Add preview card support

internal/gtsmodel/card.go

@@ -0,0 +1,68 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// 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 gtsmodel contains types used *internally* by GoToSocial and added/removed/selected from the database.
+// These types should never be serialized and/or sent out via public APIs, as they contain sensitive information.
+// The annotation used on these structs is for handling them via the bun-db ORM.
+// See here for more info on bun model annotations: https://bun.uptrace.dev/guide/models.html
+package gtsmodel
+
+type Card struct {
+	ID string `bun:"type:CHAR(26),pk,nullzero,notnull,unique"` // Unique identity string.
+	// Location of linked resource.
+	// example: https://buzzfeed.com/some/fuckin/buzzfeed/article
+	URL string `bun:",nullzero"`
+	// Title of linked resource.
+	// example: Buzzfeed - Is Water Wet?
+	Title string `bun:",nullzero"`
+	// Description of preview.
+	// example: Is water wet? We're not sure. In this article, we ask an expert...
+	Description string `bun:",nullzero"`
+	// The type of the preview card.
+	// enum:
+	// - link
+	// - photo
+	// - video
+	// - rich
+	// example: link
+	Type string `bun:",nullzero"`
+	// The author of the original resource.
+	// example: weewee@buzzfeed.com
+	AuthorName string `bun:"author_name,nullzero"`
+	// A link to the author of the original resource.
+	// example: https://buzzfeed.com/authors/weewee
+	AuthorURL string `bun:"author_url,nullzero"`
+	// The provider of the original resource.
+	// example: Buzzfeed
+	ProviderName string `bun:"provider_name,nullzero"`
+	// A link to the provider of the original resource.
+	// example: https://buzzfeed.com
+	ProviderURL string `bun:"provider_url,nullzero"`
+	// HTML to be used for generating the preview card.
+	HTML string `bun:",nullzero"`
+	// Width of preview, in pixels.
+	Width int `bun:",nullzero"`
+	// Height of preview, in pixels.
+	Height int `bun:",nullzero"`
+	// Preview thumbnail.
+	// example: https://example.org/fileserver/preview/thumb.jpg
+	Image string `bun:",nullzero"`
+	// Used for photo embeds, instead of custom html.
+	EmbedURL string `bun:",nullzero"`
+	// A hash computed by the BlurHash algorithm, for generating colorful preview thumbnails when media has not been downloaded yet.
+	Blurhash string `bun:",nullzero"`
+}

internal/gtsmodel/status.go

@@ -76,6 +76,8 @@ type Status struct {
 	PendingApproval          *bool              `bun:",nullzero,notnull,default:false"`                             // If true then status is a reply or boost wrapper that must be Approved by the reply-ee or boost-ee before being fully distributed.
 	PreApproved              bool               `bun:"-"`                                                           // If true, then status is a reply to or boost wrapper of a status on our instance, has permission to do the interaction, and an Accept should be sent out for it immediately. Field not stored in the DB.
 	ApprovedByURI            string             `bun:",nullzero"`                                                   // URI of an Accept Activity that approves the Announce or Create Activity that this status was/will be attached to.
+	CardID                   string             `bun:"type:CHAR(26),nullzero,notnull"`                              //
+	Card                     *Card              `bun:"-"`                                                           // Preview card for links included within status content.
 }
 
 // GetID implements timeline.Timelineable{}.

internal/processing/status/create.go

@@ -189,6 +189,17 @@ func (p *Processor) Create(
 		PendingApproval: util.Ptr(false),
 	}
 
+	// Get preview card
+	card, errWithCode := FetchPreview(content.Content)
+	if errWithCode != nil {
+		return nil, errWithCode
+	}
+
+	if card != nil {
+		status.CardID = id.NewULIDFromTime(now)
+		status.Card = card
+	}
+
 	// Only store ContentWarningText if the parsed
 	// result is different from the given SpoilerText,
 	// otherwise skip to avoid duplicating db columns.
@@ -315,7 +326,6 @@ func (p *Processor) Create(
 
 // backfilledStatusID tries to find an unused ULID for a backfilled status.
 func (p *Processor) backfilledStatusID(ctx context.Context, createdAt time.Time) (string, error) {
-
 	// Any fetching of statuses here is
 	// only to check availability of ID,
 	// no need for any attached models.
@@ -522,7 +532,6 @@ func processInteractionPolicy(
 	settings *gtsmodel.AccountSettings,
 	status *gtsmodel.Status,
 ) gtserror.WithCode {
-
 	// If policy is set on the
 	// form then prefer this.
 	//
@@ -535,7 +544,6 @@ func processInteractionPolicy(
 			form.InteractionPolicy,
 			form.Visibility,
 		)
-
 		if err != nil {
 			errWithCode := gtserror.NewErrorBadRequest(err, err.Error())
 			return errWithCode

