Adding upstream version 9.0.3.

Signed-off-by: Daniel Baumann <daniel@debian.org>

8 files changed, 1006 insertions, 0 deletions

diff --git a/modules/forgefed/activity.go b/modules/forgefed/activity.go
new file mode 100644
index 0000000..247abd2
--- /dev/null
+++ b/modules/forgefed/activity.go
@@ -0,0 +1,65 @@
+// Copyright 2023, 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgefed
+
+import (
+	"time"
+
+	"code.gitea.io/gitea/modules/validation"
+
+	ap "github.com/go-ap/activitypub"
+)
+
+// ForgeLike activity data type
+// swagger:model
+type ForgeLike struct {
+	// swagger:ignore
+	ap.Activity
+}
+
+func NewForgeLike(actorIRI, objectIRI string, startTime time.Time) (ForgeLike, error) {
+	result := ForgeLike{}
+	result.Type = ap.LikeType
+	result.Actor = ap.IRI(actorIRI)   // That's us, a User
+	result.Object = ap.IRI(objectIRI) // That's them, a Repository
+	result.StartTime = startTime
+	if valid, err := validation.IsValid(result); !valid {
+		return ForgeLike{}, err
+	}
+	return result, nil
+}
+
+func (like ForgeLike) MarshalJSON() ([]byte, error) {
+	return like.Activity.MarshalJSON()
+}
+
+func (like *ForgeLike) UnmarshalJSON(data []byte) error {
+	return like.Activity.UnmarshalJSON(data)
+}
+
+func (like ForgeLike) IsNewer(compareTo time.Time) bool {
+	return like.StartTime.After(compareTo)
+}
+
+func (like ForgeLike) Validate() []string {
+	var result []string
+	result = append(result, validation.ValidateNotEmpty(string(like.Type), "type")...)
+	result = append(result, validation.ValidateOneOf(string(like.Type), []any{"Like"}, "type")...)
+	if like.Actor == nil {
+		result = append(result, "Actor should not be nil.")
+	} else {
+		result = append(result, validation.ValidateNotEmpty(like.Actor.GetID().String(), "actor")...)
+	}
+	if like.Object == nil {
+		result = append(result, "Object should not be nil.")
+	} else {
+		result = append(result, validation.ValidateNotEmpty(like.Object.GetID().String(), "object")...)
+	}
+	result = append(result, validation.ValidateNotEmpty(like.StartTime.String(), "startTime")...)
+	if like.StartTime.IsZero() {
+		result = append(result, "StartTime was invalid.")
+	}
+
+	return result
+}
diff --git a/modules/forgefed/activity_test.go b/modules/forgefed/activity_test.go
new file mode 100644
index 0000000..9a7979c
--- /dev/null
+++ b/modules/forgefed/activity_test.go
@@ -0,0 +1,171 @@
+// Copyright 2023, 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgefed
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	"code.gitea.io/gitea/modules/validation"
+
+	ap "github.com/go-ap/activitypub"
+)
+
+func Test_NewForgeLike(t *testing.T) {
+	actorIRI := "https://repo.prod.meissa.de/api/v1/activitypub/user-id/1"
+	objectIRI := "https://codeberg.org/api/v1/activitypub/repository-id/1"
+	want := []byte(`{"type":"Like","startTime":"2024-03-27T00:00:00Z","actor":"https://repo.prod.meissa.de/api/v1/activitypub/user-id/1","object":"https://codeberg.org/api/v1/activitypub/repository-id/1"}`)
+
+	startTime, _ := time.Parse("2006-Jan-02", "2024-Mar-27")
+	sut, err := NewForgeLike(actorIRI, objectIRI, startTime)
+	if err != nil {
+		t.Errorf("unexpected error: %v\n", err)
+	}
+	if valid, _ := validation.IsValid(sut); !valid {
+		t.Errorf("sut expected to be valid: %v\n", sut.Validate())
+	}
+
+	got, err := sut.MarshalJSON()
+	if err != nil {
+		t.Errorf("MarshalJSON() error = \"%v\"", err)
+		return
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("MarshalJSON() got = %q, want %q", got, want)
+	}
+}
+
+func Test_LikeMarshalJSON(t *testing.T) {
+	type testPair struct {
+		item    ForgeLike
+		want    []byte
+		wantErr error
+	}
+
+	tests := map[string]testPair{
+		"empty": {
+			item: ForgeLike{},
+			want: nil,
+		},
+		"with ID": {
+			item: ForgeLike{
+				Activity: ap.Activity{
+					Actor:  ap.IRI("https://repo.prod.meissa.de/api/v1/activitypub/user-id/1"),
+					Type:   "Like",
+					Object: ap.IRI("https://codeberg.org/api/v1/activitypub/repository-id/1"),
+				},
+			},
+			want: []byte(`{"type":"Like","actor":"https://repo.prod.meissa.de/api/v1/activitypub/user-id/1","object":"https://codeberg.org/api/v1/activitypub/repository-id/1"}`),
