nserver.rules

ALL_QTYPES module-attribute

ALL_QTYPES: List[str] = list(dnslib.QTYPE.reverse.keys())

All supported Query Types

New in 2.0.

ResponseFunction module-attribute

ResponseFunction = Callable[[Query], RuleResult]

Type Alias for functions that will be called when a rule is matched

RuleResult module-attribute

RuleResult = Union[
    Response, RecordBase, List[RecordBase], None
]

Type Alias for the result of a rule response function

RegexRule

RegexRule(
    regex: Pattern,
    allowed_qtypes: List[str],
    func: ResponseFunction,
    case_sensitive: bool = False,
)

Bases: RuleBase

Rule that uses the provided regex to attempt to match the query name.

Parameters:

Name	Type	Description	Default
regex	Pattern	compiled regex for matching	required
allowed_qtypes	List[str]	match only the given query types	required
func	ResponseFunction	response function to call	required
case_sensitive	bool	how to case when matching if False will recompile regex with re.IGNORECASE	False

get_func

get_func(query: Query) -> Optional[ResponseFunction]

Same as parent class

RuleBase

Base class for all Rules to inherit from.

get_func

get_func(query: Query) -> Optional[ResponseFunction]

From the given query return the function to run, if any.

If no function should be run (i.e. because it does not match the rule), then return None.

This is to allow more efficient methods when determining a match and getting the rule function may be expensive (e.g. blueprints).

StaticRule

StaticRule(
    match_string: str,
    allowed_qtypes: List[str],
    func: ResponseFunction,
    case_sensitive: bool = False,
)

Bases: RuleBase

Rule that matches only the given string

StaticRule is more efficient than using a WildcardStringRule for static strings.

New in 2.0.

Parameters:

Name	Type	Description	Default
match_string	str	string to match	required
allowed_qtypes	List[str]	match only the given query types	required
func	ResponseFunction	response function to call	required
case_sensitive	bool	how to case when matching	False

get_func

get_func(query: Query) -> Optional[ResponseFunction]

Same as parent class

WildcardStringRule

WildcardStringRule(
    wildcard_string: str,
    allowed_qtypes: List,
    func: ResponseFunction,
    case_sensitive: bool = False,
)

Bases: RuleBase

Rule that allows a more concise way of matching query names.

The following substitutions can be made:

• * will match a single domain label
• ** will match multiple domain labels
• base_domain will match the registered domain using the Public Suffix List (PSL)

Examples:

• _dmarc.{base_domain}
• *._dkim.**
• foo.*.bar.com

When operating with case_sensitive=False, both the wildcard string and the query name are covereted to lowercase prior to matching.

Parameters:

Name	Type	Description	Default
wildcard_string	str	wildcard string to use	required
allowed_qtypes	List	match only the given query types	required
func	ResponseFunction	response function to call	required
case_sensitive	bool	how to case when matching	False

get_func

get_func(query: Query) -> Optional[ResponseFunction]

Same as parent class

ZoneRule

ZoneRule(
    zone: str,
    allowed_qtypes: List[str],
    func: ResponseFunction,
    case_sensitive: bool = False,
)

Bases: RuleBase

Rule that matches the given domain or any subdomain

An empty zone ("") will match any domain as this refers to the domain root (.).

New in 2.0.

Parameters:

Name	Type	Description	Default
zone	str	zone root	required
allowed_qtypes	List[str]	match only the given query types.	required
func	ResponseFunction	response function to call	required
case_sensitive	bool	how to case when matching	False

get_func

get_func(query: Query) -> Optional[ResponseFunction]

Same as parent class

smart_make_rule

smart_make_rule(
    rule: Union[Type[RuleBase], str, Pattern],
    *args,
    **kwargs
) -> RuleBase

Create a rule using shorthand notation.

The exact type of rule returned depends on what is povided by rule.

If rule is a

• RuleBase class, then it is used directly.
• str then it is checked to see if it contains substitutions. If it does then it will be a WildcardStringRule, else a StaticRule.
• Pattern then a RegexRule.

New in 2.0

Parameters:

Name	Type	Description	Default
rule	Union[Type[RuleBase], str, Pattern]	input to process	required
args		extra arguments to provide to the constructor	()
kwargs		extra keyword arguments to provide to the constructor	{}