Source code for tornado.simple_httpclient

#!/usr/bin/env python
from __future__ import absolute_import, division, print_function, with_statement

from tornado.escape import utf8, _unicode
from tornado import gen
from tornado.httpclient import HTTPResponse, HTTPError, AsyncHTTPClient, main, _RequestProxy
from tornado import httputil
from tornado.http1connection import HTTP1Connection, HTTP1ConnectionParameters
from tornado.iostream import StreamClosedError
from tornado.netutil import Resolver, OverrideResolver, _client_ssl_defaults
from tornado.log import gen_log
from tornado import stack_context
from tornado.tcpclient import TCPClient

import base64
import collections
import copy
import functools
import re
import socket
import sys
from io import BytesIO


try:
    import urlparse  # py2
except ImportError:
    import urllib.parse as urlparse  # py3

try:
    import ssl
except ImportError:
    # ssl is not available on Google App Engine.
    ssl = None

try:
    import certifi
except ImportError:
    certifi = None


def _default_ca_certs():
    if certifi is None:
        raise Exception("The 'certifi' package is required to use https "
                        "in simple_httpclient")
    return certifi.where()


[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(self, io_loop, max_clients=10, hostname_mapping=None, max_buffer_size=104857600, resolver=None, defaults=None, max_header_size=None, max_body_size=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(SimpleAsyncHTTPClient, self).initialize(io_loop, defaults=defaults) self.max_clients = max_clients self.queue = collections.deque() self.active = {} self.waiting = {} 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(io_loop=io_loop) 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, io_loop=io_loop)
def close(self): super(SimpleAsyncHTTPClient, self).close() if self.own_resolver: self.resolver.close() self.tcp_client.close() def fetch_impl(self, request, callback): key = object() self.queue.append((key, request, callback)) if not len(self.active) < self.max_clients: timeout_handle = self.io_loop.add_timeout( self.io_loop.time() + min(request.connect_timeout, request.request_timeout), functools.partial(self._on_timeout, key)) else: timeout_handle = None 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): with stack_context.NullContext(): 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): return _HTTPConnection def _handle_request(self, request, release_callback, final_callback): self._connection_class()( self.io_loop, 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): del self.active[key] self._process_queue() def _remove_timeout(self, key): 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): request, callback, timeout_handle = self.waiting[key] self.queue.remove((key, request, callback)) timeout_response = HTTPResponse( request, 599, error=HTTPError(599, "Timeout"), 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, io_loop, client, request, release_callback, final_callback, max_buffer_size, tcp_client, max_header_size, max_body_size): self.start_time = io_loop.time() self.io_loop = io_loop 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 self.headers = None self.chunks = [] self._decompressor = None # Timeout handle returned by IOLoop.add_timeout self._timeout = None self._sockaddr = None with stack_context.ExceptionStackContext(self._handle_exception): self.parsed = urlparse.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 request.allow_ipv6 is False: af = socket.AF_INET else: af = socket.AF_UNSPEC ssl_options = self._get_ssl_options(self.parsed.scheme) timeout = min(self.request.connect_timeout, self.request.request_timeout) if timeout: self._timeout = self.io_loop.add_timeout( self.start_time + timeout, stack_context.wrap(self._on_timeout)) self.tcp_client.connect(host, port, af=af, ssl_options=ssl_options, max_buffer_size=self.max_buffer_size, callback=self._on_connect) def _get_ssl_options(self, scheme): 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_options = {} if self.request.validate_cert: ssl_options["cert_reqs"] = ssl.CERT_REQUIRED if self.request.ca_certs is not None: ssl_options["ca_certs"] = self.request.ca_certs elif not hasattr(ssl, 'create_default_context'): # When create_default_context is present, # we can omit the "ca_certs" parameter entirely, # which avoids the dependency on "certifi" for py34. ssl_options["ca_certs"] = _default_ca_certs() if self.request.client_key is not None: ssl_options["keyfile"] = self.request.client_key if self.request.client_cert is not None: ssl_options["certfile"] = self.request.client_cert # SSL interoperability is tricky. We want to disable # SSLv2 for security reasons; it wasn't disabled by default # until openssl 1.0. The best way to do this is to use # the SSL_OP_NO_SSLv2, but that