+		},
+	}
+
+	for name, tt := range tests {
+		t.Run(name, func(t *testing.T) {
+			got, err := tt.item.MarshalJSON()
+			if (err != nil || tt.wantErr != nil) && tt.wantErr.Error() != err.Error() {
+				t.Errorf("MarshalJSON() error = \"%v\", wantErr \"%v\"", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("MarshalJSON() got = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_LikeUnmarshalJSON(t *testing.T) {
+	type testPair struct {
+		item    []byte
+		want    *ForgeLike
+		wantErr error
+	}
+
+	//revive:disable
+	tests := map[string]testPair{
+		"with ID": {
+			item: []byte(`{"type":"Like","actor":"https://repo.prod.meissa.de/api/activitypub/user-id/1","object":"https://codeberg.org/api/activitypub/repository-id/1"}`),
+			want: &ForgeLike{
+				Activity: ap.Activity{
+					Actor:  ap.IRI("https://repo.prod.meissa.de/api/activitypub/user-id/1"),
+					Type:   "Like",
+					Object: ap.IRI("https://codeberg.org/api/activitypub/repository-id/1"),
+				},
+			},
+			wantErr: nil,
+		},
+		"invalid": {
+			item:    []byte(`{"type":"Invalid","actor":"https://repo.prod.meissa.de/api/activitypub/user-id/1","object":"https://codeberg.org/api/activitypub/repository-id/1"`),
+			want:    &ForgeLike{},
+			wantErr: fmt.Errorf("cannot parse JSON:"),
+		},
+	}
+	//revive:enable
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			got := new(ForgeLike)
+			err := got.UnmarshalJSON(test.item)
+			if (err != nil || test.wantErr != nil) && !strings.Contains(err.Error(), test.wantErr.Error()) {
+				t.Errorf("UnmarshalJSON() error = \"%v\", wantErr \"%v\"", err, test.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, test.want) {
+				t.Errorf("UnmarshalJSON() got = %q, want %q, err %q", got, test.want, err.Error())
+			}
+		})
+	}
+}
+
+func TestActivityValidation(t *testing.T) {
+	sut := new(ForgeLike)
+	sut.UnmarshalJSON([]byte(`{"type":"Like",
+	"actor":"https://repo.prod.meissa.de/api/activitypub/user-id/1",
+	"object":"https://codeberg.org/api/activitypub/repository-id/1",
+	"startTime": "2014-12-31T23:00:00-08:00"}`))
+	if res, _ := validation.IsValid(sut); !res {
+		t.Errorf("sut expected to be valid: %v\n", sut.Validate())
+	}
+
+	sut.UnmarshalJSON([]byte(`{"actor":"https://repo.prod.meissa.de/api/activitypub/user-id/1",
+	"object":"https://codeberg.org/api/activitypub/repository-id/1",
+	"startTime": "2014-12-31T23:00:00-08:00"}`))
+	if sut.Validate()[0] != "type should not be empty" {
+		t.Errorf("validation error expected but was: %v\n", sut.Validate()[0])
+	}
+
+	sut.UnmarshalJSON([]byte(`{"type":"bad-type",
+		"actor":"https://repo.prod.meissa.de/api/activitypub/user-id/1",
+	"object":"https://codeberg.org/api/activitypub/repository-id/1",
+	"startTime": "2014-12-31T23:00:00-08:00"}`))
+	if sut.Validate()[0] != "Value bad-type is not contained in allowed values [Like]" {
+		t.Errorf("validation error expected but was: %v\n", sut.Validate()[0])
+	}
+
+	sut.UnmarshalJSON([]byte(`{"type":"Like",
+		"actor":"https://repo.prod.meissa.de/api/activitypub/user-id/1",
+	"object":"https://codeberg.org/api/activitypub/repository-id/1",
+	"startTime": "not a date"}`))
+	if sut.Validate()[0] != "StartTime was invalid." {
+		t.Errorf("validation error expected but was: %v\n", sut.Validate())
+	}
+
+	sut.UnmarshalJSON([]byte(`{"type":"Wrong",
+		"actor":"https://repo.prod.meissa.de/api/activitypub/user-id/1",
+	"object":"https://codeberg.org/api/activitypub/repository-id/1",
+	"startTime": "2014-12-31T23:00:00-08:00"}`))
+	if sut.Validate()[0] != "Value Wrong is not contained in allowed values [Like]" {
+		t.Errorf("validation error expected but was: %v\n", sut.Validate())
+	}
+}
+
+func TestActivityValidation_Attack(t *testing.T) {
+	sut := new(ForgeLike)
+	sut.UnmarshalJSON([]byte(`{rubbish}`))
+	if len(sut.Validate()) != 5 {
+		t.Errorf("5 validateion errors expected but was: %v\n", len(sut.Validate()))
+	}
+}
diff --git a/modules/forgefed/actor.go b/modules/forgefed/actor.go
new file mode 100644
index 0000000..0ef4618
--- /dev/null
