Python tornado.application() Examples

def get_content_type(self):
        """返回这个请求使用的 ``Content-Type`` 头.

        .. versionadded:: 3.1
        """
        mime_type, encoding = mimetypes.guess_type(self.absolute_path)
        # per RFC 6713, use the appropriate type for a gzip compressed file
        if encoding == "gzip":
            return "application/gzip"
        # As of 2015-07-21 there is no bzip2 encoding defined at
        # http://www.iana.org/assignments/media-types/media-types.xhtml
        # So for that (and any other encoding), use octet-stream.
        elif encoding is not None:
            return "application/octet-stream"
        elif mime_type is not None:
            return mime_type
        # if mime_type not detected, use application/octet-stream
        else:
            return "application/octet-stream" 

def get_handler_delegate(
        self,
        request: httputil.HTTPServerRequest,
        target_class: Type[RequestHandler],
        target_kwargs: Dict[str, Any] = None,
        path_args: List[bytes] = None,
        path_kwargs: Dict[str, bytes] = None,
    ) -> "_HandlerDelegate":
        """Returns `~.httputil.HTTPMessageDelegate` that can serve a request
        for application and `RequestHandler` subclass.

        :arg httputil.HTTPServerRequest request: current HTTP request.
        :arg RequestHandler target_class: a `RequestHandler` class.
        :arg dict target_kwargs: keyword arguments for ``target_class`` constructor.
        :arg list path_args: positional arguments for ``target_class`` HTTP method that
            will be executed while handling a request (``get``, ``post`` or any other).
        :arg dict path_kwargs: keyword arguments for ``target_class`` HTTP method.
        """
        return _HandlerDelegate(
            self, request, target_class, target_kwargs, path_args, path_kwargs
        ) 

def xsrf_form_html(self) -> str:
        """An HTML ``<input/>`` element to be included with all POST forms.

        It defines the ``_xsrf`` input value, which we check on all POST
        requests to prevent cross-site request forgery. If you have set
        the ``xsrf_cookies`` application setting, you must include this
        HTML within all of your HTML forms.

        In a template, this method should be called with ``{% module
        xsrf_form_html() %}``

        See `check_xsrf_cookie()` above for more information.
        """
        return (
            '<input type="hidden" name="_xsrf" value="'
            + escape.xhtml_escape(self.xsrf_token)
            + '"/>'
        ) 

def log_request(self, handler):
        """Writes a completed HTTP request to the logs.

        By default writes to the python root logger.  To change
        this behavior either subclass Application and override this method,
        or pass a function in the application settings dictionary as
        ``log_function``.
        """
        if "log_function" in self.settings:
            self.settings["log_function"](handler)
            return
        if handler.get_status() < 400:
            log_method = access_log.info
        elif handler.get_status() < 500:
            log_method = access_log.warning
        else:
            log_method = access_log.error
        request_time = 1000.0 * handler.request.request_time()
        log_method("%d %s %.2fms", handler.get_status(),
                   handler._request_summary(), request_time) 

def log_exception(self, typ, value, tb):
        """复写来自定义未捕获异常的日志.

        默认情况下 `HTTPError` 的日志实例作为警告(warning)没有堆栈追踪(在
        ``tornado.general`` logger), 其他作为错误(error)的异常带有堆栈
        追踪(在 ``tornado.application`` logger).

        .. versionadded:: 3.1
        """
        if isinstance(value, HTTPError):
            if value.log_message:
                format = "%d %s: " + value.log_message
                args = ([value.status_code, self._request_summary()] +
                        list(value.args))
                gen_log.warning(format, *args)
        else:
            app_log.error("Uncaught exception %s\n%r", self._request_summary(),
                          self.request, exc_info=(typ, value, tb)) 

def listen(self, port: int, address: str = "", **kwargs: Any) -> HTTPServer:
        """Starts an HTTP server for this application on the given port.

        This is a convenience alias for creating an `.HTTPServer`
        object and calling its listen method.  Keyword arguments not
        supported by `HTTPServer.listen <.TCPServer.listen>` are passed to the
        `.HTTPServer` constructor.  For advanced uses
        (e.g. multi-process mode), do not use this method; create an
        `.HTTPServer` and call its
        `.TCPServer.bind`/`.TCPServer.start` methods directly.

        Note that after calling this method you still need to call
        ``IOLoop.current().start()`` to start the server.

        Returns the `.HTTPServer` object.

