Implement URL unfurling

exchanges/exchanges_test.go

@@ -3,8 +3,9 @@ package exchanges
 import (
 	"testing"
 
-	"github.com/ethereum/go-ethereum/common"
 	"github.com/stretchr/testify/require"
+
+	"github.com/ethereum/go-ethereum/common"
 )
 
 func TestNullAddress(t *testing.T) {

go.mod

@@ -83,6 +83,7 @@ require (
 	github.com/yeqown/go-qrcode/v2 v2.2.1
 	github.com/yeqown/go-qrcode/writer/standard v1.2.1
 	go.uber.org/multierr v1.8.0
+	golang.org/x/net v0.8.0
 )
 
 require (
@@ -257,7 +258,6 @@ require (
 	go.uber.org/fx v1.18.2 // indirect
 	golang.org/x/exp v0.0.0-20230206171751-46f607a40771 // indirect
 	golang.org/x/mod v0.8.0 // indirect
-	golang.org/x/net v0.8.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/sys v0.6.0 // indirect
 	golang.org/x/term v0.6.0 // indirect

images/encode_test.go

@@ -100,3 +100,13 @@ func TestCompressToFileLimits(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, 291645, bb.Len())
 }
+
+func TestGetPayloadFromURI(t *testing.T) {
+	payload, err := GetPayloadFromURI("data:image/jpeg;base64,/9j/2wCEAFA3PEY8MlA=")
+	require.NoError(t, err)
+	require.Equal(
+		t,
+		[]byte{0xff, 0xd8, 0xff, 0xdb, 0x0, 0x84, 0x0, 0x50, 0x37, 0x3c, 0x46, 0x3c, 0x32, 0x50},
+		payload,
+	)
+}

protocol/chat_test.go

@@ -129,7 +129,7 @@ func (s *ChatTestSuite) TestSerializeJSON() {
 
 	message.From = "0x04deaafa03e3a646e54a36ec3f6968c1d3686847d88420f00c0ab6ee517ee1893398fca28aacd2af74f2654738c21d10bad3d88dc64201ebe0de5cf1e313970d3d"
 	message.Clock = 1
-	message.Text = "`some markdown text`"
+	message.Text = "`some markdown text` https://status.im"
 	s.Require().NoError(message.PrepareContent(""))
 	message.ParsedTextAst = nil
 	chat.LastMessage = message

protocol/common/message.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"io/ioutil"
+	"net/url"
 	"os"
 	"strings"
 	"unicode"
@@ -80,6 +81,25 @@ const (
 	ContactVerificationStateCanceled
 )
 
+type LinkPreviewThumbnail struct {
+	Width  int `json:"width"`
+	Height int `json:"height"`
+	// Non-empty when the thumbnail is available via the media server, i.e. after
+	// the chat message is sent.
+	URL string `json:"url,omitempty"`
+	// Non-empty when the thumbnail payload needs to be shared with the client,
+	// but before it has been persisted.
+	DataURI string `json:"dataUri,omitempty"`
+}
+
+type LinkPreview struct {
+	URL         string               `json:"url"`
+	Hostname    string               `json:"hostname"`
+	Title       string               `json:"title,omitempty"`
+	Description string               `json:"description,omitempty"`
+	Thumbnail   LinkPreviewThumbnail `json:"thumbnail,omitempty"`
+}
+
 const EveryoneMentionTag = "0x00001"
 
 type CommandParameters struct {
@@ -197,7 +217,8 @@ type Message struct {
 	Replied bool `json:"replied"`
 
 	// Links is an array of links within given message
-	Links []string
+	Links        []string
+	LinkPreviews []LinkPreview `json:"linkPreviews"`
 
 	// EditedAt indicates the clock value it was edited
 	EditedAt uint64 `json:"editedAt"`
@@ -264,6 +285,7 @@ func (m *Message) MarshalJSON() ([]byte, error) {
 		Mentioned                bool                             `json:"mentioned,omitempty"`
 		Replied                  bool                             `json:"replied,omitempty"`
 		Links                    []string                         `json:"links,omitempty"`
+		LinkPreviews             []LinkPreview                    `json:"linkPreviews,omitempty"`
 		EditedAt                 uint64                           `json:"editedAt,omitempty"`
 		Deleted                  bool                             `json:"deleted,omitempty"`
 		DeletedBy                string                           `json:"deletedBy,omitempty"`
@@ -302,6 +324,7 @@ func (m *Message) MarshalJSON() ([]byte, error) {
 		Mentioned:                m.Mentioned,
 		Replied:                  m.Replied,
 		Links:                    m.Links,
+		LinkPreviews:             m.LinkPreviews,
 		MessageType:              m.MessageType,
 		CommandParameters:        m.CommandParameters,
 		GapParameters:            m.GapParameters,
@@ -522,6 +545,10 @@ type MentionsAndLinksVisitor struct {
 	links     []string
 }
 