+++ b/modules/forgefed/actor.go
@@ -0,0 +1,218 @@
+// Copyright 2023, 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgefed
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+
+	"code.gitea.io/gitea/modules/validation"
+
+	ap "github.com/go-ap/activitypub"
+)
+
+// ----------------------------- ActorID --------------------------------------------
+type ActorID struct {
+	ID               string
+	Source           string
+	Schema           string
+	Path             string
+	Host             string
+	Port             string
+	UnvalidatedInput string
+}
+
+// Factory function for ActorID. Created struct is asserted to be valid
+func NewActorID(uri string) (ActorID, error) {
+	result, err := newActorID(uri)
+	if err != nil {
+		return ActorID{}, err
+	}
+
+	if valid, err := validation.IsValid(result); !valid {
+		return ActorID{}, err
+	}
+
+	return result, nil
+}
+
+func (id ActorID) AsURI() string {
+	var result string
+	if id.Port == "" {
+		result = fmt.Sprintf("%s://%s/%s/%s", id.Schema, id.Host, id.Path, id.ID)
+	} else {
+		result = fmt.Sprintf("%s://%s:%s/%s/%s", id.Schema, id.Host, id.Port, id.Path, id.ID)
+	}
+	return result
+}
+
+func (id ActorID) Validate() []string {
+	var result []string
+	result = append(result, validation.ValidateNotEmpty(id.ID, "userId")...)
+	result = append(result, validation.ValidateNotEmpty(id.Schema, "schema")...)
+	result = append(result, validation.ValidateNotEmpty(id.Path, "path")...)
+	result = append(result, validation.ValidateNotEmpty(id.Host, "host")...)
+	result = append(result, validation.ValidateNotEmpty(id.UnvalidatedInput, "unvalidatedInput")...)
+
+	if id.UnvalidatedInput != id.AsURI() {
+		result = append(result, fmt.Sprintf("not all input was parsed, \nUnvalidated Input:%q \nParsed URI: %q", id.UnvalidatedInput, id.AsURI()))
+	}
+
+	return result
+}
+
+// ----------------------------- PersonID --------------------------------------------
+type PersonID struct {
+	ActorID
+}
+
+// Factory function for PersonID. Created struct is asserted to be valid
+func NewPersonID(uri, source string) (PersonID, error) {
+	result, err := newActorID(uri)
+	if err != nil {
+		return PersonID{}, err
+	}
+	result.Source = source
+
+	// validate Person specific path
+	personID := PersonID{result}
+	if valid, err := validation.IsValid(personID); !valid {
+		return PersonID{}, err
+	}
+
+	return personID, nil
+}
+
+func (id PersonID) AsWebfinger() string {
+	result := fmt.Sprintf("@%s@%s", strings.ToLower(id.ID), strings.ToLower(id.Host))
+	return result
+}
+
+func (id PersonID) AsLoginName() string {
+	result := fmt.Sprintf("%s%s", strings.ToLower(id.ID), id.HostSuffix())
+	return result
+}
+
+func (id PersonID) HostSuffix() string {
+	result := fmt.Sprintf("-%s", strings.ToLower(id.Host))
+	return result
+}
+
+func (id PersonID) Validate() []string {
+	result := id.ActorID.Validate()
+	result = append(result, validation.ValidateNotEmpty(id.Source, "source")...)
+	result = append(result, validation.ValidateOneOf(id.Source, []any{"forgejo", "gitea"}, "Source")...)
+	switch id.Source {
+	case "forgejo", "gitea":
+		if strings.ToLower(id.Path) != "api/v1/activitypub/user-id" && strings.ToLower(id.Path) != "api/activitypub/user-id" {
+			result = append(result, fmt.Sprintf("path: %q has to be a person specific api path", id.Path))
+		}
+	}
+	return result
+}
+
+// ----------------------------- RepositoryID --------------------------------------------
+
+type RepositoryID struct {
+	ActorID
+}
+
+// Factory function for RepositoryID. Created struct is asserted to be valid.
+func NewRepositoryID(uri, source string) (RepositoryID, error) {
+	result, err := newActorID(uri)
+	if err != nil {
+		return RepositoryID{}, err
+	}
+	result.Source = source
+
+	// validate Person specific
+	repoID := RepositoryID{result}
+	if valid, err := validation.IsValid(repoID); !valid {
+		return RepositoryID{}, err
+	}
+
+	return repoID, nil
+}
+
+func (id RepositoryID) Validate() []string {
+	result := id.ActorID.Validate()
+	result = append(result, validation.ValidateNotEmpty(id.Source, "source")...)
