Source code for tornado.simple_httpclient

from tornado.escape import _unicode
from tornado import gen, version
from tornado.httpclient import (
    HTTPResponse,
    HTTPError,
    AsyncHTTPClient,
    main,
    _RequestProxy,
    HTTPRequest,
)
from tornado import httputil
from tornado.http1connection import HTTP1Connection, HTTP1ConnectionParameters
from tornado.ioloop import IOLoop
from tornado.iostream import StreamClosedError, IOStream
from tornado.netutil import (
    Resolver,
    OverrideResolver,
    _client_ssl_defaults,
    is_valid_ip,
)
from tornado.log import gen_log
from tornado.tcpclient import TCPClient

import base64
import collections
import copy
import functools
import re
import socket
import ssl
import sys
import time
from io import BytesIO
import urllib.parse

from typing import Dict, Any, Callable, Optional, Type, Union
from types import TracebackType
import typing

if typing.TYPE_CHECKING:
    from typing import Deque, Tuple, List  # noqa: F401


class HTTPTimeoutError(HTTPError):
    """Error raised by SimpleAsyncHTTPClient on timeout.

    For historical reasons, this is a subclass of `.HTTPClientError`
    which simulates a response code of 599.

    .. versionadded:: 5.1
    """

    def __init__(self, message: str) -> None:
        super().__init__(599, message=message)

    def __str__(self) -> str:
        return self.message or "Timeout"


class HTTPStreamClosedError(HTTPError):
    """Error raised by SimpleAsyncHTTPClient when the underlying stream is closed.

    When a more specific exception is available (such as `ConnectionResetError`),
    it may be raised instead of this one.

    For historical reasons, this is a subclass of `.HTTPClientError`
    which simulates a response code of 599.

    .. versionadded:: 5.1
    """

    def __init__(self, message: str) -> None:
        super().__init__(599, message=message)

    def __str__(self) -> str:
        return self.message or "Stream closed"


