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yt-dlp/yt_dlp/networking/common.py
coletdjnz db7b054a61
[networking] Add request handler preference framework (#7603)
Preference functions that take a request and a request handler instance can be registered to prioritize different request handlers per request.

Authored by: coletdjnz
Co-authored-by: pukkandan <pukkandan.ytdlp@gmail.com>
2023-08-04 22:17:48 +00:00

564 lines
20 KiB
Python

from __future__ import annotations
import abc
import copy
import enum
import functools
import io
import typing
import urllib.parse
import urllib.request
import urllib.response
from collections.abc import Iterable, Mapping
from email.message import Message
from http import HTTPStatus
from ._helper import make_ssl_context, wrap_request_errors
from .exceptions import (
NoSupportingHandlers,
RequestError,
TransportError,
UnsupportedRequest,
)
from ..compat.types import NoneType
from ..cookies import YoutubeDLCookieJar
from ..utils import (
bug_reports_message,
classproperty,
deprecation_warning,
error_to_str,
update_url_query,
)
from ..utils.networking import HTTPHeaderDict, normalize_url
def register_preference(*handlers: type[RequestHandler]):
assert all(issubclass(handler, RequestHandler) for handler in handlers)
def outer(preference: Preference):
@functools.wraps(preference)
def inner(handler, *args, **kwargs):
if not handlers or isinstance(handler, handlers):
return preference(handler, *args, **kwargs)
return 0
_RH_PREFERENCES.add(inner)
return inner
return outer
class RequestDirector:
"""RequestDirector class
Helper class that, when given a request, forward it to a RequestHandler that supports it.
Preference functions in the form of func(handler, request) -> int
can be registered into the `preferences` set. These are used to sort handlers
in order of preference.
@param logger: Logger instance.
@param verbose: Print debug request information to stdout.
"""
def __init__(self, logger, verbose=False):
self.handlers: dict[str, RequestHandler] = {}
self.preferences: set[Preference] = set()
self.logger = logger # TODO(Grub4k): default logger
self.verbose = verbose
def close(self):
for handler in self.handlers.values():
handler.close()
def add_handler(self, handler: RequestHandler):
"""Add a handler. If a handler of the same RH_KEY exists, it will overwrite it"""
assert isinstance(handler, RequestHandler), 'handler must be a RequestHandler'
self.handlers[handler.RH_KEY] = handler
def _get_handlers(self, request: Request) -> list[RequestHandler]:
"""Sorts handlers by preference, given a request"""
preferences = {
rh: sum(pref(rh, request) for pref in self.preferences)
for rh in self.handlers.values()
}
self._print_verbose('Handler preferences for this request: %s' % ', '.join(
f'{rh.RH_NAME}={pref}' for rh, pref in preferences.items()))
return sorted(self.handlers.values(), key=preferences.get, reverse=True)
def _print_verbose(self, msg):
if self.verbose:
self.logger.stdout(f'director: {msg}')
def send(self, request: Request) -> Response:
"""
Passes a request onto a suitable RequestHandler
"""
if not self.handlers:
raise RequestError('No request handlers configured')
assert isinstance(request, Request)
unexpected_errors = []
unsupported_errors = []
for handler in self._get_handlers(request):
self._print_verbose(f'Checking if "{handler.RH_NAME}" supports this request.')
try:
handler.validate(request)
except UnsupportedRequest as e:
self._print_verbose(
f'"{handler.RH_NAME}" cannot handle this request (reason: {error_to_str(e)})')
unsupported_errors.append(e)
continue
self._print_verbose(f'Sending request via "{handler.RH_NAME}"')
try:
response = handler.send(request)
except RequestError:
raise
except Exception as e:
self.logger.error(
f'[{handler.RH_NAME}] Unexpected error: {error_to_str(e)}{bug_reports_message()}',
is_error=False)
unexpected_errors.append(e)
continue
assert isinstance(response, Response)
return response
raise NoSupportingHandlers(unsupported_errors, unexpected_errors)
_REQUEST_HANDLERS = {}
def register_rh(handler):
"""Register a RequestHandler class"""
assert issubclass(handler, RequestHandler), f'{handler} must be a subclass of RequestHandler'
assert handler.RH_KEY not in _REQUEST_HANDLERS, f'RequestHandler {handler.RH_KEY} already registered'
_REQUEST_HANDLERS[handler.RH_KEY] = handler
return handler
class Features(enum.Enum):
ALL_PROXY = enum.auto()
NO_PROXY = enum.auto()
class RequestHandler(abc.ABC):
"""Request Handler class
Request handlers are class that, given a Request,
process the request from start to finish and return a Response.
