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package opengraph
import (
"encoding/json"
"io"
"strconv"
"time"
"golang.org/x/net/html"
"golang.org/x/net/html/atom"
)
// Image defines Open Graph Image type
type Image struct {
URL string `json:"url"`
SecureURL string `json:"secure_url"`
Type string `json:"type"`
Width uint64 `json:"width"`
Height uint64 `json:"height"`
}
// Video defines Open Graph Video type
type Video struct {
URL string `json:"url"`
SecureURL string `json:"secure_url"`
Type string `json:"type"`
Width uint64 `json:"width"`
Height uint64 `json:"height"`
}
// Audio defines Open Graph Audio Type
type Audio struct {
URL string `json:"url"`
SecureURL string `json:"secure_url"`
Type string `json:"type"`
}
// Article contain Open Graph Article structure
type Article struct {
PublishedTime *time.Time `json:"published_time"`
ModifiedTime *time.Time `json:"modified_time"`
ExpirationTime *time.Time `json:"expiration_time"`
Section string `json:"section"`
Tags []string `json:"tags"`
Authors []*Profile `json:"authors"`
}
// Profile contains Open Graph Profile structure
type Profile struct {
FirstName string `json:"first_name"`
LastName string `json:"last_name"`
Username string `json:"username"`
Gender string `json:"gender"`
}
// Book contains Open Graph Book structure
type Book struct {
ISBN string `json:"isbn"`
ReleaseDate *time.Time `json:"release_date"`
Tags []string `json:"tags"`
Authors []*Profile `json:"authors"`
}
// OpenGraph contains facebook og data
type OpenGraph struct {
isArticle bool
isBook bool
isProfile bool
Type string `json:"type"`
URL string `json:"url"`
Title string `json:"title"`
Description string `json:"description"`
Determiner string `json:"determiner"`
SiteName string `json:"site_name"`
Locale string `json:"locale"`
LocalesAlternate []string `json:"locales_alternate"`
Images []*Image `json:"images"`
Audios []*Audio `json:"audios"`
Videos []*Video `json:"videos"`
Article *Article `json:"article,omitempty"`
Book *Book `json:"book,omitempty"`
Profile *Profile `json:"profile,omitempty"`
}
// NewOpenGraph returns new instance of Open Graph structure
func NewOpenGraph() *OpenGraph {
return &OpenGraph{}
}
// ToJSON a simple wrapper around json.Marshal
func (og *OpenGraph) ToJSON() ([]byte, error) {
return json.Marshal(og)
}
// String return json representation of structure, or error string
func (og *OpenGraph) String() string {
data, err := og.ToJSON()
if err != nil {
return err.Error()
}
return string(data[:])
}
// ProcessHTML parses given html from Reader interface and fills up OpenGraph structure
func (og *OpenGraph) ProcessHTML(buffer io.Reader) error {
z := html.NewTokenizer(buffer)
for {
tt := z.Next()
switch tt {
case html.ErrorToken:
if z.Err() == io.EOF {
return nil
}
return z.Err()
case html.StartTagToken, html.SelfClosingTagToken, html.EndTagToken:
name, hasAttr := z.TagName()
if atom.Lookup(name) == atom.Body {
return nil // OpenGraph is only in head, so we don't need body
}
if atom.Lookup(name) != atom.Meta || !hasAttr {
continue
}
m := make(map[string]string)
var key, val []byte
for hasAttr {
key, val, hasAttr = z.TagAttr()
m[atom.String(key)] = string(val)
}
og.ProcessMeta(m)
}
}
}
// ProcessMeta processes meta attributes and adds them to Open Graph structure if they are suitable for that
func (og *OpenGraph) ProcessMeta(metaAttrs map[string]string) {
switch metaAttrs["property"] {
case "og:description":
og.Description = metaAttrs["content"]
case "og:type":
og.Type = metaAttrs["content"]
switch og.Type {
case "article":
og.isArticle = true
case "book":
og.isBook = true
case "profile":
og.isProfile = true
}
case "og:title":
og.Title = metaAttrs["content"]
case "og:url":
og.URL = metaAttrs["content"]
case "og:determiner":
og.Determiner = metaAttrs["content"]
case "og:site_name":
og.SiteName = metaAttrs["content"]
case "og:locale":
og.Locale = metaAttrs["content"]
case "og:locale:alternate":
og.LocalesAlternate = append(og.LocalesAlternate, metaAttrs["content"])
case "og:image":
og.Images = append(og.Images, &Image{URL: metaAttrs["content"]})
case "og:image:url":
if len(og.Images) > 0 {
og.Images[len(og.Images)-1].URL = metaAttrs["content"]
}
case "og:image:secure_url":
if len(og.Images) > 0 {
og.Images[len(og.Images)-1].SecureURL = metaAttrs["content"]
}
case "og:image:type":
if len(og.Images) > 0 {
og.Images[len(og.Images)-1].Type = metaAttrs["content"]