[docs]class SimpleAsyncHTTPClient(AsyncHTTPClient): """Non-blocking HTTP client with no external dependencies. This class implements an HTTP 1.1 client on top of Tornado's IOStreams. Some features found in the curl-based AsyncHTTPClient are not yet supported. In particular, proxies are not supported, connections are not reused, and callers cannot select the network interface to be used. """
[docs] def initialize( # type: ignore self, max_clients: int = 10, hostname_mapping: Optional[Dict[str, str]] = None, max_buffer_size: int = 104857600, resolver: Optional[Resolver] = None, defaults: Optional[Dict[str, Any]] = None, max_header_size: Optional[int] = None, max_body_size: Optional[int] = None, ) -> None: """Creates a AsyncHTTPClient. Only a single AsyncHTTPClient instance exists per IOLoop in order to provide limitations on the number of pending connections. ``force_instance=True`` may be used to suppress this behavior. Note that because of this implicit reuse, unless ``force_instance`` is used, only the first call to the constructor actually uses its arguments. It is recommended to use the ``configure`` method instead of the constructor to ensure that arguments take effect. ``max_clients`` is the number of concurrent requests that can be in progress; when this limit is reached additional requests will be queued. Note that time spent waiting in this queue still counts against the ``request_timeout``. ``hostname_mapping`` is a dictionary mapping hostnames to IP addresses. It can be used to make local DNS changes when modifying system-wide settings like ``/etc/hosts`` is not possible or desirable (e.g. in unittests). ``max_buffer_size`` (default 100MB) is the number of bytes that can be read into memory at once. ``max_body_size`` (defaults to ``max_buffer_size``) is the largest response body that the client will accept. Without a ``streaming_callback``, the smaller of these two limits applies; with a ``streaming_callback`` only ``max_body_size`` does. .. versionchanged:: 4.2 Added the ``max_body_size`` argument. """ super().initialize(defaults=defaults) self.max_clients = max_clients self.queue = ( collections.deque() ) # type: Deque[Tuple[object, HTTPRequest, Callable[[HTTPResponse], None]]] self.active = ( {} ) # type: Dict[object, Tuple[HTTPRequest, Callable[[HTTPResponse], None]]] self.waiting = ( {} ) # type: Dict[object, Tuple[HTTPRequest, Callable[[HTTPResponse], None], object]] self.max_buffer_size = max_buffer_size self.max_header_size = max_header_size self.max_body_size = max_body_size # TCPClient could create a Resolver for us, but we have to do it # ourselves to support hostname_mapping. if resolver: self.resolver = resolver self.own_resolver = False else: self.resolver = Resolver() self.own_resolver = True if hostname_mapping is not None: self.resolver = OverrideResolver( resolver=self.resolver, mapping=hostname_mapping ) self.tcp_client = TCPClient(resolver=self.resolver)
def close(self) -> None: super().close() if self.own_resolver: self.resolver.close() self.tcp_client.close() def fetch_impl( self, request: HTTPRequest, callback: Callable[[HTTPResponse], None] ) -> None: key = object() self.queue.append((key, request, callback)) assert request.connect_timeout is not None assert request.request_timeout is not None timeout_handle = None if len(self.active) >= self.max_clients: timeout = ( min(request.connect_timeout, request.request_timeout) or request.connect_timeout or request.request_timeout ) # min but skip zero if timeout: timeout_handle = self.io_loop.add_timeout( self.io_loop.time() + timeout, functools.partial(self._on_timeout, key, "in request queue"), ) self.waiting[key] = (request, callback, timeout_handle) self._process_queue() if self.queue: gen_log.debug( "max_clients limit reached, request queued. " "%d active, %d queued requests." % (len(self.active), len(self.queue)) ) def _process_queue(self) -> None: while self.queue and len(self.active) < self.max_clients: key, request, callback = self.queue.popleft() if key not in self.waiting: continue self._remove_timeout(key) self.active[key] = (request, callback) release_callback = functools.partial(self._release_fetch, key) self._handle_request(request, release_callback, callback) def _connection_class(self) -> type: return _HTTPConnection def _handle_request( self, request: HTTPRequest, release_callback: Callable[[], None], final_callback: Callable[[HTTPResponse], None], ) -> None: self._connection_class()( self, request, release_callback, final_callback, self.max_buffer_size, self.tcp_client, self.max_header_size, self.max_body_size, ) def _release_fetch(self, key: object) -> None: del self.active[key] self._process_queue() def _remove_timeout(self, key: object) -> None: if key in self.waiting: request, callback, timeout_handle = self.waiting[key] if