Concrete subclasses need to redefine the _send(request) method,
which handles the underlying request logic and returns a Response.
RH_NAME class variable may contain a display name for the RequestHandler.
By default, this is generated from the class name.
The concrete request handler MUST have "RH" as the suffix in the class name.
All exceptions raised by a RequestHandler should be an instance of RequestError.
Any other exception raised will be treated as a handler issue.
If a Request is not supported by the handler, an UnsupportedRequest
should be raised with a reason.
By default, some checks are done on the request in _validate() based on the following class variables:
- `_SUPPORTED_URL_SCHEMES`: a tuple of supported url schemes.
Any Request with an url scheme not in this list will raise an UnsupportedRequest.
- `_SUPPORTED_PROXY_SCHEMES`: a tuple of support proxy url schemes. Any Request that contains
a proxy url with an url scheme not in this list will raise an UnsupportedRequest.
- `_SUPPORTED_FEATURES`: a tuple of supported features, as defined in Features enum.
The above may be set to None to disable the checks.
Parameters:
@param logger: logger instance
@param headers: HTTP Headers to include when sending requests.
@param cookiejar: Cookiejar to use for requests.
@param timeout: Socket timeout to use when sending requests.
@param proxies: Proxies to use for sending requests.
@param source_address: Client-side IP address to bind to for requests.
@param verbose: Print debug request and traffic information to stdout.
@param prefer_system_certs: Whether to prefer system certificates over other means (e.g. certifi).
@param client_cert: SSL client certificate configuration.
dict with {client_certificate, client_certificate_key, client_certificate_password}
@param verify: Verify SSL certificates
@param legacy_ssl_support: Enable legacy SSL options such as legacy server connect and older cipher support.
Some configuration options may be available for individual Requests too. In this case,
either the Request configuration option takes precedence or they are merged.
Requests may have additional optional parameters defined as extensions.
RequestHandler subclasses may choose to support custom extensions.
If an extension is supported, subclasses should extend _check_extensions(extensions)
to pop and validate the extension.
- Extensions left in `extensions` are treated as unsupported and UnsupportedRequest will be raised.
The following extensions are defined for RequestHandler:
- `cookiejar`: Cookiejar to use for this request.
- `timeout`: socket timeout to use for this request.
To enable these, add extensions.pop('<extension>', None) to _check_extensions
Apart from the url protocol, proxies dict may contain the following keys:
- `all`: proxy to use for all protocols. Used as a fallback if no proxy is set for a specific protocol.
- `no`: comma seperated list of hostnames (optionally with port) to not use a proxy for.
Note: a RequestHandler may not support these, as defined in `_SUPPORTED_FEATURES`.
"""
_SUPPORTED_URL_SCHEMES = ()
_SUPPORTED_PROXY_SCHEMES = ()
_SUPPORTED_FEATURES = ()
def __init__(
self, *,
logger, # TODO(Grub4k): default logger
headers: HTTPHeaderDict = None,
cookiejar: YoutubeDLCookieJar = None,
timeout: float | int | None = None,
proxies: dict = None,
source_address: str = None,
verbose: bool = False,
prefer_system_certs: bool = False,
client_cert: dict[str, str | None] = None,
verify: bool = True,
legacy_ssl_support: bool = False,
**_,
):
self._logger = logger
self.headers = headers or {}
self.cookiejar = cookiejar if cookiejar is not None else YoutubeDLCookieJar()
self.timeout = float(timeout or 20)
self.proxies = proxies or {}
self.source_address = source_address
self.verbose = verbose
self.prefer_system_certs = prefer_system_certs
self._client_cert = client_cert or {}
self.verify = verify
self.legacy_ssl_support = legacy_ssl_support
super().__init__()
def _make_sslcontext(self):
return make_ssl_context(
verify=self.verify,
legacy_support=self.legacy_ssl_support,
use_certifi=not self.prefer_system_certs,
**self._client_cert,
)
def _merge_headers(self, request_headers):
return HTTPHeaderDict(self.headers, request_headers)
def _check_url_scheme(self, request: Request):
scheme = urllib.parse.urlparse(request.url).scheme.lower()
if self._SUPPORTED_URL_SCHEMES is not None and scheme not in self._SUPPORTED_URL_SCHEMES:
raise UnsupportedRequest(f'Unsupported url scheme: "{scheme}"')
return scheme # for further processing
def _check_proxies(self, proxies):
for proxy_key, proxy_url in proxies.items():
if proxy_url is None:
continue
if proxy_key == 'no':
if self._SUPPORTED_FEATURES is not None and Features.NO_PROXY not in self._SUPPORTED_FEATURES:
raise UnsupportedRequest('"no" proxy is not supported')
continue
if (
proxy_key == 'all'
and self._SUPPORTED_FEATURES is not None
and Features.ALL_PROXY not in self._SUPPORTED_FEATURES
):
raise UnsupportedRequest('"all" proxy is not supported')