        .. versionchanged:: 4.3
           Now returns the `.HTTPServer` object.
        """
        server = HTTPServer(self, **kwargs)
        server.listen(port, address)
        return server 

def listen(self, port, address="", **kwargs):
        """Starts an HTTP server for this application on the given port.

        This is a convenience alias for creating an `.HTTPServer`
        object and calling its listen method.  Keyword arguments not
        supported by `HTTPServer.listen <.TCPServer.listen>` are passed to the
        `.HTTPServer` constructor.  For advanced uses
        (e.g. multi-process mode), do not use this method; create an
        `.HTTPServer` and call its
        `.TCPServer.bind`/`.TCPServer.start` methods directly.

        Note that after calling this method you still need to call
        ``IOLoop.instance().start()`` to start the server.
        """
        # import is here rather than top level because HTTPServer
        # is not importable on appengine
        from tornado.httpserver import HTTPServer
        server = HTTPServer(self, **kwargs)
        server.listen(port, address) 

def create_template_loader(self, template_path):
        """Returns a new template loader for the given path.

        May be overridden by subclasses.  By default returns a
        directory-based loader on the given path, using the
        ``autoescape`` application setting.  If a ``template_loader``
        application setting is supplied, uses that instead.
        """
        settings = self.application.settings
        if "template_loader" in settings:
            return settings["template_loader"]
        kwargs = {}
        if "autoescape" in settings:
            # autoescape=None means "no escaping", so we have to be sure
            # to only pass this kwarg if the user asked for it.
            kwargs["autoescape"] = settings["autoescape"]
        return template.Loader(template_path, **kwargs) 

def get_secure_cookie(self, name, value=None, max_age_days=31,
                          min_version=None):
        """如果给定的签名过的cookie是有效的,则返回，否则返回None.

        解码后的cookie值作为字节字符串返回(不像 `get_cookie` ).

        .. versionchanged:: 3.2.1

           添加 ``min_version`` 参数. 引进cookie version 2;
           默认版本 1 和 2 都可以接受.
        """
        self.require_setting("cookie_secret", "secure cookies")
        if value is None:
            value = self.get_cookie(name)
        return decode_signed_value(self.application.settings["cookie_secret"],
                                   name, value, max_age_days=max_age_days,
                                   min_version=min_version) 

def create_signed_value(self, name, value, version=None):
        """产生用时间戳签名的字符串, 防止被伪造.

        一般通过set_secure_cookie 使用, 但对于无cookie使用来说就
        作为独立的方法来提供. 为了解码不作为cookie存储的值, 可以
        在 get_secure_cookie 使用可选的value参数.

        .. versionchanged:: 3.2.1

           添加 ``version`` 参数. 提出cookie version 2
           并将它作为默认设置.
        """
        self.require_setting("cookie_secret", "secure cookies")
        secret = self.application.settings["cookie_secret"]
        key_version = None
        if isinstance(secret, dict):
            if self.application.settings.get("key_version") is None:
                raise Exception("key_version setting must be used for secret_key dicts")
            key_version = self.application.settings["key_version"]

        return create_signed_value(secret, name, value, version=version,
                                   key_version=key_version) 

def __init__(self, application, request, **kwargs):
        super(RequestHandler, self).__init__()

        self.application = application
        self.request = request
        self._headers_written = False
        self._finished = False
        self._auto_finish = True
        self._transforms = None  # will be set in _execute
        self._prepared_future = None
        self.path_args = None
        self.path_kwargs = None
        self.ui = ObjectDict((n, self._ui_method(m)) for n, m in
                             application.ui_methods.items())
        # UIModules are available as both `modules` and `_tt_modules` in the
        # template namespace.  Historically only `modules` was available
        # but could be clobbered by user additions to the namespace.
        # The template {% module %} directive looks in `_tt_modules` to avoid
        # possible conflicts.
        self.ui["_tt_modules"] = _UIModuleNamespace(self,
                                                    application.ui_modules)
        self.ui["modules"] = self.ui["_tt_modules"]
        self.clear()
        self.request.connection.set_close_callback(self.on_connection_close)
        self.initialize(**kwargs) 

def write(self, chunk):
        """Writes the given chunk to the output buffer.

        To write the output to the network, use the flush() method below.

        If the given chunk is a dictionary, we write it as JSON and set
        the Content-Type of the response to be ``application/json``.
        (if you want to send JSON as a different ``Content-Type``, call
        set_header *after* calling write()).