timeout_handle is not None: self.io_loop.remove_timeout(timeout_handle) del self.waiting[key] def _on_timeout(self, key: object, info: Optional[str] = None) -> None: """Timeout callback of request. Construct a timeout HTTPResponse when a timeout occurs. :arg object key: A simple object to mark the request. :info string key: More detailed timeout information. """ request, callback, timeout_handle = self.waiting[key] self.queue.remove((key, request, callback)) error_message = "Timeout {0}".format(info) if info else "Timeout" timeout_response = HTTPResponse( request, 599, error=HTTPTimeoutError(error_message), request_time=self.io_loop.time() - request.start_time, ) self.io_loop.add_callback(callback, timeout_response) del self.waiting[key]
class _HTTPConnection(httputil.HTTPMessageDelegate): _SUPPORTED_METHODS = set( ["GET", "HEAD", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"] ) def __init__( self, client: Optional[SimpleAsyncHTTPClient], request: HTTPRequest, release_callback: Callable[[], None], final_callback: Callable[[HTTPResponse], None], max_buffer_size: int, tcp_client: TCPClient, max_header_size: int, max_body_size: int, ) -> None: self.io_loop = IOLoop.current() self.start_time = self.io_loop.time() self.start_wall_time = time.time() self.client = client self.request = request self.release_callback = release_callback self.final_callback = final_callback self.max_buffer_size = max_buffer_size self.tcp_client = tcp_client self.max_header_size = max_header_size self.max_body_size = max_body_size self.code = None # type: Optional[int] self.headers = None # type: Optional[httputil.HTTPHeaders] self.chunks = [] # type: List[bytes] self._decompressor = None # Timeout handle returned by IOLoop.add_timeout self._timeout = None # type: object self._sockaddr = None IOLoop.current().add_future( gen.convert_yielded(self.run()), lambda f: f.result() ) async def run(self) -> None: try: self.parsed = urllib.parse.urlsplit(_unicode(self.request.url)) if self.parsed.scheme not in ("http", "https"): raise ValueError("Unsupported url scheme: %s" % self.request.url) # urlsplit results have hostname and port results, but they # didn't support ipv6 literals until python 2.7. netloc = self.parsed.netloc if "@" in netloc: userpass, _, netloc = netloc.rpartition("@") host, port = httputil.split_host_and_port(netloc) if port is None: port = 443 if self.parsed.scheme == "https" else 80 if re.match(r"^\[.*\]$", host): # raw ipv6 addresses in urls are enclosed in brackets host = host[1:-1] self.parsed_hostname = host # save final host for _on_connect if self.request.allow_ipv6 is False: af = socket.AF_INET else: af = socket.AF_UNSPEC ssl_options = self._get_ssl_options(self.parsed.scheme) source_ip = None if self.request.network_interface: if is_valid_ip(self.request.network_interface): source_ip = self.request.network_interface else: raise ValueError( "Unrecognized IPv4 or IPv6 address for network_interface, got %r" % (self.request.network_interface,) ) if self.request.connect_timeout and self.request.request_timeout: timeout = min( self.request.connect_timeout, self.request.request_timeout ) elif self.request.connect_timeout: timeout = self.request.connect_timeout elif self.request.request_timeout: timeout = self.request.request_timeout else: timeout = 0 if timeout: self._timeout = self.io_loop.add_timeout( self.start_time + timeout, functools.partial(self._on_timeout, "while connecting"), ) stream = await self.tcp_client.connect( host, port, af=af, ssl_options=ssl_options, max_buffer_size=self.max_buffer_size, source_ip=source_ip, ) if self.final_callback is None: # final_callback is cleared if we've hit our timeout. stream.close() return self.stream = stream self.stream.set_close_callback(self.on_connection_close) self._remove_timeout() if self.final_callback is None: return if self.request.request_timeout: self._timeout = self.io_loop.add_timeout( self.start_time + self.request.request_timeout, functools.partial(self._on_timeout, "during request"), ) if ( self.request.method not in self._SUPPORTED_METHODS and not self.request.allow_nonstandard_methods ): raise KeyError("unknown method %s" % self.request.method) for key in ( "proxy_host", "proxy_port", "proxy_username", "proxy_password", "proxy_auth_mode", ): if getattr(self.request, key, None): raise NotImplementedError("%s not supported" % key) if "Connection" not in self.request.headers: self.request.headers["Connection"] = "close" if "Host" not in self.request.headers: if "@" in self.parsed.netloc: self.request.headers["Host"] = self.parsed.netloc.rpartition("@")[ -1 ] else: self.request.headers["Host"] = self.parsed.netloc username, password = None, None if self.parsed.username is not None: username, password = self.parsed.username, self.parsed.password elif