6 files changed, 430 insertions, 0 deletions

diff --git a/routers/api/v1/activitypub/actor.go b/routers/api/v1/activitypub/actor.go
new file mode 100644
index 0000000..4f128e7
--- /dev/null
+++ b/routers/api/v1/activitypub/actor.go
@@ -0,0 +1,83 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"net/http"
+
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/activitypub"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/context"
+
+	ap "github.com/go-ap/activitypub"
+	"github.com/go-ap/jsonld"
+)
+
+// Actor function returns the instance's Actor
+func Actor(ctx *context.APIContext) {
+	// swagger:operation GET /activitypub/actor activitypub activitypubInstanceActor
+	// ---
+	// summary: Returns the instance's Actor
+	// produces:
+	// - application/json
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/ActivityPub"
+
+	link := user_model.APActorUserAPActorID()
+	actor := ap.ActorNew(ap.IRI(link), ap.ApplicationType)
+
+	actor.PreferredUsername = ap.NaturalLanguageValuesNew()
+	err := actor.PreferredUsername.Set("en", ap.Content(setting.Domain))
+	if err != nil {
+		ctx.ServerError("PreferredUsername.Set", err)
+		return
+	}
+
+	actor.URL = ap.IRI(setting.AppURL)
+
+	actor.Inbox = ap.IRI(link + "/inbox")
+	actor.Outbox = ap.IRI(link + "/outbox")
+
+	actor.PublicKey.ID = ap.IRI(link + "#main-key")
+	actor.PublicKey.Owner = ap.IRI(link)
+
+	publicKeyPem, err := activitypub.GetPublicKey(ctx, user_model.NewAPActorUser())
+	if err != nil {
+		ctx.ServerError("GetPublicKey", err)
+		return
+	}
+	actor.PublicKey.PublicKeyPem = publicKeyPem
+
+	binary, err := jsonld.WithContext(
+		jsonld.IRI(ap.ActivityBaseURI),
+		jsonld.IRI(ap.SecurityContextURI),
+	).Marshal(actor)
+	if err != nil {
+		ctx.ServerError("MarshalJSON", err)
+		return
+	}
+	ctx.Resp.Header().Add("Content-Type", activitypub.ActivityStreamsContentType)
+	ctx.Resp.WriteHeader(http.StatusOK)
+	if _, err = ctx.Resp.Write(binary); err != nil {
+		log.Error("write to resp err: %v", err)
+	}
+}
+
+// ActorInbox function handles the incoming data for the instance Actor
+func ActorInbox(ctx *context.APIContext) {
+	// swagger:operation POST /activitypub/actor/inbox activitypub activitypubInstanceActorInbox
+	// ---
+	// summary: Send to the inbox
+	// produces:
+	// - application/json
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+
+	ctx.Status(http.StatusNoContent)
+}
diff --git a/routers/api/v1/activitypub/person.go b/routers/api/v1/activitypub/person.go
new file mode 100644
index 0000000..995a148
--- /dev/null
+++ b/routers/api/v1/activitypub/person.go
@@ -0,0 +1,106 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"code.gitea.io/gitea/modules/activitypub"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/context"
+
+	ap "github.com/go-ap/activitypub"
+	"github.com/go-ap/jsonld"
+)
+
+// Person function returns the Person actor for a user
+func Person(ctx *context.APIContext) {
+	// swagger:operation GET /activitypub/user-id/{user-id} activitypub activitypubPerson
+	// ---
+	// summary: Returns the Person actor for a user
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: user-id
+	//   in: path
+	//   description: user ID of the user
+	//   type: integer
+	//   required: true
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/ActivityPub"
+
+	// TODO: the setting.AppURL during the test doesn't follow the definition: "It always has a '/' suffix"
+	link := fmt.Sprintf("%s/api/v1/activitypub/user-id/%d", strings.TrimSuffix(setting.AppURL, "/"), ctx.ContextUser.ID)
+	person := ap.PersonNew(ap.IRI(link))
+
+	person.Name = ap.NaturalLanguageValuesNew()
+	err := person.Name.Set("en", ap.Content(ctx.ContextUser.FullName))
+	if err != nil {
+		ctx.ServerError("Set Name", err)
+		return
+	}
+
+	person.PreferredUsername = ap.NaturalLanguageValuesNew()
+	err = person.PreferredUsername.Set("en", ap.Content(ctx.ContextUser.Name))
+	if err != nil {
+		ctx.ServerError("Set PreferredUsername", err)
+		return
+	}
+
+	person.URL = ap.IRI(ctx.ContextUser.HTMLURL())
+
+	person.Icon = ap.Image{
+		Type:      ap.ImageType,
+		MediaType: "image/png",
+		URL:       ap.IRI(ctx.ContextUser.AvatarLink(ctx)),
+	}
+
+	person.Inbox = ap.IRI(link + "/inbox")
+	person.Outbox = ap.IRI(link + "/outbox")
