127 lines
3.1 KiB
Go
127 lines
3.1 KiB
Go
// Copyright 2013 by Dobrosław Żybort. All rights reserved.
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package slug
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import (
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"bytes"
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"regexp"
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"strings"
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"github.com/rainycape/unidecode"
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)
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var (
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// Custom substitution map
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CustomSub map[string]string
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// Custom rune substitution map
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CustomRuneSub map[rune]string
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// Maximum slug length. It's smart so it will cat slug after full word.
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// By default slugs aren't shortened.
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// If MaxLength is smaller than length of the first word, then returned
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// slug will contain only substring from the first word truncated
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// after MaxLength.
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MaxLength int
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regexpNonAuthorizedChars = regexp.MustCompile("[^a-z0-9-_]")
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regexpMultipleDashes = regexp.MustCompile("-+")
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)
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//=============================================================================
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// Make returns slug generated from provided string. Will use "en" as language
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// substitution.
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func Make(s string) (slug string) {
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return MakeLang(s, "en")
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}
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// MakeLang returns slug generated from provided string and will use provided
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// language for chars substitution.
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func MakeLang(s string, lang string) (slug string) {
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slug = strings.TrimSpace(s)
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// Custom substitutions
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// Always substitute runes first
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slug = SubstituteRune(slug, CustomRuneSub)
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slug = Substitute(slug, CustomSub)
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// Process string with selected substitution language
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switch lang {
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case "de":
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slug = SubstituteRune(slug, deSub)
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case "en":
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slug = SubstituteRune(slug, enSub)
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case "pl":
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slug = SubstituteRune(slug, plSub)
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case "es":
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slug = SubstituteRune(slug, esSub)
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default: // fallback to "en" if lang not found
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slug = SubstituteRune(slug, enSub)
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}
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// Process all non ASCII symbols
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slug = unidecode.Unidecode(slug)
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slug = strings.ToLower(slug)
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// Process all remaining symbols
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slug = regexpNonAuthorizedChars.ReplaceAllString(slug, "-")
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slug = regexpMultipleDashes.ReplaceAllString(slug, "-")
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slug = strings.Trim(slug, "-")
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if MaxLength > 0 {
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slug = smartTruncate(slug)
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}
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return slug
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}
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// Substitute returns string with superseded all substrings from
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// provided substitution map.
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func Substitute(s string, sub map[string]string) (buf string) {
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buf = s
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for key, val := range sub {
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buf = strings.Replace(buf, key, val, -1)
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}
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return
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}
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// SubstituteRune substitutes string chars with provided rune
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// substitution map.
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func SubstituteRune(s string, sub map[rune]string) string {
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var buf bytes.Buffer
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for _, c := range s {
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if d, ok := sub[c]; ok {
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buf.WriteString(d)
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} else {
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buf.WriteRune(c)
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}
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}
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return buf.String()
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}
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func smartTruncate(text string) string {
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if len(text) < MaxLength {
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return text
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}
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var truncated string
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words := strings.SplitAfter(text, "-")
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// If MaxLength is smaller than length of the first word return word
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// truncated after MaxLength.
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if len(words[0]) > MaxLength {
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return words[0][:MaxLength]
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}
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for _, word := range words {
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if len(truncated)+len(word)-1 <= MaxLength {
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truncated = truncated + word
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} else {
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break
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}
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}
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return strings.Trim(truncated, "-")
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}
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