func convertTagsToCard(tags map[string]string, webUrl string) (wildcard.Wildcard, error) {
resolveAliases(tags)
ogType, ok := tags["og:type"]
if !ok {
ogType = "website"
}
var card wildcard.Wildcard
url, ok := tags["og:url"]
if !ok {
url = webUrl
}
switch ogType {
case "article":
card = wildcard.NewArticleCard(webUrl, url)
case "video":
fallthrough
case "video.episode":
fallthrough
case "video.movie":
fallthrough
case "video.other":
card = wildcard.NewVideoCard(webUrl)
default:
card = wildcard.NewLinkCard(webUrl, url)
}
err := recursivelyDecode(tags, card)
if err != nil {
return nil, err
}
return card, nil
}
func (s *Scraper) ScrapeTags(url string) (interface{}, error) {
permitted, err := s.checkRobotsTxt(url)
if err != nil {
return nil, err
}
if !permitted {
return nil, errors.New(fmt.Sprintf("Not permitted to fetch %s", url))
}
req, err := s.buildRequest(url)
resp, err := s.client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != 200 {
errMsg := fmt.Sprintf("Could not fetch %s (%d)", url, resp.StatusCode)
return nil, errors.New(errMsg)
}
contentType := resp.Header.Get("Content-Type")
if contentType == "" || strings.Contains(contentType, "text/html") {
return s.ParseTags(resp.Body, url)
}
// We can't really trust the Content-Type header, so we take
// a look at what actually gets returned.
contentStart, err := ioutil.ReadAll(io.LimitReader(resp.Body, 512))
if err != nil {
contentType = http.DetectContentType(contentStart)
}
switch {
case strings.HasPrefix(contentType, "image"):
card := wildcard.NewImageCard(url, url)
card.Media.ImageContentType = contentType
return card, nil
case strings.HasPrefix(contentType, "video"):
card := wildcard.NewVideoCard(url)
card.Media.StreamUrl = url
card.Media.StreamContentType = contentType
return card, nil
default:
card := wildcard.NewLinkCard(url, url)
return card, nil
}
}