+	result = append(result, validation.ValidateOneOf(id.Source, []any{"forgejo", "gitea"}, "Source")...)
+	switch id.Source {
+	case "forgejo", "gitea":
+		if strings.ToLower(id.Path) != "api/v1/activitypub/repository-id" && strings.ToLower(id.Path) != "api/activitypub/repository-id" {
+			result = append(result, fmt.Sprintf("path: %q has to be a repo specific api path", id.Path))
+		}
+	}
+	return result
+}
+
+func containsEmptyString(ar []string) bool {
+	for _, elem := range ar {
+		if elem == "" {
+			return true
+		}
+	}
+	return false
+}
+
+func removeEmptyStrings(ls []string) []string {
+	var rs []string
+	for _, str := range ls {
+		if str != "" {
+			rs = append(rs, str)
+		}
+	}
+	return rs
+}
+
+func newActorID(uri string) (ActorID, error) {
+	validatedURI, err := url.ParseRequestURI(uri)
+	if err != nil {
+		return ActorID{}, err
+	}
+	pathWithActorID := strings.Split(validatedURI.Path, "/")
+	if containsEmptyString(pathWithActorID) {
+		pathWithActorID = removeEmptyStrings(pathWithActorID)
+	}
+	length := len(pathWithActorID)
+	pathWithoutActorID := strings.Join(pathWithActorID[0:length-1], "/")
+	id := pathWithActorID[length-1]
+
+	result := ActorID{}
+	result.ID = id
+	result.Schema = validatedURI.Scheme
+	result.Host = validatedURI.Hostname()
+	result.Path = pathWithoutActorID
+	result.Port = validatedURI.Port()
+	result.UnvalidatedInput = uri
+	return result, nil
+}
+
+// ----------------------------- ForgePerson -------------------------------------
+
+// ForgePerson activity data type
+// swagger:model
+type ForgePerson struct {
+	// swagger:ignore
+	ap.Actor
+}
+
+func (s ForgePerson) MarshalJSON() ([]byte, error) {
+	return s.Actor.MarshalJSON()
+}
+
+func (s *ForgePerson) UnmarshalJSON(data []byte) error {
+	return s.Actor.UnmarshalJSON(data)
+}
+
+func (s ForgePerson) Validate() []string {
+	var result []string
+	result = append(result, validation.ValidateNotEmpty(string(s.Type), "Type")...)
+	result = append(result, validation.ValidateOneOf(string(s.Type), []any{string(ap.PersonType)}, "Type")...)
+	result = append(result, validation.ValidateNotEmpty(s.PreferredUsername.String(), "PreferredUsername")...)
+
+	return result
+}
diff --git a/modules/forgefed/actor_test.go b/modules/forgefed/actor_test.go
new file mode 100644
index 0000000..a3c01ec
--- /dev/null
+++ b/modules/forgefed/actor_test.go
@@ -0,0 +1,225 @@
+// Copyright 2023, 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgefed
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/validation"
+
+	ap "github.com/go-ap/activitypub"
+)
+
+func TestNewPersonId(t *testing.T) {
+	expected := PersonID{}
+	expected.ID = "1"
+	expected.Source = "forgejo"
+	expected.Schema = "https"
+	expected.Path = "api/v1/activitypub/user-id"
+	expected.Host = "an.other.host"
+	expected.Port = ""
+	expected.UnvalidatedInput = "https://an.other.host/api/v1/activitypub/user-id/1"
+	sut, _ := NewPersonID("https://an.other.host/api/v1/activitypub/user-id/1", "forgejo")
+	if sut != expected {
+		t.Errorf("expected: %v\n but was: %v\n", expected, sut)
+	}
+
+	expected = PersonID{}
+	expected.ID = "1"
+	expected.Source = "forgejo"
+	expected.Schema = "https"
+	expected.Path = "api/v1/activitypub/user-id"
+	expected.Host = "an.other.host"
+	expected.Port = "443"
+	expected.UnvalidatedInput = "https://an.other.host:443/api/v1/activitypub/user-id/1"