+
+	person.PublicKey.ID = ap.IRI(link + "#main-key")
+	person.PublicKey.Owner = ap.IRI(link)
+
+	publicKeyPem, err := activitypub.GetPublicKey(ctx, ctx.ContextUser)
+	if err != nil {
+		ctx.ServerError("GetPublicKey", err)
+		return
+	}
+	person.PublicKey.PublicKeyPem = publicKeyPem
+
+	binary, err := jsonld.WithContext(jsonld.IRI(ap.ActivityBaseURI), jsonld.IRI(ap.SecurityContextURI)).Marshal(person)
+	if err != nil {
+		ctx.ServerError("MarshalJSON", err)
+		return
+	}
+	ctx.Resp.Header().Add("Content-Type", activitypub.ActivityStreamsContentType)
+	ctx.Resp.WriteHeader(http.StatusOK)
+	if _, err = ctx.Resp.Write(binary); err != nil {
+		log.Error("write to resp err: %v", err)
+	}
+}
+
+// PersonInbox function handles the incoming data for a user inbox
+func PersonInbox(ctx *context.APIContext) {
+	// swagger:operation POST /activitypub/user-id/{user-id}/inbox activitypub activitypubPersonInbox
+	// ---
+	// summary: Send to the inbox
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: user-id
+	//   in: path
+	//   description: user ID of the user
+	//   type: integer
+	//   required: true
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+
+	ctx.Status(http.StatusNoContent)
+}
diff --git a/routers/api/v1/activitypub/repository.go b/routers/api/v1/activitypub/repository.go
new file mode 100644
index 0000000..bc6e790
--- /dev/null
+++ b/routers/api/v1/activitypub/repository.go
@@ -0,0 +1,80 @@
+// Copyright 2023, 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"code.gitea.io/gitea/modules/forgefed"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/web"
+	"code.gitea.io/gitea/services/context"
+	"code.gitea.io/gitea/services/federation"
+
+	ap "github.com/go-ap/activitypub"
+)
+
+// Repository function returns the Repository actor for a repo
+func Repository(ctx *context.APIContext) {
+	// swagger:operation GET /activitypub/repository-id/{repository-id} activitypub activitypubRepository
+	// ---
+	// summary: Returns the Repository actor for a repo
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: repository-id
+	//   in: path
+	//   description: repository ID of the repo
+	//   type: integer
+	//   required: true
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/ActivityPub"
+
+	link := fmt.Sprintf("%s/api/v1/activitypub/repository-id/%d", strings.TrimSuffix(setting.AppURL, "/"), ctx.Repo.Repository.ID)
+	repo := forgefed.RepositoryNew(ap.IRI(link))
+
+	repo.Name = ap.NaturalLanguageValuesNew()
+	err := repo.Name.Set("en", ap.Content(ctx.Repo.Repository.Name))
+	if err != nil {
+		ctx.Error(http.StatusInternalServerError, "Set Name", err)
+		return
+	}
+	response(ctx, repo)
+}
+
+// PersonInbox function handles the incoming data for a repository inbox
+func RepositoryInbox(ctx *context.APIContext) {
+	// swagger:operation POST /activitypub/repository-id/{repository-id}/inbox activitypub activitypubRepositoryInbox
+	// ---
+	// summary: Send to the inbox
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: repository-id
+	//   in: path
+	//   description: repository ID of the repo
+	//   type: integer
+	//   required: true
+	// - name: body
+	//   in: body
+	//   schema:
+	//     "$ref": "#/definitions/ForgeLike"
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+
+	repository := ctx.Repo.Repository
+	log.Info("RepositoryInbox: repo: %v", repository)
+
+	form := web.GetForm(ctx)
+	httpStatus, title, err := federation.ProcessLikeActivity(ctx, form, repository.ID)
+	if err != nil {
+		ctx.Error(httpStatus, title, err)
+	}
+	ctx.Status(http.StatusNoContent)
+}
diff --git a/routers/api/v1/activitypub/repository_test.go b/routers/api/v1/activitypub/repository_test.go
new file mode 100644
index 0000000..acd588d
--- /dev/null
+++ b/routers/api/v1/activitypub/repository_test.go
@@ -0,0 +1,27 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/user"
+)
+
+func Test_UserEmailValidate(t *testing.T) {
+	sut := "ab@cd.ef"
+	if err := user.ValidateEmail(sut); err != nil {
+		t.Errorf("sut should be valid, %v, %v", sut, err)
+	}
+
+	sut = "83ce13c8-af0b-4112-8327-55a54e54e664@code.cartoon-aa.xyz"
+	if err := user.ValidateEmail(sut); err != nil {
+		t.Errorf("sut should be valid, %v, %v", sut, err)
+	}
+
+	sut = "1"
