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http_proxy.py
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http_proxy.py
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import logging
import ssl
from base64 import b64encode
from typing import Iterable, List, Mapping, Optional, Sequence, Tuple, Union
from .._backends.base import SOCKET_OPTION, AsyncNetworkBackend
from .._exceptions import ProxyError
from .._models import (
URL,
Origin,
Request,
Response,
enforce_bytes,
enforce_headers,
enforce_url,
)
from .._ssl import default_ssl_context
from .._synchronization import AsyncLock
from .._trace import Trace
from .connection import AsyncHTTPConnection
from .connection_pool import AsyncConnectionPool
from .http11 import AsyncHTTP11Connection
from .interfaces import AsyncConnectionInterface
HeadersAsSequence = Sequence[Tuple[Union[bytes, str], Union[bytes, str]]]
HeadersAsMapping = Mapping[Union[bytes, str], Union[bytes, str]]
logger = logging.getLogger("httpcore.proxy")
def merge_headers(
default_headers: Optional[Sequence[Tuple[bytes, bytes]]] = None,
override_headers: Optional[Sequence[Tuple[bytes, bytes]]] = None,
) -> List[Tuple[bytes, bytes]]:
"""
Append default_headers and override_headers, de-duplicating if a key exists
in both cases.
"""
default_headers = [] if default_headers is None else list(default_headers)
override_headers = [] if override_headers is None else list(override_headers)
has_override = set(key.lower() for key, value in override_headers)
default_headers = [
(key, value)
for key, value in default_headers
if key.lower() not in has_override
]
return default_headers + override_headers
def build_auth_header(username: bytes, password: bytes) -> bytes:
userpass = username + b":" + password
return b"Basic " + b64encode(userpass)
class AsyncHTTPProxy(AsyncConnectionPool):
"""
A connection pool that sends requests via an HTTP proxy.
"""
def __init__(
self,
proxy_url: Union[URL, bytes, str],
proxy_auth: Optional[Tuple[Union[bytes, str], Union[bytes, str]]] = None,
proxy_headers: Union[HeadersAsMapping, HeadersAsSequence, None] = None,
ssl_context: Optional[ssl.SSLContext] = None,
proxy_ssl_context: Optional[ssl.SSLContext] = None,
max_connections: Optional[int] = 10,
max_keepalive_connections: Optional[int] = None,
keepalive_expiry: Optional[float] = None,
http1: bool = True,
http2: bool = False,
retries: int = 0,
local_address: Optional[str] = None,
uds: Optional[str] = None,
network_backend: Optional[AsyncNetworkBackend] = None,
socket_options: Optional[Iterable[SOCKET_OPTION]] = None,
) -> None:
"""
A connection pool for making HTTP requests.
Parameters:
proxy_url: The URL to use when connecting to the proxy server.
For example `"http://127.0.0.1:8080/"`.
proxy_auth: Any proxy authentication as a two-tuple of
(username, password). May be either bytes or ascii-only str.
proxy_headers: Any HTTP headers to use for the proxy requests.
For example `{"Proxy-Authorization": "Basic <username>:<password>"}`.
ssl_context: An SSL context to use for verifying connections.
If not specified, the default `httpcore.default_ssl_context()`
will be used.
proxy_ssl_context: The same as `ssl_context`, but for a proxy server rather than a remote origin.
max_connections: The maximum number of concurrent HTTP connections that
the pool should allow. Any attempt to send a request on a pool that
would exceed this amount will block until a connection is available.
max_keepalive_connections: The maximum number of idle HTTP connections
that will be maintained in the pool.
keepalive_expiry: The duration in seconds that an idle HTTP connection
may be maintained for before being expired from the pool.
http1: A boolean indicating if HTTP/1.1 requests should be supported
by the connection pool. Defaults to True.
http2: A boolean indicating if HTTP/2 requests should be supported by
the connection pool. Defaults to False.
retries: The maximum number of retries when trying to establish
a connection.
local_address: Local address to connect from. Can also be used to
connect using a particular address family. Using
`local_address="0.0.0.0"` will connect using an `AF_INET` address
(IPv4), while using `local_address="::"` will connect using an
`AF_INET6` address (IPv6).
uds: Path to a Unix Domain Socket to use instead of TCP sockets.
network_backend: A backend instance to use for handling network I/O.