+	sut, _ = NewPersonID("https://an.other.host:443/api/v1/activitypub/user-id/1", "forgejo")
+	if sut != expected {
+		t.Errorf("expected: %v\n but was: %v\n", expected, sut)
+	}
+}
+
+func TestNewRepositoryId(t *testing.T) {
+	setting.AppURL = "http://localhost:3000/"
+	expected := RepositoryID{}
+	expected.ID = "1"
+	expected.Source = "forgejo"
+	expected.Schema = "http"
+	expected.Path = "api/activitypub/repository-id"
+	expected.Host = "localhost"
+	expected.Port = "3000"
+	expected.UnvalidatedInput = "http://localhost:3000/api/activitypub/repository-id/1"
+	sut, _ := NewRepositoryID("http://localhost:3000/api/activitypub/repository-id/1", "forgejo")
+	if sut != expected {
+		t.Errorf("expected: %v\n but was: %v\n", expected, sut)
+	}
+}
+
+func TestActorIdValidation(t *testing.T) {
+	sut := ActorID{}
+	sut.Source = "forgejo"
+	sut.Schema = "https"
+	sut.Path = "api/v1/activitypub/user-id"
+	sut.Host = "an.other.host"
+	sut.Port = ""
+	sut.UnvalidatedInput = "https://an.other.host/api/v1/activitypub/user-id/"
+	if sut.Validate()[0] != "userId should not be empty" {
+		t.Errorf("validation error expected but was: %v\n", sut.Validate())
+	}
+
+	sut = ActorID{}
+	sut.ID = "1"
+	sut.Source = "forgejo"
+	sut.Schema = "https"
+	sut.Path = "api/v1/activitypub/user-id"
+	sut.Host = "an.other.host"
+	sut.Port = ""
+	sut.UnvalidatedInput = "https://an.other.host/api/v1/activitypub/user-id/1?illegal=action"
+	if sut.Validate()[0] != "not all input was parsed, \nUnvalidated Input:\"https://an.other.host/api/v1/activitypub/user-id/1?illegal=action\" \nParsed URI: \"https://an.other.host/api/v1/activitypub/user-id/1\"" {
+		t.Errorf("validation error expected but was: %v\n", sut.Validate()[0])
+	}
+}
+
+func TestPersonIdValidation(t *testing.T) {
+	sut := PersonID{}
+	sut.ID = "1"
+	sut.Source = "forgejo"
+	sut.Schema = "https"
+	sut.Path = "path"
+	sut.Host = "an.other.host"
+	sut.Port = ""
+	sut.UnvalidatedInput = "https://an.other.host/path/1"
+
+	_, err := validation.IsValid(sut)
+	if validation.IsErrNotValid(err) && strings.Contains(err.Error(), "path: \"path\" has to be a person specific api path\n") {
+		t.Errorf("validation error expected but was: %v\n", err)
+	}
+
+	sut = PersonID{}
+	sut.ID = "1"
+	sut.Source = "forgejox"
+	sut.Schema = "https"
+	sut.Path = "api/v1/activitypub/user-id"
+	sut.Host = "an.other.host"
+	sut.Port = ""
+	sut.UnvalidatedInput = "https://an.other.host/api/v1/activitypub/user-id/1"
+	if sut.Validate()[0] != "Value forgejox is not contained in allowed values [forgejo gitea]" {
+		t.Errorf("validation error expected but was: %v\n", sut.Validate()[0])
+	}
+}
+
+func TestWebfingerId(t *testing.T) {
+	sut, _ := NewPersonID("https://codeberg.org/api/v1/activitypub/user-id/12345", "forgejo")
+	if sut.AsWebfinger() != "@12345@codeberg.org" {
+		t.Errorf("wrong webfinger: %v", sut.AsWebfinger())
+	}
+
+	sut, _ = NewPersonID("https://Codeberg.org/api/v1/activitypub/user-id/12345", "forgejo")
+	if sut.AsWebfinger() != "@12345@codeberg.org" {
+		t.Errorf("wrong webfinger: %v", sut.AsWebfinger())
+	}
+}
+
+func TestShouldThrowErrorOnInvalidInput(t *testing.T) {
+	var err any
+	// TODO: remove after test
+	//_, err = NewPersonId("", "forgejo")
+	//if err == nil {
+	//	t.Errorf("empty input should be invalid.")