self.request.auth_username is not None: username = self.request.auth_username password = self.request.auth_password or "" if username is not None: assert password is not None if self.request.auth_mode not in (None, "basic"): raise ValueError("unsupported auth_mode %s", self.request.auth_mode) self.request.headers["Authorization"] = "Basic " + _unicode( base64.b64encode( httputil.encode_username_password(username, password) ) ) if self.request.user_agent: self.request.headers["User-Agent"] = self.request.user_agent elif self.request.headers.get("User-Agent") is None: self.request.headers["User-Agent"] = "Tornado/{}".format(version) if not self.request.allow_nonstandard_methods: # Some HTTP methods nearly always have bodies while others # almost never do. Fail in this case unless the user has # opted out of sanity checks with allow_nonstandard_methods. body_expected = self.request.method in ("POST", "PATCH", "PUT") body_present = ( self.request.body is not None or self.request.body_producer is not None ) if (body_expected and not body_present) or ( body_present and not body_expected ): raise ValueError( "Body must %sbe None for method %s (unless " "allow_nonstandard_methods is true)" % ("not " if body_expected else "", self.request.method) ) if self.request.expect_100_continue: self.request.headers["Expect"] = "100-continue" if self.request.body is not None: # When body_producer is used the caller is responsible for # setting Content-Length (or else chunked encoding will be used). self.request.headers["Content-Length"] = str(len(self.request.body)) if ( self.request.method == "POST" and "Content-Type" not in self.request.headers ): self.request.headers[ "Content-Type" ] = "application/x-www-form-urlencoded" if self.request.decompress_response: self.request.headers["Accept-Encoding"] = "gzip" req_path = (self.parsed.path or "/") + ( ("?" + self.parsed.query) if self.parsed.query else "" ) self.connection = self._create_connection(stream) start_line = httputil.RequestStartLine(self.request.method, req_path, "") self.connection.write_headers(start_line, self.request.headers) if self.request.expect_100_continue: await self.connection.read_response(self) else: await self._write_body(True) except Exception: if not self._handle_exception(*sys.exc_info()): raise def _get_ssl_options( self, scheme: str ) -> Union[None, Dict[str, Any], ssl.SSLContext]: if scheme == "https": if self.request.ssl_options is not None: return self.request.ssl_options # If we are using the defaults, don't construct a # new SSLContext. if ( self.request.validate_cert and self.request.ca_certs is None and self.request.client_cert is None and self.request.client_key is None ): return _client_ssl_defaults ssl_ctx = ssl.create_default_context( ssl.Purpose.SERVER_AUTH, cafile=self.request.ca_certs ) if not self.request.validate_cert: ssl_ctx.check_hostname = False ssl_ctx.verify_mode = ssl.CERT_NONE if self.request.client_cert is not None: ssl_ctx.load_cert_chain( self.request.client_cert, self.request.client_key ) if hasattr(ssl, "OP_NO_COMPRESSION"): # See netutil.ssl_options_to_context ssl_ctx.options |= ssl.OP_NO_COMPRESSION return ssl_ctx return None def _on_timeout(self, info: Optional[str] = None) -> None: """Timeout callback of _HTTPConnection instance. Raise a `HTTPTimeoutError` when a timeout occurs. :info string key: More detailed timeout information. """ self._timeout = None error_message = "Timeout {0}".format(info) if info else "Timeout" if self.final_callback is not None: self._handle_exception( HTTPTimeoutError, HTTPTimeoutError(error_message), None ) def _remove_timeout(self) -> None: if self._timeout is not None: self.io_loop.remove_timeout(self._timeout) self._timeout = None def _create_connection(self, stream: IOStream) -> HTTP1Connection: stream.set_nodelay(True) connection = HTTP1Connection( stream, True, HTTP1ConnectionParameters( no_keep_alive=True, max_header_size=self.max_header_size, max_body_size=self.max_body_size, decompress=bool(self.request.decompress_response), ), self._sockaddr, ) return connection async def _write_body(self, start_read: bool) -> None: if self.request.body is not None: self.connection.write(self.request.body) elif self.request.body_producer is not None: fut = self.request.body_producer(self.connection.write) if fut is not None: await fut self.connection.finish() if start_read: try: await self.connection.read_response(self) except StreamClosedError: if not self._handle_exception(*sys.exc_info()): raise def _release(self) -> None: if self.release_callback is not None: release_callback = self.release_callback self.release_callback = None # type: ignore release_callback() def _run_callback(self, response: HTTPResponse) -> None: self._release() if self.final_callback is not None: final_callback = self.final_callback