Add category pkg

This supports categories in Write.as / WriteFreely.

Ref T809

category/category.go

@@ -0,0 +1,30 @@
+// Package category supports post categories
+package category
+
+import (
+	"errors"
+	"github.com/writeas/slug"
+)
+
+var (
+	ErrNotFound = errors.New("category doesn't exist")
+)
+
+// Category represents a post tag with additional metadata, like a title and slug.
+type Category struct {
+	ID      int64  `json:"-"`
+	Hashtag string `json:"hashtag"`
+	Slug    string `json:"slug"`
+	Title   string `json:"title"`
+}
+
+// NewCategory creates a Category you can insert into the database, based on a hashtag. It automatically breaks up the
+// hashtag by words, based on capitalization, for both the title and a URL-friendly slug.
+func NewCategory(hashtag string) *Category {
+	title := titleFromHashtag(hashtag)
+	return &Category{
+		Hashtag: hashtag,
+		Slug:    slug.Make(title),
+		Title:   title,
+	}
+}

category/tags.go

@@ -0,0 +1,26 @@
+package category
+
+import (
+	"strings"
+	"unicode"
+)
+
+// titleFromHashtag generates an all-lowercase title, with spaces inserted based on initial capitalization -- e.g.
+// "MyWordyTag" becomes "my wordy tag".
+func titleFromHashtag(hashtag string) string {
+	var t strings.Builder
+	var prev rune
+	for i, c := range hashtag {
+		if unicode.IsUpper(c) {
+			if i > 0 && !unicode.IsUpper(prev) {
+				// Insert space if previous rune wasn't also uppercase (e.g. an abbreviation)
+				t.WriteRune(' ')
+			}
+			t.WriteRune(unicode.ToLower(c))
+		} else {
+			t.WriteRune(c)
+		}
+		prev = c
+	}
+	return t.String()
+}

category/tags_test.go

@@ -0,0 +1,31 @@
+package category
+
+import "testing"
+
+func TestTitleFromHashtag(t *testing.T) {
+	tests := []struct {
+		name     string
+		hashtag  string
+		expTitle string
+	}{
+		{"proper noun", "Jane", "jane"},
+		{"full name", "JaneDoe", "jane doe"},
+		{"us words", "unitedStates", "united states"},
+		{"usa", "USA", "usa"},
+		{"us monoword", "unitedstates", "unitedstates"},
+		{"100dto", "100DaysToOffload", "100 days to offload"},
+		{"iphone", "iPhone", "iphone"},
+		{"ilike", "iLikeThis", "i like this"},
+		{"abird", "aBird", "a bird"},
+		{"all caps", "URGENT", "urgent"},
+		{"smartphone", "スマートフォン", "スマートフォン"},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			res := titleFromHashtag(test.hashtag)
+			if res != test.expTitle {
+				t.Fatalf("#%s: got '%s' expected '%s'", test.hashtag, res, test.expTitle)
+			}
+		})
+	}
+}

go.mod

@@ -6,11 +6,13 @@ require (
 	github.com/gofrs/uuid v3.3.0+incompatible
 	github.com/kylemcc/twitter-text-go v0.0.0-20180726194232-7f582f6736ec
 	github.com/microcosm-cc/bluemonday v1.0.5
+	github.com/rainycape/unidecode v0.0.0-20150907023854-cb7f23ec59be // indirect
 	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
 	github.com/writeas/go-strip-markdown v2.0.1+incompatible
 	github.com/writeas/impart v1.1.1
 	github.com/writeas/openssl-go v1.0.0
 	github.com/writeas/saturday v1.7.1
+	github.com/writeas/slug v1.2.0
 	golang.org/x/crypto v0.0.0-20200109152110-61a87790db17
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 	gopkg.in/yaml.v1 v1.0.0-20140924161607-9f9df34309c0 // indirect

go.sum

@@ -15,6 +15,8 @@ github.com/kylemcc/twitter-text-go v0.0.0-20180726194232-7f582f6736ec h1:ZXWuspq
 github.com/kylemcc/twitter-text-go v0.0.0-20180726194232-7f582f6736ec/go.mod h1:voECJzdraJmolzPBgL9Z7ANwXf4oMXaTCsIkdiPpR/g=
 github.com/microcosm-cc/bluemonday v1.0.5 h1:cF59UCKMmmUgqN1baLvqU/B1ZsMori+duLVTLpgiG3w=
 github.com/microcosm-cc/bluemonday v1.0.5/go.mod h1:8iwZnFn2CDDNZ0r6UXhF4xawGvzaqzCRa1n3/lO3W2w=
+github.com/rainycape/unidecode v0.0.0-20150907023854-cb7f23ec59be h1:ta7tUOvsPHVHGom5hKW5VXNc2xZIkfCKP8iaqOyYtUQ=
+github.com/rainycape/unidecode v0.0.0-20150907023854-cb7f23ec59be/go.mod h1:MIDFMn7db1kT65GmV94GzpX9Qdi7N/pQlwb+AN8wh+Q=
 github.com/shurcooL/sanitized_anchor_name v1.0.0 h1:PdmoCO6wvbs+7yrJyMORt4/BmY5IYyJwS/kOiWx8mHo=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/writeas/go-strip-markdown v2.0.1+incompatible h1:IIqxTM5Jr7RzhigcL6FkrCNfXkvbR+Nbu1ls48pXYcw=
@@ -25,6 +27,8 @@ github.com/writeas/openssl-go v1.0.0 h1:YXM1tDXeYOlTyJjoMlYLQH1xOloUimSR1WMF8kjF
 github.com/writeas/openssl-go v1.0.0/go.mod h1:WsKeK5jYl0B5y8ggOmtVjbmb+3rEGqSD25TppjJnETA=
 github.com/writeas/saturday v1.7.1 h1:lYo1EH6CYyrFObQoA9RNWHVlpZA5iYL5Opxo7PYAnZE=
 github.com/writeas/saturday v1.7.1/go.mod h1:ETE1EK6ogxptJpAgUbcJD0prAtX48bSloie80+tvnzQ=
+github.com/writeas/slug v1.2.0 h1:EMQ+cwLiOcA6EtFwUgyw3Ge18x9uflUnOnR6bp/J+/g=
+github.com/writeas/slug v1.2.0/go.mod h1:RE8shOqQP3YhsfsQe0L3RnuejfQ4Mk+JjY5YJQFubfQ=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200109152110-61a87790db17 h1:nVJ3guKA9qdkEQ3TUdXI9QSINo2CUPM/cySEvw2w8I0=
 golang.org/x/crypto v0.0.0-20200109152110-61a87790db17/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=