+	//}
+
+	_, err = NewPersonID("http://localhost:3000/api/v1/something", "forgejo")
+	if err == nil {
+		t.Errorf("localhost uris are not external")
+	}
+	_, err = NewPersonID("./api/v1/something", "forgejo")
+	if err == nil {
+		t.Errorf("relative uris are not allowed")
+	}
+	_, err = NewPersonID("http://1.2.3.4/api/v1/something", "forgejo")
+	if err == nil {
+		t.Errorf("uri may not be ip-4 based")
+	}
+	_, err = NewPersonID("http:///[fe80::1ff:fe23:4567:890a%25eth0]/api/v1/something", "forgejo")
+	if err == nil {
+		t.Errorf("uri may not be ip-6 based")
+	}
+	_, err = NewPersonID("https://codeberg.org/api/v1/activitypub/../activitypub/user-id/12345", "forgejo")
+	if err == nil {
+		t.Errorf("uri may not contain relative path elements")
+	}
+	_, err = NewPersonID("https://myuser@an.other.host/api/v1/activitypub/user-id/1", "forgejo")
+	if err == nil {
+		t.Errorf("uri may not contain unparsed elements")
+	}
+
+	_, err = NewPersonID("https://an.other.host/api/v1/activitypub/user-id/1", "forgejo")
+	if err != nil {
+		t.Errorf("this uri should be valid but was: %v", err)
+	}
+}
+
+func Test_PersonMarshalJSON(t *testing.T) {
+	sut := ForgePerson{}
+	sut.Type = "Person"
+	sut.PreferredUsername = ap.NaturalLanguageValuesNew()
+	sut.PreferredUsername.Set("en", ap.Content("MaxMuster"))
+	result, _ := sut.MarshalJSON()
+	if string(result) != "{\"type\":\"Person\",\"preferredUsername\":\"MaxMuster\"}" {
+		t.Errorf("MarshalJSON() was = %q", result)
+	}
+}
+
+func Test_PersonUnmarshalJSON(t *testing.T) {
+	expected := &ForgePerson{
+		Actor: ap.Actor{
+			Type: "Person",
+			PreferredUsername: ap.NaturalLanguageValues{
+				ap.LangRefValue{Ref: "en", Value: []byte("MaxMuster")},
+			},
+		},
+	}
+	sut := new(ForgePerson)
+	err := sut.UnmarshalJSON([]byte(`{"type":"Person","preferredUsername":"MaxMuster"}`))
+	if err != nil {
+		t.Errorf("UnmarshalJSON() unexpected error: %v", err)
+	}
+	x, _ := expected.MarshalJSON()
+	y, _ := sut.MarshalJSON()
+	if !reflect.DeepEqual(x, y) {
+		t.Errorf("UnmarshalJSON() expected: %q got: %q", x, y)
+	}
+
+	expectedStr := strings.ReplaceAll(strings.ReplaceAll(`{
+		"id":"https://federated-repo.prod.meissa.de/api/v1/activitypub/user-id/10",
+		"type":"Person",
+		"icon":{"type":"Image","mediaType":"image/png","url":"https://federated-repo.prod.meissa.de/avatar/fa7f9c4af2a64f41b1bef292bf872614"},
+		"url":"https://federated-repo.prod.meissa.de/stargoose9",
+		"inbox":"https://federated-repo.prod.meissa.de/api/v1/activitypub/user-id/10/inbox",
+		"outbox":"https://federated-repo.prod.meissa.de/api/v1/activitypub/user-id/10/outbox",
+		"preferredUsername":"stargoose9",
+		"publicKey":{"id":"https://federated-repo.prod.meissa.de/api/v1/activitypub/user-id/10#main-key",
+			"owner":"https://federated-repo.prod.meissa.de/api/v1/activitypub/user-id/10",
+			"publicKeyPem":"-----BEGIN PUBLIC KEY-----\nMIIBoj...XAgMBAAE=\n-----END PUBLIC KEY-----\n"}}`,
+		"\n", ""),
+		"\t", "")
+	err = sut.UnmarshalJSON([]byte(expectedStr))
+	if err != nil {
+		t.Errorf("UnmarshalJSON() unexpected error: %v", err)
+	}
+	result, _ := sut.MarshalJSON()
+	if expectedStr != string(result) {
+		t.Errorf("UnmarshalJSON() expected: %q got: %q", expectedStr, result)
+	}
+}
+
+func TestForgePersonValidation(t *testing.T) {
+	sut := new(ForgePerson)
+	sut.UnmarshalJSON([]byte(`{"type":"Person","preferredUsername":"MaxMuster"}`))
+	if res, _ := validation.IsValid(sut); !res {
+		t.Errorf("sut expected to be valid: %v\n", sut.Validate())
+	}
+}
diff --git a/modules/forgefed/forgefed.go b/modules/forgefed/forgefed.go
new file mode 100644
index 0000000..2344dc7
--- /dev/null
+++ b/modules/forgefed/forgefed.go
@@ -0,0 +1,52 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgefed
+
+import (
+	ap "github.com/go-ap/activitypub"
+	"github.com/valyala/fastjson"
+)
+
+const ForgeFedNamespaceURI = "https://forgefed.org/ns"
+
+// GetItemByType instantiates a new ForgeFed object if the type matches
+// otherwise it defaults to existing activitypub package typer function.
+func GetItemByType(typ ap.ActivityVocabularyType) (ap.Item, error) {
+	switch typ {
+	case RepositoryType:
+		return RepositoryNew(""), nil
+	default:
+		return ap.GetItemByType(typ)
+	}
+}
+
+// JSONUnmarshalerFn is the function that will load the data from a fastjson.Value into an Item
+// that the go-ap/activitypub package doesn't know about.