"""
super().__init__(
ssl_context=ssl_context,
max_connections=max_connections,
max_keepalive_connections=max_keepalive_connections,
keepalive_expiry=keepalive_expiry,
http1=http1,
http2=http2,
network_backend=network_backend,
retries=retries,
local_address=local_address,
uds=uds,
socket_options=socket_options,
)
self._proxy_url = enforce_url(proxy_url, name="proxy_url")
if (
self._proxy_url.scheme == b"http" and proxy_ssl_context is not None
): # pragma: no cover
raise RuntimeError(
"The `proxy_ssl_context` argument is not allowed for the http scheme"
)
self._ssl_context = ssl_context
self._proxy_ssl_context = proxy_ssl_context
self._proxy_headers = enforce_headers(proxy_headers, name="proxy_headers")
if proxy_auth is not None:
username = enforce_bytes(proxy_auth[0], name="proxy_auth")
password = enforce_bytes(proxy_auth[1], name="proxy_auth")
authorization = build_auth_header(username, password)
self._proxy_headers = [
(b"Proxy-Authorization", authorization)
] + self._proxy_headers
def create_connection(self, origin: Origin) -> AsyncConnectionInterface:
if origin.scheme == b"http":
return AsyncForwardHTTPConnection(
proxy_origin=self._proxy_url.origin,
proxy_headers=self._proxy_headers,
remote_origin=origin,
keepalive_expiry=self._keepalive_expiry,
network_backend=self._network_backend,
proxy_ssl_context=self._proxy_ssl_context,
)
return AsyncTunnelHTTPConnection(
proxy_origin=self._proxy_url.origin,
proxy_headers=self._proxy_headers,
remote_origin=origin,
ssl_context=self._ssl_context,
proxy_ssl_context=self._proxy_ssl_context,
keepalive_expiry=self._keepalive_expiry,
http1=self._http1,
http2=self._http2,
network_backend=self._network_backend,
)
class AsyncForwardHTTPConnection(AsyncConnectionInterface):
def __init__(
self,
proxy_origin: Origin,
remote_origin: Origin,
proxy_headers: Union[HeadersAsMapping, HeadersAsSequence, None] = None,
keepalive_expiry: Optional[float] = None,
network_backend: Optional[AsyncNetworkBackend] = None,
socket_options: Optional[Iterable[SOCKET_OPTION]] = None,
proxy_ssl_context: Optional[ssl.SSLContext] = None,
) -> None:
self._connection = AsyncHTTPConnection(
origin=proxy_origin,
keepalive_expiry=keepalive_expiry,
network_backend=network_backend,
socket_options=socket_options,
ssl_context=proxy_ssl_context,
)
self._proxy_origin = proxy_origin
self._proxy_headers = enforce_headers(proxy_headers, name="proxy_headers")
self._remote_origin = remote_origin
async def handle_async_request(self, request: Request) -> Response:
headers = merge_headers(self._proxy_headers, request.headers)
url = URL(
scheme=self._proxy_origin.scheme,
host=self._proxy_origin.host,
port=self._proxy_origin.port,
target=bytes(request.url),
)
proxy_request = Request(
method=request.method,
url=url,
headers=headers,
content=request.stream,
extensions=request.extensions,
)
return await self._connection.handle_async_request(proxy_request)
def can_handle_request(self, origin: Origin) -> bool:
return origin == self._remote_origin
async def aclose(self) -> None:
await self._connection.aclose()
def info(self) -> str:
return self._connection.info()
def is_available(self) -> bool:
return self._connection.is_available()
def has_expired(self) -> bool:
return self._connection.has_expired()
def is_idle(self) -> bool:
return self._connection.is_idle()
def is_closed(self) -> bool:
return self._connection.is_closed()
def __repr__(self) -> str:
return f"<{self.__class__.__name__} [{self.info()}]>"
class AsyncTunnelHTTPConnection(AsyncConnectionInterface):
def __init__(
self,
proxy_origin: Origin,
remote_origin: Origin,
ssl_context: Optional[ssl.SSLContext] = None,
proxy_ssl_context: Optional[ssl.SSLContext] = None,
proxy_headers: Optional[Sequence[Tuple[bytes, bytes]]] = None,
