108 lines
3.6 KiB
Go
108 lines
3.6 KiB
Go
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// Copyright (c) 2015, Daniel Martí <mvdan@mvdan.cc>
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// See LICENSE for licensing information
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// Package xurls extracts urls from plain text using regular expressions.
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package xurls
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import (
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"bytes"
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"regexp"
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)
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//go:generate go run generate/tldsgen/main.go
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//go:generate go run generate/schemesgen/main.go
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const (
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letter = `\p{L}`
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mark = `\p{M}`
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number = `\p{N}`
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iriChar = letter + mark + number
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currency = `\p{Sc}`
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otherSymb = `\p{So}`
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endChar = iriChar + `/\-+_&~*%=#` + currency + otherSymb
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otherPunc = `\p{Po}`
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midChar = endChar + `|` + otherPunc
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wellParen = `\([` + midChar + `]*(\([` + midChar + `]*\)[` + midChar + `]*)*\)`
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wellBrack = `\[[` + midChar + `]*(\[[` + midChar + `]*\][` + midChar + `]*)*\]`
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wellBrace = `\{[` + midChar + `]*(\{[` + midChar + `]*\}[` + midChar + `]*)*\}`
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wellAll = wellParen + `|` + wellBrack + `|` + wellBrace
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pathCont = `([` + midChar + `]*(` + wellAll + `|[` + endChar + `])+)+`
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iri = `[` + iriChar + `]([` + iriChar + `\-]*[` + iriChar + `])?`
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domain = `(` + iri + `\.)+`
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octet = `(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])`
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ipv4Addr = `\b` + octet + `\.` + octet + `\.` + octet + `\.` + octet + `\b`
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ipv6Addr = `([0-9a-fA-F]{1,4}:([0-9a-fA-F]{1,4}:([0-9a-fA-F]{1,4}:([0-9a-fA-F]{1,4}:([0-9a-fA-F]{1,4}:[0-9a-fA-F]{0,4}|:[0-9a-fA-F]{1,4})?|(:[0-9a-fA-F]{1,4}){0,2})|(:[0-9a-fA-F]{1,4}){0,3})|(:[0-9a-fA-F]{1,4}){0,4})|:(:[0-9a-fA-F]{1,4}){0,5})((:[0-9a-fA-F]{1,4}){2}|:(25[0-5]|(2[0-4]|1[0-9]|[1-9])?[0-9])(\.(25[0-5]|(2[0-4]|1[0-9]|[1-9])?[0-9])){3})|(([0-9a-fA-F]{1,4}:){1,6}|:):[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){7}:`
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ipAddr = `(` + ipv4Addr + `|` + ipv6Addr + `)`
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port = `(:[0-9]*)?`
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)
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// AnyScheme can be passed to StrictMatchingScheme to match any possibly valid
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// scheme, and not just the known ones.
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var AnyScheme = `([a-zA-Z][a-zA-Z.\-+]*://|` + anyOf(SchemesNoAuthority...) + `:)`
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// SchemesNoAuthority is a sorted list of some well-known url schemes that are
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// followed by ":" instead of "://".
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var SchemesNoAuthority = []string{
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`bitcoin`, // Bitcoin
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`file`, // Files
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`magnet`, // Torrent magnets
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`mailto`, // Mail
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`sms`, // SMS
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`tel`, // Telephone
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`xmpp`, // XMPP
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}
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func anyOf(strs ...string) string {
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var b bytes.Buffer
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b.WriteByte('(')
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for i, s := range strs {
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if i != 0 {
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b.WriteByte('|')
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}
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b.WriteString(regexp.QuoteMeta(s))
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}
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b.WriteByte(')')
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return b.String()
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}
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func strictExp() string {
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schemes := `(` + anyOf(Schemes...) + `://|` + anyOf(SchemesNoAuthority...) + `:)`
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return `(?i)` + schemes + `(?-i)` + pathCont
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}
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func relaxedExp() string {
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site := domain + `(?i)` + anyOf(append(TLDs, PseudoTLDs...)...) + `(?-i)`
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hostName := `(` + site + `|` + ipAddr + `)`
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webURL := hostName + port + `(/|/` + pathCont + `?|\b|$)`
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return strictExp() + `|` + webURL
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}
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// Strict produces a regexp that matches any URL with a scheme in either the
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// Schemes or SchemesNoAuthority lists.
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func Strict() *regexp.Regexp {
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re := regexp.MustCompile(strictExp())
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re.Longest()
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return re
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}
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// Relaxed produces a regexp that matches any URL matched by Strict, plus any
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// URL with no scheme.
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func Relaxed() *regexp.Regexp {
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re := regexp.MustCompile(relaxedExp())
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re.Longest()
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return re
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}
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// StrictMatchingScheme produces a regexp similar to Strict, but requiring that
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// the scheme match the given regular expression. See AnyScheme too.
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func StrictMatchingScheme(exp string) (*regexp.Regexp, error) {
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strictMatching := `(?i)(` + exp + `)(?-i)` + pathCont
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re, err := regexp.Compile(strictMatching)
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if err != nil {
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return nil, err
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}
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re.Longest()
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return re, nil
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}
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