+	if err := user.ValidateEmail(sut); err == nil {
+		t.Errorf("sut should not be valid, %v", sut)
+	}
+}
diff --git a/routers/api/v1/activitypub/reqsignature.go b/routers/api/v1/activitypub/reqsignature.go
new file mode 100644
index 0000000..6003f66
--- /dev/null
+++ b/routers/api/v1/activitypub/reqsignature.go
@@ -0,0 +1,99 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"crypto"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+
+	"code.gitea.io/gitea/modules/activitypub"
+	"code.gitea.io/gitea/modules/httplib"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	gitea_context "code.gitea.io/gitea/services/context"
+
+	ap "github.com/go-ap/activitypub"
+	"github.com/go-fed/httpsig"
+)
+
+func getPublicKeyFromResponse(b []byte, keyID *url.URL) (p crypto.PublicKey, err error) {
+	person := ap.PersonNew(ap.IRI(keyID.String()))
+	err = person.UnmarshalJSON(b)
+	if err != nil {
+		return nil, fmt.Errorf("ActivityStreams type cannot be converted to one known to have publicKey property: %w", err)
+	}
+	pubKey := person.PublicKey
+	if pubKey.ID.String() != keyID.String() {
+		return nil, fmt.Errorf("cannot find publicKey with id: %s in %s", keyID, string(b))
+	}
+	pubKeyPem := pubKey.PublicKeyPem
+	block, _ := pem.Decode([]byte(pubKeyPem))
+	if block == nil || block.Type != "PUBLIC KEY" {
+		return nil, fmt.Errorf("could not decode publicKeyPem to PUBLIC KEY pem block type")
+	}
+	p, err = x509.ParsePKIXPublicKey(block.Bytes)
+	return p, err
+}
+
+func fetch(iri *url.URL) (b []byte, err error) {
+	req := httplib.NewRequest(iri.String(), http.MethodGet)
+	req.Header("Accept", activitypub.ActivityStreamsContentType)
+	req.Header("User-Agent", "Gitea/"+setting.AppVer)
+	resp, err := req.Response()
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("url IRI fetch [%s] failed with status (%d): %s", iri, resp.StatusCode, resp.Status)
+	}
+	b, err = io.ReadAll(io.LimitReader(resp.Body, setting.Federation.MaxSize))
+	return b, err
+}
+
+func verifyHTTPSignatures(ctx *gitea_context.APIContext) (authenticated bool, err error) {
+	r := ctx.Req
+
+	// 1. Figure out what key we need to verify
+	v, err := httpsig.NewVerifier(r)
+	if err != nil {
+		return false, err
+	}
+	ID := v.KeyId()
+	idIRI, err := url.Parse(ID)
+	if err != nil {
+		return false, err
+	}
+	// 2. Fetch the public key of the other actor
+	b, err := fetch(idIRI)
+	if err != nil {
+		return false, err
+	}
+	pubKey, err := getPublicKeyFromResponse(b, idIRI)
+	if err != nil {
+		return false, err
+	}
+	// 3. Verify the other actor's key
+	algo := httpsig.Algorithm(setting.Federation.Algorithms[0])
+	authenticated = v.Verify(pubKey, algo) == nil
+	return authenticated, err
+}
+
+// ReqHTTPSignature function
+func ReqHTTPSignature() func(ctx *gitea_context.APIContext) {
+	return func(ctx *gitea_context.APIContext) {
+		if authenticated, err := verifyHTTPSignatures(ctx); err != nil {
+			log.Warn("verifyHttpSignatures failed: %v", err)
+			ctx.Error(http.StatusBadRequest, "reqSignature", "request signature verification failed")
+		} else if !authenticated {
+			ctx.Error(http.StatusForbidden, "reqSignature", "request signature verification failed")
+		}
+	}
+}
diff --git a/routers/api/v1/activitypub/response.go b/routers/api/v1/activitypub/response.go
new file mode 100644
index 0000000..42ef375
--- /dev/null
+++ b/routers/api/v1/activitypub/response.go
@@ -0,0 +1,35 @@
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"net/http"
+
+	"code.gitea.io/gitea/modules/activitypub"
+	"code.gitea.io/gitea/modules/forgefed"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/services/context"
+
+	ap "github.com/go-ap/activitypub"
+	"github.com/go-ap/jsonld"
+)
+
+// Respond with an ActivityStreams object
+func response(ctx *context.APIContext, v any) {
+	binary, err := jsonld.WithContext(
+		jsonld.IRI(ap.ActivityBaseURI),
+		jsonld.IRI(ap.SecurityContextURI),
+		jsonld.IRI(forgefed.ForgeFedNamespaceURI),
+	).Marshal(v)
+	if err != nil {
+		ctx.ServerError("Marshal", err)
+		return
+	}
+
+	ctx.Resp.Header().Add("Content-Type", activitypub.ActivityStreamsContentType)
+	ctx.Resp.WriteHeader(http.StatusOK)
+	if _, err = ctx.Resp.Write(binary); err != nil {
+		log.Error("write to resp err: %v", err)
+	}
+}