keepalive_expiry: Optional[float] = None,
http1: bool = True,
http2: bool = False,
network_backend: Optional[AsyncNetworkBackend] = None,
socket_options: Optional[Iterable[SOCKET_OPTION]] = None,
) -> None:
self._connection: AsyncConnectionInterface = AsyncHTTPConnection(
origin=proxy_origin,
keepalive_expiry=keepalive_expiry,
network_backend=network_backend,
socket_options=socket_options,
ssl_context=proxy_ssl_context,
)
self._proxy_origin = proxy_origin
self._remote_origin = remote_origin
self._ssl_context = ssl_context
self._proxy_ssl_context = proxy_ssl_context
self._proxy_headers = enforce_headers(proxy_headers, name="proxy_headers")
self._keepalive_expiry = keepalive_expiry
self._http1 = http1
self._http2 = http2
self._connect_lock = AsyncLock()
self._connected = False
self._connect_response: Response = None
async def handle_async_request(self, request: Request) -> Response:
timeouts = request.extensions.get("timeout", {})
timeout = timeouts.get("connect", None)
async with self._connect_lock:
if not self._connected:
target = b"%b:%d" % (self._remote_origin.host, self._remote_origin.port)
connect_url = URL(
scheme=self._proxy_origin.scheme,
host=self._proxy_origin.host,
port=self._proxy_origin.port,
target=target,
)
connect_headers = merge_headers(
[(b"Host", target), (b"Accept", b"*/*")], self._proxy_headers
)
connect_request = Request(
method=b"CONNECT",
url=connect_url,
headers=connect_headers,
extensions=request.extensions,
)
connect_response = await self._connection.handle_async_request(
connect_request
)
self._connect_response = connect_response
if connect_response.status < 200 or connect_response.status > 299:
reason_bytes = connect_response.extensions.get("reason_phrase", b"")
reason_str = reason_bytes.decode("ascii", errors="ignore")
msg = "%d %s" % (connect_response.status, reason_str)
await self._connection.aclose()
raise ProxyError(msg)
stream = connect_response.extensions["network_stream"]
# Upgrade the stream to SSL
ssl_context = (
default_ssl_context()
if self._ssl_context is None
else self._ssl_context
)
alpn_protocols = ["http/1.1", "h2"] if self._http2 else ["http/1.1"]
ssl_context.set_alpn_protocols(alpn_protocols)
kwargs = {
"ssl_context": ssl_context,
"server_hostname": self._remote_origin.host.decode("ascii"),
"timeout": timeout,
}
async with Trace("start_tls", logger, request, kwargs) as trace:
stream = await stream.start_tls(**kwargs)
trace.return_value = stream
# Determine if we should be using HTTP/1.1 or HTTP/2
ssl_object = stream.get_extra_info("ssl_object")
http2_negotiated = (
ssl_object is not None
and ssl_object.selected_alpn_protocol() == "h2"
)
# Create the HTTP/1.1 or HTTP/2 connection
if http2_negotiated or (self._http2 and not self._http1):
from .http2 import AsyncHTTP2Connection
self._connection = AsyncHTTP2Connection(
origin=self._remote_origin,
stream=stream,
keepalive_expiry=self._keepalive_expiry,
)
else:
self._connection = AsyncHTTP11Connection(
origin=self._remote_origin,
stream=stream,
keepalive_expiry=self._keepalive_expiry,
)
self._connected = True
return await self._connection.handle_async_request(request)
def can_handle_request(self, origin: Origin) -> bool:
return origin == self._remote_origin
async def aclose(self) -> None:
await self._connection.aclose()
def info(self) -> str:
return self._connection.info()
def is_available(self) -> bool:
return self._connection.is_available()
def has_expired(self) -> bool:
return self._connection.has_expired()
def is_idle(self) -> bool:
return self._connection.is_idle()
def is_closed(self) -> bool:
return self._connection.is_closed()
def __repr__(self) -> str:
return f"<{self.__class__.__name__} [{self.info()}]>"