# Source code for tornado.httpclient

    """Blocking and non-blocking HTTP client interfaces.

    This module defines a common interface shared by two implementations,
    ``simple_httpclient`` and ``curl_httpclient``.  Applications may either
    instantiate their chosen implementation class directly or use the
    `AsyncHTTPClient` class from this module, which selects an implementation
    that can be overridden with the `AsyncHTTPClient.configure` method.

    The default implementation is ``simple_httpclient``, and this is expected
    to be suitable for most users' needs.  However, some applications may wish
    to switch to ``curl_httpclient`` for reasons such as the following:

    * ``curl_httpclient`` has some features not found in ``simple_httpclient``,
      including support for HTTP proxies and the ability to use a specified
      network interface.

    * ``curl_httpclient`` is more likely to be compatible with sites that are
      not-quite-compliant with the HTTP spec, or sites that use little-exercised
      features of HTTP.

    * ``curl_httpclient`` is faster.

    * ``curl_httpclient`` was the default prior to Tornado 2.0.

    Note that if you are using ``curl_httpclient``, it is highly
    recommended that you use a recent version of ``libcurl`` and
    ``pycurl``.  Currently the minimum supported version of libcurl is
    7.22.0, and the minimum version of pycurl is 7.18.2.  It is highly
    recommended that your ``libcurl`` installation is built with
    asynchronous DNS resolver (threaded or c-ares), otherwise you may
    encounter various problems with request timeouts (for more
    information, see
    http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTCONNECTTIMEOUTMS
    and comments in curl_httpclient.py).

    To select ``curl_httpclient``, call `AsyncHTTPClient.configure` at startup::

        AsyncHTTPClient.configure("tornado4.curl_httpclient.CurlAsyncHTTPClient")
    """

    from __future__ import absolute_import, division, print_function

    import functools
    import time
    import weakref

    from tornado4.concurrent import TracebackFuture
    from tornado4.escape import utf8, native_str
    from tornado4 import httputil, stack_context
    from tornado4.ioloop import IOLoop
    from tornado4.util import Configurable

    class HTTPClient(object):
        """A blocking HTTP client.

        This interface is provided for convenience and testing; most applications
        that are running an IOLoop will want to use `AsyncHTTPClient` instead.
        Typical usage looks like this::

            http_client = httpclient.HTTPClient()
            try:
                response = http_client.fetch("http://www.google.com/")
                print(response.body)
            except httpclient.HTTPError as e:
                # HTTPError is raised for non-200 responses; the response
                # can be found in e.response.
                print("Error: " + str(e))
            except Exception as e:
                # Other errors are possible, such as IOError.
                print("Error: " + str(e))
            http_client.close()
        """
        def __init__(self, async_client_class=None, **kwargs):
            self._io_loop = IOLoop(make_current=False)
            if async_client_class is None:
                async_client_class = AsyncHTTPClient
            self._async_client = async_client_class(self._io_loop, **kwargs)
            self._closed = False

        def __del__(self):
            self.close()

        def close(self):
            """Closes the HTTPClient, freeing any resources used."""
            if not self._closed:
                self._async_client.close()
                self._io_loop.close()
                self._closed = True

        def fetch(self, request, **kwargs):
            """Executes a request, returning an `HTTPResponse`.

            The request may be either a string URL or an `HTTPRequest` object.
            If it is a string, we construct an `HTTPRequest` using any additional
            kwargs: ``HTTPRequest(request, **kwargs)``

            If an error occurs during the fetch, we raise an `HTTPError` unless
            the ``raise_error`` keyword argument is set to False.
            """
            response = self._io_loop.run_sync(functools.partial(
                self._async_client.fetch, request, **kwargs))
            return response

    class AsyncHTTPClient(Configurable):
        """An non-blocking HTTP client.