wasn't exposed to python # until 3.2. Python 2.7 adds the ciphers argument, which # can also be used to disable SSLv2. As a last resort # on python 2.6, we set ssl_version to TLSv1. This is # more narrow than we'd like since it also breaks # compatibility with servers configured for SSLv3 only, # but nearly all servers support both SSLv3 and TLSv1: # http://blog.ivanristic.com/2011/09/ssl-survey-protocol-support.html if sys.version_info >= (2, 7): # In addition to disabling SSLv2, we also exclude certain # classes of insecure ciphers. ssl_options["ciphers"] = "DEFAULT:!SSLv2:!EXPORT:!DES" else: # This is really only necessary for pre-1.0 versions # of openssl, but python 2.6 doesn't expose version # information. ssl_options["ssl_version"] = ssl.PROTOCOL_TLSv1 return ssl_options return None def _on_timeout(self): self._timeout = None if self.final_callback is not None: raise HTTPError(599, "Timeout") def _remove_timeout(self): if self._timeout is not None: self.io_loop.remove_timeout(self._timeout) self._timeout = None def _on_connect(self, stream): 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, stack_context.wrap(self._on_timeout)) 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 ('network_interface', 'proxy_host', 'proxy_port', 'proxy_username', 'proxy_password'): 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: if self.request.auth_mode not in (None, "basic"): raise ValueError("unsupported auth_mode %s", self.request.auth_mode) auth = utf8(username) + b":" + utf8(password) self.request.headers["Authorization"] = (b"Basic " + base64.b64encode(auth)) if self.request.user_agent: self.request.headers["User-Agent"] = self.request.user_agent 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: self._read_response() else: self._write_body(True) def _create_connection(self, stream): 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=self.request.decompress_response), self._sockaddr) return connection def _write_body(self, start_read): 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: fut = gen.convert_yielded(fut) def on_body_written(fut): fut.result() self.connection.finish() if start_read: self._read_response() self.io_loop.add_future(fut, on_body_written) return self.connection.finish() if start_read: self._read_response() def _read_response(self): # Ensure that any exception raised in read_response ends up in our # stack context. self.io_loop.add_future( self.connection.read_response(self), lambda f: f.result()) def _release(self): if self.release_callback is not None: release_callback = self.release_callback self.release_callback = None release_callback() def _run_callback(self, response): self._release() if self.final_callback is not None: final_callback = self.final_callback self.final_callback = None self.io_loop.add_callback(final_callback, response) def _handle_exception(self, typ, value, tb): if self.final_callback: self._remove_timeout() if isinstance(value, StreamClosedError): if value.real_error is None: value = HTTPError(599, "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, )) 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): if self.final_callback is not None: message = "Connection closed" if self.stream.error: raise self.stream.error try: raise HTTPError(599, message) except HTTPError: self._handle_exception(*sys.exc_info()) def headers_received(self, first_line, headers): if self.request.expect_100_continue and first_line.code == 100: 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): return (self.request.follow_redirects and self.request.max_redirects > 0 and self.code in (301, 302, 303, 307)) def finish(self): 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) new_request = copy.copy(self.request.request) new_request.url = urlparse.urljoin(self.request.url, self.headers["Location"]) new_request.max_redirects = self.request.max_redirects - 1 del new_request.headers["Host"] # http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.4 # Client SHOULD make a GET request after a 303. # According to the spec, 302 should be followed by the same # method as the original request, but in practice browsers # treat 302 the same as 303, and many servers use 302 for # compatibility with pre-HTTP/1.1 user agents which don't # understand the 303 status. if self.code in (302, 303): new_request.method = "GET" new_request.body = None 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 final_callback = self.final_callback self.final_callback = None self._release() self.client.fetch(new_request, final_callback) 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, buffer=buffer, effective_url=self.request.url) self._run_callback(response) self._on_end_request() def _on_end_request(self): self.stream.close() def data_received(self, chunk): 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()