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Diffstat (limited to 'internal/web/opengraph.go')
| -rw-r--r-- | internal/web/opengraph.go | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/internal/web/opengraph.go b/internal/web/opengraph.go new file mode 100644 index 000000000..ce333171e --- /dev/null +++ b/internal/web/opengraph.go @@ -0,0 +1,151 @@ +/* + GoToSocial + Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU Affero General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Affero General Public License for more details. + + You should have received a copy of the GNU Affero General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +package web + +import ( + "html" + "strconv" + "strings" + + apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model" + "github.com/superseriousbusiness/gotosocial/internal/text" +) + +const maxOGDescriptionLength = 300 + +// ogMeta represents supported OpenGraph Meta tags +// +// see eg https://developer.yoast.com/features/opengraph/functional-specification/ +type ogMeta struct { + // vanilla og tags + + Locale string // og:locale + ResourceType string // og:type + Title string // og:title + URL string // og:url + SiteName string // og:site_name + Description string // og:description + Image string // og:image + ImageWidth string // og:image:width + ImageHeight string // og:image:height + + // article tags + + ArticlePublisher string // article:publisher + ArticleAuthor string // article:author + ArticleModifiedTime string // article:modified_time + ArticlePublishedTime string // article:published_time +} + +// ogBase returns an *ogMeta suitable for serving at +// the base root of an instance. It also serves as a +// foundation for building account / status ogMeta on +// top of. +func ogBase(instance *apimodel.Instance) *ogMeta { + var locale string + if len(instance.Languages) > 0 { + locale = instance.Languages[0] + } + + og := &ogMeta{ + Locale: locale, + ResourceType: "website", + Title: text.SanitizePlaintext(instance.Title) + " - GoToSocial", + URL: instance.URI, + SiteName: instance.AccountDomain, + Description: parseDescription(instance.ShortDescription), + Image: instance.Thumbnail, + } + + return og +} + +// withAccount uses the given account to build an ogMeta +// struct specific to that account. It's suitable for serving +// at account profile pages. +func (og *ogMeta) withAccount(account *apimodel.Account) *ogMeta { + og.ResourceType = "profile" + og.Title = parseTitle(account, og.SiteName) + og.URL = account.URL + og.Description = parseDescription(account.Note) + og.Image = account.Avatar + return og +} + +// withStatus uses the given status to build an ogMeta +// struct specific to that status. It's suitable for serving +// at status pages. +func (og *ogMeta) withStatus(status *apimodel.Status) *ogMeta { + if !status.Sensitive && len(status.MediaAttachments) > 0 { + a := status.MediaAttachments[0] + og.Image = a.PreviewURL + og.ImageWidth = strconv.Itoa(a.Meta.Small.Width) + og.ImageHeight = strconv.Itoa(a.Meta.Small.Height) + } else { + og.Image = status.Account.Avatar + } + + if status.SpoilerText != "" { + og.Description = parseDescription("CW: " + status.SpoilerText) + } else { + og.Description = parseDescription(status.Text) + } + + og.Locale = status.Language + og.ResourceType = "article" + og.Title = "Post by " + parseTitle(status.Account, og.SiteName) + og.URL = status.URL + og.ArticlePublisher = status.Account.URL + og.ArticleAuthor = status.Account.URL + og.ArticlePublishedTime = status.CreatedAt + og.ArticleModifiedTime = status.CreatedAt + return og +} + +// parseTitle parses a page title from account and accountDomain +func parseTitle(account *apimodel.Account, accountDomain string) string { + user := "@" + account.Acct + "@" + accountDomain + + if len(account.DisplayName) == 0 { + return user + } + + return account.DisplayName + " (" + user + ")" +} + +// parseDescription returns a string description which is +// safe to use as a template.HTMLAttr inside templates. +func parseDescription(in string) string { + i := html.UnescapeString(in) + i = text.SanitizePlaintext(i) + i = strings.ReplaceAll(i, "\"", "'") + i = strings.ReplaceAll(i, `\`, "") + i = strings.ReplaceAll(i, "\n", " ") + i = trim(i, maxOGDescriptionLength) + return `content="` + i + `"` +} + +// trim strings trim s to specified length +func trim(s string, length int) string { + if len(s) < length { + return s + } + + return s[:length] +} |