        Note that lists are not converted to JSON because of a potential
        cross-site security vulnerability.  All JSON output should be
        wrapped in a dictionary.  More details at
        http://haacked.com/archive/2008/11/20/anatomy-of-a-subtle-json-vulnerability.aspx
        """
        if self._finished:
            raise RuntimeError("Cannot write() after finish().  May be caused "
                               "by using async operations without the "
                               "@asynchronous decorator.")
        if isinstance(chunk, dict):
            chunk = escape.json_encode(chunk)
            self.set_header("Content-Type", "application/json; charset=UTF-8")
        chunk = utf8(chunk)
        self._write_buffer.append(chunk) 

def get_content_type(self):
        """返回这个请求使用的 ``Content-Type`` 头.

        .. versionadded:: 3.1
        """
        mime_type, encoding = mimetypes.guess_type(self.absolute_path)
        # per RFC 6713, use the appropriate type for a gzip compressed file
        if encoding == "gzip":
            return "application/gzip"
        # As of 2015-07-21 there is no bzip2 encoding defined at
        # http://www.iana.org/assignments/media-types/media-types.xhtml
        # So for that (and any other encoding), use octet-stream.
        elif encoding is not None:
            return "application/octet-stream"
        elif mime_type is not None:
            return mime_type
        # if mime_type not detected, use application/octet-stream
        else:
            return "application/octet-stream" 

def __init__(self, application, request, **kwargs):
        super(RequestHandler, self).__init__()

        self.application = application
        self.request = request
        self._headers_written = False
        self._finished = False
        self._auto_finish = True
        self._transforms = None  # will be set in _execute
        self._prepared_future = None
        self.path_args = None
        self.path_kwargs = None
        self.ui = ObjectDict((n, self._ui_method(m)) for n, m in
                             application.ui_methods.items())
        # UIModules are available as both `modules` and `_tt_modules` in the
        # template namespace.  Historically only `modules` was available
        # but could be clobbered by user additions to the namespace.
        # The template {% module %} directive looks in `_tt_modules` to avoid
        # possible conflicts.
        self.ui["_tt_modules"] = _UIModuleNamespace(self,
                                                    application.ui_modules)
        self.ui["modules"] = self.ui["_tt_modules"]
        self.clear()
        self.request.connection.set_close_callback(self.on_connection_close)
        self.initialize(**kwargs) 

def write(self, chunk):
        """Writes the given chunk to the output buffer.

        To write the output to the network, use the flush() method below.

        If the given chunk is a dictionary, we write it as JSON and set
        the Content-Type of the response to be ``application/json``.
        (if you want to send JSON as a different ``Content-Type``, call
        set_header *after* calling write()).

        Note that lists are not converted to JSON because of a potential
        cross-site security vulnerability.  All JSON output should be
        wrapped in a dictionary.  More details at
        http://haacked.com/archive/2008/11/20/anatomy-of-a-subtle-json-vulnerability.aspx
        """
        if self._finished:
            raise RuntimeError("Cannot write() after finish().  May be caused "
                               "by using async operations without the "
                               "@asynchronous decorator.")
        if isinstance(chunk, dict):
            chunk = escape.json_encode(chunk)
            self.set_header("Content-Type", "application/json; charset=UTF-8")
        chunk = utf8(chunk)
        self._write_buffer.append(chunk) 

def log_exception(self, typ, value, tb):
        """复写来自定义未捕获异常的日志.

        默认情况下 `HTTPError` 的日志实例作为警告(warning)没有堆栈追踪(在
        ``tornado.general`` logger), 其他作为错误(error)的异常带有堆栈
        追踪(在 ``tornado.application`` logger).

        .. versionadded:: 3.1
        """
        if isinstance(value, HTTPError):
            if value.log_message:
                format = "%d %s: " + value.log_message
                args = ([value.status_code, self._request_summary()] +
                        list(value.args))
                gen_log.warning(format, *args)
        else:
            app_log.error("Uncaught exception %s\n%r", self._request_summary(),
                          self.request, exc_info=(typ, value, tb)) 

def create_signed_value(
        self, name: str, value: Union[str, bytes], version: int = None
    ) -> bytes:
        """Signs and timestamps a string so it cannot be forged.

        Normally used via set_secure_cookie, but provided as a separate
        method for non-cookie uses.  To decode a value not stored
        as a cookie use the optional value argument to get_secure_cookie.