}
case "og:image:width":
if len(og.Images) > 0 {
w, err := strconv.ParseUint(metaAttrs["content"], 10, 64)
if err == nil {
og.Images[len(og.Images)-1].Width = w
}
}
case "og:image:height":
if len(og.Images) > 0 {
h, err := strconv.ParseUint(metaAttrs["content"], 10, 64)
if err == nil {
og.Images[len(og.Images)-1].Height = h
}
}
case "og:video":
og.Videos = append(og.Videos, &Video{URL: metaAttrs["content"]})
case "og:video:url":
if len(og.Videos) > 0 {
og.Videos[len(og.Videos)-1].URL = metaAttrs["content"]
}
case "og:video:secure_url":
if len(og.Videos) > 0 {
og.Videos[len(og.Videos)-1].SecureURL = metaAttrs["content"]
}
case "og:video:type":
if len(og.Videos) > 0 {
og.Videos[len(og.Videos)-1].Type = metaAttrs["content"]
}
case "og:video:width":
if len(og.Videos) > 0 {
w, err := strconv.ParseUint(metaAttrs["content"], 10, 64)
if err == nil {
og.Videos[len(og.Videos)-1].Width = w
}
}
case "og:video:height":
if len(og.Videos) > 0 {
h, err := strconv.ParseUint(metaAttrs["content"], 10, 64)
if err == nil {
og.Videos[len(og.Videos)-1].Height = h
}
}
default:
if og.isArticle {
og.processArticleMeta(metaAttrs)
} else if og.isBook {
og.processBookMeta(metaAttrs)
} else if og.isProfile {
og.processProfileMeta(metaAttrs)
}
}
}
func (og *OpenGraph) processArticleMeta(metaAttrs map[string]string) {
if og.Article == nil {
og.Article = &Article{}
}
switch metaAttrs["property"] {
case "article:published_time":
t, err := time.Parse(time.RFC3339, metaAttrs["content"])
if err == nil {
og.Article.PublishedTime = &t
}
case "article:modified_time":
t, err := time.Parse(time.RFC3339, metaAttrs["content"])
if err == nil {
og.Article.ModifiedTime = &t
}
case "article:expiration_time":
t, err := time.Parse(time.RFC3339, metaAttrs["content"])
if err == nil {
og.Article.ExpirationTime = &t
}
case "article:section":
og.Article.Section = metaAttrs["content"]
case "article:tag":
og.Article.Tags = append(og.Article.Tags, metaAttrs["content"])
case "article:author:first_name":
if len(og.Article.Authors) == 0 {
og.Article.Authors = append(og.Article.Authors, &Profile{})
}
og.Article.Authors[len(og.Article.Authors)-1].FirstName = metaAttrs["content"]
case "article:author:last_name":
if len(og.Article.Authors) == 0 {
og.Article.Authors = append(og.Article.Authors, &Profile{})
}
og.Article.Authors[len(og.Article.Authors)-1].LastName = metaAttrs["content"]
case "article:author:username":
if len(og.Article.Authors) == 0 {
og.Article.Authors = append(og.Article.Authors, &Profile{})
}
og.Article.Authors[len(og.Article.Authors)-1].Username = metaAttrs["content"]
case "article:author:gender":
if len(og.Article.Authors) == 0 {
og.Article.Authors = append(og.Article.Authors, &Profile{})
}
og.Article.Authors[len(og.Article.Authors)-1].Gender = metaAttrs["content"]
}
}
func (og *OpenGraph) processBookMeta(metaAttrs map[string]string) {
if og.Book == nil {
og.Book = &Book{}
}
switch metaAttrs["property"] {
case "book:release_date":
t, err := time.Parse(time.RFC3339, metaAttrs["content"])
if err == nil {
og.Book.ReleaseDate = &t
}
case "book:isbn":
og.Book.ISBN = metaAttrs["content"]
case "book:tag":
og.Book.Tags = append(og.Book.Tags, metaAttrs["content"])
case "book:author:first_name":
if len(og.Book.Authors) == 0 {
og.Book.Authors = append(og.Book.Authors, &Profile{})
}
og.Book.Authors[len(og.Book.Authors)-1].FirstName = metaAttrs["content"]
case "book:author:last_name":
if len(og.Book.Authors) == 0 {
og.Book.Authors = append(og.Book.Authors, &Profile{})
}
og.Book.Authors[len(og.Book.Authors)-1].LastName = metaAttrs["content"]
case "book:author:username":
if len(og.Book.Authors) == 0 {
og.Book.Authors = append(og.Book.Authors, &Profile{})
}
og.Book.Authors[len(og.Book.Authors)-1].Username = metaAttrs["content"]
case "book:author:gender":
if len(og.Book.Authors) == 0 {
og.Book.Authors = append(og.Book.Authors, &Profile{})
}
og.Book.Authors[len(og.Book.Authors)-1].Gender = metaAttrs["content"]
}
}
func (og *OpenGraph) processProfileMeta(metaAttrs map[string]string) {
if og.Profile == nil {
og.Profile = &Profile{}
}
switch metaAttrs["property"] {
case "profile:first_name":
og.Profile.FirstName = metaAttrs["content"]
case "profile:last_name":
og.Profile.LastName = metaAttrs["content"]
case "profile:username":
og.Profile.Username = metaAttrs["content"]
case "profile:gender":
og.Profile.Gender = metaAttrs["content"]
}
}
|