        Example usage::

            def handle_response(response):
                if response.error:
                    print("Error: %s" % response.error)
                else:
                    print(response.body)

            http_client = AsyncHTTPClient()
            http_client.fetch("http://www.google.com/", handle_response)

        The constructor for this class is magic in several respects: It
        actually creates an instance of an implementation-specific
        subclass, and instances are reused as a kind of pseudo-singleton
        (one per `.IOLoop`).  The keyword argument ``force_instance=True``
        can be used to suppress this singleton behavior.  Unless
        ``force_instance=True`` is used, no arguments other than
        ``io_loop`` should be passed to the `AsyncHTTPClient` constructor.
        The implementation subclass as well as arguments to its
        constructor can be set with the static method `configure()`

        All `AsyncHTTPClient` implementations support a ``defaults``
        keyword argument, which can be used to set default values for
        `HTTPRequest` attributes.  For example::

            AsyncHTTPClient.configure(
                None, defaults=dict(user_agent="MyUserAgent"))
            # or with force_instance:
            client = AsyncHTTPClient(force_instance=True,
                defaults=dict(user_agent="MyUserAgent"))

        .. versionchanged:: 4.1
           The ``io_loop`` argument is deprecated.
        """
        @classmethod
        def configurable_base(cls):
            return AsyncHTTPClient

        @classmethod
        def configurable_default(cls):
            from tornado4.simple_httpclient import SimpleAsyncHTTPClient
            return SimpleAsyncHTTPClient

        @classmethod
        def _async_clients(cls):
            attr_name = '_async_client_dict_' + cls.__name__
            if not hasattr(cls, attr_name):
                setattr(cls, attr_name, weakref.WeakKeyDictionary())
            return getattr(cls, attr_name)

        def __new__(cls, io_loop=None, force_instance=False, **kwargs):
            io_loop = io_loop or IOLoop.current()
            if force_instance:
                instance_cache = None
            else:
                instance_cache = cls._async_clients()
            if instance_cache is not None and io_loop in instance_cache:
                return instance_cache[io_loop]
            instance = super(AsyncHTTPClient, cls).__new__(cls, io_loop=io_loop,
                                                           **kwargs)
            # Make sure the instance knows which cache to remove itself from.
            # It can't simply call _async_clients() because we may be in
            # __new__(AsyncHTTPClient) but instance.__class__ may be
            # SimpleAsyncHTTPClient.
            instance._instance_cache = instance_cache
            if instance_cache is not None:
                instance_cache[instance.io_loop] = instance
            return instance

        def initialize(self, io_loop, defaults=None):
            self.io_loop = io_loop
            self.defaults = dict(HTTPRequest._DEFAULTS)
            if defaults is not None:
                self.defaults.update(defaults)
            self._closed = False

        def close(self):
            """Destroys this HTTP client, freeing any file descriptors used.

            This method is **not needed in normal use** due to the way
            that `AsyncHTTPClient` objects are transparently reused.
            ``close()`` is generally only necessary when either the
            `.IOLoop` is also being closed, or the ``force_instance=True``
            argument was used when creating the `AsyncHTTPClient`.

            No other methods may be called on the `AsyncHTTPClient` after
            ``close()``.

            """
            if self._closed:
                return
            self._closed = True
            if self._instance_cache is not None:
                if self._instance_cache.get(self.io_loop) is not self:
                    raise RuntimeError("inconsistent AsyncHTTPClient cache")
                del self._instance_cache[self.io_loop]

        def fetch(self, request, callback=None, raise_error=True, **kwargs):
            """Executes a request, asynchronously returning an `HTTPResponse`.

            The request may be either a string URL or an `HTTPRequest` object.
            If it is a string, we construct an `HTTPRequest` using any additional
            kwargs: ``HTTPRequest(request, **kwargs)``

            This method returns a `.Future` whose result is an
            `HTTPResponse`. By default, the ``Future`` will raise an
            `HTTPError` if the request returned a non-200 response code
            (other errors may also be raised if the server could not be
            contacted). Instead, if ``raise_error`` is set to False, the
            response will always be returned regardless of the response
            code.