# Unlikely this handler will use this proxy, so ignore.
# This is to allow a case where a proxy may be set for a protocol
# for one handler in which such protocol (and proxy) is not supported by another handler.
if self._SUPPORTED_URL_SCHEMES is not None and proxy_key not in (*self._SUPPORTED_URL_SCHEMES, 'all'):
continue
if self._SUPPORTED_PROXY_SCHEMES is None:
# Skip proxy scheme checks
continue
try:
if urllib.request._parse_proxy(proxy_url)[0] is None:
# Scheme-less proxies are not supported
raise UnsupportedRequest(f'Proxy "{proxy_url}" missing scheme')
except ValueError as e:
# parse_proxy may raise on some invalid proxy urls such as "/a/b/c"
raise UnsupportedRequest(f'Invalid proxy url "{proxy_url}": {e}')
scheme = urllib.parse.urlparse(proxy_url).scheme.lower()
if scheme not in self._SUPPORTED_PROXY_SCHEMES:
raise UnsupportedRequest(f'Unsupported proxy type: "{scheme}"')
def _check_extensions(self, extensions):
"""Check extensions for unsupported extensions. Subclasses should extend this."""
assert isinstance(extensions.get('cookiejar'), (YoutubeDLCookieJar, NoneType))
assert isinstance(extensions.get('timeout'), (float, int, NoneType))
def _validate(self, request):
self._check_url_scheme(request)
self._check_proxies(request.proxies or self.proxies)
extensions = request.extensions.copy()
self._check_extensions(extensions)
if extensions:
# TODO: add support for optional extensions
raise UnsupportedRequest(f'Unsupported extensions: {", ".join(extensions.keys())}')
@wrap_request_errors
def validate(self, request: Request):
if not isinstance(request, Request):
raise TypeError('Expected an instance of Request')
self._validate(request)
@wrap_request_errors
def send(self, request: Request) -> Response:
if not isinstance(request, Request):
raise TypeError('Expected an instance of Request')
return self._send(request)
@abc.abstractmethod
def _send(self, request: Request):
"""Handle a request from start to finish. Redefine in subclasses."""
pass
def close(self):
pass
@classproperty
def RH_NAME(cls):
return cls.__name__[:-2]
@classproperty
def RH_KEY(cls):
assert cls.__name__.endswith('RH'), 'RequestHandler class names must end with "RH"'
return cls.__name__[:-2]
def __enter__(self):
return self
def __exit__(self, *args):
self.close()
class Request:
"""
Represents a request to be made.
Partially backwards-compatible with urllib.request.Request.
@param url: url to send. Will be sanitized.
@param data: payload data to send. Must be bytes, iterable of bytes, a file-like object or None
@param headers: headers to send.
@param proxies: proxy dict mapping of proto:proxy to use for the request and any redirects.
@param query: URL query parameters to update the url with.
@param method: HTTP method to use. If no method specified, will use POST if payload data is present else GET
@param extensions: Dictionary of Request extensions to add, as supported by handlers.
