activitypub: add the public key to Person (#14186)

Refs: https://github.com/go-gitea/gitea/issues/14186

Signed-off-by: Loïc Dachary <loic@dachary.org>

routers/api/v1/activitypub/person.go

@@ -9,12 +9,38 @@ import (
 	"net/url"
 	"strings"
 
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/activitypub"
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/routers/api/v1/user"
 	"github.com/go-fed/activity/streams"
 )
 
+// hack waiting on https://github.com/go-gitea/gitea/pull/16834
+func GetPublicKey(user *models.User) (string, error) {
+	if settings, err := models.GetUserSetting(user.ID, []string{"activitypub_pubPem"}); err != nil {
+		return "", err
+	} else if len(settings) == 0 {
+		if priv, pub, err := activitypub.GenerateKeyPair(); err != nil {
+			return "", err
+		} else {
+			privPem := &models.UserSetting{UserID: user.ID, Name: "activitypub_privPem", Value: priv}
+			if err := models.SetUserSetting(privPem); err != nil {
+				return "", err
+			}
+			pubPem := &models.UserSetting{UserID: user.ID, Name: "activitypub_pubPem", Value: pub}
+			if err := models.SetUserSetting(pubPem); err != nil {
+				return "", err
+			}
+			return pubPem.Value, nil
+		}
+	} else {
+		return settings[0].Value, nil
+	}
+}
+
+// NodeInfo returns the NodeInfo for the Gitea instance to allow for federation
 func Person(ctx *context.APIContext) {
 	// swagger:operation GET /activitypub/user/{username} information
 	// ---
@@ -31,15 +57,15 @@ func Person(ctx *context.APIContext) {
 	//   "200":
 	//     "$ref": "#/responses/ActivityPub"
 
-	user.GetUserByParamsName(ctx, "username")
+	user := user.GetUserByParamsName(ctx, "username")
 	username := ctx.Params("username")
 
 	person := streams.NewActivityStreamsPerson()
 
 	id := streams.NewJSONLDIdProperty()
 	link := strings.TrimSuffix(setting.AppURL, "/") + strings.TrimSuffix(ctx.Req.URL.EscapedPath(), "/")
-	url_object, _ := url.Parse(link)
-	id.SetIRI(url_object)
+	idIRI, _ := url.Parse(link)
+	id.SetIRI(idIRI)
 	person.SetJSONLDId(id)
 
 	name := streams.NewActivityStreamsNameProperty()
@@ -47,7 +73,7 @@ func Person(ctx *context.APIContext) {
 	person.SetActivityStreamsName(name)
 
 	ibox := streams.NewActivityStreamsInboxProperty()
-	url_object, _ = url.Parse(link + "/inbox")
+	url_object, _ := url.Parse(link + "/inbox")
 	ibox.SetIRI(url_object)
 	person.SetActivityStreamsInbox(ibox)
 
@@ -56,6 +82,30 @@ func Person(ctx *context.APIContext) {
 	obox.SetIRI(url_object)
 	person.SetActivityStreamsOutbox(obox)
 
+	publicKeyProp := streams.NewW3IDSecurityV1PublicKeyProperty()
+
+	publicKeyType := streams.NewW3IDSecurityV1PublicKey()
+
+	pubKeyIdProp := streams.NewJSONLDIdProperty()
+	pubKeyIRI, _ := url.Parse(link + "/#main-key")
+	pubKeyIdProp.SetIRI(pubKeyIRI)
+	publicKeyType.SetJSONLDId(pubKeyIdProp)
+
+	ownerProp := streams.NewW3IDSecurityV1OwnerProperty()
+	ownerProp.SetIRI(idIRI)
+	publicKeyType.SetW3IDSecurityV1Owner(ownerProp)
+
+	publicKeyPemProp := streams.NewW3IDSecurityV1PublicKeyPemProperty()
+	if publicKeyPem, err := GetPublicKey(user); err != nil {
+		ctx.Error(http.StatusInternalServerError, "GetPublicKey", err)
+	} else {
+		publicKeyPemProp.Set(publicKeyPem)
+	}
+	publicKeyType.SetW3IDSecurityV1PublicKeyPem(publicKeyPemProp)
+
+	publicKeyProp.AppendW3IDSecurityV1PublicKey(publicKeyType)
+	person.SetW3IDSecurityV1PublicKey(publicKeyProp)
+
 	var jsonmap map[string]interface{}
 	jsonmap, _ = streams.Serialize(person)
 	ctx.JSON(http.StatusOK, jsonmap)