Don't return errors for mentions which are an object

Partially related to #69.

Full fix probably involves actually scanning the markdown for links. It
is unclear where this format is coming from and where it is specified.

service/domain/feeds/content/transport/mapping_about.go

@@ -2,8 +2,10 @@ package transport
 
 import (
 	"encoding/json"
+	"strings"
 
 	"github.com/boreq/errors"
+	"github.com/hashicorp/go-multierror"
 	"github.com/planetary-social/scuttlego/service/domain/feeds/content"
 	"github.com/planetary-social/scuttlego/service/domain/refs"
 )
@@ -67,6 +69,53 @@ type transportAbout struct {
 	Image json.RawMessage `json:"image"`
 }
 
+func unmarshalMentions(j json.RawMessage) ([]refs.Blob, error) {
+	var returnErr error
+
+	if len(j) == 0 {
+		return nil, nil
+	}
+
+	var mentionsSlice []json.RawMessage
+	if err := json.Unmarshal(j, &mentionsSlice); err != nil {
+		returnErr = multierror.Append(returnErr, errors.Wrap(err, "slice unmarshal error"))
+	} else {
+		return unmarshalMentionsSlice(mentionsSlice)
+	}
+
+	var mentionsMap map[string]json.RawMessage
+	if err := json.Unmarshal(j, &mentionsMap); err != nil {
+		returnErr = multierror.Append(returnErr, errors.Wrap(err, "map unmarshal error"))
+	} else {
+		return nil, nil
+	}
+
+	return nil, returnErr
+}
+
+func unmarshalMentionsSlice(slice []json.RawMessage) ([]refs.Blob, error) {
+	var blobs []refs.Blob
+	for _, rawJSON := range slice {
+		mention, err := unmarshalMention(rawJSON)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal a blob link")
+		}
+
+		if !strings.HasPrefix(mention.Link, "&") {
+			continue
+		}
+
+		blob, err := refs.NewBlob(mention.Link)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not create a blob ref")
+		}
+
+		blobs = append(blobs, blob)
+	}
+
+	return blobs, nil
+}
+
 type mention struct {
 	Link string `json:"link"`
 }

service/domain/feeds/content/transport/mapping_post.go

@@ -2,11 +2,9 @@ package transport
 
 import (
 	"encoding/json"
-	"strings"
 
 	"github.com/boreq/errors"
 	"github.com/planetary-social/scuttlego/service/domain/feeds/content"
-	"github.com/planetary-social/scuttlego/service/domain/refs"
 )
 
 var postMapping = MessageContentMapping{
@@ -20,23 +18,9 @@ var postMapping = MessageContentMapping{
 			return nil, errors.Wrap(err, "json unmarshal failed")
 		}
 
-		var blobs []refs.Blob
-		for _, rawJSON := range t.Mentions {
-			mention, err := unmarshalMention(rawJSON)
-			if err != nil {
-				return nil, errors.Wrap(err, "could not unmarshal a blob link")
-			}
-
-			if !strings.HasPrefix(mention.Link, "&") {
-				continue
-			}
-
-			blob, err := refs.NewBlob(mention.Link)
-			if err != nil {
-				return nil, errors.Wrap(err, "could not create a blob ref")
-			}
-
-			blobs = append(blobs, blob)
+		blobs, err := unmarshalMentions(t.Mentions)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not unmarshal mentions")
 		}
 
 		return content.NewPost(blobs)
@@ -46,5 +30,5 @@ var postMapping = MessageContentMapping{
 type transportPost struct {
 	messageContentType // todo this is stupid
 
-	Mentions []json.RawMessage `json:"mentions"`
+	Mentions json.RawMessage `json:"mentions"`
 }

service/domain/feeds/content/transport/mapping_post_test.go

@@ -19,6 +19,14 @@ func TestMappingPostUnmarshal(t *testing.T) {
 		Content      string
 		ExpectedPost msgcontents.Post
 	}{
+		{
+			Name: "no_mentions",
+			Content: `{
+				"type": "post",
+				"text": "YES WE CAN! :heart: :smiley_cat:"
+			}`,
+			ExpectedPost: postWithoutBlobs,
+		},
 		{
 			Name: "complex",
 			Content: `{
@@ -53,6 +61,17 @@ func TestMappingPostUnmarshal(t *testing.T) {
 			}`,
 			ExpectedPost: postWithoutBlobs,
 		},
+		{
+			Name: "mentions_which_are_a_map",
+			Content: `{
+				"type": "post",
+				"text": "a new photo from #dweb-camp 2022! ![photo.bmp](&O0h21NiGLLmjCF1kD2xWllvPExwe6t5P+F7YK3HAX4g=.sha256)",
+				"mentions": {
+					"0":{"name":"photo.bmp","type": "image/bmp"}
+				}
+			}`,
+			ExpectedPost: postWithoutBlobs, // todo probably actually scan the markdown
+		},
 	}
 
 	for _, testCase := range testCases {