filterutil

Documentation

Overview

Package filterutil contains helper functions used by urlfilter

Index

• func ExtractHostname(url string) (hostname string)
• func FastHash(str string) uint32
• func FastHashBetween(str string, begin, end int) uint32
• func IsDomainName(name string) bool
• func IsProbablyIP(s string) (ok bool)

Functions

func ExtractHostname

func ExtractHostname(url string) (hostname string)

ExtractHostname quickly retrieves hostname from the given URL.

NOTE: ExtractHostname is an optimized, best-effort function to retrieve a hostname from a URL-like string. The result is not guaranteed to be correct for some edge cases, which include non-hierarchical URLs and IPv6 hostnames.

TODO(a.garipov): Consider moving to golibs.

func FastHash

func FastHash(str string) uint32

FastHash implements the djb2 hash algorithm.

TODO(e.burkov): Inspect all uses. Perhaps use maphash.

func FastHashBetween

func FastHashBetween(str string, begin, end int) uint32

FastHashBetween implements the djb2 hash algorithm.

func IsDomainName

func IsDomainName(name string) bool

IsDomainName - check if input string is a valid domain name Syntax: [label.]... label.label

Each label is 1 to 63 characters long, and may contain:

. ASCII letters a-z and A-Z
. digits 0-9
. hyphen ('-')

. labels cannot start or end with hyphens (RFC 952) . max length of ascii hostname including dots is 253 characters . TLD is >=2 characters . TLD is [a-zA-Z]+ or "xn--[a-zA-Z0-9]+"

func IsProbablyIP

func IsProbablyIP(s string) (ok bool)

IsProbablyIP returns true if s only contains characters that can be part of an IP address. It's needed to avoid unnecessary allocations when parsing with [netip.ParseAddr].