Source code for wmflib.requests

"""Requests module."""
from typing import Any

from requests import PreparedRequest, Response, Session
from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util.retry import Retry  # pylint: disable=import-error

from wmflib import __version__

DEFAULT_TIMEOUT: float = 5.0
""":py:class:`float`: the default timeout to use if none is passed, in seconds."""

[docs]class TimeoutHTTPAdapter(HTTPAdapter): """Requests HTTP Adapter with default timeout for all requests. See Also: """ def __init__(self, **kwargs: Any): """Initialize the adapter with a default timeout, that can be overriden. To override the default timeout of :py:const:`wmflib.requests.DEFAULT_REQUESTS_TIMEOUT`` pass the ``timeout`` parameter when initializing an instance of this class. Params: As required by requests's HTTPAdapter: """ self.timeout = DEFAULT_TIMEOUT if 'timeout' in kwargs: self.timeout = kwargs['timeout'] del kwargs['timeout'] super().__init__(**kwargs)
[docs] def send(self, request: PreparedRequest, # type: ignore # pylint: disable=arguments-differ **kwargs: Any) -> Response: """Override the send method to pass the default timeout if not set. Params: As required by requests's HTTPAdapter: The ``noqa`` is needed unless the exact signature is replicated. """ kwargs['timeout'] = kwargs.get('timeout', self.timeout) return super().send(request, **kwargs)
[docs]def http_session(name: str, *, timeout: float = DEFAULT_TIMEOUT, tries: int = 3, backoff: float = 1.0) -> Session: """Return a new requests Session with User-Agent, default timeout and retry logic on failure already setup. The returned session will retry any ``DELETE, GET, HEAD, OPTIONS, PUT, TRACE`` request that returns one of the following HTTP status code: - 429 Too Many Requests - 500 Internal Server Error - 502 Bad Gateway - 503 Service Unavailable - 504 Gateway Timeout It will also retry any request that times out before the specified timeout. For non-idempotent HTTP methods the request will not be retried if the data has reached the server. The retry interval between requests is determined by the ``backoff`` parameter, see below. The timeout functionality is provided via the :py:class:`wmflib.requests.TimeoutHTTPAdapter` and individual request can override the session timeout by specifying a ``timeout`` parameter. See Also: Arguments: name (str): the name to use for the User-Agent header. It can be specified in the ``name/version`` format, if applicable. The resulting header will be set to:: pywmflib/{version} {name} + timeout (float): the default timeout to use in all requests within this session, in seconds. Any request can override it passing the ``timeout`` parameter explicitely. tries (int): the total number of requests to perform before bailing out. backoff (float): the backoff factor to use, will generate a sleep between retries, in seconds, of:: {backoff factor} * (2 ** ({number of total retries} - 1)) Returns: requests.Session: the pre-configured session. """ retry_strategy = Retry(total=tries, backoff_factor=backoff, status_forcelist=[429, 500, 502, 503, 504]) adapter = TimeoutHTTPAdapter(timeout=timeout, max_retries=retry_strategy) session = Session() user_agent = 'pywmflib/{version} {name} +'.format( version=__version__, name=name) session.headers.update({'User-Agent': user_agent}) session.mount('http://', adapter) session.mount('https://', adapter) return session