Mini Shell

"""Pytest fixtures and other helpers for doing testing by end-users."""

from contextlib import closing, contextmanager
import errno
import socket
import threading
import time
import http.client

import pytest

import cheroot.server
from cheroot.test import webtest
import cheroot.wsgi

EPHEMERAL_PORT = 0
NO_INTERFACE = None  # Using this or '' will cause an exception
ANY_INTERFACE_IPV4 = '0.0.0.0'
ANY_INTERFACE_IPV6 = '::'

config = {
    cheroot.wsgi.Server: {
        'bind_addr': (NO_INTERFACE, EPHEMERAL_PORT),
        'wsgi_app': None,
    },
    cheroot.server.HTTPServer: {
        'bind_addr': (NO_INTERFACE, EPHEMERAL_PORT),
        'gateway': cheroot.server.Gateway,
    },
}


@contextmanager
def cheroot_server(server_factory):  # noqa: WPS210
    """Set up and tear down a Cheroot server instance."""
    conf = config[server_factory].copy()
    bind_port = conf.pop('bind_addr')[-1]

    for interface in ANY_INTERFACE_IPV6, ANY_INTERFACE_IPV4:
        try:
            actual_bind_addr = (interface, bind_port)
            httpserver = server_factory(  # create it
                bind_addr=actual_bind_addr,
                **conf,
            )
        except OSError:
            pass
        else:
            break

    httpserver.shutdown_timeout = 0  # Speed-up tests teardown

    # FIXME: Expose this thread through a fixture so that it
    # FIXME: could be awaited in tests.
    server_thread = threading.Thread(target=httpserver.safe_start)
    server_thread.start()  # spawn it
    while not httpserver.ready:  # wait until fully initialized and bound
        time.sleep(0.1)

    try:
        yield server_thread, httpserver
    finally:
        httpserver.stop()  # destroy it
        server_thread.join()  # wait for the thread to be turn down


@pytest.fixture
def thread_and_wsgi_server():
    """Set up and tear down a Cheroot WSGI server instance.

    This emits a tuple of a thread and a server instance.
    """
    with cheroot_server(cheroot.wsgi.Server) as (server_thread, srv):
        yield server_thread, srv


@pytest.fixture
def thread_and_native_server():
    """Set up and tear down a Cheroot HTTP server instance.

    This emits a tuple of a thread and a server instance.
    """
    with cheroot_server(cheroot.server.HTTPServer) as (server_thread, srv):
        yield server_thread, srv


@pytest.fixture
def wsgi_server(thread_and_wsgi_server):  # noqa: WPS442
    """Set up and tear down a Cheroot WSGI server instance."""
    _server_thread, srv = thread_and_wsgi_server
    return srv


@pytest.fixture
def native_server(thread_and_native_server):  # noqa: WPS442
    """Set up and tear down a Cheroot HTTP server instance."""
    _server_thread, srv = thread_and_native_server
    return srv


class _TestClient:
    def __init__(self, server):
        self._interface, self._host, self._port = _get_conn_data(
            server.bind_addr,
        )
        self.server_instance = server
        self._http_connection = self.get_connection()

    def get_connection(self):
        name = '{interface}:{port}'.format(
            interface=self._interface,
            port=self._port,
        )
        conn_cls = (
            http.client.HTTPConnection
            if self.server_instance.ssl_adapter is None else
            http.client.HTTPSConnection
        )
        return conn_cls(name)

    def request(
        self, uri, method='GET', headers=None, http_conn=None,
        protocol='HTTP/1.1',
    ):
        return webtest.openURL(
            uri, method=method,
            headers=headers,
            host=self._host, port=self._port,
            http_conn=http_conn or self._http_connection,
            protocol=protocol,
        )

    def __getattr__(self, attr_name):
        def _wrapper(uri, **kwargs):
            http_method = attr_name.upper()
            return self.request(uri, method=http_method, **kwargs)

        return _wrapper


def _probe_ipv6_sock(interface):
    # Alternate way is to check IPs on interfaces using glibc, like:
    # github.com/Gautier/minifail/blob/master/minifail/getifaddrs.py
    try:
        with closing(socket.socket(family=socket.AF_INET6)) as sock:
            sock.bind((interface, 0))
    except OSError as sock_err:
        if sock_err.errno != errno.EADDRNOTAVAIL:
            raise
    else:
        return True

    return False


def _get_conn_data(bind_addr):
    if isinstance(bind_addr, tuple):
        host, port = bind_addr
    else:
        host, port = bind_addr, 0

    interface = webtest.interface(host)

    if ':' in interface and not _probe_ipv6_sock(interface):
        interface = '127.0.0.1'
        if ':' in host:
            host = interface

    return interface, host, port


def get_server_client(server):
    """Create and return a test client for the given server."""
    return _TestClient(server)