+type LinksVisitor struct {
+	Links []string
+}
+
 func (v *MentionsAndLinksVisitor) Visit(node ast.Node, entering bool) ast.WalkStatus {
 	// only on entering we fetch, otherwise we go on
 	if !entering {
@@ -541,12 +568,31 @@ func (v *MentionsAndLinksVisitor) Visit(node ast.Node, entering bool) ast.WalkSt
 	return ast.GoToNext
 }
 
+func (v *LinksVisitor) Visit(node ast.Node, entering bool) ast.WalkStatus {
+	if !entering {
+		return ast.GoToNext
+	}
+
+	switch n := node.(type) {
+	case *ast.Link:
+		v.Links = append(v.Links, string(n.Destination))
+	}
+
+	return ast.GoToNext
+}
+
 func runMentionsAndLinksVisitor(parsedText ast.Node, identity string) *MentionsAndLinksVisitor {
 	visitor := &MentionsAndLinksVisitor{identity: identity}
 	ast.Walk(parsedText, visitor)
 	return visitor
 }
 
+func RunLinksVisitor(parsedText ast.Node) *LinksVisitor {
+	visitor := &LinksVisitor{}
+	ast.Walk(parsedText, visitor)
+	return visitor
+}
+
 // PrepareContent return the parsed content of the message, the line-count and whether
 // is a right-to-left message
 func (m *Message) PrepareContent(identity string) error {
@@ -711,6 +757,88 @@ func (m *Message) LoadImage() error {
 	return nil
 }
 
+func isValidLinkPreviewForProto(preview LinkPreview) bool {
+	return preview.Title != "" && preview.URL != "" &&
+		((preview.Thumbnail.DataURI == "" && preview.Thumbnail.Width == 0 && preview.Thumbnail.Height == 0) ||
+			(preview.Thumbnail.DataURI != "" && preview.Thumbnail.Width > 0 && preview.Thumbnail.Height > 0))
+}
+
+// ConvertLinkPreviewsToProto expects previews to be correctly sent by the
+// client because we can't attempt to re-unfurl URLs at this point (it's
+// actually undesirable). We run a basic validation as an additional safety net.
+func (m *Message) ConvertLinkPreviewsToProto() ([]*protobuf.UnfurledLink, error) {
+	if len(m.LinkPreviews) == 0 {
+		return nil, nil
+	}
+
+	unfurledLinks := make([]*protobuf.UnfurledLink, 0, len(m.LinkPreviews))
+
+	for _, preview := range m.LinkPreviews {
+		// Do not process subsequent previews because we do expect all previews to
+		// be valid at this stage.
+		if !isValidLinkPreviewForProto(preview) {
+			return nil, fmt.Errorf("invalid link preview, url='%s'", preview.URL)
+		}
+
+		var payload []byte
+		var err error
+		if preview.Thumbnail.DataURI != "" {
+			payload, err = images.GetPayloadFromURI(preview.Thumbnail.DataURI)
+			if err != nil {
+				return nil, fmt.Errorf("could not get data URI payload, url='%s': %w", preview.URL, err)
+			}
+		}
+
+		ul := &protobuf.UnfurledLink{
+			Url:              preview.URL,
+			Title:            preview.Title,
+			Description:      preview.Description,
+			ThumbnailWidth:   uint32(preview.Thumbnail.Width),
+			ThumbnailHeight:  uint32(preview.Thumbnail.Height),
+			ThumbnailPayload: payload,
+		}
+		unfurledLinks = append(unfurledLinks, ul)
+	}
+
+	return unfurledLinks, nil
+}
+
+func (m *Message) ConvertFromProtoToLinkPreviews(makeMediaServerURL func(msgID string, previewURL string) string) []LinkPreview {
+	var links []*protobuf.UnfurledLink
+
+	if links = m.GetUnfurledLinks(); links == nil {
+		return nil
+	}
+
+	previews := make([]LinkPreview, 0, len(links))
+	for _, link := range links {
+		parsedURL, err := url.Parse(link.Url)
+		var hostname string
+		// URL parsing in Go can fail with URLs that weren't correctly URL encoded.
+		// This shouldn't happen in general, but if an error happens we just reuse
+		// the full URL.
+		if err != nil {
+			hostname = link.Url
+		} else {
+			hostname = parsedURL.Hostname()
+		}
+		lp := LinkPreview{
+			Description: link.Description,
+			Hostname:    hostname,
+			Title:       link.Title,
+			URL:         link.Url,
+		}
+		if payload := link.GetThumbnailPayload(); payload != nil {
+			lp.Thumbnail.Width = int(link.ThumbnailWidth)
+			lp.Thumbnail.Height = int(link.ThumbnailHeight)
+			lp.Thumbnail.URL = makeMediaServerURL(m.ID, link.Url)
+		}
+		previews = append(previews, lp)
+	}
+
+	return previews
+}
+
 func (m *Message) SetAlbumIDAndImagesCount(albumID string, imagesCount uint32) error {
 	imageMessage := m.GetImage()
 	if imageMessage == nil {