+func JSONUnmarshalerFn(typ ap.ActivityVocabularyType, val *fastjson.Value, i ap.Item) error {
+	switch typ {
+	case RepositoryType:
+		return OnRepository(i, func(r *Repository) error {
+			return JSONLoadRepository(val, r)
+		})
+	default:
+		return nil
+	}
+}
+
+// NotEmpty is the function that checks if an object is empty
+func NotEmpty(i ap.Item) bool {
+	if ap.IsNil(i) {
+		return false
+	}
+	switch i.GetType() {
+	case RepositoryType:
+		r, err := ToRepository(i)
+		if err != nil {
+			return false
+		}
+		return ap.NotEmpty(r.Actor)
+	default:
+		return ap.NotEmpty(i)
+	}
+}
diff --git a/modules/forgefed/nodeinfo.go b/modules/forgefed/nodeinfo.go
new file mode 100644
index 0000000..b22d295
--- /dev/null
+++ b/modules/forgefed/nodeinfo.go
@@ -0,0 +1,19 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgefed
+
+import (
+	"fmt"
+)
+
+func (id ActorID) AsWellKnownNodeInfoURI() string {
+	wellKnownPath := ".well-known/nodeinfo"
+	var result string
+	if id.Port == "" {
+		result = fmt.Sprintf("%s://%s/%s", id.Schema, id.Host, wellKnownPath)
+	} else {
+		result = fmt.Sprintf("%s://%s:%s/%s", id.Schema, id.Host, id.Port, wellKnownPath)
+	}
+	return result
+}
diff --git a/modules/forgefed/repository.go b/modules/forgefed/repository.go
new file mode 100644
index 0000000..63680cc
--- /dev/null
+++ b/modules/forgefed/repository.go
@@ -0,0 +1,111 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgefed
+
+import (
+	"reflect"
+	"unsafe"
+
+	ap "github.com/go-ap/activitypub"
+	"github.com/valyala/fastjson"
+)
+
+const (
+	RepositoryType ap.ActivityVocabularyType = "Repository"
+)
+
+type Repository struct {
+	ap.Actor
+	// Team Collection of actors who have management/push access to the repository
+	Team ap.Item `jsonld:"team,omitempty"`
+	// Forks OrderedCollection of repositories that are forks of this repository
+	Forks ap.Item `jsonld:"forks,omitempty"`
+	// ForkedFrom Identifies the repository which this repository was created as a fork
+	ForkedFrom ap.Item `jsonld:"forkedFrom,omitempty"`
+}
+
+// RepositoryNew initializes a Repository type actor
+func RepositoryNew(id ap.ID) *Repository {
+	a := ap.ActorNew(id, RepositoryType)
+	a.Type = RepositoryType
+	o := Repository{Actor: *a}
+	return &o
+}
+
+func (r Repository) MarshalJSON() ([]byte, error) {
+	b, err := r.Actor.MarshalJSON()
+	if len(b) == 0 || err != nil {
+		return nil, err
+	}
+
+	b = b[:len(b)-1]
+	if r.Team != nil {
+		ap.JSONWriteItemProp(&b, "team", r.Team)
+	}
+	if r.Forks != nil {
+		ap.JSONWriteItemProp(&b, "forks", r.Forks)
+	}
+	if r.ForkedFrom != nil {
+		ap.JSONWriteItemProp(&b, "forkedFrom", r.ForkedFrom)
+	}
+	ap.JSONWrite(&b, '}')
+	return b, nil
+}
+
+func JSONLoadRepository(val *fastjson.Value, r *Repository) error {
+	if err := ap.OnActor(&r.Actor, func(a *ap.Actor) error {
+		return ap.JSONLoadActor(val, a)
+	}); err != nil {
+		return err
+	}
+
+	r.Team = ap.JSONGetItem(val, "team")
+	r.Forks = ap.JSONGetItem(val, "forks")
+	r.ForkedFrom = ap.JSONGetItem(val, "forkedFrom")
+	return nil
+}
+
+func (r *Repository) UnmarshalJSON(data []byte) error {
+	p := fastjson.Parser{}
+	val, err := p.ParseBytes(data)
+	if err != nil {
+		return err
+	}
+	return JSONLoadRepository(val, r)
+}
+
+// ToRepository tries to convert the it Item to a Repository Actor.
