Resolver

The tool to check the availability or syntax of domain, IP or URL.

::

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Provides a way to provide the nameserver to use.

Author: Nissar Chababy, @funilrys, contactTATAfunilrysTODTODcom

Special thanks: https://pyfunceble.github.io/#/special-thanks

Contributors: https://pyfunceble.github.io/#/contributors

Project link: https://github.com/funilrys/PyFunceble

Project documentation: https://docs.pyfunceble.com

Project homepage: https://pyfunceble.github.io/

License: ::

Copyright 2017, 2018, 2019, 2020, 2022, 2023, 2024, 2025 Nissar Chababy

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Resolver

Provides the right resolver.

Parameters:

Name	Type	Description	Default
nameservers	Optional[List[str]]	The list of nameservers to communicate with.	None

Source code in PyFunceble/query/dns/resolver.py

class Resolver:
    """
    Provides the right resolver.

    :param nameservers:
        The list of nameservers to communicate with.
    """

    STD_TIMEOUT: float = 5.0

    _timeout: float = 3.0

    _nameservers: Nameservers = None
    _internal_resolver: Optional[dns.resolver.Resolver] = None

    def __init__(
        self, nameservers: Optional[List[str]] = None, timeout: Optional[float] = None
    ) -> None:
        self._nameservers = Nameservers()

        if nameservers is not None:
            self.nameservers = nameservers
        else:
            self.nameservers.guess_and_set_nameservers()

        if timeout is not None:
            self.timeout = timeout
        else:
            self.guess_and_set_timeout()

    @property
    def resolver(self) -> dns.resolver.Resolver:
        """
        Provides the resolver to work with.
        """

        if not self._internal_resolver:
            if self.get_raw_nameservers():
                self._internal_resolver = dns.resolver.Resolver(configure=False)
            else:  # pragma: no cover ## I don't want to play with the default resolver.
                self._internal_resolver = dns.resolver.Resolver()

            self._internal_resolver.lifetime = self.timeout + 2.0
            self._internal_resolver.timeout = self.timeout
            self._internal_resolver.nameservers = self.get_raw_nameservers()
            self._internal_resolver.nameserver_ports = self.get_raw_nameserver_ports()

        return self._internal_resolver

    @property
    def nameservers(self) -> Nameservers:
        """
        Provides the nameservers to use.
        """

        return self._nameservers

    @nameservers.setter
    def nameservers(self, value: List[str]) -> None:
        """
        Sets the nameservers to use.
        """

        self.nameservers.set_nameservers(value)
        self._internal_resolver = None  # Invalidate

    def set_nameservers(self, value: List[str]) -> "Resolver":
        """
        Sets the given nameserver.
        """

        self.nameservers = value

        return self

    @property
    def timeout(self) -> float:
        """
        Provides the timeout to use.
        """

        return self._timeout

    @timeout.setter
    def timeout(self, value: float) -> None:
        """
        Sets the timeout to use.
        """

        if not isinstance(value, (float, int)):
            raise TypeError(f"<value> should be {float}, {type(value)} given.")

        self._timeout = float(value)
        self._internal_resolver = None  # Invalidate

    def set_timeout(self, value: Union[float, int]) -> "Resolver":
        """
        Sets the timeout of a query.
        """

        self.timeout = value

        return self

    def get_raw_nameservers(self) -> Optional[List[str]]:
        """
        Provides the currently set list of nameserver.
        """

        return self.nameservers.get_nameservers()

    def get_raw_nameserver_ports(self) -> Optional[dict]:
        """
        Provides the currently set list of nameserver ports.
        """

        return self.nameservers.get_nameserver_ports()

    def guess_and_set_timeout(self) -> "Resolver":
        """
        Tries to guess the the timeout from the configuration.
        """

        if PyFunceble.facility.ConfigLoader.is_already_loaded():
            self.timeout = PyFunceble.storage.CONFIGURATION.lookup.timeout
        else:
            self.timeout = self.STD_TIMEOUT

        return self

    def guess_all_settings(
        self,
    ) -> "Resolver":  # pragma: no cover ## Method themselves are more important
        """
        Try to guess all settings.
        """

        to_ignore = ["guess_all_settings"]

        for method in dir(self):
            if method in to_ignore or not method.startswith("guess_"):
                continue

            getattr(self, method)()

        return self

nameservers property writable

Provides the nameservers to use.

resolver property

Provides the resolver to work with.

timeout property writable

Provides the timeout to use.

get_raw_nameserver_ports()

Provides the currently set list of nameserver ports.

Source code in PyFunceble/query/dns/resolver.py

def get_raw_nameserver_ports(self) -> Optional[dict]:
    """
    Provides the currently set list of nameserver ports.
    """

    return self.nameservers.get_nameserver_ports()

get_raw_nameservers()

Provides the currently set list of nameserver.

Source code in PyFunceble/query/dns/resolver.py

def get_raw_nameservers(self) -> Optional[List[str]]:
    """
    Provides the currently set list of nameserver.
    """

    return self.nameservers.get_nameservers()

guess_all_settings()

Try to guess all settings.

Source code in PyFunceble/query/dns/resolver.py

def guess_all_settings(
    self,
) -> "Resolver":  # pragma: no cover ## Method themselves are more important
    """
    Try to guess all settings.
    """

    to_ignore = ["guess_all_settings"]

    for method in dir(self):
        if method in to_ignore or not method.startswith("guess_"):
            continue

        getattr(self, method)()

    return self

guess_and_set_timeout()

Tries to guess the the timeout from the configuration.

Source code in PyFunceble/query/dns/resolver.py

def guess_and_set_timeout(self) -> "Resolver":
    """
    Tries to guess the the timeout from the configuration.
    """

    if PyFunceble.facility.ConfigLoader.is_already_loaded():
        self.timeout = PyFunceble.storage.CONFIGURATION.lookup.timeout
    else:
        self.timeout = self.STD_TIMEOUT

    return self

set_nameservers(value)

Sets the given nameserver.

Source code in PyFunceble/query/dns/resolver.py

def set_nameservers(self, value: List[str]) -> "Resolver":
    """
    Sets the given nameserver.
    """

    self.nameservers = value

    return self

set_timeout(value)

Sets the timeout of a query.

Source code in PyFunceble/query/dns/resolver.py

def set_timeout(self, value: Union[float, int]) -> "Resolver":
    """
    Sets the timeout of a query.
    """

    self.timeout = value

    return self