what the outside world sees. |
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| 240 | |
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| 241 | You can also use ``scheme`` to explicitly set the scheme (like |
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| 242 | ``scheme = https``). |
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| 243 | """ |
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| 244 | def __init__(self, app, global_conf=None, prefix='/', |
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| 245 | translate_forwarded_server=True, |
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| 246 | force_port=None, scheme=None): |
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| 247 | self.app = app |
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| 248 | self.prefix = prefix.rstrip('/') |
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| 249 | self.translate_forwarded_server = translate_forwarded_server |
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| 250 | self.regprefix = re.compile("^%s(.*)$" % self.prefix) |
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| 251 | self.force_port = force_port |
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| 252 | self.scheme = scheme |
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| 253 | |
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| 254 | def __call__(self, environ, start_response): |
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| 255 | url = environ['PATH_INFO'] |
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| 256 | url = re.sub(self.regprefix, r'\1', url) |
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| 257 | if not url: url = '/' |
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| 258 | environ['PATH_INFO'] = url |
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| 259 | environ['SCRIPT_NAME'] = self.prefix |
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| 260 | if self.translate_forwarded_server: |
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| 261 | if 'HTTP_X_FORWARDED_SERVER' in environ: |
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| 262 | environ['SERVER_NAME'] = environ['HTTP_HOST'] = environ.pop('HTTP_X_FORWARDED_SERVER').split(',')[0] |
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| 263 | if 'HTTP_X_FORWARDED_HOST' in environ: |
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| 264 | environ['HTTP_HOST'] = environ.pop('HTTP_X_FORWARDED_HOST').split(',')[0] |
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| 265 | if 'HTTP_X_FORWARDED_FOR' in environ: |
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| 266 | environ['REMOTE_ADDR'] = environ.pop('HTTP_X_FORWARDED_FOR') |
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| 267 | if 'HTTP_X_FORWARDED_SCHEME' in environ: |
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| 268 | environ['wsgi.url_scheme'] = environ.pop('HTTP_X_FORWARDED_SCHEME') |
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| 269 | elif 'HTTP_X_FORWARDED_PROTO' in environ: |
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| 270 | environ['wsgi.url_scheme'] = environ.pop('HTTP_X_FORWARDED_PROTO') |
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| 271 | if self.force_port is not None: |
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| 272 | host = environ.get('HTTP_HOST', '').split(':', 1)[0] |
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| 273 | if self.force_port: |
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| 274 | host = '%s:%s' % (host, self.force_port) |
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| 275 | environ['SERVER_PORT'] = str(self.force_port) |
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| 276 | else: |
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| 277 | if environ['wsgi.url_scheme'] == 'http': |
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| 278 | port = '80' |
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| 279 | else: |
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| 280 | port = '443' |
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| 281 | environ['SERVER_PORT'] = port |
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| 282 | environ['HTTP_HOST'] = host |
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| 283 | if self.scheme is not None: |
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| 284 | environ['wsgi.url_scheme'] = self.scheme |
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| 285 | return self.app(environ, start_response) |
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| 286 | |
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| 287 | def make_prefix_middleware( |
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| 288 | app, global_conf, prefix='/', |
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| 289 | translate_forwarded_server=True, |
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| 290 | force_port=None, scheme=None): |
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| 291 | from paste.deploy.converters import asbool |
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| 292 | translate_forwarded_server = asbool(translate_forwarded_server) |
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| 293 | return PrefixMiddleware( |
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| 294 | app, prefix=prefix, |
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| 295 | translate_forwarded_server=translate_forwarded_server, |
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| 296 | force_port=force_port, scheme=scheme) |
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| 297 | |
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| 298 | make_prefix_middleware.__doc__ = PrefixMiddleware.__doc__ |
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