            If a ``callback`` is given, it will be invoked with the `HTTPResponse`.
            In the callback interface, `HTTPError` is not automatically raised.
            Instead, you must check the response's ``error`` attribute or
            call its `~HTTPResponse.rethrow` method.
            """
            if self._closed:
                raise RuntimeError("fetch() called on closed AsyncHTTPClient")
            if not isinstance(request, HTTPRequest):
                request = HTTPRequest(url=request, **kwargs)
            else:
                if kwargs:
                    raise ValueError("kwargs can't be used if request is an HTTPRequest object")
            # We may modify this (to add Host, Accept-Encoding, etc),
            # so make sure we don't modify the caller's object.  This is also
            # where normal dicts get converted to HTTPHeaders objects.
            request.headers = httputil.HTTPHeaders(request.headers)
            request = _RequestProxy(request, self.defaults)
            future = TracebackFuture()
            if callback is not None:
                callback = stack_context.wrap(callback)

                def handle_future(future):
                    exc = future.exception()
                    if isinstance(exc, HTTPError) and exc.response is not None:
                        response = exc.response
                    elif exc is not None:
                        response = HTTPResponse(
                            request, 599, error=exc,
                            request_time=time.time() - request.start_time)
                    else:
                        response = future.result()
                    self.io_loop.add_callback(callback, response)
                future.add_done_callback(handle_future)

            def handle_response(response):
                if raise_error and response.error:
                    future.set_exception(response.error)
                else:
                    future.set_result(response)
            self.fetch_impl(request, handle_response)
            return future

        def fetch_impl(self, request, callback):
            raise NotImplementedError()

        @classmethod
        def configure(cls, impl, **kwargs):
            """Configures the `AsyncHTTPClient` subclass to use.

            ``AsyncHTTPClient()`` actually creates an instance of a subclass.
            This method may be called with either a class object or the
            fully-qualified name of such a class (or ``None`` to use the default,
            ``SimpleAsyncHTTPClient``)

            If additional keyword arguments are given, they will be passed
            to the constructor of each subclass instance created.  The
            keyword argument ``max_clients`` determines the maximum number
            of simultaneous `~AsyncHTTPClient.fetch()` operations that can
            execute in parallel on each `.IOLoop`.  Additional arguments
            may be supported depending on the implementation class in use.

            Example::

               AsyncHTTPClient.configure("tornado4.curl_httpclient.CurlAsyncHTTPClient")
            """
            super(AsyncHTTPClient, cls).configure(impl, **kwargs)

    class HTTPRequest(object):
        """HTTP client request object."""

        # Default values for HTTPRequest parameters.
        # Merged with the values on the request object by AsyncHTTPClient
        # implementations.
        _DEFAULTS = dict(
            connect_timeout=20.0,
            request_timeout=20.0,
            follow_redirects=True,
            max_redirects=5,
            decompress_response=True,
            proxy_password='',
            allow_nonstandard_methods=False,
            validate_cert=True)

        def __init__(self, url, method="GET", headers=None, body=None,
                     auth_username=None, auth_password=None, auth_mode=None,
                     connect_timeout=None, request_timeout=None,
                     if_modified_since=None, follow_redirects=None,
                     max_redirects=None, user_agent=None, use_gzip=None,
                     network_interface=None, streaming_callback=None,
                     header_callback=None, prepare_curl_callback=None,
                     proxy_host=None, proxy_port=None, proxy_username=None,
                     proxy_password=None, proxy_auth_mode=None,
                     allow_nonstandard_methods=None, validate_cert=None,
                     ca_certs=None, allow_ipv6=None, client_key=None,
                     client_cert=None, body_producer=None,
                     expect_100_continue=False, decompress_response=None,
                     ssl_options=None):
            r"""All parameters except ``url`` are optional.