"""
def __init__(
self,
url: str,
data: RequestData = None,
headers: typing.Mapping = None,
proxies: dict = None,
query: dict = None,
method: str = None,
extensions: dict = None
):
self._headers = HTTPHeaderDict()
self._data = None
if query:
url = update_url_query(url, query)
self.url = url
self.method = method
if headers:
self.headers = headers
self.data = data # note: must be done after setting headers
self.proxies = proxies or {}
self.extensions = extensions or {}
@property
def url(self):
return self._url
@url.setter
def url(self, url):
if not isinstance(url, str):
raise TypeError('url must be a string')
elif url.startswith('//'):
url = 'http:' + url
self._url = normalize_url(url)
@property
def method(self):
return self._method or ('POST' if self.data is not None else 'GET')
@method.setter
def method(self, method):
if method is None:
self._method = None
elif isinstance(method, str):
self._method = method.upper()
else:
raise TypeError('method must be a string')
@property
def data(self):
return self._data
@data.setter
def data(self, data: RequestData):
# Try catch some common mistakes
if data is not None and (
not isinstance(data, (bytes, io.IOBase, Iterable)) or isinstance(data, (str, Mapping))
):
raise TypeError('data must be bytes, iterable of bytes, or a file-like object')
if data == self._data and self._data is None:
self.headers.pop('Content-Length', None)
# https://docs.python.org/3/library/urllib.request.html#urllib.request.Request.data
if data != self._data:
if self._data is not None:
self.headers.pop('Content-Length', None)
self._data = data
if self._data is None:
self.headers.pop('Content-Type', None)
if 'Content-Type' not in self.headers and self._data is not None:
self.headers['Content-Type'] = 'application/x-www-form-urlencoded'
@property
def headers(self) -> HTTPHeaderDict:
return self._headers
@headers.setter
def headers(self, new_headers: Mapping):
"""Replaces headers of the request. If not a CaseInsensitiveDict, it will be converted to one."""
if isinstance(new_headers, HTTPHeaderDict):
self._headers = new_headers
elif isinstance(new_headers, Mapping):
self._headers = HTTPHeaderDict(new_headers)
else:
raise TypeError('headers must be a mapping')
def update(self, url=None, data=None, headers=None, query=None):
self.data = data if data is not None else self.data
self.headers.update(headers or {})
self.url = update_url_query(url or self.url, query or {})
def copy(self):
return self.__class__(
url=self.url,
headers=copy.deepcopy(self.headers),
proxies=copy.deepcopy(self.proxies),
data=self._data,
extensions=copy.copy(self.extensions),
method=self._method,
)
HEADRequest = functools.partial(Request, method='HEAD')
PUTRequest = functools.partial(Request, method='PUT')
class Response(io.IOBase):
"""
Base class for HTTP response adapters.
By default, it provides a basic wrapper for a file-like response object.
Interface partially backwards-compatible with addinfourl and http.client.HTTPResponse.
@param fp: Original, file-like, response.
@param url: URL that this is a response of.
@param headers: response headers.
@param status: Response HTTP status code. Default is 200 OK.
@param reason: HTTP status reason. Will use built-in reasons based on status code if not provided.
"""
def __init__(
self,
fp: typing.IO,
url: str,
headers: Mapping[str, str],
status: int = 200,
reason: str = None):
self.fp = fp
self.headers = Message()
for name, value in headers.items():
self.headers.add_header(name, value)
self.status = status
self.url = url
try:
self.reason = reason or HTTPStatus(status).phrase
except ValueError:
self.reason = None
def readable(self):
return self.fp.readable()
def read(self, amt: int = None) -> bytes:
# Expected errors raised here should be of type RequestError or subclasses.
# Subclasses should redefine this method with more precise error handling.
try:
return self.fp.read(amt)
except Exception as e:
raise TransportError(cause=e) from e
def close(self):
self.fp.close()
return super().close()
def get_header(self, name, default=None):
"""Get header for name.
If there are multiple matching headers, return all seperated by comma."""
headers = self.headers.get_all(name)
if not headers:
return default
if name.title() == 'Set-Cookie':
# Special case, only get the first one
# https://www.rfc-editor.org/rfc/rfc9110.html#section-5.3-4.1
return headers[0]
return ', '.join(headers)
# The following methods are for compatability reasons and are deprecated
@property
def code(self):
deprecation_warning('Response.code is deprecated, use Response.status', stacklevel=2)
return self.status
def getcode(self):
deprecation_warning('Response.getcode() is deprecated, use Response.status', stacklevel=2)
return self.status
def geturl(self):
deprecation_warning('Response.geturl() is deprecated, use Response.url', stacklevel=2)
return self.url
def info(self):
deprecation_warning('Response.info() is deprecated, use Response.headers', stacklevel=2)
return self.headers
def getheader(self, name, default=None):
deprecation_warning('Response.getheader() is deprecated, use Response.get_header', stacklevel=2)
return self.get_header(name, default)
if typing.TYPE_CHECKING:
RequestData = bytes | Iterable[bytes] | typing.IO | None
Preference = typing.Callable[[RequestHandler, Request], int]
_RH_PREFERENCES: set[Preference] = set()