        .. versionchanged:: 3.2.1

           Added the ``version`` argument.  Introduced cookie version 2
           and made it the default.
        """
        self.require_setting("cookie_secret", "secure cookies")
        secret = self.application.settings["cookie_secret"]
        key_version = None
        if isinstance(secret, dict):
            if self.application.settings.get("key_version") is None:
                raise Exception("key_version setting must be used for secret_key dicts")
            key_version = self.application.settings["key_version"]

        return create_signed_value(
            secret, name, value, version=version, key_version=key_version
        ) 

def get_content_type(self) -> str:
        """Returns the ``Content-Type`` header to be used for this request.

        .. versionadded:: 3.1
        """
        assert self.absolute_path is not None
        mime_type, encoding = mimetypes.guess_type(self.absolute_path)
        # per RFC 6713, use the appropriate type for a gzip compressed file
        if encoding == "gzip":
            return "application/gzip"
        # As of 2015-07-21 there is no bzip2 encoding defined at
        # http://www.iana.org/assignments/media-types/media-types.xhtml
        # So for that (and any other encoding), use octet-stream.
        elif encoding is not None:
            return "application/octet-stream"
        elif mime_type is not None:
            return mime_type
        # if mime_type not detected, use application/octet-stream
        else:
            return "application/octet-stream" 

def log_request(self, handler: RequestHandler) -> None:
        """Writes a completed HTTP request to the logs.

        By default writes to the python root logger.  To change
        this behavior either subclass Application and override this method,
        or pass a function in the application settings dictionary as
        ``log_function``.
        """
        if "log_function" in self.settings:
            self.settings["log_function"](handler)
            return
        if handler.get_status() < 400:
            log_method = access_log.info
        elif handler.get_status() < 500:
            log_method = access_log.warning
        else:
            log_method = access_log.error
        request_time = 1000.0 * handler.request.request_time()
        log_method(
            "%d %s %.2fms",
            handler.get_status(),
            handler._request_summary(),
            request_time,
        ) 

def _execute(self, transforms, *args, **kwargs):
        """Executes this request with the given output transforms."""
        self._transforms = transforms
        try:
            if self.request.method not in self.SUPPORTED_METHODS:
                raise HTTPError(405)
            self.path_args = [self.decode_argument(arg) for arg in args]
            self.path_kwargs = dict((k, self.decode_argument(v, name=k))
                                    for (k, v) in kwargs.items())
            # If XSRF cookies are turned on, reject form submissions without
            # the proper cookie
            if self.request.method not in ("GET", "HEAD", "OPTIONS") and \
                    self.application.settings.get("xsrf_cookies"):
                self.check_xsrf_cookie()
            self._when_complete(self.prepare(), self._execute_method)
        except Exception as e:
            self._handle_request_exception(e) 

def create_template_loader(self, template_path):
        """返回给定路径的新模板装载器.

        可以被子类复写. 默认返回一个在给定路径上基于目录的装载器,
        使用应用程序的 ``autoescape`` 和 ``template_whitespace``
        设置. 如果应用设置中提供了一个 ``template_loader`` ,
        则使用它来替代.
        """
        settings = self.application.settings
        if "template_loader" in settings:
            return settings["template_loader"]
        kwargs = {}
        if "autoescape" in settings:
            # autoescape=None means "no escaping", so we have to be sure
            # to only pass this kwarg if the user asked for it.
            kwargs["autoescape"] = settings["autoescape"]
        if "template_whitespace" in settings:
            kwargs["whitespace"] = settings["template_whitespace"]
        return template.Loader(template_path, **kwargs) 

def get_secure_cookie(self, name, value=None, max_age_days=31,
                          min_version=None):
        """如果给定的签名过的cookie是有效的,则返回，否则返回None.

        解码后的cookie值作为字节字符串返回(不像 `get_cookie` ).

        .. versionchanged:: 3.2.1

           添加 ``min_version`` 参数. 引进cookie version 2;
           默认版本 1 和 2 都可以接受.
        """
        self.require_setting("cookie_secret", "secure cookies")
        if value is None:
            value = self.get_cookie(name)
        return decode_signed_value(self.application.settings["cookie_secret"],
                                   name, value, max_age_days=max_age_days,
                                   min_version=min_version) 

def create_signed_value(self, name, value, version=None):
        """产生用时间戳签名的字符串, 防止被伪造.

        一般通过set_secure_cookie 使用, 但对于无cookie使用来说就
        作为独立的方法来提供. 为了解码不作为cookie存储的值, 可以
        在 get_secure_cookie 使用可选的value参数.