            :arg string url: URL to fetch
            :arg string method: HTTP method, e.g. "GET" or "POST"
            :arg headers: Additional HTTP headers to pass on the request
            :type headers: `~tornado4.httputil.HTTPHeaders` or `dict`
            :arg body: HTTP request body as a string (byte or unicode; if unicode
               the utf-8 encoding will be used)
            :arg body_producer: Callable used for lazy/asynchronous request bodies.
               It is called with one argument, a ``write`` function, and should
               return a `.Future`.  It should call the write function with new
               data as it becomes available.  The write function returns a
               `.Future` which can be used for flow control.
               Only one of ``body`` and ``body_producer`` may
               be specified.  ``body_producer`` is not supported on
               ``curl_httpclient``.  When using ``body_producer`` it is recommended
               to pass a ``Content-Length`` in the headers as otherwise chunked
               encoding will be used, and many servers do not support chunked
               encoding on requests.  New in Tornado 4.0
            :arg string auth_username: Username for HTTP authentication
            :arg string auth_password: Password for HTTP authentication
            :arg string auth_mode: Authentication mode; default is "basic".
               Allowed values are implementation-defined; ``curl_httpclient``
               supports "basic" and "digest"; ``simple_httpclient`` only supports
               "basic"
            :arg float connect_timeout: Timeout for initial connection in seconds,
               default 20 seconds
            :arg float request_timeout: Timeout for entire request in seconds,
               default 20 seconds
            :arg if_modified_since: Timestamp for ``If-Modified-Since`` header
            :type if_modified_since: `datetime` or `float`
            :arg bool follow_redirects: Should redirects be followed automatically
               or return the 3xx response? Default True.
            :arg int max_redirects: Limit for ``follow_redirects``, default 5.
            :arg string user_agent: String to send as ``User-Agent`` header
            :arg bool decompress_response: Request a compressed response from
               the server and decompress it after downloading.  Default is True.
               New in Tornado 4.0.
            :arg bool use_gzip: Deprecated alias for ``decompress_response``
               since Tornado 4.0.
            :arg string network_interface: Network interface to use for request.
               ``curl_httpclient`` only; see note below.
            :arg callable streaming_callback: If set, ``streaming_callback`` will
               be run with each chunk of data as it is received, and
               ``HTTPResponse.body`` and ``HTTPResponse.buffer`` will be empty in
               the final response.
            :arg callable header_callback: If set, ``header_callback`` will
               be run with each header line as it is received (including the
               first line, e.g. ``HTTP/1.0 200 OK\r\n``, and a final line
               containing only ``\r\n``.  All lines include the trailing newline
               characters).  ``HTTPResponse.headers`` will be empty in the final
               response.  This is most useful in conjunction with
               ``streaming_callback``, because it's the only way to get access to
               header data while the request is in progress.
            :arg callable prepare_curl_callback: If set, will be called with
               a ``pycurl.Curl`` object to allow the application to make additional
               ``setopt`` calls.
            :arg string proxy_host: HTTP proxy hostname.  To use proxies,
               ``proxy_host`` and ``proxy_port`` must be set; ``proxy_username``,
               ``proxy_pass`` and ``proxy_auth_mode`` are optional.  Proxies are
               currently only supported with ``curl_httpclient``.
            :arg int proxy_port: HTTP proxy port
            :arg string proxy_username: HTTP proxy username
            :arg string proxy_password: HTTP proxy password
            :arg string proxy_auth_mode: HTTP proxy Authentication mode;
               default is "basic". supports "basic" and "digest"
            :arg bool allow_nonstandard_methods: Allow unknown values for ``method``
               argument? Default is False.
            :arg bool validate_cert: For HTTPS requests, validate the server's
               certificate? Default is True.
            :arg string ca_certs: filename of CA certificates in PEM format,
               or None to use defaults.  See note below when used with
               ``curl_httpclient``.
            :arg string client_key: Filename for client SSL key, if any.  See
               note below when used with ``curl_httpclient``.
            :arg string client_cert: Filename for client SSL certificate, if any.
               See note below when used with ``curl_httpclient``.
            :arg ssl.SSLContext ssl_options: `ssl.SSLContext` object for use in
               ``simple_httpclient`` (unsupported by ``curl_httpclient``).
               Overrides ``validate_cert``, ``ca_certs``, ``client_key``,
               and ``client_cert``.
            :arg bool allow_ipv6: Use IPv6 when available?  Default is true.
            :arg bool expect_100_continue: If true, send the
               ``Expect: 100-continue`` header and wait for a continue response
               before sending the request body.  Only supported with
               simple_httpclient.