self.final_callback = None # type: ignore self.io_loop.add_callback(final_callback, response) def _handle_exception( self, typ: "Optional[Type[BaseException]]", value: Optional[BaseException], tb: Optional[TracebackType], ) -> bool: if self.final_callback: self._remove_timeout() if isinstance(value, StreamClosedError): if value.real_error is None: value = HTTPStreamClosedError("Stream closed") else: value = value.real_error self._run_callback( HTTPResponse( self.request, 599, error=value, request_time=self.io_loop.time() - self.start_time, start_time=self.start_wall_time, ) ) if hasattr(self, "stream"): # TODO: this may cause a StreamClosedError to be raised # by the connection's Future. Should we cancel the # connection more gracefully? self.stream.close() return True else: # If our callback has already been called, we are probably # catching an exception that is not caused by us but rather # some child of our callback. Rather than drop it on the floor, # pass it along, unless it's just the stream being closed. return isinstance(value, StreamClosedError) def on_connection_close(self) -> None: if self.final_callback is not None: message = "Connection closed" if self.stream.error: raise self.stream.error try: raise HTTPStreamClosedError(message) except HTTPStreamClosedError: self._handle_exception(*sys.exc_info()) async def headers_received( self, first_line: Union[httputil.ResponseStartLine, httputil.RequestStartLine], headers: httputil.HTTPHeaders, ) -> None: assert isinstance(first_line, httputil.ResponseStartLine) if self.request.expect_100_continue and first_line.code == 100: await self._write_body(False) return self.code = first_line.code self.reason = first_line.reason self.headers = headers if self._should_follow_redirect(): return if self.request.header_callback is not None: # Reassemble the start line. self.request.header_callback("%s %s %s\r\n" % first_line) for k, v in self.headers.get_all(): self.request.header_callback("%s: %s\r\n" % (k, v)) self.request.header_callback("\r\n") def _should_follow_redirect(self) -> bool: if self.request.follow_redirects: assert self.request.max_redirects is not None return ( self.code in (301, 302, 303, 307, 308) and self.request.max_redirects > 0 and self.headers is not None and self.headers.get("Location") is not None ) return False def finish(self) -> None: assert self.code is not None data = b"".join(self.chunks) self._remove_timeout() original_request = getattr(self.request, "original_request", self.request) if self._should_follow_redirect(): assert isinstance(self.request, _RequestProxy) assert self.headers is not None new_request = copy.copy(self.request.request) new_request.url = urllib.parse.urljoin( self.request.url, self.headers["Location"] ) assert self.request.max_redirects is not None new_request.max_redirects = self.request.max_redirects - 1 del new_request.headers["Host"] # https://tools.ietf.org/html/rfc7231#section-6.4 # # The original HTTP spec said that after a 301 or 302 # redirect, the request method should be preserved. # However, browsers implemented this by changing the # method to GET, and the behavior stuck. 303 redirects # always specified this POST-to-GET behavior, arguably # for *all* methods, but libcurl < 7.70 only does this # for POST, while libcurl >= 7.70 does it for other methods. if (self.code == 303 and self.request.method != "HEAD") or ( self.code in (301, 302) and self.request.method == "POST" ): new_request.method = "GET" new_request.body = None # type: ignore for h in [ "Content-Length", "Content-Type", "Content-Encoding", "Transfer-Encoding", ]: try: del self.request.headers[h] except KeyError: pass new_request.original_request = original_request # type: ignore final_callback = self.final_callback self.final_callback = None # type: ignore self._release() assert self.client is not None fut = self.client.fetch(new_request, raise_error=False) fut.add_done_callback(lambda f: final_callback(f.result())) self._on_end_request() return if self.request.streaming_callback: buffer = BytesIO() else: buffer = BytesIO(data) # TODO: don't require one big string? response = HTTPResponse( original_request, self.code, reason=getattr(self, "reason", None), headers=self.headers, request_time=self.io_loop.time() - self.start_time, start_time=self.start_wall_time, buffer=buffer, effective_url=self.request.url, ) self._run_callback(response) self._on_end_request() def _on_end_request(self) -> None: self.stream.close() def data_received(self, chunk: bytes) -> None: if self._should_follow_redirect(): # We're going to follow a redirect so just discard the body. return if self.request.streaming_callback is not None: self.request.streaming_callback(chunk) else: self.chunks.append(chunk) if __name__ == "__main__": AsyncHTTPClient.configure(SimpleAsyncHTTPClient) main()