        .. versionchanged:: 3.2.1

           添加 ``version`` 参数. 提出cookie version 2
           并将它作为默认设置.
        """
        self.require_setting("cookie_secret", "secure cookies")
        secret = self.application.settings["cookie_secret"]
        key_version = None
        if isinstance(secret, dict):
            if self.application.settings.get("key_version") is None:
                raise Exception("key_version setting must be used for secret_key dicts")
            key_version = self.application.settings["key_version"]

        return create_signed_value(secret, name, value, version=version,
                                   key_version=key_version) 

def log_exception(self, typ, value, tb):
        """Override to customize logging of uncaught exceptions.

        By default logs instances of `HTTPError` as warnings without
        stack traces (on the ``tornado.general`` logger), and all
        other exceptions as errors with stack traces (on the
        ``tornado.application`` logger).

        .. versionadded:: 3.1
        """
        if isinstance(value, HTTPError):
            if value.log_message:
                format = "%d %s: " + value.log_message
                args = ([value.status_code, self._request_summary()] +
                        list(value.args))
                gen_log.warning(format, *args)
        else:
            app_log.error("Uncaught exception %s\n%r", self._request_summary(),
                          self.request, exc_info=(typ, value, tb)) 

def get_template_path(self):
        """Override to customize template path for each handler.

        By default, we use the ``template_path`` application setting.
        Return None to load templates relative to the calling file.
        """
        return self.application.settings.get("template_path") 

def create_signed_value(self, name, value):
        """Signs and timestamps a string so it cannot be forged.

        Normally used via set_secure_cookie, but provided as a separate
        method for non-cookie uses.  To decode a value not stored
        as a cookie use the optional value argument to get_secure_cookie.
        """
        self.require_setting("cookie_secret", "secure cookies")
        return create_signed_value(self.application.settings["cookie_secret"],
                                   name, value) 

def __init__(self, application: "Application", rules: _RuleList = None) -> None:
        assert isinstance(application, Application)
        self.application = application
        super(_ApplicationRouter, self).__init__(rules) 

def reverse_url(self, name: str, *args: Any) -> str:
        """Returns a URL path for handler named ``name``

        The handler must be added to the application as a named `URLSpec`.

        Args will be substituted for capturing groups in the `URLSpec` regex.
        They will be converted to strings if necessary, encoded as utf8,
        and url-escaped.
        """
        reversed_url = self.default_router.reverse_url(name, *args)
        if reversed_url is not None:
            return reversed_url

        raise KeyError("%s not found in named urls" % name) 

def get_target_delegate(
        self, target: Any, request: httputil.HTTPServerRequest, **target_params: Any
    ) -> Optional[httputil.HTTPMessageDelegate]:
        if isclass(target) and issubclass(target, RequestHandler):
            return self.application.get_handler_delegate(
                request, target, **target_params
            )

        return super(_ApplicationRouter, self).get_target_delegate(
            target, request, **target_params
        ) 

def execute(self) -> Optional[Awaitable[None]]:
        # If template cache is disabled (usually in the debug mode),
        # re-compile templates and reload static files on every
        # request so you don't need to restart to see changes
        if not self.application.settings.get("compiled_template_cache", True):
            with RequestHandler._template_loader_lock:
                for loader in RequestHandler._template_loaders.values():
                    loader.reset()
        if not self.application.settings.get("static_hash_cache", True):
            StaticFileHandler.reset()

        self.handler = self.handler_class(
            self.application, self.request, **self.handler_kwargs
        )
        transforms = [t(self.request) for t in self.application.transforms]

        if self.stream_request_body:
            self.handler._prepared_future = Future()
        # Note that if an exception escapes handler._execute it will be
        # trapped in the Future it returns (which we are ignoring here,
        # leaving it to be logged when the Future is GC'd).
        # However, that shouldn't happen because _execute has a blanket
        # except handler, and we cannot easily access the IOLoop here to
        # call add_future (because of the requirement to remain compatible
        # with WSGI)
        fut = gen.convert_yielded(
            self.handler._execute(transforms, *self.path_args, **self.path_kwargs)
        )
        fut.add_done_callback(lambda f: f.result())
        # If we are streaming the request body, then execute() is finished
        # when the handler has prepared to receive the body.  If not,
        # it doesn't matter when execute() finishes (so we return None)
        return self.handler._prepared_future