            .. note::

                When using ``curl_httpclient`` certain options may be
                inherited by subsequent fetches because ``pycurl`` does
                not allow them to be cleanly reset.  This applies to the
                ``ca_certs``, ``client_key``, ``client_cert``, and
                ``network_interface`` arguments.  If you use these
                options, you should pass them on every request (you don't
                have to always use the same values, but it's not possible
                to mix requests that specify these options with ones that
                use the defaults).

            .. versionadded:: 3.1
               The ``auth_mode`` argument.

            .. versionadded:: 4.0
               The ``body_producer`` and ``expect_100_continue`` arguments.

            .. versionadded:: 4.2
               The ``ssl_options`` argument.

            .. versionadded:: 4.5
               The ``proxy_auth_mode`` argument.
            """
            # Note that some of these attributes go through property setters
            # defined below.
            self.headers = headers
            if if_modified_since:
                self.headers["If-Modified-Since"] = httputil.format_timestamp(
                    if_modified_since)
            self.proxy_host = proxy_host
            self.proxy_port = proxy_port
            self.proxy_username = proxy_username
            self.proxy_password = proxy_password
            self.proxy_auth_mode = proxy_auth_mode
            self.url = url
            self.method = method
            self.body = body
            self.body_producer = body_producer
            self.auth_username = auth_username
            self.auth_password = auth_password
            self.auth_mode = auth_mode
            self.connect_timeout = connect_timeout
            self.request_timeout = request_timeout
            self.follow_redirects = follow_redirects
            self.max_redirects = max_redirects
            self.user_agent = user_agent
            if decompress_response is not None:
                self.decompress_response = decompress_response
            else:
                self.decompress_response = use_gzip
            self.network_interface = network_interface
            self.streaming_callback = streaming_callback
            self.header_callback = header_callback
            self.prepare_curl_callback = prepare_curl_callback
            self.allow_nonstandard_methods = allow_nonstandard_methods
            self.validate_cert = validate_cert
            self.ca_certs = ca_certs
            self.allow_ipv6 = allow_ipv6
            self.client_key = client_key
            self.client_cert = client_cert
            self.ssl_options = ssl_options
            self.expect_100_continue = expect_100_continue
            self.start_time = time.time()

        @property
        def headers(self):
            return self._headers

        @headers.setter
        def headers(self, value):
            if value is None:
                self._headers = httputil.HTTPHeaders()
            else:
                self._headers = value

        @property
        def body(self):
            return self._body

        @body.setter
        def body(self, value):
            self._body = utf8(value)

        @property
        def body_producer(self):
            return self._body_producer

        @body_producer.setter
        def body_producer(self, value):
            self._body_producer = stack_context.wrap(value)

        @property
        def streaming_callback(self):
            return self._streaming_callback

        @streaming_callback.setter
        def streaming_callback(self, value):
            self._streaming_callback = stack_context.wrap(value)

        @property
        def header_callback(self):
            return self._header_callback

        @header_callback.setter
        def header_callback(self, value):
            self._header_callback = stack_context.wrap(value)

        @property
        def prepare_curl_callback(self):
            return self._prepare_curl_callback

        @prepare_curl_callback.setter
        def prepare_curl_callback(self, value):
            self._prepare_curl_callback = stack_context.wrap(value)

    class HTTPResponse(object):
        """HTTP Response object.