+func ToRepository(it ap.Item) (*Repository, error) {
+	switch i := it.(type) {
+	case *Repository:
+		return i, nil
+	case Repository:
+		return &i, nil
+	case *ap.Actor:
+		return (*Repository)(unsafe.Pointer(i)), nil
+	case ap.Actor:
+		return (*Repository)(unsafe.Pointer(&i)), nil
+	default:
+		// NOTE(marius): this is an ugly way of dealing with the interface conversion error: types from different scopes
+		typ := reflect.TypeOf(new(Repository))
+		if i, ok := reflect.ValueOf(it).Convert(typ).Interface().(*Repository); ok {
+			return i, nil
+		}
+	}
+	return nil, ap.ErrorInvalidType[ap.Actor](it)
+}
+
+type withRepositoryFn func(*Repository) error
+
+// OnRepository calls function fn on it Item if it can be asserted to type *Repository
+func OnRepository(it ap.Item, fn withRepositoryFn) error {
+	if it == nil {
+		return nil
+	}
+	ob, err := ToRepository(it)
+	if err != nil {
+		return err
+	}
+	return fn(ob)
+}
diff --git a/modules/forgefed/repository_test.go b/modules/forgefed/repository_test.go
new file mode 100644
index 0000000..13a73c1
--- /dev/null
+++ b/modules/forgefed/repository_test.go
@@ -0,0 +1,145 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package forgefed
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+
+	"code.gitea.io/gitea/modules/json"
+
+	ap "github.com/go-ap/activitypub"
+)
+
+func Test_RepositoryMarshalJSON(t *testing.T) {
+	type testPair struct {
+		item    Repository
+		want    []byte
+		wantErr error
+	}
+
+	tests := map[string]testPair{
+		"empty": {
+			item: Repository{},
+			want: nil,
+		},
+		"with ID": {
+			item: Repository{
+				Actor: ap.Actor{
+					ID: "https://example.com/1",
+				},
+				Team: nil,
+			},
+			want: []byte(`{"id":"https://example.com/1"}`),
+		},
+		"with Team as IRI": {
+			item: Repository{
+				Team: ap.IRI("https://example.com/1"),
+				Actor: ap.Actor{
+					ID: "https://example.com/1",
+				},
+			},
+			want: []byte(`{"id":"https://example.com/1","team":"https://example.com/1"}`),
+		},
+		"with Team as IRIs": {
+			item: Repository{
+				Team: ap.ItemCollection{
+					ap.IRI("https://example.com/1"),
+					ap.IRI("https://example.com/2"),
+				},
+				Actor: ap.Actor{
+					ID: "https://example.com/1",
+				},
+			},
+			want: []byte(`{"id":"https://example.com/1","team":["https://example.com/1","https://example.com/2"]}`),
+		},
+		"with Team as Object": {
+			item: Repository{
+				Team: ap.Object{ID: "https://example.com/1"},
+				Actor: ap.Actor{
+					ID: "https://example.com/1",
+				},
+			},
+			want: []byte(`{"id":"https://example.com/1","team":{"id":"https://example.com/1"}}`),
+		},
+		"with Team as slice of Objects": {
+			item: Repository{
+				Team: ap.ItemCollection{
+					ap.Object{ID: "https://example.com/1"},
+					ap.Object{ID: "https://example.com/2"},
+				},
+				Actor: ap.Actor{
+					ID: "https://example.com/1",
+				},
+			},
+			want: []byte(`{"id":"https://example.com/1","team":[{"id":"https://example.com/1"},{"id":"https://example.com/2"}]}`),
+		},
+	}
+
+	for name, tt := range tests {
+		t.Run(name, func(t *testing.T) {
+			got, err := tt.item.MarshalJSON()
+			if (err != nil || tt.wantErr != nil) && tt.wantErr.Error() != err.Error() {
+				t.Errorf("MarshalJSON() error = \"%v\", wantErr \"%v\"", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("MarshalJSON() got = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_RepositoryUnmarshalJSON(t *testing.T) {
+	type testPair struct {
+		data    []byte
+		want    *Repository
+		wantErr error
+	}
+
+	tests := map[string]testPair{
+		"nil": {
+			data:    nil,
+			wantErr: fmt.Errorf("cannot parse JSON: %w", fmt.Errorf("cannot parse empty string; unparsed tail: %q", "")),
+		},
+		"empty": {
+			data:    []byte{},
+			wantErr: fmt.Errorf("cannot parse JSON: %w", fmt.Errorf("cannot parse empty string; unparsed tail: %q", "")),
+		},
+		"with Type": {
+			data: []byte(`{"type":"Repository"}`),
+			want: &Repository{
+				Actor: ap.Actor{
+					Type: RepositoryType,
+				},
+			},
+		},
+		"with Type and ID": {
+			data: []byte(`{"id":"https://example.com/1","type":"Repository"}`),
+			want: &Repository{
+				Actor: ap.Actor{
+					ID:   "https://example.com/1",
+					Type: RepositoryType,
+				},
+			},
+		},
+	}
+
+	for name, tt := range tests {
+		t.Run(name, func(t *testing.T) {
+			got := new(Repository)
+			err := got.UnmarshalJSON(tt.data)
+			if (err != nil || tt.wantErr != nil) && tt.wantErr.Error() != err.Error() {
+				t.Errorf("UnmarshalJSON() error = \"%v\", wantErr \"%v\"", err, tt.wantErr)
+				return
+			}
+			if tt.want != nil && !reflect.DeepEqual(got, tt.want) {
+				jGot, _ := json.Marshal(got)
+				jWant, _ := json.Marshal(tt.want)
+				t.Errorf("UnmarshalJSON() got = %s, want %s", jGot, jWant)
+			}
+		})
+	}
+}