internal/processing/status/preview_card.go

@@ -0,0 +1,111 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// 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 status
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"regexp"
+
+	"github.com/PuerkitoBio/goquery"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+var urlRegex = regexp.MustCompile(`https?://[a-zA-Z0-9./?=_-]+`)
+
+func extractLastURL(text string) string {
+	matches := urlRegex.FindAllString(text, -1)
+	if len(matches) == 0 {
+		return ""
+	}
+	return matches[len(matches)-1]
+}
+
+// FetchPreview retrieves OpenGraph metadata from a URL.
+func FetchPreview(text string) (*gtsmodel.Card, gtserror.WithCode) {
+	link := extractLastURL(text)
+	if link == "" {
+		return nil, nil
+	}
+
+	parsed, err := url.ParseRequestURI(link)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err, "invalid URL")
+	}
+
+	if parsed.Scheme != "http" && parsed.Scheme != "https" {
+		return nil, gtserror.NewErrorInternalError(fmt.Errorf("unsupported scheme: %s", parsed.Scheme))
+	}
+
+	resp, err := http.Get(link)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err, "request failed")
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, gtserror.NewErrorInternalError(fmt.Errorf("unexpected status: %s", resp.Status))
+	}
+
+	doc, err := goquery.NewDocumentFromReader(resp.Body)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(fmt.Errorf("failed to parse HTML: %w", err))
+	}
+
+	card := &gtsmodel.Card{
+		URL: link,
+	}
+
+	doc.Find("meta").Each(func(i int, s *goquery.Selection) {
+		property, _ := s.Attr("property")
+		content, _ := s.Attr("content")
+
+		switch property {
+		case "og:title":
+			card.Title = content
+		case "og:description":
+			card.Description = content
+		case "og:type":
+			card.Type = content
+		case "og:image":
+			card.Image = content
+		case "og:url":
+			if content != "" {
+				card.URL = content
+			}
+		case "og:site_name":
+			card.ProviderName = content
+		}
+	})
+
+	if card.Title == "" {
+		card.Title = doc.Find("title").Text()
+	}
+
+	if card.Description == "" {
+		desc, exists := doc.Find("meta[name='description']").Attr("content")
+		if exists {
+			card.Description = desc
+		}
+	}
+
+	return card, nil
+}

internal/typeutils/internaltofrontend.go

@@ -240,7 +240,6 @@ func (c *Converter) AccountToWebAccount(
 
 // accountToAPIAccountPublic provides all the logic for AccountToAPIAccount, MINUS fetching moved account, to prevent possible recursion.
 func (c *Converter) accountToAPIAccountPublic(ctx context.Context, a *gtsmodel.Account) (*apimodel.Account, error) {
-
 	// Populate account struct fields.
 	err := c.state.DB.PopulateAccount(ctx, a)
 
@@ -1375,6 +1374,8 @@ func (c *Converter) baseStatusToFrontend(
 		log.Errorf(ctx, "error converting status emojis: %v", err)
 	}
 
+	apiCard := c.convertCardToAPICard(s.Card, s.CardID)
+
 	// Take status's interaction policy, or
 	// fall back to default for its visibility.
 	var p *gtsmodel.InteractionPolicy
@@ -1411,7 +1412,7 @@ func (c *Converter) baseStatusToFrontend(
 		Mentions:           apiMentions,
 		Tags:               apiTags,
 		Emojis:             apiEmojis,
-		Card:               nil, // TODO: implement cards
+		Card:               apiCard,
 		Text:               s.Text,
 		ContentType:        ContentTypeToAPIContentType(s.ContentType),
 		InteractionPolicy:  *apiInteractionPolicy,
@@ -2598,6 +2599,29 @@ func (c *Converter) convertAttachmentsToAPIAttachments(ctx context.Context, atta
 	return apiAttachments, errs.Combine()
 }
 
+func (c *Converter) convertCardToAPICard(card *gtsmodel.Card, _ string) *apimodel.Card {
+	if card == nil {
+		return nil
+	}
+
+	return &apimodel.Card{
+		URL:          card.URL,
+		Title:        card.Title,
+		Description:  card.Description,
+		Type:         card.Type,
+		AuthorName:   card.AuthorName,
+		AuthorURL:    card.AuthorURL,
+		ProviderName: card.ProviderName,
+		ProviderURL:  card.ProviderURL,
+		HTML:         card.HTML,
+		Width:        card.Width,
+		Height:       card.Height,
+		Image:        card.Image,
+		EmbedURL:     card.EmbedURL,
+		Blurhash:     card.Blurhash,
+	}
+}
+
 // FilterToAPIFiltersV1 converts one GTS model filter into an API v1 filter list
 func (c *Converter) FilterToAPIFiltersV1(ctx context.Context, filter *gtsmodel.Filter) ([]*apimodel.FilterV1, error) {
 	apiFilters := make([]*apimodel.FilterV1, 0, len(filter.Keywords))
@@ -2922,7 +2946,6 @@ func (c *Converter) InteractionPolicyToAPIInteractionPolicy(
 }
 
 func policyValsToAPIPolicyVals(vals gtsmodel.PolicyValues) []apimodel.PolicyValue {
-
 	var (
 		valsLen = len(vals)