        Attributes:

        * request: HTTPRequest object

        * code: numeric HTTP status code, e.g. 200 or 404

        * reason: human-readable reason phrase describing the status code

        * headers: `tornado4.httputil.HTTPHeaders` object

        * effective_url: final location of the resource after following any
          redirects

        * buffer: ``cStringIO`` object for response body

        * body: response body as bytes (created on demand from ``self.buffer``)

        * error: Exception object, if any

        * request_time: seconds from request start to finish

        * time_info: dictionary of diagnostic timing information from the request.
          Available data are subject to change, but currently uses timings
          available from http://curl.haxx.se/libcurl/c/curl_easy_getinfo.html,
          plus ``queue``, which is the delay (if any) introduced by waiting for
          a slot under `AsyncHTTPClient`'s ``max_clients`` setting.
        """
        def __init__(self, request, code, headers=None, buffer=None,
                     effective_url=None, error=None, request_time=None,
                     time_info=None, reason=None):
            if isinstance(request, _RequestProxy):
                self.request = request.request
            else:
                self.request = request
            self.code = code
            self.reason = reason or httputil.responses.get(code, "Unknown")
            if headers is not None:
                self.headers = headers
            else:
                self.headers = httputil.HTTPHeaders()
            self.buffer = buffer
            self._body = None
            if effective_url is None:
                self.effective_url = request.url
            else:
                self.effective_url = effective_url
            if error is None:
                if self.code < 200 or self.code >= 300:
                    self.error = HTTPError(self.code, message=self.reason,
                                           response=self)
                else:
                    self.error = None
            else:
                self.error = error
            self.request_time = request_time
            self.time_info = time_info or {}

        @property
        def body(self):
            if self.buffer is None:
                return None
            elif self._body is None:
                self._body = self.buffer.getvalue()

            return self._body

        def rethrow(self):
            """If there was an error on the request, raise an `HTTPError`."""
            if self.error:
                raise self.error

        def __repr__(self):
            args = ",".join("%s=%r" % i for i in sorted(self.__dict__.items()))
            return "%s(%s)" % (self.__class__.__name__, args)

    class HTTPError(Exception):
        """Exception thrown for an unsuccessful HTTP request.

        Attributes:

        * ``code`` - HTTP error integer error code, e.g. 404.  Error code 599 is
          used when no HTTP response was received, e.g. for a timeout.

        * ``response`` - `HTTPResponse` object, if any.

        Note that if ``follow_redirects`` is False, redirects become HTTPErrors,
        and you can look at ``error.response.headers['Location']`` to see the
        destination of the redirect.
        """
        def __init__(self, code, message=None, response=None):
            self.code = code
            self.message = message or httputil.responses.get(code, "Unknown")
            self.response = response
            super(HTTPError, self).__init__(code, message, response)

        def __str__(self):
            return "HTTP %d: %s" % (self.code, self.message)

        # There is a cyclic reference between self and self.response,
        # which breaks the default __repr__ implementation.
        # (especially on pypy, which doesn't have the same recursion
        # detection as cpython).
        __repr__ = __str__

    class _RequestProxy(object):
        """Combines an object with a dictionary of defaults.

        Used internally by AsyncHTTPClient implementations.
        """
        def __init__(self, request, defaults):
            self.request = request
            self.defaults = defaults

        def __getattr__(self, name):
            request_attr = getattr(self.request, name)
            if request_attr is not None:
                return request_attr
            elif self.defaults is not None:
                return self.defaults.get(name, None)
            else:
                return None

    def main():
        from tornado4.options import define, options, parse_command_line
        define("print_headers", type=bool, default=False)
        define("print_body", type=bool, default=True)
        define("follow_redirects", type=bool, default=True)
        define("validate_cert", type=bool, default=True)
        args = parse_command_line()
        client = HTTPClient()
        for arg in args:
            try:
                response = client.fetch(arg,
                                        follow_redirects=options.follow_redirects,
                                        validate_cert=options.validate_cert,
                                        )
            except HTTPError as e:
                if e.response is not None:
                    response = e.response
                else:
                    raise
            if options.print_headers:
                print(response.headers)
            if options.print_body:
                print(native_str(response.body))
        client.close()

    if __name__ == "__main__":
        main()