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@mvdan @skhare-r7 @sztanpet
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// Copyright (c) 2015, Daniel Martí <mvdan@mvdan.cc>
// See LICENSE for licensing information
// Package xurls extracts urls from plain text using regular expressions.
package xurls
import (
"bytes"
"regexp"
)
//go:generate go run generate/tldsgen/main.go
//go:generate go run generate/schemesgen/main.go
const (
letter = `\p{L}`
mark = `\p{M}`
number = `\p{N}`
iriChar = letter + mark + number
currency = `\p{Sc}`
otherSymb = `\p{So}`
endChar = iriChar + `/\-+&~%=#` + currency + otherSymb
otherPunc = `\p{Po}`
midChar = endChar + "_*" + otherPunc
wellParen = `\([` + midChar + `]*(\([` + midChar + `]*\)[` + midChar + `]*)*\)`
wellBrack = `\[[` + midChar + `]*(\[[` + midChar + `]*\][` + midChar + `]*)*\]`
wellBrace = `\{[` + midChar + `]*(\{[` + midChar + `]*\}[` + midChar + `]*)*\}`
wellAll = wellParen + `|` + wellBrack + `|` + wellBrace
pathCont = `([` + midChar + `]*(` + wellAll + `|[` + endChar + `])+)+`
iri = `[` + iriChar + `]([` + iriChar + `\-]*[` + iriChar + `])?`
domain = `(` + iri + `\.)+`
octet = `(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])`
ipv4Addr = `\b` + octet + `\.` + octet + `\.` + octet + `\.` + octet + `\b`
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}:`
ipAddr = `(` + ipv4Addr + `|` + ipv6Addr + `)`
port = `(:[0-9]*)?`
)
// AnyScheme can be passed to StrictMatchingScheme to match any possibly valid
// scheme, and not just the known ones.
var AnyScheme = `([a-zA-Z][a-zA-Z.\-+]*://|` + anyOf(SchemesNoAuthority...) + `:)`
// SchemesNoAuthority is a sorted list of some well-known url schemes that are
// followed by ":" instead of "://".
var SchemesNoAuthority = []string{
`bitcoin`, // Bitcoin
`file`, // Files
`magnet`, // Torrent magnets
`mailto`, // Mail
`sms`, // SMS
`tel`, // Telephone
`xmpp`, // XMPP
}
func anyOf(strs ...string) string {
var b bytes.Buffer
b.WriteByte('(')
for i, s := range strs {
if i != 0 {
b.WriteByte('|')
}
b.WriteString(regexp.QuoteMeta(s))
}
b.WriteByte(')')
return b.String()
}
func strictExp() string {
schemes := `(` + anyOf(Schemes...) + `://|` + anyOf(SchemesNoAuthority...) + `:)`
return `(?i)` + schemes + `(?-i)` + pathCont
}
func relaxedExp() string {
punycode := `xn--[a-z0-9-]+`
knownTLDs := anyOf(append(TLDs, PseudoTLDs...)...)
site := domain + `(?i)(` + punycode + `|` + knownTLDs + `)(?-i)`
hostName := `(` + site + `|` + ipAddr + `)`
webURL := hostName + port + `(/|/` + pathCont + `?|\b|(?m)$)`
return strictExp() + `|` + webURL
}
// Strict produces a regexp that matches any URL with a scheme in either the
// Schemes or SchemesNoAuthority lists.
func Strict() *regexp.Regexp {
re := regexp.MustCompile(strictExp())
re.Longest()
return re
}
// Relaxed produces a regexp that matches any URL matched by Strict, plus any
// URL with no scheme.
func Relaxed() *regexp.Regexp {
re := regexp.MustCompile(relaxedExp())
re.Longest()
return re
}
// StrictMatchingScheme produces a regexp similar to Strict, but requiring that
// the scheme match the given regular expression. See AnyScheme too.
func StrictMatchingScheme(exp string) (*regexp.Regexp, error) {
strictMatching := `(?i)(` + exp + `)(?-i)` + pathCont
re, err := regexp.Compile(strictMatching)
if err != nil {
return nil, err
}
re.Longest()
return re, nil
}
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